Geotechnical Site Exploration in the Year 2012 and Beyond

Paul W. Mayne, PhD, P.E.Georgia Institute of Technology

10 May 2012

16th Nordic Geotechnical MeetingCopenhagen

Purposes: Geotechnical Site Investigation

A must prior to all geotechnical projects

Determine geostratigraphy for site development

Information for construction and foundation selection

Collect geotechnical data for parameter evaluation

Input to analytical models and numerical FEM

Minimize surprises during construction 

Mitigate potential for legal involvement

Geotechnical Site Characterization in 2012 State‐of‐the‐Art (SOA)  = What we CAN do State‐of‐the‐Practice (SOP)  = what we ARE doing Brief remarks on International Geotechnical Experimentation Sites (IGES) Geotech Education: overemphasis on lab Best Practices:.... small projects.... vs. medium  ..... vs. large‐projects This talk = short SOA to improve current SOP

Mayne ≠ SOB

INDICES Geologic Origin Age, AG

Grain Sizes, D50

Mineralogy Plasticity, PI Shape (fractals) Sphericity, Sph Roundness, Rn

Angularity, Ang

Packing limits: emax and emin

Specific Surface, SS Particle characteristics for DEM (crushing strength, modulus, roughness, friction)

STATE Void Ratio, e0 Unit Weight, T Relative Density, DR

State Parameter,  Vertical Stress, vo

Hydrostatic Pressure, uo Yield Stress Ratio, YSR Saturation, S (%) Geostatic K0 = ho’/vo’ Stiffness, G0 = Gmax

State Parameter, ψ Degree of cementation Fabric and void index, Ivo Continuity (intact or fissured) 

Z

Zw

Soil Element A

Initial Conditions

CONDUCTIVITY Hydraulic:  kv, kh Thermal:  ke Electrical:  Chemical:  Df Transmissivity, Tm Permittivity, Pm

STIFFNESS Stiffness:  G0 = Gmax Shear Modulus, G' and Gu Elastic Modulus, E' and Eu Bulk Modulus, K’ Constrained Modulus, D’ Tensile Stiffness, KT Poisson’s Ratio,  Effects of Anisotropy (Gvh/Ghh) Nonlinearity (G/Gmax vs s) Subgrade Modulus, ks Spring Constants, kz, kx, k, kθ

COMPRESSIBILITY Recompression index, Cr Yield Stress, y' (and YSR) Preconsolidation, p’ (and OCR) Coefficient of Consolidation, cv Virgin Compression index, Cc Swelling index, Cs

STRENGTH Drained and Undrained, max

Peak (su, c’, ’) Post‐peak, ' Remolded strength Softened or critical state, su (rem) Residual (cr’, r’) Cyclic Behavior (cyc/vo')

RHEOLOGICAL Strain rate, t Time since consolidation (T) Coef. secondary compression, C Creep rate, R Time to failure, tf

Geotechnical Parameters

Jaksa (2005)

“...when you can measure what you are 

speaking about and express it in numbers, 

you know something about it; but when 

you cannot express it in numbers, your 

knowledge is of a meager and 

unsatisfactory kind"    Lord Kelvin (1883)

US National Geotechnical Experimentation Sites (NGES)

ASCE GeotechnicalSpecial Publication (GSP) No. 93 (2000)

Established in USA jointly by:

National Science Foundation (NSF) 

Federal Highway Administration (FHWA)

ASCE Geo‐Institute

6 NGES in continental USA

NGES: Texas A&M Sand SiteUS National Geotechnical Test Site(Briaud & Gibbens, 1999;  Briaud, 2007)

 UpperPleistocene Clean Sands (SP)

 silty Sands (SP‐SM)

  Silty to Clayey Sands (SC ‐ SM)

 Hard Eocene Clay Shale

0 10 20

Tip Resistance, qt (MPa)

0 500 1000 1500

Limit Pressure, PL (kPa)

0

1

2

3

4

5

6

7

8

9

10

11

12

0 10 20 30 40 50 60 70

SPT‐N value, N60 (bpf)De

pth (m

eters) 

0 10 20 30 40 50

DMT Pressures (bars)

p0

p1

0 100 200 300 400

Velocity, Vs (m/s)

Crosshole 2‐1

CHTDMT

CPT

SPT

PMT

NGES:  Opelika, AlabamaPiedmont residual fine sandy silts(Vinson and Brown, 1997;  Mayne & Brown, 2003)

LAB TESTING Grain size Hydrometer Plasticity indices Unit weights Triaxial shear (CIUC, CIDC) Direct shear, UU, and UC Fixed wall permeameter Flex‐wall permeability Resonant column tests One‐dim consolidation

IN‐SITU TESTING and GEOPHYSICS Standard penetration tests (SPT) Full‐displacement  pressuremeter (FDPMT)Menard pre‐bored pressuremeter (PMT) Flat plate dilatometer tests (DMT) Cone penetration tests (CPT) Piezocone tests with dissipations (CPTù) Seismic dilatometer tests (SDMT) Dual element piezocones (CPTu1u2) Resistivity cones (RCPTu) Seismic piezocones (SCPTu) Dielectric cones (DCPTu) Borehole shear tests (IBST) Geophysical crosshole tests (CHT) Spectral analysis of surface waves (SASW) Torque measurements following SPT Penetration rate effects studies Frequent interval  Vs profiling Surface resistivity surveys

FULL‐SCALE LOAD TESTS Drilled shaft foundations Axial tests on drilled shafts Lateral tests on drilled shafts Time and construction effects studies Driven pipe piles at varied rates De Waal piles Lateral loading testing of pile groups Shafts with self‐compacting concrete

Opelika NGES, Alabama ‐ Piedmont Residuum

Geotechnical Experimentation Sites

Volumes 1 and 2 (2003)           Volumes 3 and 4 (2007)

Todate:  68 International Test Sites

Holmen Sand Site, Norway  (Lunne, et al. 2003)

NGI:  1956 to 2012= 56 years testing

International Geotechnical Test Sites Each site required decades of study

Years worth of laboratory tests Many types of field testing Considerable amount of funds needed Backfigured soil engineering parameters from full-scale load tests Not have enough time ! Conclusion: Need multiple measurements

UDtube

CasedBoreholes Dynamic 

PenetrationSPT:  N60

'DR

Vane Shear (VST):  suv = shear strengthSt = sensitivity

CrossholeVs, Vp

Gmax

FIRMCLAY

DENSESAND

CONVENTIONAL DRILLING 

& SAMPLING

Drop Hammer

Oscilloscope

Pressuremeter (PMT)P0 = lateral stress G’ = shear modulussuPMT = shear strengthPL  = limit pressure

SOILS LABORATORY 

TX = triaxial shearCS = consolidationRC = resonant columnPM = permeameter

TX      CS      RC     PM 

Pumpingkvh

SievesHyd

Tv

Grain size analysesHydrometerWater content by ovenLiquid limit cupElectron microscopyPlastic limit threadFall cone devicePocket penetrometerTorvaneUnconfined compressionMiniature vaneDigital image analysis

Mechanical oedometerConsolidometerConstant rate of shear (CRS)Falling‐head permeameterConstant‐head permeameterFlow permeameterDirect shear boxX‐ray diffractionRing shearUnconsolidated undrained TxSimple shearDirectional shear cell

Triaxial apparatus (iso‐consols, CIUC, CKoUC, CAUC, CIUE, CAUE, CKoUE, stress path, CIDC, CKoDC, CIDE, CKoDE, constant P’)Plane strain apparatus (PSC, PSE)True triaxial (cuboidal)Hollow cylinderTorsional ShearResonant Column Test deviceNon‐resonant columnBender elements

Ppwn

CupOed

FallCone

Vst

DSB

DSS

RSPermeameters

Consolidometers

UC TTx PSC   PSE

DSC

HC   RCT

Iso Consol

CIUCCIDC

CKoUCCKoDC

CKoUECKoDE

CIUECIDE

BE

Pan

Geotechnical Laboratory Testing Devices

Evolution of Geotechnical Site CharacterizationModified after Lacasse (1985)

Geotechnical Methods for Site Investigation

Soils Laboratory        In‐Situ Testing            Geophysics

Lab Rat            Field Mouse        Fruit Bat

Field mouse withball penetrometer

"Typical" Intro Undergrad Geotechnical Textbook

• Soil is a 3‐phase material 1 0• Grain size distribution 1 1• Atterberg limits 1 1• Proctor compaction 1 1• Site investigation    0.5 0• Overburden stresses 1 0• Permeability 1 1• Consolidation theory 2 1• Stress‐strain behavior of soils  2 1• Triaxial testing and strength 2 1• Bearing capacity 2 0• Footing settlements 0.5 0

Table of Content Lectures Labs

OVEREMPHASIS ON LAB

Laboratory Soils Testing Limited Number (discrete points) Long Duration for Completion Expensive (Time is Money) Cost per specimen:

• Oedometer = $500 (2 weeks)• Automated Consolidation = $700 (2‐3 days)• CIUC Triaxial = $500  (2 to 3 days)• CK0UC Triaxial = $1200 ea (5 days)• Resonant Column= $2000 ea (1 week)• Permeability = $600 (1 to 2 weeks)

Large Projects

Swedish Landslides Finnish Railway System

Offshore Platforms, NorwayStorebælt Link, Denmark

Consolidation Data ‐ Burswood, Australia(courtesy of Mark Randolph, Univ. Western Australia)

0

2

4

6

8

10

12

14

16

18

20

0 50 100 150 200

Dep

th (m

)

Effective Stress, v' (kPa)

p' (lab)

vo'

0

2

4

6

8

10

12

14

16

18

20

0 1 2 3 4

Overconsolidation, OCR

erosion(OCD = 20 kPa) plus secondarycompression

n = 14

Port of Anchorage:  CIUC Triaxial Tests

0

100

200

300

400

0 100 200 300 400 500 600

q =

½

(1

- 3

) (

kPa)

p' = ½(1' + 3') (kPa)

POA Triaxial Summary OC Envelope

TB 9 (138 ft)

TP11 (155 ft)

TB15 (109 ft)

TB15 (124 ft)

TB15 (149 ft)

TB25 (69 ft)

TB25 (90 ft)

TB25 (190 ft)

TB28 (95 ft)

TB31 (126 ft)

TB31 (126 ft)

TB31 (126 ft)

TB39 (115 ft)

TB39 (160 ft)

TB47 (120 ft)

TB49 (100 ft)

TB49 (115 ft)

TB56 (115 ft)

Effective Strength Envelope ' = 27o

c' = 0

n = 18

Lab‐Based Site Characterization• Expensive and time‐consuming• Predominant approach in our textbooks• Only possible on large or critical projects• For 99% of geotechnics (small‐ to medium‐size projects, insufficient funding  +  inadequate amount of time  .......

• Therefore, as a last resort ... Overreliance on simple SPT N‐values Overuse of plasticity index correlations

Estimating Undrained Strength from Plasticity Index

0,0

0,1

0,2

0,3

0,4

0,5

0,6

0 10 20 30 40 50 60 70 80 90 100

Valu

e of

c/p

' rat

io

Plasticity Index, Ip (%)

Skempton (1957)

Raw Vane Data: c/p'  = 0.11 + 0.0037 PIn = 19;   r2 = 0.946:   SEY = 0.028

CLAY SITES: RioGosport GrangemouthFens KopingWaterview HertenShellhaven TilburyDrammen Manglerud

Estimating Undrained Strength from Plasticity IndexRaw Vane

Estimation of Friction Angle from Plasticity Index

HomeAppliances

Note:   Not to scale

TelegraphStove

Horse & Buggy

Sewing Machine

Casagrande Cup

Abacus

Split‐Spoon

OfficeEquipment

1902

HomeAppliances

Note:   Not to scale

Telephone Television

Refridgerator

Gas Automobile

Washer

Casagrande Cup

Slide Rule

Split‐Spoon

OfficeEquipment

1950

Note:   Not to scale

Split‐Spoon

Tablet

Liquid Limit

3‐d LED Televisionsmartphone

Refridgerator

Electric Automobile

Washer

HomeAppliances

OfficeEquipment2012

N

DR = relative densityT = unit weightLI = liquefaction index' = friction anglec' = cohesion intercepteo = void ratioqa = bearing capacityp' = preconsolidationVs = shear waveE' = Young's modulus = dilatancy angleqb = pile end bearingfs = pile skin friction

SAND

cu = undrained strengthT = unit weightIR = rigidity index' = friction angleOCR = overconsolidationK0 = lateral stress stateeo = void ratioVs = shear waveE' = Young's modulusCc = compression indexqb = pile end bearingfs = pile skin frictionk = permeabilityqa = bearing stress CLAY

Is One Number Enough???

Both Pictures from DFI European Foundations - Fall 2009

What the Public Sees and Our Image to Structural Engineers & Architects 

Geotech Site Investigation New Construction Equipment

Direct Push Borehole MethodsContinuous Push Sampling 

Sonic DrillingContinuous Sampling of Soil & Rock

ElectroVane Equipment torque and rotation measured downhole

Computerized DMTFlat Plate Dilatometer Systems

Computerized DMTFlat Plate Dilatometer Systems

p0p1VPVS

Menard Pressuremeter (PMT)Push‐in Pressuremeter (PiPMT)Self‐Boring Pressuremeter (SBPMT)Full‐Displacement Type (FDPMT)

Po, G, su or ', and PL

Specialty probes Vision Cone Resistivity Probes and Cone Conductivity Measurements Dielectric Piezocone Gamma and Nuclear

Hryciw (2005)

Full‐Flow Penetrometers• Plate • T‐bar • Ball penetrometer• Piezo‐ball

Randolph (2004); DeJong et al. (2010)

Applications: Very soft soils Offshore seabed Mine tailings

New Developments: Twitch TestingRandolph & Hope (2004); Randolph (2004)

DrainedUndrainedPartially‐drained

SPT

TxPT LPTVST

PMT

CPMT

DMT

SPLT

K0SB

SWS

HF

BST

TSC

FTSCPT

CPTu

RCPTu

SCPTu

SDMT

TBPTBPT

Full Flow PenetrometersSPTT

SCPMTù

SPT = Standard Penetration TestTxPT = Texas Penetration TestVST = Vane Shear TestPMT = Pressuremeter TestCPMT = Cone PressuremeterDMT = Dilatometer TestSPLT = Screw Plate Load TestISB = Iowa K0 Stepped BladeSWS = Swedish Weight SoundingHF = Hydraulic FractureBST = Borehole Shear Test

TSC = Total Stress Cell (spade cell)FTS = Freestand Torsional ShearPV   = PiezovaneMPT = Macintosh Probe TestCPT = Cone Penetration TestCPTu = Piezocone PenetrationRCPTu = Resistivity PiezoconeSCPTu = Seismic ConeSDMT = Seismic Flat DilatometerTBPT = T‐Bar Penetrometer TestBPT = Ball Penetrometer

PPT = Plate Penetration TestPLT = plate load testHPT = Helical Probe TestPBPT = piezoball penetration testRapSochs = Rapid soil characterization systemCPTù = piezodissipation testDMTà = Dilatometer with A‐reading dissipationsSPTT = Standard Penetration Test with TorqueLPT = Large Penetration TestDEPPT = Dual Element PiezoProbe TestSCPMTu = Seismic Piezocone Pressuremeter

PLTDEPPT

HPT

Field Geotechnical In‐Situ Testing Methods

PPT

MPT

PV PBPT

RapSochs

CPTù

DMTà

Manly BeachSydney, Australia

Cone Penetration Tests (CPT) ‐ Portsmouth, VA

0

20

40

60

80

100

120

140

0 100 200 300 400

Cone Tip Resistanceqt (tsf)

Dep

th (f

eet)

-10 0 10 20 30 40

Porewater Pressure u2 (tsf)

0 1 2 3 4

Sleeve Frictionfs (tsf)

qt

u2

fs

CPT• Current Phase Tranformer• Cross Product Team• Cellular Paging Teleservice• Chest Percussion Therapy• Crisis Planning Team• Consumer Protection Trends• Computer Placement Test• Current Procedural Terminolgy• Cost Per Treatment• Choroid Plexus Tumor• Cardiopulmonary Physical 

Therapy• Corrugated Plastic Tubing• Cumulative Price Threshold

• Certified Proctology Technologist• Cell Preparation Tube• Central Payment Tool• Cockpit Procedures Trainer• Cone Penetration Test• Color Picture Tube• Critical Pitting Temperature• Certified Phelbotomy Technician• Control Power Transformer• Cost Production Team• Channel Product Table• Conditional Probability Table• Command Post Terminal

Cone Penetrometers

• 10-cm2

• 15-cm2

• mechanical• electric• cabled• piezo-• electronic• seismic-• digital• wireless

Cone Penetrometers

33- 15- 10- 5- 1-cm22- 10- 15- 40-cm2

• US Navy XDP• Canadian FFCPT• German MARUM

100-cm2 Harpoon CPT

Mini-CPTs for Centrifuge0.5 cm2

Micro-Cone PenetrometersKim, Choi, Lee & Lee: Korea University

(GeoFlorida 2010)

FBG = Fibre Bragg Grating sensor

Cone Penetrometer Rigs

AutoCoson - Robotic CPTby A.P. van den Berg, Holland

PROD = Portable Remotely Operated Drill

by Benthic Geotech Australia

Cone Penetrometer Testing

Chinese CPT Equipmentwww.madeinchina.com

圆锥贯入试验

Interpretation Methods for In-Situ TestsEmpirical Analytical

Statistical Dislocation Theory

)/1(

2

'195.112

vo

t uqM

OCR

Interpretation Methods for In-Situ TestsFinite Elements Strain Path Method

Finite Differences Discrete Elements

Cone Penetrometer TestingHand-held electronic cone penetrometers

Rimik CP40

Measured Penetration Resistance

Excellent Repeatability

SpectrumScout SC 900

Eijkelcamp

Recent Economic Losses in PensionsNON SEQUITURBy Wiley Miller The NEW GeoRETIREMENT PLAN

Georgia Tech

Natural Clean Siliceous Sands

Georgia Tech

Friction Angle of Sands CIDC Triaxial Tests

1

2

3

4

5

6

0 5 10 15 20 25 30 35

Axial Strain, a (%)

Stre

ss R

atio

, 1'/ 3

'

DR = 82.6 %DR = 74.5 %DR = 59.3 %DR = 38.5 %DR = 22.3 %

1)'/'(1)'/'('sin

31

31

41.5º41.0º

38.8º

36.7º35.2º

33.7º cv'

P' = peak friction angle

Data on SaturatedQuartz Sand(Koerner, 1970)

Georgia Tech

Undisturbed vs. Reconstituted Sands• Reconstituted:  Artificial Air Pluviation Moist Tamped Water Sedimented Slurried Compacted Vibration

• Undisturbed:  Natural 1‐d Freezing (tubes or coring) Agar Injection

SPT    SCPTu

N60

Vs

fsub

qtEstimatedRelativeDensity, DR

UndisturbedFrozenSpecimens

YoungArtificialSpecimens

In‐Situ e0In‐place DRFabricOCAnisotropyStructureAge

EstimatedNC e0DR

dwn

Triaxial Testing

Interpreted Friction Angle:   Preparation Methods

AirPluviation

MoistTamped

WaterSedimentation

Slurry

Vibration

CompactionCoolantSystem

1‐dGroundFreezing

LiquidNitrogen(‐20º)Coring

Disturbed SoilAugeringRotary DrillTube SampleDrive Sample

CLASS A METHOD METHOD B

Georgia Tech

Silty Sand (Høeg, Dyvik, & Sandækken, 2000)

0

100

200

300

400

500

600

0 5 10 15 20 25

Axial Strain, a (%)

Shea

r Str

ess,

1 -

3)

Undisturbed

Pluviated

Slurried

e0 (consolidated) = 0.71 vc' = 500 kPa; hc' = 250 kPa

SOA-1: 17 ICSMGE - Egypt 2009

Silty Sand (Høeg, Dyvik, & Sandbækken, 2000)

Undrained Behaviour: Undisturbed vs. Reconstituted Sands

-200

-100

0

100

200

0 5 10 15 20 25

Axial Strain, a (%)

Pore

wat

er P

ress

ure,

u

(kPa

)

UndisturbedPluviated

Slurried

CAUC Triaxial Tests

Bad News

SOA-1: 17 ICSMGE - Egypt 2009

Data from Høeg, Dyvik, & Sandækken (ASCE JGGE, 2000)

Undrained Behavior: Undisturbed vs. Reconstituted Sands

0

200

400

600

800

1000

0 200 400 600 800 1000 1200

Shea

r Str

ess,

q =

0.5

(1

-3)

Average Stress, p' = 0.5(1' + 3')

Undisturbed

Pluviated

Slurried

sin'

' = 36.5ºc' = 0

Good News

Undisturbed vs Reconstituted SandDrained Triaxial Compression Tests (Mimura 2003)

SOA‐1: 17th ICSMGE 2009 ‐ Alexandria

0

100

200

300

400

0 2 4 6 8 10 12 14 16

Axial Strain, a (%)

Dev

iato

r Str

ess

= (

1 -

3) k

Pa

Reconstituted (air pluviation)

Undisturbed (1-d freezing)

Edo River Sand (Mimura, 2003)CIDC Triaxial TestsDepth = 3.7 to 4.0 m c ' = 49 kPa

D 50 = 0.29 mm UC = 2.2e 0 = 1.04 G s = 2.68e max = 1.227 e min = 0.812D R = 45%

Undisturbed vs Reconstituted SandDrained Triaxial Compression Tests (Mimura 2003)

SOA‐1: 17th ICSMGE 2009 ‐ Alexandria

0

50

100

150

0 50 100 150 200

Ave Stress, p' = 0.5(1' + 3') (kPa)

Shea

r Str

ess,

s =

0.5

( 1 -

3)

(kPa

)

Undisturbed

Pluviated

(q/p')f

' = 41.4o

c' = 0 kPa

sin' = 0.661

Edo River Sand

Good News

30

35

40

45

50

0 50 100 150 200 250 300

Normalized Tip Resistance, qt1 = (qt/atm)/(vo'/atm)0.5

Tria

xial

Fric

tion

Ang

le,

' (de

g.)

Yodo River Natori RiverTone River Edo RiverMildred Lake MasseyKidd J-PitLL-Dam HighmontHolmen W. KowloonGioia Tauro K&M'90

)/'()/q(

log116.17(deg)'atmvo

atmt

Sands with mica, smectite, illite, and other minerals

DuncanDam

DuncanDam

HiberniaHibernia

Friction Angle of Quartz‐Silica Sands from CPTClean silica toquartz sands

Sandbox

Why was the sand wet ?

Because the sea weed

Friction Angle ' from CPTU for clays & silts

1

10

100

20 25 30 35 40 45

' (degrees)Res

ista

nce

Num

ber,

Nm

Bq

0.1 0.2 0.4 0.6 0.8 1.0

Bq = 0 Notes for NTNU Method:

1. Define Cone Resistance Number: Nm = (qt-vo)/(vo'+a')

2. Attraction: a' = c'cot' where ' = effective friction angle andc' = effective cohesion intercept.

3. For case where a' = c' = 0: NM = Q = (qt-vo)/vo'

4. Define Porewater Pressure Parameter: Bq = u2/(qt-vo)

5. Approximate Expression Given for Ranges: 0.1<Bq < 1.0and 20º < ' < 45º

Robertson & Campanella (1983) for Sands

Approx: ' ≈ 29.5º Bq0.121[0.256 + 0.336·Bq + logQ ]

NTH: (Senneset, et al 1989; Sandven, et al. 1995) 

Qt

6. Plastification angle, p = 0

CPTu Sounding, Sandpoint, Idaho 

0

10

20

30

40

50

60

70

80

0 2 4 6 8 10

Tip Resistance, qt (MPa)D

epth

(met

ers)

0 50 100 150

Sleeve Friction, fs (kPa)0 1 2 3

Pore Pressure, u2 (MPa)

Evaluating ’ at Sandpoint, Idaho (NTH Method)

0

500

1000

1500

2000

2500

3000

0 100 200 300 400 500 600

Effective Vertical Stress, vo' (kPa)

Net

Con

e R

esis

tanc

e, q

t -

vo (k

Pa)

Nm = Q = 4.2

Evaluation of ’ at Sandpoint, Idaho (NTH Method)

0

500

1000

1500

2000

2500

0 1000 2000 3000

Net Cone Resistance, qt - vo (kPa)

Exce

ss P

ress

ure,

u2 -

u0 (

kPa)

Bq = 0.75

Evaluation of ’ by CPTu (NTH Method)

1

10

100

20 30 40 50' (degrees)

Resist

ance

Num

ber,

Nm

Bq = 0.1 0.2 0.4 0.6 0.8 1.0

Bq = (u2-u0)/(qt-vo)

NM = (qt-vo)/vo'

= 32.30    

Triaxial Data ‐ Sandpoint IdahoMaximum q Criterion - TRIAXIAL DATA SUMMARY - IDAHO

0

50

100

150

200

250

0 100 200 300 400 500

p' = (1' + 3')/2

q =

( 1'-

3')/2

' = 32.3 deg

c' = 0 kPa

Triaxial Data from Sandpoint, Idaho(courtesy of Dean Harris, CH2M‐Hill)

q = 0.546 p'r2 = 0.996

n = 30

0

100

200

300

0 100 200 300 400 500

q =

(

1'- 3

')/2

(k

Pa)

p' = (1' + 3')/2 (kPa)

Max. (q/p') ratio criterion - IDAHO Triaxial Data

' = 33.1 deg

c' = 0 kPa

Georgia Tech

Evaluation of OCR in Clays by Piezocone TestsHybrid Cavity Expansion‐Critical State Model

Soil Properties:M = 6 sin’/(3‐sin’)

’ = effective friction angle

Cc = compression index

Cs = swelling index

= 1 – Cs/CcIR = G/su = Rigidity Index

G = shear modulus

su = undrained shear strength = (M/2)(OCR/2)vo'

’, Cc, Cs

Hybrid SCE‐CSSM Theory)/1(

234

2

1)1)(ln('/))((2

R

vovotM

IqOCR

For = 1

)]ln(1[)('

31

R

votP IM

q

’ = 30º → M = 1.2IR = 100

)(33.0' votP q First‐Order Approximation

Profiling Yield Stress in Clays by Cone Penetrometer

10

100

1000

10000

100 1000 10000Net Cone Resistance, qt - vo (kPa)

Yiel

d St

ress

, p

' (k

Pa)

Fissured

Intact Clays: p' = 0.33 (qt - vo) qt

Calcareous

Intact

9 Swedish clays (Larsson & Mulabdic 1991)

22 Canadian Clays (Demers & Leroueil 2002)

Pisa clay (Jamiolkowski and Pepe 2001)

Clays: Lateral Stress Coefficient, K0

0

1

2

3

4

1 10 100

Late

ral S

tress

Coe

ffici

ent,

K 0

Overconsolidation Ratio, OCR

BothkennarBrent CrossMadingleyOnsoyTarantoPorto TolleDrammenMassenaHamiltonBandas AbbasMontalto403020DrammenCowden TillSaint AlbanCanons ParkGrangemouthStrong PitLower 232rd StBritish Library

SBP = Self-Boring PressuremeterTSC = Total Stress Cell

'sin0 )'sin1( OCRK

= '

Sel

f-Bor

ing

Pre

ssur

emet

erTo

tal S

tress

Cel

l

Sands: Lateral Stress Coefficient, K0

0

1

2

3

4

1 10 100

Overconsolidation Ratio, OCR

Late

ral S

tres

s C

oeffi

cien

t, K

0Triaxial: n = 121Oedometer: n = 307Chambers: n=597Po River: n = 28Stockholm: n = 33Holmen: n = 2Thanet Sands: n =20304050

0

= ' (deg)

'sin0 )'sin1( OCRK

Kp

Georgia Tech

Calibration Chamber Testing Mineralogy Grain Distribution Angularity Index Parameters Age Origin Dry or Saturated Stress History hc'

vc'

DR

eo

T

qc and fs

p0 and p1

N60

PL

ArtificialSandDeposit

BC1, BC2, BC3BC4, and BC5

CPT Calibration Chamber DatabaseAnisotropically-Consolidated Sands

10

100

1000

10 100 1000

ho' = 0.30 qc0.22vo'0.69 OCR0.27

App

lied

Late

ral St

ress

, h

c' (kP

a)NC Sands

1 < OCR < 4

4 < OCR < 6

6 < OCR < 10

10 < OCR < 15

Note: stresses in kPa

26 Seriesn = 636

Earlston Edgar Erksak Frankston Hilton Mines Hokksund Hostun Lanchester Leighton Buzzard LB #2 Light Castle Sand Oosterschelde Lone Star Monterey #0 Montery #60 Ottawa Reid‐Bedford South Oakleigh Ticino Ticino #2 Toyoura Washed Mortar Sand

SAND SERIES

CPT Method for Ko and OCR in Silica Sands

Regression from CPT Calibration Chamber Database  (n = 705 data points; r2 = 0.871):         Ko = 0.192(qt/atm)0.22 (vo’/atm)‐0.31 OCR 0.27

Relationship between Ko and OCR a priori:           Ko = (1‐sin’) OCRsin ’

Evaluate Effective Stress Friction Angle:           ’ = 17.6+11log(qt1) 

where:  qt1 = (qt/atm)/(vo’/atm)0.5

CPT Method for Clean Quartz‐Silica Sands Combine Ko equations

Overconsolidation Ratio, OCR:

where KoNC = 1 ‐ sin’ = 1 ‐

Tip Stress in MPa and vo’ in kPa

Effective Friction Angle from CPT

27.01

31.0

22.0

)'(33.1

vo

t

oNC

qK

OCR

Rhymes with Orange  by Hilary Price    "THE LAB"

CPT Methodology in Clean Quartz Sands Overconsolidation Ratio, OCR:

Assume characteristic value:  ’ = 35 Sands:   qt ≈  (qt ‐ vo)    Simplified:

Preconsolidation Stress:     

27.0'sin1

31.0

22.0

)/'()/(

)'sin1(192.0

atmvo

atmtqOCR

''

)/'(8.13]/)[(

02.1

22.0

vo

p

atmvo

atmvotqOCR

7.0)(3.0)(' votp qkPa

CPT methodology for all soil types Reduced expression from SCE‐CSSM model for clays:

Simplified regression equations from chamber tests data on clean sands:  

General form: 

Exponent m' varies:  clay m' = 1.0;  sand m' = 0.72 

7.0)(3.0)(' votp qkPa

)(33.0' votp q

')(33.0)(' mvotp qkPa

Generalized Pc' Method for CPTs in all soil types

10

100

1000

10000

10 100 1000 10000 100000Net Cone Resistance, qt - vo (kPa)

App

aren

t Yie

ld S

tres

s,

p' (

kPa)

General Trend:p' = 0.33(qt-vo)m

Intact clays: m = 1.00 Organic clays: m = 0.90 Silts: m = 0.85 Silty Sands: m = 0.80Clean Sands: m = 0.72

'1' )100/()(33.0' matm

mvotp q Amherst, MA

Washington DCAtchafalyala LABoston Blue Clay, MAColebrook Road BCEmpire LAEvanston ILSF Bay Mud, CALower 232rd St BCPort Huron MISt. Alban, QuebecNRCC, OntarioYorktown VASt.Jean Vianney, QESurry, VABaton Rouge, LAStrong Pit, BCOttawa STP, OntarioVarennes, QETaranto, ItalyBrent Cross UKMadingley UKSurrey UKCanons Park UKCretaceous DCBothkennarTrendStockholm SandPo River SandHolmen SandNorth Sea SandHibernia SandTrend 2Opelika Sandy SiltTrend 3Rio de JaneiroAtlanta Silty SandPentre SiltDutch PeatEuripides Silty SandTrend 4Trend

m'

Stockholm, Sweden (Dahlberg, ESOPT 1974)

• Original 24 m natural sand

• 16 m of sand quarried for construction

• Calculated OCR = (v+vo’)/vo’ from excavated quantity

• SPT, CPT, in-place density tests, PMT, triaxials

• Screw-Plate Load Test (SPLT) or field compressiometer to obtain in-situ p’

Stockholm Sand, SwedenStockholm Sand, Sweden

Bedrock

8 meters remained

16 meters quarried

Preloaded Natural Sand Deposit

D50 (av) = 0.9 mm

DR (av) = 60 %qcqc

Stockholm Sand, Sweden

0

1

2

3

4

5

6

7

8

0 50 100 150 200 250

Dep

th (m

eters)

Cone Tip Stress, qt (bars)

CPT 12

CPT 03

CPT 11

CPT 06

0

1

2

3

4

5

6

7

8

30 35 40 45 50 55

Friction Angle, ' (deg)

DrainedTriaxialTests

CPT Eqn

Stockholm Sand

0

1

2

3

4

5

6

7

8

0 1 2 3 4 5 6 7 8D

epth

(met

ers)Preconsolidation Stress, p' (kg/cm2)

Screw Plate Tests(interpretation by Prof. Dahlberg)

Calculated from quarried overburden

CPT Evaluation:p' = 0.33 qtnet

0.75

(stresses in kPa)vo'

Stockholm Sand

0

1

2

3

4

5

6

7

8

0 5 10 15 20 25D

epth

(m)Overconsolidation Ratio, OCR

Calculated from quarried overburden:OCR = (v'+vo')/vo'

CPT Evaluation:

OCR = 0.33 (qtnet)0.75 /vo'

(stresses in kPa)

Yield stress in soils from CPT22 )log22.1()log47.3(: FQIindexmaterialCPT c

Bernie Bott’sEvery Flavor Bean

Field Geophysics ‐Mechanical Wave Methods

SRFS = Surface Refraction SurveySFLS = Surface Reflection SurveySASW = Spectral Analysis of Surface WavesMASW = Modal Analysis (Rayleigh Waves)CSW = Continuous Surface WavesPSW = Passive Surface Wave TestingReMi =  Reflection MicroSeisSLP = Suspension Logger ProblngCHT = Crosshole TestRCHT = Rotary CrossholeDHT = Downhole TestUHT = Uphole TestSCPTu = Seismic Piezocone TestSDMT = Seismic Flat Dilatometer TestBTSD = Borehole Torsional Shear Device

Seismograph+ Source

Receivers Geophones

SFLS SFRS

RotarySource

VerticalSource

TorsionalSource

Cased Boreholes

VsHV

VsHH

VsHH

VsHH

Oscilloscope+ Source

Vp

VsVH

SpectralAnalyzer+ Source

SASW MASW CSW PSW ReMi

Rayleigh Wave Methods

CHT

RCHT

BTSD SLP

VsVV

high frequencies

medium frequencycontent

lowfrequencycontent

VsRW

DHT

UHT

Cone Penetration Tests (CPT)Piezocone Penetration Test (CPTu)Seismic Piezocone Penetration Testing (SCPTu)

D 7400

SCPTu Sounding – Memphis, TN

0

5

10

15

20

25

30

35

0 10 20 30 40

Dep

th (m

)

qt (MPa)

0

5

10

15

20

25

30

35

0 100 200 300

fs (kPa)

0

5

10

15

20

25

30

35

0 1000 2000 3000

u2 (kPa)

0

5

10

15

20

25

30

35

0 100 200 300 400

Vs (m/sec) d = 35.7 mm

qt

fs

u2

Vs

Seismic Piezocone Test in New Orleans East

Economy of S‐Wave Velocity Measurements

Cost to Profile Vs to 30 m depth:

Crosshole $ 15,000 to $18,000

Downhole $  8,000 to $ 9,000

SASW / MASW $  3,000 to $4,500

ReMi survey      $  2,500 to $3,000

*SCPTu $  1,500 to $2,000 

*includes 5 readings: qt, fs, ub, t50, Vs

100-m SCPTu in Fraser River, British Columbia

V

Qsu =  (fp dAs)

Qt =  Qs + Qb

Qbu = qb Ab

} fp = fctn ( fs and u)

Clays:  qb = qt ‐ ub  Sands:  qb 0.1 qt

RIGID PILE RESPONSERandolph Solution

qb = unit end bearing

unit side friction, fp

CPT

qt

ub

fs

Vs →  Emax = 2 t Vs2 (1+)

Top Displacement, wt

])/(1[ 3.0max tut

tt QQEd

IQw

Load Transfer

)]1)(/(5ln[)/(

)1(11

1

2 vdLdL

I

21

IQQ

t

b}

PILE

Summary Seismic Piezocone TestsOpelika NGES, Alabama

Axial Load Tests: Opelika, Alabama (Brown 2002)

Drilled Shaft (cased method)d = 0.91 mL = 11.0 m

Qt (total)

Qs shaft

Qb base

104

www.hindu.com www2.dot.ca.gov

www.statnamiceurope.com

Reaction FrameDead Weight

Osterberg CellStatnamic Load Testwww.fhwa.dot.gov

Pile Load Tests

O-Cell Elastic Solution

01

1

111o1s

1

rL2

wrGP

P = applied forceL = pile lengthro = pile radiusEp = pile modulusGs = soil side shear modulus = Poisson's ratio of soil

2o

2

222o2s

2

rL2

)1(4

wrGP

Rigid pile under compression loading

Rigid pile shaft under upward loadingupper

segment

lower segment

O-Cell

w = pile displacementl = Ep/GsL = soil-pile stiffness ratio = Gs2/Gsb (Note: floating pile: = 1)Gsb = soil modulus below pile base/toe = ln(rm/ro) = soil zone of influencerm = L{0.25 + [2.5 (1-) – 0.25]}

P1 = P2

Diameterd1 = 2r1Length

L1

Diameterd2 = 2r2Length

L2

Seismic Piezocone Tests Calgary Medical Center, Alberta

0

2

4

6

8

10

12

14

16

18

20

22

24

0 10000 20000 Tip Stress, qt (kPa)

Dep

th (met

ers)

0 200 400 600Sleeve Friction, fS (kPa)

-500 0 500 1000Porewater, u2 (kPa)

u2

uo-hydro

0 100 200 300 400 500 600Shear Wave, VS (m/s)

DrilledShaft O-CellLoad Test

Dimensionsd = 1.4 mL = 14 m

O-Cell 10m

14m

Evaluation of Calgary O-Cell Shaft Response by Seismic Piezocone Tests

-40-30-20-10

01020304050607080

0 1000 2000 3000 4000 5000 6000 7000 8000

O-Cell Load, Q (kN)

Displac

emen

t, w

(mm)

Loading Down Measured Below O-CellMeasured Above O-Cell Loading Up

d = 1.4 m

L = 10 m

L = 4 m

Frequent-interval Vs profiling Charleston, South Carolina

0 0.1 0.2 0.3 0.4 0.5

0

5

10

15

20

25

30

Time (sec)

Dep

th (m

) GT AutoSeis

SDMTà = Seismic Dilatometer TestVenice

Frequent‐Interval SCPTu, Aiken, SC

02468

1012141618202224262830323436384042444648

0 10 20 30 40 50

Dep

th (m

)

qT (MPa)Cone Resistance

-500 0 500 1000 1500 2000

u2 (kPa)Porewater Pressure

0 1 2 3 4 5 6

FR (%)Friction Ratio

0 100 200 300 400 500 600 700 800

Vs (m/s)Shear Wave Velocity

Roto CH4 P-I

Continuous Vs profilingto 45 meters

GT AutoSeis

0

10

20

30

40

m

0 100 200 300 ms

Continuous‐Interval Seismic Piezocone, BC

0

5

10

15

20

25

30

35

40

45

50

0 10 20 30

Dep

th (m

)

qt (kPa)

0

5

10

15

20

25

30

35

40

45

50

0 100 200

fs (kPa)

0

5

10

15

20

25

30

35

40

45

50

0 1000 2000

u2 (kPa)

0

5

10

15

20

25

30

35

40

45

50

0 100 200 300 400 500

Vs (m/sec)

Freq. Domain

ConventionalDHT

113

Continuous‐interval SCPTu at Norfolk, VAContinuous‐interval SCPTu at Norfolk, VA

NorfolkFormation(Holocene)

YorktownFormation(Miocene)

CPT User = "Conehead"

ConeHeads arefrom ...FRANCE

No Confirmationby the French

If you come home from the garbage dump with more than you went in with.......

....You might just be a redneck

Comedian defines "redneck" as "a person who gloriously lacks of sophistication"

Geotechnical Parody - - -You might just be a ConeHead

Parody on "You might just be a redneck"

If you believe that the best means to evaluate N60 is from CPT data.......

...then you just might be a ConeHead

Geotech Parody on "You might just be a redneck"

If you think our professional image may be improved using CPT rather than SPT

....then you just might be a ConeHead

Geotech Parody on "You might just be a redneck"

If you believe in..... Fast

Economical

Efficient

Continuous

Collection of digital data

from multiple readings

Logged directly to your computer

qt

u2

fs

VstGmaxE’’’OCRPc'kvh

suK0

}

t50

...then you just might be a ConeHead

If you would like more high tech used in our geotechnical practice......

....then you just might just be a ConeHead

If you think the Washington Monument is a tribute to cone penetration testing

....then you just might just be a ConeHead

Geotech Parody on "You might just be a redneck"

High‐Frequency Geophysics

Electromagnetic methods

(dielectric, resistivity, conductivity)

Ground penetrating radar

Electromagnetic conductivity

Electrical resistivity

Permittivity

Magnetometer surveys

15 m squareSouth Carolina

15 m square

PWO4‐49U

PWO4‐49UNew Orleans 99/100 surveys

1/100 surveys

MASW Arrays for MappingSubsurface Heterogeneity

Surface Distance (m)Shear Wave, Vs (m/s)

Depth (m

)

FIRMCLAY

DIRECT‐PUSH TECHNOLOGY

SDMTàVpVstflexp1p0

NON‐INVASIVE GEOPHYSICS

(Resistivity, Radar, Conductivity)

SCPTùVs  fst50u2qt

DENSESAND

loosesand

softclay

Types of Piezo‐Dissipation Responses 

7

Piezo-Dissipations at Evergreen, North Carolina

0

100

200

300

400

500

600

700

800

900

1000

0.01 0.1 1 10 100

Time (minutes)

Mea

sure

d u 2

(k

Pa)

02D at 13.8 feet (4.2 m)

01D at 24.9 feet (7.6 m)

07D at 27 feet (8.3 m)

08D at 18 feet (5.5 m)

MONOTONIC

DILATORY

SCPTù at Atlanta Airport Runway 5

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

0 5 10 15 20

qT (MPa)

Dep

th (m

)

0 200 400 600

fs (kPa)

-100 0 100 200 300

ub (kPa)0 100 200 300 400

Vs (m/s)t50 (seconds)1 10 100 1000

Five Independent Readings of Soil Behavior:   qt, fs, ub, t50, Vs

Danish Sonic Multi‐Sensor Probe(DSMSP) for hard ground, glacial till, and cemented geomaterials

Enlargement

Hydraulic Rig

SquareRods

Square Wedge Penetrometer

Tip Stress, qd

Lateral Stress, L

Resistivity,

Shear WaveVelocity, VS

Dynamic Driver Module (Impact, Sonic)

DSMSPdesign

will provide4 continuousreadings with

depth

Summary and ConclusionsGeotechnical Site Exploration in 2012 and Beyond

Best practice:  drilling + sampling + lab testing  + in‐situ + geophysics   =  $$$$  +  Only possible on large projects Small‐ to medium‐size projects ‐ stop relying so much on single‐numbered tests (i.e. SPT‐N) and plasticity index correlations Routine explorations:

• Quick mapping by non‐invasive geophysics• Multi‐channel SCPTu or SDMT

Conetec ‐ Vancouver, BC

US Dept of Energy ‐ SRS, SC

S&ME ‐ Charleston, SC

thanks

Organizing Committee 16th NGM