1

Contents Title: Unconsolidated Undrained Triaxial Test/ Triaxial Compression Test .................................. 2

Aim: ................................................................................................................................................ 2

Objective: ........................................................................................................................................ 2

Apparatus: ....................................................................................................................................... 2

Theory: ............................................................................................................................................ 3

Procedures: ...................................................................................................................................... 4

Results: ............................................................................................................................................ 5

Sample Calculations: .................................................................................................................... 12

Discussion: .................................................................................................................................... 13

Conclusion: ................................................................................................................................... 15

Title: Consolidation Test ............................................................................................................... 16

Aim: .............................................................................................................................................. 16

Objective: ...................................................................................................................................... 16

Apparatus: ..................................................................................................................................... 16

Theory: .......................................................................................................................................... 17

Procedures: .................................................................................................................................... 18

Results: .......................................................................................................................................... 18

Sample Calculations: .................................................................................................................... 20

Discussion: .................................................................................................................................... 21

Conclusion: ................................................................................................................................... 22

Bibliography: ................................................................................................................................ 23

Appendix: ...................................................................................................................................... 24

2

Title: Unconsolidated Undrained Triaxial Test/ Triaxial Compression

Test

Aim:

The aim of this test was to carry out a triaxial test to determine the soil strength parameter for a

cohesionless soil.

Objective:

The objectives set forth for this experiment were, to determine:

i) the friction angle, ii) the cohesion, c, for the given sample.

Apparatus:

Compression Machine Triaxial Cell Specimen mold Rubber membrane Porous stones Vacuum pump Air-pressure source Calipers

Figure 1 Diagram of a Triaxial Cell (Soil Mechanics & Foundations 3rd Edition, Budhu)

3

Theory:

The strength of a soil develops from contact between particles which have the capacity to

transmit vertical (normal) forces as well as shear stresses (i.e. interparticle forces). If at any point

in a plane within a soil the shear stresses becomes equal to its shear strength, subsequently,

failure may ensue. The effect of water (moisture) on the soil is also of importance. Said water

can lead to the creation of either positive or negative (suction) pressures in the soil according to

its concentration, bringing about effective stresses.

The relationship between the soil strength parameters is given by the equation:

where is the shear strength, is the cohesion, is the effective normal stress and is the

internal friction angle.

The triaxial test, is one in which a cylindrical soil sample is used to estimate cohesive strength

and the angle of shearing resistance. A cylindrical soil sample is contained in a rubber tube and

surrounded by water under pressure inside a cylinder. A load is applied by a piston to pressurize

the water and subject the sample to an all-around pressure. Deformations, loads and pressures are

recorded. Undrained tests are rapid but drained tests are slower. This test one of the means

through which the strength parameters of a soil can be ascertained. These parameters are the

internal friction angle and cohesion. Its results can be used to plot an approximation of the Mohr-

Coulomb failure curve.

The following formulae was used in order to carry out the necessary calculations required to

analyse results of this experiment:

4

Procedures:

1. A volume of water was measured, added to the soil sample to achieve the required

moisture content and mixed thoroughly.

2. The sample was then placed into the mould in three (3) layers with fifteen (15) tamps per

layer and then extruded.

3. The height and diameter of the specimen was measured at several locations, as well as,

the mass and an average value for each parameter was determined.

4. The extruded specimen was placed into the membrane along with the base and top caps.

5. The specimen was then placed in the compression machine, the cell was filled with water

and pressurized.

6. The sample was then loaded continually and the dial (deviator) readings were recorded at

regular intervals until they became redundant.

7. Subsequently the sample was then removed from the machine and placed into the

moisture tin and weighed. The weight of the tin was previously determined.

8. Next, the moisture tin was placed into the oven and the following day it was weighed

again.

9. Procedures one (1) to eight (8) were repeated for two (2) other samples and cell

pressures.

10. These results were tabulated and used to determine the required parameters.

5

Results:

Sample1

CompressionGauge

ProvingRingGauge

0.002 0.00573 Deformation(mm)

Load(kN) Deformation(m)

Strain CorrectedArea(m2)

Stress(kN/m2)

0 0 0.0 0.00 0.0000 0.0000 0.0011515 0.0050 20 0.1 0.11 0.0001 0.0012 0.0011528 99.41100 30 0.2 0.17 0.0002 0.0023 0.0011542 148.93150 39 0.3 0.22 0.0003 0.0035 0.0011556 193.39200 45 0.4 0.26 0.0004 0.0047 0.0011569 222.88250 52 0.5 0.30 0.0005 0.0059 0.0011583 257.24300 57 0.6 0.33 0.0006 0.0070 0.0011597 281.64350 62 0.7 0.36 0.0007 0.0082 0.0011610 305.99400 66 0.8 0.38 0.0008 0.0094 0.0011624 325.34450 71 0.9 0.41 0.0009 0.0106 0.0011638 349.58500 74 1.0 0.42 0.0010 0.0117 0.0011652 363.91600 81 1.2 0.46 0.0012 0.0141 0.0011679 397.39700 87 1.4 0.50 0.0014 0.0164 0.0011707 425.81800 91 1.6 0.52 0.0016 0.0188 0.0011735 444.33900 96 1.8 0.55 0.0018 0.0211 0.0011763 467.621000 99 2.0 0.57 0.0020 0.0235 0.0011792 481.081100 103 2.2 0.59 0.0022 0.0258 0.0011820 499.311200 106 2.4 0.61 0.0024 0.0282 0.0011849 512.621300 108 2.6 0.62 0.0026 0.0305 0.0011877 521.031400 110 2.8 0.63 0.0028 0.0329 0.0011906 529.391500 112 3.0 0.64 0.0030 0.0352 0.0011935 537.711600 114 3.2 0.65 0.0032 0.0376 0.0011964 545.981700 115 3.4 0.66 0.0034 0.0399 0.0011993 549.421800 117 3.6 0.67 0.0036 0.0423 0.0012023 557.611900 118 3.8 0.68 0.0038 0.0446 0.0012052 561.002000 120 4.0 0.69 0.0040 0.0469 0.0012082 569.112100 121 4.2 0.69 0.0042 0.0493 0.0012112 572.442200 122 4.4 0.70 0.0044 0.0516 0.0012142 575.742300 123 4.6 0.70 0.0046 0.0540 0.0012172 579.022400 124 4.8 0.71 0.0048 0.0563 0.0012202 582.282500 125 5.0 0.72 0.0050 0.0587 0.0012233 585.522600 126 5.2 0.72 0.0052 0.0610 0.0012263 588.732700 127 5.4 0.73 0.0054 0.0634 0.0012294 591.922800 128 5.6 0.73 0.0056 0.0657 0.0012325 595.092900 128 5.8 0.73 0.0058 0.0681 0.0012356 593.593000 130 6.0 0.74 0.0060 0.0704 0.0012387 601.353100 130 6.2 0.74 0.0062 0.0728 0.0012419 599.833200 130 6.4 0.74 0.0064 0.0751 0.0012450 598.313300 131 6.6 0.75 0.0066 0.0775 0.0012482 601.383400 132 6.8 0.76 0.0068 0.0798 0.0012514 604.43

6

3500 132 7.0 0.76 0.0070 0.0822 0.0012546 602.893600 133 7.2 0.76 0.0072 0.0845 0.0012578 605.903700 133 7.4 0.76 0.0074 0.0868 0.0012610 604.353800 134 7.6 0.77 0.0076 0.0892 0.0012643 607.333900 135 7.8 0.77 0.0078 0.0915 0.0012675 610.284000 135 8.0 0.77 0.0080 0.0939 0.0012708 608.714100 136 8.2 0.78 0.0082 0.0962 0.0012741 611.634200 136 8.4 0.78 0.0084 0.0986 0.0012774 610.044300 137 8.6 0.79 0.0086 0.1009 0.0012808 612.934400 137 8.8 0.79 0.0088 0.1033 0.0012841 611.334500 137 9.0 0.79 0.0090 0.1056 0.0012875 609.724600 137 9.2 0.79 0.0092 0.1080 0.0012909 608.124700 137 9.4 0.79 0.0094 0.1103 0.0012943 606.52

Sample2

CompressionGauge

ProvingRingGauge

0.002 0.00573 Deformation(mm)

Load(kN) Deformation(m)

Strain CorrectedArea(m2)

Stress(kN/m2)

0 0 0.0 0.00 0.0000 0.0000 0.0011515 0.00

100 1 0.2 0.01 0.0002 0.0023 0.0011542 4.96

200 20 0.4 0.11 0.0004 0.0047 0.0011569 99.06

400 61 0.8 0.35 0.0008 0.0094 0.0011624 300.70

600 88 1.2 0.50 0.0012 0.0141 0.0011679 431.73

800 110 1.6 0.63 0.0016 0.0188 0.0011735 537.10

1000 134 2.0 0.77 0.0020 0.0235 0.0011792 651.15

1200 151 2.4 0.87 0.0024 0.0282 0.0011849 730.24

1400 162 2.8 0.93 0.0028 0.0329 0.0011906 779.65

1600 171 3.2 0.98 0.0032 0.0376 0.0011964 818.97

1800 178 3.6 1.02 0.0036 0.0423 0.0012023 848.33

2000 185 4.0 1.06 0.0040 0.0469 0.0012082 877.37

2200 192 4.4 1.10 0.0044 0.0516 0.0012142 906.08

2400 199 4.8 1.14 0.0048 0.0563 0.0012202 934.47

2600 202 5.2 1.16 0.0052 0.0610 0.0012263 943.84

2800 205 5.6 1.17 0.0056 0.0657 0.0012325 953.07

3000 207 6.0 1.19 0.0060 0.0704 0.0012387 957.53

3200 209 6.4 1.20 0.0064 0.0751 0.0012450 961.90

3400 210 6.8 1.20 0.0068 0.0798 0.0012514 961.60

3600 211 7.2 1.21 0.0072 0.0845 0.0012578 961.25

3800 210 7.6 1.20 0.0076 0.0892 0.0012643 951.78

4000 209 8.0 1.20 0.0080 0.0939 0.0012708 942.37

7

Sample3

CompressionGauge

ProvingRingGauge

0.002 0.00573 Deformation(mm)

Load(kN) Deformation(m)

Strain CorrectedArea(m2)

Stress(kN/m2)

0 0 0.0 0.00 0.0000 0.0000 0.0011515 0.00

50 1 0.1 0.01 0.0001 0.0012 0.0011528 4.97

100 3 0.2 0.02 0.0002 0.0023 0.0011542 14.89

150 6 0.3 0.03 0.0003 0.0035 0.0011556 29.75

200 42 0.4 0.24 0.0004 0.0047 0.0011569 208.02

250 69 0.5 0.40 0.0005 0.0059 0.0011583 341.34

300 91 0.6 0.52 0.0006 0.0070 0.0011597 449.64

350 109 0.7 0.62 0.0007 0.0082 0.0011610 537.95

400 124 0.8 0.71 0.0008 0.0094 0.0011624 611.25

450 137 0.9 0.79 0.0009 0.0106 0.0011638 674.53

500 148 1.0 0.85 0.0010 0.0117 0.0011652 727.83

600 167 1.2 0.96 0.0012 0.0141 0.0011679 819.31

700 181 1.4 1.04 0.0014 0.0164 0.0011707 885.89

800 193 1.6 1.11 0.0016 0.0188 0.0011735 942.36

900 203 1.8 1.16 0.0018 0.0211 0.0011763 988.82

1000 211 2.0 1.21 0.0020 0.0235 0.0011792 1025.32

1100 218 2.2 1.25 0.0022 0.0258 0.0011820 1056.79

1200 223 2.4 1.28 0.0024 0.0282 0.0011849 1078.43

1300 228 2.6 1.31 0.0026 0.0305 0.0011877 1099.94

1400 232 2.8 1.33 0.0028 0.0329 0.0011906 1116.53

1500 236 3.0 1.35 0.0030 0.0352 0.0011935 1133.02

1600 239 3.2 1.37 0.0032 0.0376 0.0011964 1144.64

1800 246 3.6 1.41 0.0036 0.0423 0.0012023 1172.41

2000 250 4.0 1.43 0.0040 0.0469 0.0012082 1185.64

2200 254 4.4 1.46 0.0044 0.0516 0.0012142 1198.67

2400 257 4.8 1.47 0.0048 0.0563 0.0012202 1206.83

2600 260 5.2 1.49 0.0052 0.0610 0.0012263 1214.84

2800 262 5.6 1.50 0.0056 0.0657 0.0012325 1218.07

3000 263 6.0 1.51 0.0060 0.0704 0.0012387 1216.57

3200 265 6.4 1.52 0.0064 0.0751 0.0012450 1219.63

3400 266 6.8 1.52 0.0068 0.0798 0.0012514 1218.02

3600 268 7.2 1.54 0.0072 0.0845 0.0012578 1220.92

3800 268 7.6 1.54 0.0076 0.0892 0.0012643 1214.66

4000 269 8.0 1.54 0.0080 0.0939 0.0012708 1212.91

4200 270 8.4 1.55 0.0084 0.0986 0.0012774 1211.11

4400 271 8.8 1.55 0.0088 0.1033 0.0012841 1209.26

4600 271 9.2 1.55 0.0092 0.1080 0.0012909 1202.93

8

4800 272 9.6 1.56 0.0096 0.1127 0.0012977 1201.02

5000 272 10.0 1.56 0.0100 0.1174 0.0013046 1194.66

5200 272 10.4 1.56 0.0104 0.1221 0.0013116 1188.31

5400 270 10.8 1.55 0.0108 0.1268 0.0013186 1173.26

5600 269 11.2 1.54 0.0112 0.1314 0.0013258 1162.64

Sample1 Sample2 Sample3

Tin V A F2/H2

MassofHolder(g) 214.18 214.18 214.18

MassofHolder&Sample(g) N/A 331.69 330.77

MassofTin(g) 196 201.2 207.62

MassofTinandSample(BeforeDrying)(g)

329.71 317.02 323.56

MassofTinandSampleAfterDrying)(g)

318.02 306.05 313.51

Before(g) N/A 117.51 116.59

BeforeDrying(g) 133.71 115.82 115.94

AfterDrying(g) 122.02 104.85 105.89

MoistureContent 0.096 0.105 0.095

Height(m) 85.15 85.21 85.26 85.21 0.0852

Diameter(m) 38.29 38.31 38.27 38.29 0.0383

Area(m2) 1151.491 1.2E03

Volume(m2) 98114.725 9.8E05

BulkDensity(kg/m3)

1362.79

DryDensity(kg/m3)

1243.65

UnitWeight(kN/m3)

13.37

DryUnitWeight(kN/m3)

12.20

9

0.00

100.00

200.00

300.00

400.00

500.00

600.00

700.00

0.0000 0.0200 0.0400 0.0600 0.0800 0.1000 0.1200

Stress(kN/m2)

Strain

GraphShowingStressvs.StrainforSample1

0.00

200.00

400.00

600.00

800.00

1000.00

1200.00

0.0000 0.0100 0.0200 0.0300 0.0400 0.0500 0.0600 0.0700 0.0800 0.0900 0.1000

Stress(kN/m2)

Strain

GraphShowingStressvs.StrainforSample2

10

0.00

200.00

400.00

600.00

800.00

1000.00

1200.00

1400.00

0.0000 0.0200 0.0400 0.0600 0.0800 0.1000 0.1200 0.1400

Stress(kN/m2)

Strain

GraphShowingStressvs.StrainforSample2

11

900

700

500

300

100

100

300

500

700

900

0.00 200.00 400.00 600.00 800.00 1000.00 1200.00 1400.00 1600.00 1800.00

GraphShowingMohrCircleConstruction(MohrCoulombFailureCriterion)

12

Sample Calculations:

4

0.0383

4 1.2 10

1.2 10 0.0852 9.8 10

& 329.71 196.00 133.71 0.13371

..

0.096 9.6%

0.133719.8 10

1362.79 /

1

1362.791 0.096

1243.65 /

1000

1362.79 9.81

1000 13.37/

1

13.371 0.096

12.20 /

206.84 /

206.84 612.9 819.77 /

2

819.77 206.842

306.46 /

2

206.84 819.772

513.31 /

13

Discussion:

Several individuals have carried out extensive work in the field of soil mechanics. One of the

most important figures is Charles Coulomb, who presented to law of soil shear strength, which

states that:

The shear strength of a soil is directly proportional to the apparent cohesion and product of the

normal force and friction angle. Given by the formula:

Which means that if inter granular friction increases the normal stress acting on the shear surface

also increases. Whereas, the cohesion is dependent on the type of the soil, size of the soil grains

and the packing of the soil grains and on the suction properties of the soil.

Coulombs Law was subsequently modified to include the effect of water (pressure) on a soil,

with the subsequent parameters being known as the effective normal stress, cohesion and friction

angle, respectively, denoted by:

Where: and is the water pressure

Coulombs Law proposed that failure would occur at any point given a critical combination of

shear stress and effective normal stress being developed.

Mohr and Coulomb subsequently postulated a method to determine the point beyond which

failure of a soil would occur. This was done via the use of the effective principal stresses (, )

which are then used to construct Mohr circles. After drawing these circles, a tangential line is

drawn touching all the circles towards the origin of the graph plotted. These constructions

produces what is known as the Mohr Coulomb failure envelope and denotes the strength

parameters for that particular soil. Any subsequent change in either of the principal stresses may

lead to failure of the soil.

In order to ascertain these major and minor principal stresses, a triaxial test was carried out in

which used three (3) different samples with a different fixed cell pressure or confining stress ()

for each and varying normal stress (). The values of the normal stress were plotted against

strain and the maximum was used to construct the necessary Mohr circles. The results were

14

presented above and the cohesion of the soil was found to be -100 kN/m2 and the friction angle

was found to be 450.

The maximum values of normal stress increased as the confining stress was increased showing

that there is a direct relation between the strength of the soil and the principal stresses. This is

shown by the increasing size of the Mohr circles constructed.

Given that the soil sample was sandy the friction angle can be considered to be accurate.

Intuitively, the cohesion value cannot be negative but instead must be relatively close to zero.

Considering this, it can be said that there were obvious errors in the experiment. This was also

indicated during the preparation of the samples to be tested, where majour difficulties were

experienced when extruding the samples from the mould. As a result of this, there may be an

error with the first sample in particular since it was at this moisture content that most difficulty

was experienced.

Apart from this error, other errors brought on more so by the human factor may also have been

introduced into the experiment. These sources of error are inherent and lead to inequalities in

measured quantities as compared to their actual (true) value. It is important to note these sources

of error and take necessary precautions in order to reduce their influence. Some of the sources of

error that were inherent in this experiment were:

1. Parallax error, in taking the dial readings. Also in determining the volume of water to be

added to the soil samples.

2. Zero errors, in resetting the dials and gauges, which would lead to erroneous

displacements being found. Also zero errors in the scale used to determine the masses of

the various elements of the apparatus. Some of the equipment in the lab, due to their age,

may also be out of calibration.

3. Environmental errors, such as air drying of samples while preparations are made with the

apparatus leading to changes in the moisture content of the sample and thus affecting the

accuracy of the results obtained.

Precautions that can be taken are thus, ensure that instruments are read at eye level to minimize

parallax. Also other group member can be asked to perform an independent check in order to

verify readings obtained. Ensure that all tools used for measuring are properly zeroed before

15

commencing measurement. Finally, the samples should be handled away from any windows,

doors or fans where air can be introduced to it thus causing evaporation of water or vice versa.

Conclusion:

The internal friction angle and cohesion value of the given soil sample were determined. In this

regard it can be said that the aims and objectives set forth for this experiment were successfully

completed. In the process an appreciation was gained for the triaxial test, its suitability for

determining the aforementioned parameters of soil strength and the application of these

parameters in Civil Engineering practices.

16

Title: Consolidation Test

Aim:

The aim of this test was to carry out a consolidation test to determine the consolidation/

settlement parameters of a given soil.

Objective:

The objectives set forth for this experiment were, to determine:

i) the coefficient of consolidation, cv, via two methods. ii) the coefficient of volume compressibility, mv iii) the permeability, k, of the sample iv) the porewater pressure, u, at the centre of the sample v) the degree of consolidation

Apparatus:

Oedometer Dial gauge Loading device Stop watch/ timer Calipers Weights Squeeze bottle Moisture tins Scale Oven

Figure 2 Diagram of Consolidation Apparatus (Principles of Geotechnical Engineering 7th Edition, Das)

17

Theory:

The gradual compression of a cohesive soil by a weight on it to drive the water and air out of the

voids in the soil, is known as consolidation. This is one of the most important concepts in Civil

Engineering, as most if not all structures built involves the placement of some load on a soil. The

usual result of said loading is settlement. Consolidation occurs in soils of low permeability and is

not the same as compaction, which is immediate and occurs only where there is some sand.

It is therefore of particular importance to determine various parameters associated with the

consolidation of a sample of soil for various load stages. These parameters are integral for the

determination of the settlement of a soil. They are:

the coefficient of consolidation cv, via the log time and root time methods the coefficient of volume compressibility, mv the permeability, k the porewater pressure, u the degree of consolidation the settlement,

The formulae used to determine these parameters are:

/: .

/: 0.848

: ,

sin

where

2 1 0,1,2,3

:

: 1 2

sin

: 1 2

18

Procedures:

1. The sample was prepared as set forth in the lab manual

2. The specimen was placed in the consolidation cell, sandwiched between two porous

stones.

3. The cell was then filled with water and placed in the load frame. A deformation gauge

was placed over the specimen.

4. The load was placed and the stop watch was started simultaneously and the deformation

readings were taken at the necessary time intervals.

5. The results were tabulated and used to carry out the relevant calculations for each

method.

Results:

Deformation/mm TimeElapsed/min

5.424 0.005.370 0.255.356 1.005.346 2.255.338 4.005.330 6.255.324 9.005.318 12.255.316 16.005.312 20.255.308 25.005.300 36.005.294 49.005.288 64.005.286 74.005.282 84.005.276 94.005.274 104.005.272 114.005.268 124.005.254 1177.005.252 1237.005.250 1297.005.250 1357.005.250 1477.00

(See additional results in Excel sheet attached)

19

5.240

5.260

5.280

5.300

5.320

5.340

5.360

5.380

0.10 1.00 10.00 100.00 1000.00 10000.00

Deformation(mm)

Time(mins)

GraphShowingDeformationvs.Time

0

0.02

0.04

0.06

0.08

0.1

0.12

1 10 100 1000

Settlement(mm)

Time(mins)

GraphShowingTheoretical&ExperimentalSettlementvs.Time

TheoreticalValues

ExperimentalValues

20

Sample Calculations:

21

Discussion:

The graphs plotted (see appendix) were according to the Casagrande and Taylor methods, with

the former using the deformation and time (plotted on a log scale) and the latter using

deformation and the square root of time (plotted on a special graph). These were used to find the

cv values which were 0.55 and according to the Casagrande and Taylor methods,

respectively.

The values of cv were different in both methods based on the times (t50 & t90) used in either

method. This is intuitively expected since the times are different in each case. Therefore it is

important to specify which method was used to obtain the value of cv.

The third graph plotted compared the theoretical and experimental settlement values at various

times. In each instance the theoretical and experimental values complimented each other as there

was little or no major difference in the values. This shows that theoretical method can used to

receive the same results that experimentation yields, simply by using the cv value. It is also

indicative of the usefulness of cv in determining the settlement of a soil.

As mentioned previously, the consolidation test is an important one in determining the behaviour

of a soil under loading. Its results can be used to calculate void ratio changes and settlement.

This is of particular importance in the field of Civil Engineering.

There exist a few limitations to the consolidation test, based on the assumptions set forth for this

method in particular. These limitations affect the inferences that can be drawn from the

experiment but notwithstanding such, the experiment does produce useful information in terms

of soil consolidation and settlement.

In the one dimensional (1D) equation the permeability (k) and coefficient of volume

compressibility (mv) are assumed constant, but as the consolidation of a soil progresses, the void

spaces decrease and this results in a decreased permeability and therefore permeability is not

constant. In a similar fashion, the coefficient of volume compressibility also changes with stress

level. Therefore cv is not constant. Also the flow is assumed to be one dimensional (1D) but in

reality flow is three dimensional (3D). The application of external load is assumed to produce

excess pore water pressure over the entire soil but in some cases the excess pore water pressure

does not develop over its entirety.

22

As with any other laboratory experiment several errors are inherent and as a result this may

reduce the accuracy of the data obtained. Some of the errors in this experiment are:

1. Parallax error, in taking the dial readings.

2. Zero errors, in resetting the dials and gauges, which would lead to erroneous

displacements being found. Some of the equipment in the lab, due to their age, may also

be out of calibration.

3. Error in reading the dial at the exact time required.

4. Environmental errors, such as air drying of samples while leading to changes in the

moisture content of the sample and thus affecting the accuracy of the results obtained.

Precautions that can be taken are to ensure that instruments are read at eye level to minimize

parallax. Also other group member can be asked to perform an independent check in order to

verify readings obtained. Ensure that all tools used for measuring are properly zeroed before

commencing measurement. Finally, the samples should be handled away from any windows,

doors or fans where air can be introduced to it thus causing evaporation of water or vice versa.

The lab can be further improved by using a greater number of load stages and determining the

settlement from such. This would enable the parameters for the soil to be found under different

loading conditions.

Also the use of several samples from that one soil specimen can also improve the results

obtained as the soil may vary from place to place even in a relatively small location. Therefore

the more samples can lead to a better picture being painted as it relates to the consolidation and

settlement of the soil.

Conclusion:

Given the aims and objectives which were dictated for this experiment, it can be said that it was

successfully completed. The values of all required parameters were calculated and can be found

above. It can also be concluded that theoretical settlement values are indeed similar to that of

experimental values and can be used to determine the settlement of a soil, provided that the

coefficient of consolidation cv is accurately calculated. Thus the importance of consolidation

theory and settlement to the field of Civil Engineering was observed and a greater appreciation

was gained as such.

23

Bibliography:

Craig, R.F. Craigs Soil Mechanics. Seventh Edition. New York 2004.

Budhu, M. Soil Mechanics and Foundations. Third Edition. New Jersey. 2010.

Das, B.M. Principles of Geotechnical Engineering. Seventh Edition. Connecticut. 2010.

Das, B.M. Advanced Soil Mechanics. Third Edition. New York. 2008.

Kalinski, M.E Soil Mechanics Lab Manual. 2nd Edition. New Jersey. 2011

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