1

Introduction to Soil Mechanics

According to Terzaghi (1948)ldquoSoil Mechanics is the application of laws of

mechanics and hydraulics to engineering problemsdealing with sediments and other unconsolidatedaccumulations of solid particles produced by themechanical and chemical disintegration of rocks

regardless of whether or not they contain anadmixture of organic constituentrdquo

2

Soil Formation

3

Soil Formation

4

Determination of Particle SizeDistribution

1048698 Mechanical analysis is used in the determination of the size range of particles present in a soil expressed as a percentage of the total dry weight1048698 There are two methods that generally utilized todetermine the particle size distribution of soil1048698 Sieve Analysis (for particle sizes gt 0075mm in diameter)1048698 Hydrometer Analysis ( ldquo ldquo ldquo lt 0075mm ldquo ldquo )

5

Particle Size Distributions and SoilParticle Characteristics

1048698 Particle size distribution curve is a representation in graphical ortabular form of the various (diameter) grain sizes in a soil determined through sieving and sedimentation1048698 The particle diameters are plotted in log scale and the corresponding percent finer in arithmetic scale

6

Particle Size Distribution Curve

7

Particle Size Distribution

8

Hydrometer Analysis

9

Hydrometer Analysis

10

Some commonly used measures are

Effective size (D10)It is the diameter in the particle size distribution curve corresponding to 10 finer (maximum size of the smallest 10of the soilUniformity Coefficient Cu =D60D10It is the ratio of the maximum diameter of the smallest 60 to the effective size A well graded soil will haveCu gt 6 for sandsCu gt4 for gravels

11

Some commonly used measures are

12

Definitions

e) Well-Graded Material ndash Contains particles of a wide range of sizes The smaller particles fill the spaces left between the larger particles therefore the soil has greater strength than a poorly graded soil and lower permeabilityf) Poorly ndash Graded Material ndash Contains a large portion of uniformly sized particles This particular soil has larger voids in its structureand poor strength along with high permeabilitypermeability

13

Definitions

14

Soil Plasticity amp Consistency Limits

In the early 1900s a Swedish scientist ldquoAtterbergrdquo developed a method to describe the consistency of fine grained soils with varying degree of moisture content1048698 If a soil is gradually dried from a slurry it passes from state of viscous liquid to a plastic state then to a semi-solid and finally into a solid state The moisture contents at which the soil passes fromone state to the next are known as consistency limits (also called ldquoAtterberg Limitsrdquo)1048698 Consistency limits are utilized to compare soils from different locations and different depths1048698 There are 4 basic states

15

Atterberg Limits

16

Consistency Limits

17

Definitions

a) Liquid Limit (LL) is the minimum moisture content at which the soil will flow under its own weight The moisture content (in ) required to close a distance of 127mm along the bottom of the groove after 25 blows is thellb) Plastic Limit (PL) is the moisture content (in ) at which the soil when rolled into threads of 32mm in diameter crumbles PL is the lower limit of the plastic stage of the soil The test is simple and performed by repeated rollings of ellipsoidal size soil mass by hand on a ground glass plate2162009 Mechanics of Soils 20 platec) Shrinkage Limit (SL) is the moisture content (in ) at which the volume change of the soil mass ceases

18

Definitions

d) Plasticity Index (PI) is a measure of the range of the moisture contents over which a soil is plastic PI=LL-PLe) Liquidity Index (LI) The relative consistency of a cohesive soil in a natural state can be defined by the ratio called LILI=(w-PL) (LL-PL)f) Activity is the ratio of PI to the clay fraction by dry weight of particles lt 2μm)A = PI (Clay fraction)

19

CLASSIFICATION OF SOILS

The sizes of particles that make up soil may vary widelydepending on the predominant size of particles Soils areclassified as 1) Gravel2) Sand3) Silt4) Clay1048698 The most comprehensive is the Unified Soil ClassificationSystem (USCS)

20

CLASSIFICATION OF SOILS

USCS This system classifies soils under two broadcategories1048698 Coarse Grained Soils -are gravelly and sandy innature with lt50 passing through a 200 sieve(diameter=0075mm)1048698 G ldquoGravelrdquo1048698 S ldquoSandrdquo1048698 Fine Grained Soils have 50 or more passingthrough the 200 sieve1048698 M inorganic Silt O Organic Silts and Clays1048698 C inorganic Clay Pt Peat muck highly organic soils

21

CLASSIFICATION OF SOILS (USCS)

USCS 1048698 The standard system used worldwide for most majorconstruction projects is known as the Unified SoilClassification System (USCS)1048698 This is based on an original system devised byCassagrande Soils are identified by symbols determinedfrom1048698 Sieve analysis and1048698 Atterberg Limit tests

22

SOILS CLASSIFICATION (USCS Table)

23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

24

CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

25

CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

27

Casagrande Plasticity Chart

28

Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

• Slide 1
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29

2

Soil Formation

3

Soil Formation

4

Determination of Particle SizeDistribution

1048698 Mechanical analysis is used in the determination of the size range of particles present in a soil expressed as a percentage of the total dry weight1048698 There are two methods that generally utilized todetermine the particle size distribution of soil1048698 Sieve Analysis (for particle sizes gt 0075mm in diameter)1048698 Hydrometer Analysis ( ldquo ldquo ldquo lt 0075mm ldquo ldquo )

5

Particle Size Distributions and SoilParticle Characteristics

1048698 Particle size distribution curve is a representation in graphical ortabular form of the various (diameter) grain sizes in a soil determined through sieving and sedimentation1048698 The particle diameters are plotted in log scale and the corresponding percent finer in arithmetic scale

6

Particle Size Distribution Curve

7

Particle Size Distribution

8

Hydrometer Analysis

9

Hydrometer Analysis

10

Some commonly used measures are

Effective size (D10)It is the diameter in the particle size distribution curve corresponding to 10 finer (maximum size of the smallest 10of the soilUniformity Coefficient Cu =D60D10It is the ratio of the maximum diameter of the smallest 60 to the effective size A well graded soil will haveCu gt 6 for sandsCu gt4 for gravels

11

Some commonly used measures are

12

Definitions

e) Well-Graded Material ndash Contains particles of a wide range of sizes The smaller particles fill the spaces left between the larger particles therefore the soil has greater strength than a poorly graded soil and lower permeabilityf) Poorly ndash Graded Material ndash Contains a large portion of uniformly sized particles This particular soil has larger voids in its structureand poor strength along with high permeabilitypermeability

13

Definitions

14

Soil Plasticity amp Consistency Limits

In the early 1900s a Swedish scientist ldquoAtterbergrdquo developed a method to describe the consistency of fine grained soils with varying degree of moisture content1048698 If a soil is gradually dried from a slurry it passes from state of viscous liquid to a plastic state then to a semi-solid and finally into a solid state The moisture contents at which the soil passes fromone state to the next are known as consistency limits (also called ldquoAtterberg Limitsrdquo)1048698 Consistency limits are utilized to compare soils from different locations and different depths1048698 There are 4 basic states

15

Atterberg Limits

16

Consistency Limits

17

Definitions

a) Liquid Limit (LL) is the minimum moisture content at which the soil will flow under its own weight The moisture content (in ) required to close a distance of 127mm along the bottom of the groove after 25 blows is thellb) Plastic Limit (PL) is the moisture content (in ) at which the soil when rolled into threads of 32mm in diameter crumbles PL is the lower limit of the plastic stage of the soil The test is simple and performed by repeated rollings of ellipsoidal size soil mass by hand on a ground glass plate2162009 Mechanics of Soils 20 platec) Shrinkage Limit (SL) is the moisture content (in ) at which the volume change of the soil mass ceases

18

Definitions

d) Plasticity Index (PI) is a measure of the range of the moisture contents over which a soil is plastic PI=LL-PLe) Liquidity Index (LI) The relative consistency of a cohesive soil in a natural state can be defined by the ratio called LILI=(w-PL) (LL-PL)f) Activity is the ratio of PI to the clay fraction by dry weight of particles lt 2μm)A = PI (Clay fraction)

19

CLASSIFICATION OF SOILS

The sizes of particles that make up soil may vary widelydepending on the predominant size of particles Soils areclassified as 1) Gravel2) Sand3) Silt4) Clay1048698 The most comprehensive is the Unified Soil ClassificationSystem (USCS)

20

CLASSIFICATION OF SOILS

USCS This system classifies soils under two broadcategories1048698 Coarse Grained Soils -are gravelly and sandy innature with lt50 passing through a 200 sieve(diameter=0075mm)1048698 G ldquoGravelrdquo1048698 S ldquoSandrdquo1048698 Fine Grained Soils have 50 or more passingthrough the 200 sieve1048698 M inorganic Silt O Organic Silts and Clays1048698 C inorganic Clay Pt Peat muck highly organic soils

21

CLASSIFICATION OF SOILS (USCS)

USCS 1048698 The standard system used worldwide for most majorconstruction projects is known as the Unified SoilClassification System (USCS)1048698 This is based on an original system devised byCassagrande Soils are identified by symbols determinedfrom1048698 Sieve analysis and1048698 Atterberg Limit tests

22

SOILS CLASSIFICATION (USCS Table)

23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

24

CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

25

CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

27

Casagrande Plasticity Chart

28

Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

• Slide 1
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29

3

Soil Formation

4

Determination of Particle SizeDistribution

1048698 Mechanical analysis is used in the determination of the size range of particles present in a soil expressed as a percentage of the total dry weight1048698 There are two methods that generally utilized todetermine the particle size distribution of soil1048698 Sieve Analysis (for particle sizes gt 0075mm in diameter)1048698 Hydrometer Analysis ( ldquo ldquo ldquo lt 0075mm ldquo ldquo )

5

Particle Size Distributions and SoilParticle Characteristics

1048698 Particle size distribution curve is a representation in graphical ortabular form of the various (diameter) grain sizes in a soil determined through sieving and sedimentation1048698 The particle diameters are plotted in log scale and the corresponding percent finer in arithmetic scale

6

Particle Size Distribution Curve

7

Particle Size Distribution

8

Hydrometer Analysis

9

Hydrometer Analysis

10

Some commonly used measures are

Effective size (D10)It is the diameter in the particle size distribution curve corresponding to 10 finer (maximum size of the smallest 10of the soilUniformity Coefficient Cu =D60D10It is the ratio of the maximum diameter of the smallest 60 to the effective size A well graded soil will haveCu gt 6 for sandsCu gt4 for gravels

11

Some commonly used measures are

12

Definitions

e) Well-Graded Material ndash Contains particles of a wide range of sizes The smaller particles fill the spaces left between the larger particles therefore the soil has greater strength than a poorly graded soil and lower permeabilityf) Poorly ndash Graded Material ndash Contains a large portion of uniformly sized particles This particular soil has larger voids in its structureand poor strength along with high permeabilitypermeability

13

Definitions

14

Soil Plasticity amp Consistency Limits

In the early 1900s a Swedish scientist ldquoAtterbergrdquo developed a method to describe the consistency of fine grained soils with varying degree of moisture content1048698 If a soil is gradually dried from a slurry it passes from state of viscous liquid to a plastic state then to a semi-solid and finally into a solid state The moisture contents at which the soil passes fromone state to the next are known as consistency limits (also called ldquoAtterberg Limitsrdquo)1048698 Consistency limits are utilized to compare soils from different locations and different depths1048698 There are 4 basic states

15

Atterberg Limits

16

Consistency Limits

17

Definitions

a) Liquid Limit (LL) is the minimum moisture content at which the soil will flow under its own weight The moisture content (in ) required to close a distance of 127mm along the bottom of the groove after 25 blows is thellb) Plastic Limit (PL) is the moisture content (in ) at which the soil when rolled into threads of 32mm in diameter crumbles PL is the lower limit of the plastic stage of the soil The test is simple and performed by repeated rollings of ellipsoidal size soil mass by hand on a ground glass plate2162009 Mechanics of Soils 20 platec) Shrinkage Limit (SL) is the moisture content (in ) at which the volume change of the soil mass ceases

18

Definitions

d) Plasticity Index (PI) is a measure of the range of the moisture contents over which a soil is plastic PI=LL-PLe) Liquidity Index (LI) The relative consistency of a cohesive soil in a natural state can be defined by the ratio called LILI=(w-PL) (LL-PL)f) Activity is the ratio of PI to the clay fraction by dry weight of particles lt 2μm)A = PI (Clay fraction)

19

CLASSIFICATION OF SOILS

The sizes of particles that make up soil may vary widelydepending on the predominant size of particles Soils areclassified as 1) Gravel2) Sand3) Silt4) Clay1048698 The most comprehensive is the Unified Soil ClassificationSystem (USCS)

20

CLASSIFICATION OF SOILS

USCS This system classifies soils under two broadcategories1048698 Coarse Grained Soils -are gravelly and sandy innature with lt50 passing through a 200 sieve(diameter=0075mm)1048698 G ldquoGravelrdquo1048698 S ldquoSandrdquo1048698 Fine Grained Soils have 50 or more passingthrough the 200 sieve1048698 M inorganic Silt O Organic Silts and Clays1048698 C inorganic Clay Pt Peat muck highly organic soils

21

CLASSIFICATION OF SOILS (USCS)

USCS 1048698 The standard system used worldwide for most majorconstruction projects is known as the Unified SoilClassification System (USCS)1048698 This is based on an original system devised byCassagrande Soils are identified by symbols determinedfrom1048698 Sieve analysis and1048698 Atterberg Limit tests

22

SOILS CLASSIFICATION (USCS Table)

23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

24

CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

25

CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

27

Casagrande Plasticity Chart

28

Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

• Slide 1
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29

4

Determination of Particle SizeDistribution

1048698 Mechanical analysis is used in the determination of the size range of particles present in a soil expressed as a percentage of the total dry weight1048698 There are two methods that generally utilized todetermine the particle size distribution of soil1048698 Sieve Analysis (for particle sizes gt 0075mm in diameter)1048698 Hydrometer Analysis ( ldquo ldquo ldquo lt 0075mm ldquo ldquo )

5

Particle Size Distributions and SoilParticle Characteristics

1048698 Particle size distribution curve is a representation in graphical ortabular form of the various (diameter) grain sizes in a soil determined through sieving and sedimentation1048698 The particle diameters are plotted in log scale and the corresponding percent finer in arithmetic scale

6

Particle Size Distribution Curve

7

Particle Size Distribution

8

Hydrometer Analysis

9

Hydrometer Analysis

10

Some commonly used measures are

Effective size (D10)It is the diameter in the particle size distribution curve corresponding to 10 finer (maximum size of the smallest 10of the soilUniformity Coefficient Cu =D60D10It is the ratio of the maximum diameter of the smallest 60 to the effective size A well graded soil will haveCu gt 6 for sandsCu gt4 for gravels

11

Some commonly used measures are

12

Definitions

e) Well-Graded Material ndash Contains particles of a wide range of sizes The smaller particles fill the spaces left between the larger particles therefore the soil has greater strength than a poorly graded soil and lower permeabilityf) Poorly ndash Graded Material ndash Contains a large portion of uniformly sized particles This particular soil has larger voids in its structureand poor strength along with high permeabilitypermeability

13

Definitions

14

Soil Plasticity amp Consistency Limits

In the early 1900s a Swedish scientist ldquoAtterbergrdquo developed a method to describe the consistency of fine grained soils with varying degree of moisture content1048698 If a soil is gradually dried from a slurry it passes from state of viscous liquid to a plastic state then to a semi-solid and finally into a solid state The moisture contents at which the soil passes fromone state to the next are known as consistency limits (also called ldquoAtterberg Limitsrdquo)1048698 Consistency limits are utilized to compare soils from different locations and different depths1048698 There are 4 basic states

15

Atterberg Limits

16

Consistency Limits

17

Definitions

a) Liquid Limit (LL) is the minimum moisture content at which the soil will flow under its own weight The moisture content (in ) required to close a distance of 127mm along the bottom of the groove after 25 blows is thellb) Plastic Limit (PL) is the moisture content (in ) at which the soil when rolled into threads of 32mm in diameter crumbles PL is the lower limit of the plastic stage of the soil The test is simple and performed by repeated rollings of ellipsoidal size soil mass by hand on a ground glass plate2162009 Mechanics of Soils 20 platec) Shrinkage Limit (SL) is the moisture content (in ) at which the volume change of the soil mass ceases

18

Definitions

d) Plasticity Index (PI) is a measure of the range of the moisture contents over which a soil is plastic PI=LL-PLe) Liquidity Index (LI) The relative consistency of a cohesive soil in a natural state can be defined by the ratio called LILI=(w-PL) (LL-PL)f) Activity is the ratio of PI to the clay fraction by dry weight of particles lt 2μm)A = PI (Clay fraction)

19

CLASSIFICATION OF SOILS

The sizes of particles that make up soil may vary widelydepending on the predominant size of particles Soils areclassified as 1) Gravel2) Sand3) Silt4) Clay1048698 The most comprehensive is the Unified Soil ClassificationSystem (USCS)

20

CLASSIFICATION OF SOILS

USCS This system classifies soils under two broadcategories1048698 Coarse Grained Soils -are gravelly and sandy innature with lt50 passing through a 200 sieve(diameter=0075mm)1048698 G ldquoGravelrdquo1048698 S ldquoSandrdquo1048698 Fine Grained Soils have 50 or more passingthrough the 200 sieve1048698 M inorganic Silt O Organic Silts and Clays1048698 C inorganic Clay Pt Peat muck highly organic soils

21

CLASSIFICATION OF SOILS (USCS)

USCS 1048698 The standard system used worldwide for most majorconstruction projects is known as the Unified SoilClassification System (USCS)1048698 This is based on an original system devised byCassagrande Soils are identified by symbols determinedfrom1048698 Sieve analysis and1048698 Atterberg Limit tests

22

SOILS CLASSIFICATION (USCS Table)

23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

24

CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

25

CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

27

Casagrande Plasticity Chart

28

Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

• Slide 1
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29

5

Particle Size Distributions and SoilParticle Characteristics

1048698 Particle size distribution curve is a representation in graphical ortabular form of the various (diameter) grain sizes in a soil determined through sieving and sedimentation1048698 The particle diameters are plotted in log scale and the corresponding percent finer in arithmetic scale

6

Particle Size Distribution Curve

7

Particle Size Distribution

8

Hydrometer Analysis

9

Hydrometer Analysis

10

Some commonly used measures are

Effective size (D10)It is the diameter in the particle size distribution curve corresponding to 10 finer (maximum size of the smallest 10of the soilUniformity Coefficient Cu =D60D10It is the ratio of the maximum diameter of the smallest 60 to the effective size A well graded soil will haveCu gt 6 for sandsCu gt4 for gravels

11

Some commonly used measures are

12

Definitions

e) Well-Graded Material ndash Contains particles of a wide range of sizes The smaller particles fill the spaces left between the larger particles therefore the soil has greater strength than a poorly graded soil and lower permeabilityf) Poorly ndash Graded Material ndash Contains a large portion of uniformly sized particles This particular soil has larger voids in its structureand poor strength along with high permeabilitypermeability

13

Definitions

14

Soil Plasticity amp Consistency Limits

In the early 1900s a Swedish scientist ldquoAtterbergrdquo developed a method to describe the consistency of fine grained soils with varying degree of moisture content1048698 If a soil is gradually dried from a slurry it passes from state of viscous liquid to a plastic state then to a semi-solid and finally into a solid state The moisture contents at which the soil passes fromone state to the next are known as consistency limits (also called ldquoAtterberg Limitsrdquo)1048698 Consistency limits are utilized to compare soils from different locations and different depths1048698 There are 4 basic states

15

Atterberg Limits

16

Consistency Limits

17

Definitions

a) Liquid Limit (LL) is the minimum moisture content at which the soil will flow under its own weight The moisture content (in ) required to close a distance of 127mm along the bottom of the groove after 25 blows is thellb) Plastic Limit (PL) is the moisture content (in ) at which the soil when rolled into threads of 32mm in diameter crumbles PL is the lower limit of the plastic stage of the soil The test is simple and performed by repeated rollings of ellipsoidal size soil mass by hand on a ground glass plate2162009 Mechanics of Soils 20 platec) Shrinkage Limit (SL) is the moisture content (in ) at which the volume change of the soil mass ceases

18

Definitions

d) Plasticity Index (PI) is a measure of the range of the moisture contents over which a soil is plastic PI=LL-PLe) Liquidity Index (LI) The relative consistency of a cohesive soil in a natural state can be defined by the ratio called LILI=(w-PL) (LL-PL)f) Activity is the ratio of PI to the clay fraction by dry weight of particles lt 2μm)A = PI (Clay fraction)

19

CLASSIFICATION OF SOILS

The sizes of particles that make up soil may vary widelydepending on the predominant size of particles Soils areclassified as 1) Gravel2) Sand3) Silt4) Clay1048698 The most comprehensive is the Unified Soil ClassificationSystem (USCS)

20

CLASSIFICATION OF SOILS

USCS This system classifies soils under two broadcategories1048698 Coarse Grained Soils -are gravelly and sandy innature with lt50 passing through a 200 sieve(diameter=0075mm)1048698 G ldquoGravelrdquo1048698 S ldquoSandrdquo1048698 Fine Grained Soils have 50 or more passingthrough the 200 sieve1048698 M inorganic Silt O Organic Silts and Clays1048698 C inorganic Clay Pt Peat muck highly organic soils

21

CLASSIFICATION OF SOILS (USCS)

USCS 1048698 The standard system used worldwide for most majorconstruction projects is known as the Unified SoilClassification System (USCS)1048698 This is based on an original system devised byCassagrande Soils are identified by symbols determinedfrom1048698 Sieve analysis and1048698 Atterberg Limit tests

22

SOILS CLASSIFICATION (USCS Table)

23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

24

CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

25

CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

27

Casagrande Plasticity Chart

28

Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

• Slide 1
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29

6

Particle Size Distribution Curve

7

Particle Size Distribution

8

Hydrometer Analysis

9

Hydrometer Analysis

10

Some commonly used measures are

Effective size (D10)It is the diameter in the particle size distribution curve corresponding to 10 finer (maximum size of the smallest 10of the soilUniformity Coefficient Cu =D60D10It is the ratio of the maximum diameter of the smallest 60 to the effective size A well graded soil will haveCu gt 6 for sandsCu gt4 for gravels

11

Some commonly used measures are

12

Definitions

e) Well-Graded Material ndash Contains particles of a wide range of sizes The smaller particles fill the spaces left between the larger particles therefore the soil has greater strength than a poorly graded soil and lower permeabilityf) Poorly ndash Graded Material ndash Contains a large portion of uniformly sized particles This particular soil has larger voids in its structureand poor strength along with high permeabilitypermeability

13

Definitions

14

Soil Plasticity amp Consistency Limits

In the early 1900s a Swedish scientist ldquoAtterbergrdquo developed a method to describe the consistency of fine grained soils with varying degree of moisture content1048698 If a soil is gradually dried from a slurry it passes from state of viscous liquid to a plastic state then to a semi-solid and finally into a solid state The moisture contents at which the soil passes fromone state to the next are known as consistency limits (also called ldquoAtterberg Limitsrdquo)1048698 Consistency limits are utilized to compare soils from different locations and different depths1048698 There are 4 basic states

15

Atterberg Limits

16

Consistency Limits

17

Definitions

a) Liquid Limit (LL) is the minimum moisture content at which the soil will flow under its own weight The moisture content (in ) required to close a distance of 127mm along the bottom of the groove after 25 blows is thellb) Plastic Limit (PL) is the moisture content (in ) at which the soil when rolled into threads of 32mm in diameter crumbles PL is the lower limit of the plastic stage of the soil The test is simple and performed by repeated rollings of ellipsoidal size soil mass by hand on a ground glass plate2162009 Mechanics of Soils 20 platec) Shrinkage Limit (SL) is the moisture content (in ) at which the volume change of the soil mass ceases

18

Definitions

d) Plasticity Index (PI) is a measure of the range of the moisture contents over which a soil is plastic PI=LL-PLe) Liquidity Index (LI) The relative consistency of a cohesive soil in a natural state can be defined by the ratio called LILI=(w-PL) (LL-PL)f) Activity is the ratio of PI to the clay fraction by dry weight of particles lt 2μm)A = PI (Clay fraction)

19

CLASSIFICATION OF SOILS

The sizes of particles that make up soil may vary widelydepending on the predominant size of particles Soils areclassified as 1) Gravel2) Sand3) Silt4) Clay1048698 The most comprehensive is the Unified Soil ClassificationSystem (USCS)

20

CLASSIFICATION OF SOILS

USCS This system classifies soils under two broadcategories1048698 Coarse Grained Soils -are gravelly and sandy innature with lt50 passing through a 200 sieve(diameter=0075mm)1048698 G ldquoGravelrdquo1048698 S ldquoSandrdquo1048698 Fine Grained Soils have 50 or more passingthrough the 200 sieve1048698 M inorganic Silt O Organic Silts and Clays1048698 C inorganic Clay Pt Peat muck highly organic soils

21

CLASSIFICATION OF SOILS (USCS)

USCS 1048698 The standard system used worldwide for most majorconstruction projects is known as the Unified SoilClassification System (USCS)1048698 This is based on an original system devised byCassagrande Soils are identified by symbols determinedfrom1048698 Sieve analysis and1048698 Atterberg Limit tests

22

SOILS CLASSIFICATION (USCS Table)

23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

24

CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

25

CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

27

Casagrande Plasticity Chart

28

Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

• Slide 1
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29

7

Particle Size Distribution

8

Hydrometer Analysis

9

Hydrometer Analysis

10

Some commonly used measures are

Effective size (D10)It is the diameter in the particle size distribution curve corresponding to 10 finer (maximum size of the smallest 10of the soilUniformity Coefficient Cu =D60D10It is the ratio of the maximum diameter of the smallest 60 to the effective size A well graded soil will haveCu gt 6 for sandsCu gt4 for gravels

11

Some commonly used measures are

12

Definitions

e) Well-Graded Material ndash Contains particles of a wide range of sizes The smaller particles fill the spaces left between the larger particles therefore the soil has greater strength than a poorly graded soil and lower permeabilityf) Poorly ndash Graded Material ndash Contains a large portion of uniformly sized particles This particular soil has larger voids in its structureand poor strength along with high permeabilitypermeability

13

Definitions

14

Soil Plasticity amp Consistency Limits

In the early 1900s a Swedish scientist ldquoAtterbergrdquo developed a method to describe the consistency of fine grained soils with varying degree of moisture content1048698 If a soil is gradually dried from a slurry it passes from state of viscous liquid to a plastic state then to a semi-solid and finally into a solid state The moisture contents at which the soil passes fromone state to the next are known as consistency limits (also called ldquoAtterberg Limitsrdquo)1048698 Consistency limits are utilized to compare soils from different locations and different depths1048698 There are 4 basic states

15

Atterberg Limits

16

Consistency Limits

17

Definitions

a) Liquid Limit (LL) is the minimum moisture content at which the soil will flow under its own weight The moisture content (in ) required to close a distance of 127mm along the bottom of the groove after 25 blows is thellb) Plastic Limit (PL) is the moisture content (in ) at which the soil when rolled into threads of 32mm in diameter crumbles PL is the lower limit of the plastic stage of the soil The test is simple and performed by repeated rollings of ellipsoidal size soil mass by hand on a ground glass plate2162009 Mechanics of Soils 20 platec) Shrinkage Limit (SL) is the moisture content (in ) at which the volume change of the soil mass ceases

18

Definitions

d) Plasticity Index (PI) is a measure of the range of the moisture contents over which a soil is plastic PI=LL-PLe) Liquidity Index (LI) The relative consistency of a cohesive soil in a natural state can be defined by the ratio called LILI=(w-PL) (LL-PL)f) Activity is the ratio of PI to the clay fraction by dry weight of particles lt 2μm)A = PI (Clay fraction)

19

CLASSIFICATION OF SOILS

The sizes of particles that make up soil may vary widelydepending on the predominant size of particles Soils areclassified as 1) Gravel2) Sand3) Silt4) Clay1048698 The most comprehensive is the Unified Soil ClassificationSystem (USCS)

20

CLASSIFICATION OF SOILS

USCS This system classifies soils under two broadcategories1048698 Coarse Grained Soils -are gravelly and sandy innature with lt50 passing through a 200 sieve(diameter=0075mm)1048698 G ldquoGravelrdquo1048698 S ldquoSandrdquo1048698 Fine Grained Soils have 50 or more passingthrough the 200 sieve1048698 M inorganic Silt O Organic Silts and Clays1048698 C inorganic Clay Pt Peat muck highly organic soils

21

CLASSIFICATION OF SOILS (USCS)

USCS 1048698 The standard system used worldwide for most majorconstruction projects is known as the Unified SoilClassification System (USCS)1048698 This is based on an original system devised byCassagrande Soils are identified by symbols determinedfrom1048698 Sieve analysis and1048698 Atterberg Limit tests

22

SOILS CLASSIFICATION (USCS Table)

23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

24

CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

25

CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

27

Casagrande Plasticity Chart

28

Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

• Slide 1
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29

8

Hydrometer Analysis

9

Hydrometer Analysis

10

Some commonly used measures are

Effective size (D10)It is the diameter in the particle size distribution curve corresponding to 10 finer (maximum size of the smallest 10of the soilUniformity Coefficient Cu =D60D10It is the ratio of the maximum diameter of the smallest 60 to the effective size A well graded soil will haveCu gt 6 for sandsCu gt4 for gravels

11

Some commonly used measures are

12

Definitions

e) Well-Graded Material ndash Contains particles of a wide range of sizes The smaller particles fill the spaces left between the larger particles therefore the soil has greater strength than a poorly graded soil and lower permeabilityf) Poorly ndash Graded Material ndash Contains a large portion of uniformly sized particles This particular soil has larger voids in its structureand poor strength along with high permeabilitypermeability

13

Definitions

14

Soil Plasticity amp Consistency Limits

In the early 1900s a Swedish scientist ldquoAtterbergrdquo developed a method to describe the consistency of fine grained soils with varying degree of moisture content1048698 If a soil is gradually dried from a slurry it passes from state of viscous liquid to a plastic state then to a semi-solid and finally into a solid state The moisture contents at which the soil passes fromone state to the next are known as consistency limits (also called ldquoAtterberg Limitsrdquo)1048698 Consistency limits are utilized to compare soils from different locations and different depths1048698 There are 4 basic states

15

Atterberg Limits

16

Consistency Limits

17

Definitions

a) Liquid Limit (LL) is the minimum moisture content at which the soil will flow under its own weight The moisture content (in ) required to close a distance of 127mm along the bottom of the groove after 25 blows is thellb) Plastic Limit (PL) is the moisture content (in ) at which the soil when rolled into threads of 32mm in diameter crumbles PL is the lower limit of the plastic stage of the soil The test is simple and performed by repeated rollings of ellipsoidal size soil mass by hand on a ground glass plate2162009 Mechanics of Soils 20 platec) Shrinkage Limit (SL) is the moisture content (in ) at which the volume change of the soil mass ceases

18

Definitions

d) Plasticity Index (PI) is a measure of the range of the moisture contents over which a soil is plastic PI=LL-PLe) Liquidity Index (LI) The relative consistency of a cohesive soil in a natural state can be defined by the ratio called LILI=(w-PL) (LL-PL)f) Activity is the ratio of PI to the clay fraction by dry weight of particles lt 2μm)A = PI (Clay fraction)

19

CLASSIFICATION OF SOILS

The sizes of particles that make up soil may vary widelydepending on the predominant size of particles Soils areclassified as 1) Gravel2) Sand3) Silt4) Clay1048698 The most comprehensive is the Unified Soil ClassificationSystem (USCS)

20

CLASSIFICATION OF SOILS

USCS This system classifies soils under two broadcategories1048698 Coarse Grained Soils -are gravelly and sandy innature with lt50 passing through a 200 sieve(diameter=0075mm)1048698 G ldquoGravelrdquo1048698 S ldquoSandrdquo1048698 Fine Grained Soils have 50 or more passingthrough the 200 sieve1048698 M inorganic Silt O Organic Silts and Clays1048698 C inorganic Clay Pt Peat muck highly organic soils

21

CLASSIFICATION OF SOILS (USCS)

USCS 1048698 The standard system used worldwide for most majorconstruction projects is known as the Unified SoilClassification System (USCS)1048698 This is based on an original system devised byCassagrande Soils are identified by symbols determinedfrom1048698 Sieve analysis and1048698 Atterberg Limit tests

22

SOILS CLASSIFICATION (USCS Table)

23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

24

CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

25

CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

27

Casagrande Plasticity Chart

28

Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

• Slide 1
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29

9

Hydrometer Analysis

10

Some commonly used measures are

Effective size (D10)It is the diameter in the particle size distribution curve corresponding to 10 finer (maximum size of the smallest 10of the soilUniformity Coefficient Cu =D60D10It is the ratio of the maximum diameter of the smallest 60 to the effective size A well graded soil will haveCu gt 6 for sandsCu gt4 for gravels

11

Some commonly used measures are

12

Definitions

e) Well-Graded Material ndash Contains particles of a wide range of sizes The smaller particles fill the spaces left between the larger particles therefore the soil has greater strength than a poorly graded soil and lower permeabilityf) Poorly ndash Graded Material ndash Contains a large portion of uniformly sized particles This particular soil has larger voids in its structureand poor strength along with high permeabilitypermeability

13

Definitions

14

Soil Plasticity amp Consistency Limits

In the early 1900s a Swedish scientist ldquoAtterbergrdquo developed a method to describe the consistency of fine grained soils with varying degree of moisture content1048698 If a soil is gradually dried from a slurry it passes from state of viscous liquid to a plastic state then to a semi-solid and finally into a solid state The moisture contents at which the soil passes fromone state to the next are known as consistency limits (also called ldquoAtterberg Limitsrdquo)1048698 Consistency limits are utilized to compare soils from different locations and different depths1048698 There are 4 basic states

15

Atterberg Limits

16

Consistency Limits

17

Definitions

a) Liquid Limit (LL) is the minimum moisture content at which the soil will flow under its own weight The moisture content (in ) required to close a distance of 127mm along the bottom of the groove after 25 blows is thellb) Plastic Limit (PL) is the moisture content (in ) at which the soil when rolled into threads of 32mm in diameter crumbles PL is the lower limit of the plastic stage of the soil The test is simple and performed by repeated rollings of ellipsoidal size soil mass by hand on a ground glass plate2162009 Mechanics of Soils 20 platec) Shrinkage Limit (SL) is the moisture content (in ) at which the volume change of the soil mass ceases

18

Definitions

d) Plasticity Index (PI) is a measure of the range of the moisture contents over which a soil is plastic PI=LL-PLe) Liquidity Index (LI) The relative consistency of a cohesive soil in a natural state can be defined by the ratio called LILI=(w-PL) (LL-PL)f) Activity is the ratio of PI to the clay fraction by dry weight of particles lt 2μm)A = PI (Clay fraction)

19

CLASSIFICATION OF SOILS

The sizes of particles that make up soil may vary widelydepending on the predominant size of particles Soils areclassified as 1) Gravel2) Sand3) Silt4) Clay1048698 The most comprehensive is the Unified Soil ClassificationSystem (USCS)

20

CLASSIFICATION OF SOILS

USCS This system classifies soils under two broadcategories1048698 Coarse Grained Soils -are gravelly and sandy innature with lt50 passing through a 200 sieve(diameter=0075mm)1048698 G ldquoGravelrdquo1048698 S ldquoSandrdquo1048698 Fine Grained Soils have 50 or more passingthrough the 200 sieve1048698 M inorganic Silt O Organic Silts and Clays1048698 C inorganic Clay Pt Peat muck highly organic soils

21

CLASSIFICATION OF SOILS (USCS)

USCS 1048698 The standard system used worldwide for most majorconstruction projects is known as the Unified SoilClassification System (USCS)1048698 This is based on an original system devised byCassagrande Soils are identified by symbols determinedfrom1048698 Sieve analysis and1048698 Atterberg Limit tests

22

SOILS CLASSIFICATION (USCS Table)

23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

24

CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

25

CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

27

Casagrande Plasticity Chart

28

Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

• Slide 1
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29

10

Some commonly used measures are

Effective size (D10)It is the diameter in the particle size distribution curve corresponding to 10 finer (maximum size of the smallest 10of the soilUniformity Coefficient Cu =D60D10It is the ratio of the maximum diameter of the smallest 60 to the effective size A well graded soil will haveCu gt 6 for sandsCu gt4 for gravels

11

Some commonly used measures are

12

Definitions

e) Well-Graded Material ndash Contains particles of a wide range of sizes The smaller particles fill the spaces left between the larger particles therefore the soil has greater strength than a poorly graded soil and lower permeabilityf) Poorly ndash Graded Material ndash Contains a large portion of uniformly sized particles This particular soil has larger voids in its structureand poor strength along with high permeabilitypermeability

13

Definitions

14

Soil Plasticity amp Consistency Limits

In the early 1900s a Swedish scientist ldquoAtterbergrdquo developed a method to describe the consistency of fine grained soils with varying degree of moisture content1048698 If a soil is gradually dried from a slurry it passes from state of viscous liquid to a plastic state then to a semi-solid and finally into a solid state The moisture contents at which the soil passes fromone state to the next are known as consistency limits (also called ldquoAtterberg Limitsrdquo)1048698 Consistency limits are utilized to compare soils from different locations and different depths1048698 There are 4 basic states

15

Atterberg Limits

16

Consistency Limits

17

Definitions

a) Liquid Limit (LL) is the minimum moisture content at which the soil will flow under its own weight The moisture content (in ) required to close a distance of 127mm along the bottom of the groove after 25 blows is thellb) Plastic Limit (PL) is the moisture content (in ) at which the soil when rolled into threads of 32mm in diameter crumbles PL is the lower limit of the plastic stage of the soil The test is simple and performed by repeated rollings of ellipsoidal size soil mass by hand on a ground glass plate2162009 Mechanics of Soils 20 platec) Shrinkage Limit (SL) is the moisture content (in ) at which the volume change of the soil mass ceases

18

Definitions

d) Plasticity Index (PI) is a measure of the range of the moisture contents over which a soil is plastic PI=LL-PLe) Liquidity Index (LI) The relative consistency of a cohesive soil in a natural state can be defined by the ratio called LILI=(w-PL) (LL-PL)f) Activity is the ratio of PI to the clay fraction by dry weight of particles lt 2μm)A = PI (Clay fraction)

19

CLASSIFICATION OF SOILS

The sizes of particles that make up soil may vary widelydepending on the predominant size of particles Soils areclassified as 1) Gravel2) Sand3) Silt4) Clay1048698 The most comprehensive is the Unified Soil ClassificationSystem (USCS)

20

CLASSIFICATION OF SOILS

USCS This system classifies soils under two broadcategories1048698 Coarse Grained Soils -are gravelly and sandy innature with lt50 passing through a 200 sieve(diameter=0075mm)1048698 G ldquoGravelrdquo1048698 S ldquoSandrdquo1048698 Fine Grained Soils have 50 or more passingthrough the 200 sieve1048698 M inorganic Silt O Organic Silts and Clays1048698 C inorganic Clay Pt Peat muck highly organic soils

21

CLASSIFICATION OF SOILS (USCS)

USCS 1048698 The standard system used worldwide for most majorconstruction projects is known as the Unified SoilClassification System (USCS)1048698 This is based on an original system devised byCassagrande Soils are identified by symbols determinedfrom1048698 Sieve analysis and1048698 Atterberg Limit tests

22

SOILS CLASSIFICATION (USCS Table)

23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

24

CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

25

CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

27

Casagrande Plasticity Chart

28

Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

• Slide 1
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29

11

Some commonly used measures are

12

Definitions

e) Well-Graded Material ndash Contains particles of a wide range of sizes The smaller particles fill the spaces left between the larger particles therefore the soil has greater strength than a poorly graded soil and lower permeabilityf) Poorly ndash Graded Material ndash Contains a large portion of uniformly sized particles This particular soil has larger voids in its structureand poor strength along with high permeabilitypermeability

13

Definitions

14

Soil Plasticity amp Consistency Limits

In the early 1900s a Swedish scientist ldquoAtterbergrdquo developed a method to describe the consistency of fine grained soils with varying degree of moisture content1048698 If a soil is gradually dried from a slurry it passes from state of viscous liquid to a plastic state then to a semi-solid and finally into a solid state The moisture contents at which the soil passes fromone state to the next are known as consistency limits (also called ldquoAtterberg Limitsrdquo)1048698 Consistency limits are utilized to compare soils from different locations and different depths1048698 There are 4 basic states

15

Atterberg Limits

16

Consistency Limits

17

Definitions

a) Liquid Limit (LL) is the minimum moisture content at which the soil will flow under its own weight The moisture content (in ) required to close a distance of 127mm along the bottom of the groove after 25 blows is thellb) Plastic Limit (PL) is the moisture content (in ) at which the soil when rolled into threads of 32mm in diameter crumbles PL is the lower limit of the plastic stage of the soil The test is simple and performed by repeated rollings of ellipsoidal size soil mass by hand on a ground glass plate2162009 Mechanics of Soils 20 platec) Shrinkage Limit (SL) is the moisture content (in ) at which the volume change of the soil mass ceases

18

Definitions

d) Plasticity Index (PI) is a measure of the range of the moisture contents over which a soil is plastic PI=LL-PLe) Liquidity Index (LI) The relative consistency of a cohesive soil in a natural state can be defined by the ratio called LILI=(w-PL) (LL-PL)f) Activity is the ratio of PI to the clay fraction by dry weight of particles lt 2μm)A = PI (Clay fraction)

19

CLASSIFICATION OF SOILS

The sizes of particles that make up soil may vary widelydepending on the predominant size of particles Soils areclassified as 1) Gravel2) Sand3) Silt4) Clay1048698 The most comprehensive is the Unified Soil ClassificationSystem (USCS)

20

CLASSIFICATION OF SOILS

USCS This system classifies soils under two broadcategories1048698 Coarse Grained Soils -are gravelly and sandy innature with lt50 passing through a 200 sieve(diameter=0075mm)1048698 G ldquoGravelrdquo1048698 S ldquoSandrdquo1048698 Fine Grained Soils have 50 or more passingthrough the 200 sieve1048698 M inorganic Silt O Organic Silts and Clays1048698 C inorganic Clay Pt Peat muck highly organic soils

21

CLASSIFICATION OF SOILS (USCS)

USCS 1048698 The standard system used worldwide for most majorconstruction projects is known as the Unified SoilClassification System (USCS)1048698 This is based on an original system devised byCassagrande Soils are identified by symbols determinedfrom1048698 Sieve analysis and1048698 Atterberg Limit tests

22

SOILS CLASSIFICATION (USCS Table)

23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

24

CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

25

CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

27

Casagrande Plasticity Chart

28

Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

• Slide 1
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29

12

Definitions

e) Well-Graded Material ndash Contains particles of a wide range of sizes The smaller particles fill the spaces left between the larger particles therefore the soil has greater strength than a poorly graded soil and lower permeabilityf) Poorly ndash Graded Material ndash Contains a large portion of uniformly sized particles This particular soil has larger voids in its structureand poor strength along with high permeabilitypermeability

13

Definitions

14

Soil Plasticity amp Consistency Limits

In the early 1900s a Swedish scientist ldquoAtterbergrdquo developed a method to describe the consistency of fine grained soils with varying degree of moisture content1048698 If a soil is gradually dried from a slurry it passes from state of viscous liquid to a plastic state then to a semi-solid and finally into a solid state The moisture contents at which the soil passes fromone state to the next are known as consistency limits (also called ldquoAtterberg Limitsrdquo)1048698 Consistency limits are utilized to compare soils from different locations and different depths1048698 There are 4 basic states

15

Atterberg Limits

16

Consistency Limits

17

Definitions

a) Liquid Limit (LL) is the minimum moisture content at which the soil will flow under its own weight The moisture content (in ) required to close a distance of 127mm along the bottom of the groove after 25 blows is thellb) Plastic Limit (PL) is the moisture content (in ) at which the soil when rolled into threads of 32mm in diameter crumbles PL is the lower limit of the plastic stage of the soil The test is simple and performed by repeated rollings of ellipsoidal size soil mass by hand on a ground glass plate2162009 Mechanics of Soils 20 platec) Shrinkage Limit (SL) is the moisture content (in ) at which the volume change of the soil mass ceases

18

Definitions

d) Plasticity Index (PI) is a measure of the range of the moisture contents over which a soil is plastic PI=LL-PLe) Liquidity Index (LI) The relative consistency of a cohesive soil in a natural state can be defined by the ratio called LILI=(w-PL) (LL-PL)f) Activity is the ratio of PI to the clay fraction by dry weight of particles lt 2μm)A = PI (Clay fraction)

19

CLASSIFICATION OF SOILS

The sizes of particles that make up soil may vary widelydepending on the predominant size of particles Soils areclassified as 1) Gravel2) Sand3) Silt4) Clay1048698 The most comprehensive is the Unified Soil ClassificationSystem (USCS)

20

CLASSIFICATION OF SOILS

USCS This system classifies soils under two broadcategories1048698 Coarse Grained Soils -are gravelly and sandy innature with lt50 passing through a 200 sieve(diameter=0075mm)1048698 G ldquoGravelrdquo1048698 S ldquoSandrdquo1048698 Fine Grained Soils have 50 or more passingthrough the 200 sieve1048698 M inorganic Silt O Organic Silts and Clays1048698 C inorganic Clay Pt Peat muck highly organic soils

21

CLASSIFICATION OF SOILS (USCS)

USCS 1048698 The standard system used worldwide for most majorconstruction projects is known as the Unified SoilClassification System (USCS)1048698 This is based on an original system devised byCassagrande Soils are identified by symbols determinedfrom1048698 Sieve analysis and1048698 Atterberg Limit tests

22

SOILS CLASSIFICATION (USCS Table)

23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

24

CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

25

CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

27

Casagrande Plasticity Chart

28

Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

• Slide 1
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29

13

Definitions

14

Soil Plasticity amp Consistency Limits

In the early 1900s a Swedish scientist ldquoAtterbergrdquo developed a method to describe the consistency of fine grained soils with varying degree of moisture content1048698 If a soil is gradually dried from a slurry it passes from state of viscous liquid to a plastic state then to a semi-solid and finally into a solid state The moisture contents at which the soil passes fromone state to the next are known as consistency limits (also called ldquoAtterberg Limitsrdquo)1048698 Consistency limits are utilized to compare soils from different locations and different depths1048698 There are 4 basic states

15

Atterberg Limits

16

Consistency Limits

17

Definitions

a) Liquid Limit (LL) is the minimum moisture content at which the soil will flow under its own weight The moisture content (in ) required to close a distance of 127mm along the bottom of the groove after 25 blows is thellb) Plastic Limit (PL) is the moisture content (in ) at which the soil when rolled into threads of 32mm in diameter crumbles PL is the lower limit of the plastic stage of the soil The test is simple and performed by repeated rollings of ellipsoidal size soil mass by hand on a ground glass plate2162009 Mechanics of Soils 20 platec) Shrinkage Limit (SL) is the moisture content (in ) at which the volume change of the soil mass ceases

18

Definitions

d) Plasticity Index (PI) is a measure of the range of the moisture contents over which a soil is plastic PI=LL-PLe) Liquidity Index (LI) The relative consistency of a cohesive soil in a natural state can be defined by the ratio called LILI=(w-PL) (LL-PL)f) Activity is the ratio of PI to the clay fraction by dry weight of particles lt 2μm)A = PI (Clay fraction)

19

CLASSIFICATION OF SOILS

The sizes of particles that make up soil may vary widelydepending on the predominant size of particles Soils areclassified as 1) Gravel2) Sand3) Silt4) Clay1048698 The most comprehensive is the Unified Soil ClassificationSystem (USCS)

20

CLASSIFICATION OF SOILS

USCS This system classifies soils under two broadcategories1048698 Coarse Grained Soils -are gravelly and sandy innature with lt50 passing through a 200 sieve(diameter=0075mm)1048698 G ldquoGravelrdquo1048698 S ldquoSandrdquo1048698 Fine Grained Soils have 50 or more passingthrough the 200 sieve1048698 M inorganic Silt O Organic Silts and Clays1048698 C inorganic Clay Pt Peat muck highly organic soils

21

CLASSIFICATION OF SOILS (USCS)

USCS 1048698 The standard system used worldwide for most majorconstruction projects is known as the Unified SoilClassification System (USCS)1048698 This is based on an original system devised byCassagrande Soils are identified by symbols determinedfrom1048698 Sieve analysis and1048698 Atterberg Limit tests

22

SOILS CLASSIFICATION (USCS Table)

23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

24

CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

25

CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

27

Casagrande Plasticity Chart

28

Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

• Slide 1
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29

14

Soil Plasticity amp Consistency Limits

In the early 1900s a Swedish scientist ldquoAtterbergrdquo developed a method to describe the consistency of fine grained soils with varying degree of moisture content1048698 If a soil is gradually dried from a slurry it passes from state of viscous liquid to a plastic state then to a semi-solid and finally into a solid state The moisture contents at which the soil passes fromone state to the next are known as consistency limits (also called ldquoAtterberg Limitsrdquo)1048698 Consistency limits are utilized to compare soils from different locations and different depths1048698 There are 4 basic states

15

Atterberg Limits

16

Consistency Limits

17

Definitions

a) Liquid Limit (LL) is the minimum moisture content at which the soil will flow under its own weight The moisture content (in ) required to close a distance of 127mm along the bottom of the groove after 25 blows is thellb) Plastic Limit (PL) is the moisture content (in ) at which the soil when rolled into threads of 32mm in diameter crumbles PL is the lower limit of the plastic stage of the soil The test is simple and performed by repeated rollings of ellipsoidal size soil mass by hand on a ground glass plate2162009 Mechanics of Soils 20 platec) Shrinkage Limit (SL) is the moisture content (in ) at which the volume change of the soil mass ceases

18

Definitions

d) Plasticity Index (PI) is a measure of the range of the moisture contents over which a soil is plastic PI=LL-PLe) Liquidity Index (LI) The relative consistency of a cohesive soil in a natural state can be defined by the ratio called LILI=(w-PL) (LL-PL)f) Activity is the ratio of PI to the clay fraction by dry weight of particles lt 2μm)A = PI (Clay fraction)

19

CLASSIFICATION OF SOILS

The sizes of particles that make up soil may vary widelydepending on the predominant size of particles Soils areclassified as 1) Gravel2) Sand3) Silt4) Clay1048698 The most comprehensive is the Unified Soil ClassificationSystem (USCS)

20

CLASSIFICATION OF SOILS

USCS This system classifies soils under two broadcategories1048698 Coarse Grained Soils -are gravelly and sandy innature with lt50 passing through a 200 sieve(diameter=0075mm)1048698 G ldquoGravelrdquo1048698 S ldquoSandrdquo1048698 Fine Grained Soils have 50 or more passingthrough the 200 sieve1048698 M inorganic Silt O Organic Silts and Clays1048698 C inorganic Clay Pt Peat muck highly organic soils

21

CLASSIFICATION OF SOILS (USCS)

USCS 1048698 The standard system used worldwide for most majorconstruction projects is known as the Unified SoilClassification System (USCS)1048698 This is based on an original system devised byCassagrande Soils are identified by symbols determinedfrom1048698 Sieve analysis and1048698 Atterberg Limit tests

22

SOILS CLASSIFICATION (USCS Table)

23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

24

CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

25

CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

27

Casagrande Plasticity Chart

28

Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

• Slide 1
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29

15

Atterberg Limits

16

Consistency Limits

17

Definitions

a) Liquid Limit (LL) is the minimum moisture content at which the soil will flow under its own weight The moisture content (in ) required to close a distance of 127mm along the bottom of the groove after 25 blows is thellb) Plastic Limit (PL) is the moisture content (in ) at which the soil when rolled into threads of 32mm in diameter crumbles PL is the lower limit of the plastic stage of the soil The test is simple and performed by repeated rollings of ellipsoidal size soil mass by hand on a ground glass plate2162009 Mechanics of Soils 20 platec) Shrinkage Limit (SL) is the moisture content (in ) at which the volume change of the soil mass ceases

18

Definitions

d) Plasticity Index (PI) is a measure of the range of the moisture contents over which a soil is plastic PI=LL-PLe) Liquidity Index (LI) The relative consistency of a cohesive soil in a natural state can be defined by the ratio called LILI=(w-PL) (LL-PL)f) Activity is the ratio of PI to the clay fraction by dry weight of particles lt 2μm)A = PI (Clay fraction)

19

CLASSIFICATION OF SOILS

The sizes of particles that make up soil may vary widelydepending on the predominant size of particles Soils areclassified as 1) Gravel2) Sand3) Silt4) Clay1048698 The most comprehensive is the Unified Soil ClassificationSystem (USCS)

20

CLASSIFICATION OF SOILS

USCS This system classifies soils under two broadcategories1048698 Coarse Grained Soils -are gravelly and sandy innature with lt50 passing through a 200 sieve(diameter=0075mm)1048698 G ldquoGravelrdquo1048698 S ldquoSandrdquo1048698 Fine Grained Soils have 50 or more passingthrough the 200 sieve1048698 M inorganic Silt O Organic Silts and Clays1048698 C inorganic Clay Pt Peat muck highly organic soils

21

CLASSIFICATION OF SOILS (USCS)

USCS 1048698 The standard system used worldwide for most majorconstruction projects is known as the Unified SoilClassification System (USCS)1048698 This is based on an original system devised byCassagrande Soils are identified by symbols determinedfrom1048698 Sieve analysis and1048698 Atterberg Limit tests

22

SOILS CLASSIFICATION (USCS Table)

23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

24

CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

25

CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

27

Casagrande Plasticity Chart

28

Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

• Slide 1
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29

16

Consistency Limits

17

Definitions

a) Liquid Limit (LL) is the minimum moisture content at which the soil will flow under its own weight The moisture content (in ) required to close a distance of 127mm along the bottom of the groove after 25 blows is thellb) Plastic Limit (PL) is the moisture content (in ) at which the soil when rolled into threads of 32mm in diameter crumbles PL is the lower limit of the plastic stage of the soil The test is simple and performed by repeated rollings of ellipsoidal size soil mass by hand on a ground glass plate2162009 Mechanics of Soils 20 platec) Shrinkage Limit (SL) is the moisture content (in ) at which the volume change of the soil mass ceases

18

Definitions

d) Plasticity Index (PI) is a measure of the range of the moisture contents over which a soil is plastic PI=LL-PLe) Liquidity Index (LI) The relative consistency of a cohesive soil in a natural state can be defined by the ratio called LILI=(w-PL) (LL-PL)f) Activity is the ratio of PI to the clay fraction by dry weight of particles lt 2μm)A = PI (Clay fraction)

19

CLASSIFICATION OF SOILS

The sizes of particles that make up soil may vary widelydepending on the predominant size of particles Soils areclassified as 1) Gravel2) Sand3) Silt4) Clay1048698 The most comprehensive is the Unified Soil ClassificationSystem (USCS)

20

CLASSIFICATION OF SOILS

USCS This system classifies soils under two broadcategories1048698 Coarse Grained Soils -are gravelly and sandy innature with lt50 passing through a 200 sieve(diameter=0075mm)1048698 G ldquoGravelrdquo1048698 S ldquoSandrdquo1048698 Fine Grained Soils have 50 or more passingthrough the 200 sieve1048698 M inorganic Silt O Organic Silts and Clays1048698 C inorganic Clay Pt Peat muck highly organic soils

21

CLASSIFICATION OF SOILS (USCS)

USCS 1048698 The standard system used worldwide for most majorconstruction projects is known as the Unified SoilClassification System (USCS)1048698 This is based on an original system devised byCassagrande Soils are identified by symbols determinedfrom1048698 Sieve analysis and1048698 Atterberg Limit tests

22

SOILS CLASSIFICATION (USCS Table)

23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

24

CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

25

CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

27

Casagrande Plasticity Chart

28

Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

• Slide 1
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29

17

Definitions

a) Liquid Limit (LL) is the minimum moisture content at which the soil will flow under its own weight The moisture content (in ) required to close a distance of 127mm along the bottom of the groove after 25 blows is thellb) Plastic Limit (PL) is the moisture content (in ) at which the soil when rolled into threads of 32mm in diameter crumbles PL is the lower limit of the plastic stage of the soil The test is simple and performed by repeated rollings of ellipsoidal size soil mass by hand on a ground glass plate2162009 Mechanics of Soils 20 platec) Shrinkage Limit (SL) is the moisture content (in ) at which the volume change of the soil mass ceases

18

Definitions

d) Plasticity Index (PI) is a measure of the range of the moisture contents over which a soil is plastic PI=LL-PLe) Liquidity Index (LI) The relative consistency of a cohesive soil in a natural state can be defined by the ratio called LILI=(w-PL) (LL-PL)f) Activity is the ratio of PI to the clay fraction by dry weight of particles lt 2μm)A = PI (Clay fraction)

19

CLASSIFICATION OF SOILS

The sizes of particles that make up soil may vary widelydepending on the predominant size of particles Soils areclassified as 1) Gravel2) Sand3) Silt4) Clay1048698 The most comprehensive is the Unified Soil ClassificationSystem (USCS)

20

CLASSIFICATION OF SOILS

USCS This system classifies soils under two broadcategories1048698 Coarse Grained Soils -are gravelly and sandy innature with lt50 passing through a 200 sieve(diameter=0075mm)1048698 G ldquoGravelrdquo1048698 S ldquoSandrdquo1048698 Fine Grained Soils have 50 or more passingthrough the 200 sieve1048698 M inorganic Silt O Organic Silts and Clays1048698 C inorganic Clay Pt Peat muck highly organic soils

21

CLASSIFICATION OF SOILS (USCS)

USCS 1048698 The standard system used worldwide for most majorconstruction projects is known as the Unified SoilClassification System (USCS)1048698 This is based on an original system devised byCassagrande Soils are identified by symbols determinedfrom1048698 Sieve analysis and1048698 Atterberg Limit tests

22

SOILS CLASSIFICATION (USCS Table)

23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

24

CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

25

CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

27

Casagrande Plasticity Chart

28

Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

• Slide 1
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29

18

Definitions

d) Plasticity Index (PI) is a measure of the range of the moisture contents over which a soil is plastic PI=LL-PLe) Liquidity Index (LI) The relative consistency of a cohesive soil in a natural state can be defined by the ratio called LILI=(w-PL) (LL-PL)f) Activity is the ratio of PI to the clay fraction by dry weight of particles lt 2μm)A = PI (Clay fraction)

19

CLASSIFICATION OF SOILS

The sizes of particles that make up soil may vary widelydepending on the predominant size of particles Soils areclassified as 1) Gravel2) Sand3) Silt4) Clay1048698 The most comprehensive is the Unified Soil ClassificationSystem (USCS)

20

CLASSIFICATION OF SOILS

USCS This system classifies soils under two broadcategories1048698 Coarse Grained Soils -are gravelly and sandy innature with lt50 passing through a 200 sieve(diameter=0075mm)1048698 G ldquoGravelrdquo1048698 S ldquoSandrdquo1048698 Fine Grained Soils have 50 or more passingthrough the 200 sieve1048698 M inorganic Silt O Organic Silts and Clays1048698 C inorganic Clay Pt Peat muck highly organic soils

21

CLASSIFICATION OF SOILS (USCS)

USCS 1048698 The standard system used worldwide for most majorconstruction projects is known as the Unified SoilClassification System (USCS)1048698 This is based on an original system devised byCassagrande Soils are identified by symbols determinedfrom1048698 Sieve analysis and1048698 Atterberg Limit tests

22

SOILS CLASSIFICATION (USCS Table)

23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

24

CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

25

CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

27

Casagrande Plasticity Chart

28

Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

• Slide 1
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29

19

CLASSIFICATION OF SOILS

The sizes of particles that make up soil may vary widelydepending on the predominant size of particles Soils areclassified as 1) Gravel2) Sand3) Silt4) Clay1048698 The most comprehensive is the Unified Soil ClassificationSystem (USCS)

20

CLASSIFICATION OF SOILS

USCS This system classifies soils under two broadcategories1048698 Coarse Grained Soils -are gravelly and sandy innature with lt50 passing through a 200 sieve(diameter=0075mm)1048698 G ldquoGravelrdquo1048698 S ldquoSandrdquo1048698 Fine Grained Soils have 50 or more passingthrough the 200 sieve1048698 M inorganic Silt O Organic Silts and Clays1048698 C inorganic Clay Pt Peat muck highly organic soils

21

CLASSIFICATION OF SOILS (USCS)

USCS 1048698 The standard system used worldwide for most majorconstruction projects is known as the Unified SoilClassification System (USCS)1048698 This is based on an original system devised byCassagrande Soils are identified by symbols determinedfrom1048698 Sieve analysis and1048698 Atterberg Limit tests

22

SOILS CLASSIFICATION (USCS Table)

23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

24

CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

25

CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

27

Casagrande Plasticity Chart

28

Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

• Slide 1
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29

20

CLASSIFICATION OF SOILS

USCS This system classifies soils under two broadcategories1048698 Coarse Grained Soils -are gravelly and sandy innature with lt50 passing through a 200 sieve(diameter=0075mm)1048698 G ldquoGravelrdquo1048698 S ldquoSandrdquo1048698 Fine Grained Soils have 50 or more passingthrough the 200 sieve1048698 M inorganic Silt O Organic Silts and Clays1048698 C inorganic Clay Pt Peat muck highly organic soils

21

CLASSIFICATION OF SOILS (USCS)

USCS 1048698 The standard system used worldwide for most majorconstruction projects is known as the Unified SoilClassification System (USCS)1048698 This is based on an original system devised byCassagrande Soils are identified by symbols determinedfrom1048698 Sieve analysis and1048698 Atterberg Limit tests

22

SOILS CLASSIFICATION (USCS Table)

23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

24

CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

25

CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

27

Casagrande Plasticity Chart

28

Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

• Slide 1
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29

21

CLASSIFICATION OF SOILS (USCS)

USCS 1048698 The standard system used worldwide for most majorconstruction projects is known as the Unified SoilClassification System (USCS)1048698 This is based on an original system devised byCassagrande Soils are identified by symbols determinedfrom1048698 Sieve analysis and1048698 Atterberg Limit tests

22

SOILS CLASSIFICATION (USCS Table)

23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

24

CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

25

CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

27

Casagrande Plasticity Chart

28

Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

• Slide 1
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29

22

SOILS CLASSIFICATION (USCS Table)

23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

24

CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

25

CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

27

Casagrande Plasticity Chart

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Soil Triangle

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Practice Problems

ReadingsDAS Textbook

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23

CLASSIFICATION PROCEDURE

Coarse Grained Materials1048698 If more than half of the material is coarser than the 75 μmsieve the soil is classified as coarse The following steps are then followed to determine the appropriate 2 lettersymbol1048698 Determine the1st letter of the symbol1048698 If more than half of the coarse fraction is sand then use prefix S1048698 If more than half of the coarse fraction is gravel then use prefix G1048698 Determine the 2nd letter of symbol1048698 This depends on the uniformity coefficient Cu and thecoefficient of curvature Cc obtained from the grading curve onthe percentage of fines and the type of fines

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CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

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CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

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CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

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Casagrande Plasticity Chart

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Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

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CLASSIFICATION PROCEDURE

First determine the percentage of fines that is the of materialpassing the 75 μm sieve1048698 Then if fines is1048698 lt 5 use W or P as suffix1048698 gt 12 use M or C as suffix1048698 between 5 and 12 use dual symbols Use the prefix from abovewith first one of W or P and then with one of M or C1048698 If W or P are required for the suffix then Cu and Cc must beevaluated1048698 If prefix is G then suffix is W if Cu gt 4 and Cc is between 1 amp 3 otherwise use P1048698 If prefix is S then suffix is W if Cu gt 6 and Cc is between 1 amp 3 otherwise use P

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CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

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CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

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Casagrande Plasticity Chart

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Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

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CLASSIFICATION PROCEDURE

If M or C are required they have to be determined fromthe procedure used for fine grained materials discussedbelow Note that M stands for Silt and C for Clay This isdetermined from whether the soil lies above or below theA-line in the plasticity chart1048698 For a coarse grained soil which is predominantly sandthe following symbols are possible1048698 SW SP SM SC1048698 SW-SM SW-SC SP-SM SP-SC

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CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

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Casagrande Plasticity Chart

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Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

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26

CLASSIFICATION PROCEDURE

These are classified solely according to the results from the Atterberg Limit Tests Values of the Plasticity Indexand Liquid Limit are used to determine a point in theplasticity chart The classification symbol is determinedfrom the region of the chart in which the point liesExamples1048698 CH High plasticity clay1048698 CL Low plasticity clayMH Hi h l ti it ilt1048698 High plasticity silt1048698 ML Low plasticity silt1048698 OH High plasticity organic soil (Rare)1048698 Pt Peat

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Casagrande Plasticity Chart

28

Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

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Casagrande Plasticity Chart

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Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

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Soil Triangle

29

Practice Problems

ReadingsDAS Textbook

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29

Practice Problems

ReadingsDAS Textbook

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