5/13/2013

1

Geotechnics 2013 in the Atlantic Piedmont Province

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

07 May 2013

The 16th Annual Sowers LectureGeorge F. Sowers(1921 – 1996)

Professor, Civil and Environmental                     Engineering, Georgia Tech

Senior Consultant, Law Engineering Testing Company (LETCO→  MACTEC →  AMEC)

International authority:

• earth and rockfill dams• foundations• soil mechanics• engineering geology• karst limestone

• geotechnical engineering• ports and harbors• stability• residual soils• common sense

George F. Sowers 1942 – BSCE from Case Institute, Ohio

Hydraulics Engineer for Tennessee Valley Authority 

US Navy from 1944 – 1946 in electronics

Married Frances Lott and together they had 4 children:  Carol, Janet, Nancy, and George Jr.

Attended Harvard University with classes under:

• Karl Terzaghi

• Arthur Casagrande

• Rec’d MS in 1947 

Moved to Atlanta to begin his professional career

George F. Sowers Law Engineering: 

• 1955 – Vice President• 1967 – Senior VP• 1971 – Chairman of Board• 1980 – Senior Consultant

GT: 1953 – Professor CE;  1965 – Regents Professor

Member:  ASCE, ISSMGE, EERI, NSPE, ASTM, SSA, AEG

Author of over 150 papers and 8 Books:

• Introduction to Soil Mechanics & Foundations (MacMillan: 1951, 1961, 1970, 1979)                         – English, Spanish, Chinese

• Building on Sinkholes (ASCE 1996)

Awards ‐ George F. Sowers

Engineer of the Year 1973 – GSPE

Herschel Prize 1976 – Boston SCE

ASCE Middlebrooks Award 1977

ASCE Terzaghi Lecture 1979

ASCE Martin Kapp Lecture 1985

Brooks Award in 1990

ASCE Middlebrooks Award 1994

Elected to National Academy of Engineering 1994

ASCE Terzaghi Award 1995

George F. Sowers Quotes:

Reston Dam, VA CIA, McLean, Virginia Pennfield PA

“An earth dam is likea beautiful woman…….”

“Its one dam projectafter another” “Working at the 

CIA is a huge PIA”

“Using drilled shafts vs. driven pilings in karst is like 

the difference of being hung or being shot. Either 

way you are screwed”

Concerns after Teton Dam Failed High K0 stresses on basement walls Karst Limestone

5/13/2013

2

LETCO in Thule, Greenland 1984 1952Magnetic North Pole 1984

LETCO in Thule, GreenlandSatellite Tracking Antenna for Ford Aerospace

Jefferson Accelerator ‐ JLAB(CEBAF) – Newport News, Virginia

Nuclear physics experimental hall for study of hadrons and quarks 1800 electromagnets in an elliptical ring for high‐energy beam Tolerate only 3 mm differential between adjacent units per month

Jefferson Accelerator ‐ JLAB(CEBAF) – Newport News, Virginia Embankment

Over Tunnel

Minimize primaryconsolidation 

settlements and long‐term creep

Jefferson Accelerator ‐ JLAB(CEBAF) – Newport News, Virginia

YORKTOWNFORMATION

GT Geotechnical Group"Old Highway Lab"

5/13/2013

3

Georgia Tech Geotechnical EngineeringMike Jamiolkowski(2008 Sowers Lecture)

Georgia Tech Geotechs Co‐Taught CE 6159 Rock Mechanics (1991, 1995) Textbook:  Goodman, R.E. (Dick gave 3rd Sowers Lecture) Classes in Old Highway Lab Tour of rock tunnels at Duke Power Energy Station Sowers, G.F. (1996):  Building on Sinkholes, ASCE Press 

ASCE Interview with Professor Sowers:  "How long did it take you to write this book"

George answered:  "My whole life"

GT Geotechnical EngineeringMonie Ferst Award (1994) to J. Mike Duncan

Wayne Clough1st Sowers Lecture

Mike Duncan2nd Sowers Lecture

GeorgeSowers

Terzaghi Lectures by GT Geotechs

16

1979 ‐ George F. Sowers  "There were Giants on the Earth in those days"

1994 ‐ G. Wayne Clough"Soft Ground Tunneling"

2014 ‐ J. Carlos SantamarinaASCE GeoCongress ‐ Atlanta

George F. SowersFamous for:

Case Studies

Lessons Learned

Importance of Engineering Geology

Practical Aspects of Geotechnical Engineering

Be careful, cautious, and stand your ground

Tell it like it is

Anecdotes

Geotechnics 2013 in the Piedmont

State‐of‐the‐Art (SOA)  = What we COULD be doing:   Guney Olgun

State‐of‐the‐Practice (SOP)  = what we ARE doing:  Ken Been

Limited time, so focus on Geocharacterizationfor Foundation Systems in the Piedmont

This talk = part SOA + part SOP → be erment

Mayne ≠ SOB

5/13/2013

4

Atlantic PiedmontGeologic Province

Surficial Extent of Appalachian Piedmont

VA‐MD‐DC

GA‐AL‐SC‐NC

Piedmont GeologicProvince

AL

GASC

NC

VA         

MD          DE

PA              NJ

VM Quarry, I‐85

Stone MountainRed Top Mountain

Lake Lanier

Primary Rock Types by Geologic Origin

Grain

Aspects

Clastic Carbonate Foliated Massive Intrusive Extrusive

Coarse Conglomerate

Breccia

Limestone

Conglomerate

Gneiss Marble Pegmatite

Granite

Volcanic Breccia

Medium Sandstone

Siltsone

Limestone

Chalk

Schist

Phyllite

Quartzite Diorite

Diabase

Tuff

Fine‐

Grained

Shale

Mudstone

Calcareous Mudstone

Slate Amphi‐bolite

Rhyotite Basalt

Obsidian

Sedimentary Types Metaphorphic Igneous Types

PIEDMONT

GeologicTimeScale

Era Period Epoch Time Boundaries (Years Ago) Holocene - Recent Quaternary 10,000 Pleistocene 2 million Pliocene 5 million Cenozoic Miocene 26 million Tertiary Oligocene 38 million Eocene 54 million Paleocene 65 million Cretaceous 130 million Mesozoic Jurassic 185 million Triassic 230 million Permian 265 million Pennsylvanian Carboniferous 310 million Mississippian 355 million Paleozoic Devonian 413 million Silurian 425 million Ordovician 475 million Cambrian 570 million Precambrian 3.9 billion Earth Beginning 4.7 billion

PiedmontGneiss

and Schist

PiedmontGranite

Z‐Age  ≈ 1 billion years ago  

Piedmont Residuum: a.k.a. “Georgia Red Clay” 

5/13/2013

5

Piedmont Subsurface Profile

"Georgia Red Clay"(CL ‐ML)

RESIDUUM (ML to SM)

SAPROLITE

Partially‐WeatheredRock (PWR)

Intact Rock: GneissSchist, Granite

GT Load Test Site, West Campus

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50 60 70 80 90 100

SPT N-values (bpf)

Dep

th (fe

et)

GRANITIC GNEISS

Piedmont Residuum:Silty Fine Sand (SM)

PWR

Major Rock Formations in USA

Piedmont

In‐Situ Testing in the Piedmont• SPT = standard penetration testing

• PMT = pressuremeter testing

• DP = dynamic penetrometers

• percussive soundings (air‐track)

• VST = vane shear testing

• DMT = flat plate dilatometer   

• CPT =  cone penetration testing

• CPTu = piezocone testing

• Vs = shear wave velocity 

• SCPTu = seismic piezocone

• SDMT = seismic dilatometer

Miller & Sowers (1967). Shear characteristics of 

Piedmont soils using rotating vanes

SCPTU in Piedmont residual siltsWinston‐Salem, NC

Fairfax Hospital, Northern Virginia (1984)Case Study: Drilled shaft (L = 65' and d = 3') in Piedmont residuum

5/13/2013

6

Axial Pile Influence Factors (Rigid Pile)

Randolph & Wroth (1979); Poulos & Davis (1980)

Rigid Pile in an Infinite Elastic Medium

0.01

0.10

1.00

0 10 20 30 40 50 60 70 80 90 100

Slenderness Ratio, L/d

Infl

uen

ce F

act

or,

I o

Boundary Elements

Closed Form v = 0.5

Closed Form v = 0.2

Closed Form v = 0s

ptt Ed

IPw

Poulos & Davis (1980) Solution vs. Randolph Solution

Pt = load at top = Ps + Pb

Homogeneous Soil: Es = Elastic modulus' =  Poisson's ratio

RIGID PILE RESPONSELength L and diameter d

Side Load, Ps= Pt ‐ Pb

Top Displacement, wt

s

tt Ed

IPw

Load Transfered to Base:

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

)1(1

11

2 vdLdL

I

21

I

P

P

t

bPb = Base load

Ground Surface

Randolph Solution

Fairfax Hospital, Northern Virginia

s

ptt Ed

IPw

E'  ≈  ED (ave. 64 DMTs) = 35  MPa =  364 tsfL  = 65 feet and d = 3 feetRatio L/d = 21.7 Ip = 0.076  

Buildings on Piedmont ‐ Northern Virginia and Washington DC

DMT‐SPT Correlation in Piedmont Residuum(Mayne & Frost, TRR 1988) Also EPRI Manual (1990)

Foundation Systems in the Piedmont Spread footings

Mat foundations

Augercast pilings

Drilled shafts

Micropiles

Driven pipe piles

H‐pilings

Monotubes

Step‐taper piles

Franki piles (PIFs)

5/13/2013

7

Case Study: First American Bank, Northern Virginia Case Study: First American Bank, Northern Virginia

Franki Piles, a.k.a. "Pressure Injected Footings"

Compacted Bulbof Zero‐SlumpConcrete

Pipe Casing

Concrete Shaft

Base

Case Study:  Lincoln Center, Fairfax County, VA

150 Franki Piles Installed

Load Test → 5" settlement

Mat Foundation (raft)

Geotechnical Meeting• Dames & Moore• Law Engineering• Woodward-Clyde• Schnabel Engineering• ASCE National

Geotechnical Section

• No more PIFs in NoVA• Also, no law suit

First AmericanBank Mat 

22-story Bank Building - Mat Foundation Tysons Corner, Virginia

0

50

100

150

200

0 50 100 150 200

West Side (feet)

No

rth

Sid

e (

feet

)

Structural ReinforcedConcrete Mat Foundation: t = 4.5 feet

Foundation Perimeter

Bank Tower:Total Q = 73,400k

Bearing Elev = +495 feet mslMat Thickness, t = 4.5 ftApplied Stress: q = 3.47 ksf

Georgia Tech

Wachovia/Wells FargoTysons Corner, VA

PREDICTED

Corner

Edge

Center

5/13/2013

8

Georgia Tech

GSU Dormitory B Settlements

0

1

2

0 1 2 3 4 5 6

Finite Layer Thickness, h/d

Influe

nce

Fact

or, I H

d

c

c/d10 5 3 21.5 1

Harr (1966)Approximation

s

Hc E

IdqDeflectionCenter

)1(:

2

c

Dormitory B Settlement Contours

0

5

10

15

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105

Breadth Distance (m)

Wid

th D

ista

nce

(m)

100 mm 120 mm 140 mm 160 mm

180 mm 200 mm 220 mm 240 mm

North

Reinforced Concrete Mat Foundation: c = 105 m; d = 18.3 m, thickness t = 1.07 m

0

50

100

150

200

250

300

0 10 20 30 40 50 60 70 80 90 100

Distance (meters)

Set

tle

me

nt

(mm

)

SW-NE DiagonalNW-SE DiagonalDMT Calculated (h = 12 m)DMT Calculated (h = 18 m)DMT Calculated (h = 24 m)

10" mat settlements DMT ED = 85 tsfwww.geoengineer.org

Elastic Solution for Foundation Displacement

0

2 )1(

s

EFGHecenter E

IIIdqs

q  = applied surface stress

de = equiv. footing width

IGH = displacement influence factor

IF = foundation rigidity factor

IE = embedment factor

= Poisson’s ratio Es0 = soil modulus (bearing elev)

(Mayne and Poulos, JGGE 1999, 2001)

Harry Poulos(2002 Sowers Lecture)

Closed‐Form Solution for Finite Gibson Soil (Elhakim, 2005)

*22

*41sinh

2

1sinh

)14(

8

1*4)14(

*22

14

2

1*4*22

*22ln 11

5.12

3

2222 h

h

h

h

hh

hIG

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0.01 0.1 1 10 100

Normalized Gibson Modulus, =E o /(k E d)

Dis

pla

cem

ent

Infl

uen

ce F

acto

r, I G

h/d = 0.5

h/d = 1

h/d = 2

h/d = 5h/d = 10h/d > 30

h/d = 0.2

Mayne & Poulos, 1999 - dotsClosed-Form Solution - lines

so

o

E

qdIs

)1( 2

ADSC‐ASCE‐FHWA Load Test Program Georgia Tech, Atlanta 

Load Tests

End‐bearing drilled shaft:   d = 0.76 m    L = 19.2 m

Friction‐type drilled shaft:  d = 0.76 m    L = 16.9 m

Deep plate load test:   d = 0.61 m   z = 16.9 m

GT End‐Bearing Shaft C1: d = 2.5' by L = 70' 

Axial Load Transfer Distribution

0

10

20

30

40

50

60

70

80

0 200 400 600 800 1000

Axial Load, Q (tons)

Dep

th (

feet

)

50 tons

100 tons

200 tons

300 tons

400 tons

500 tons

600 tons

700 tons

800 tons

900 tons

1000 tonsBas

LOAD Q

Base

Elastic Continuum Response ‐ GT Shaft C1

0

10

20

30

0 2000 4000 6000 8000 10000

Axial Load, Q (kN)

Top

Def

lect

ion,

wt (m

m)

Qtotal = Qs + Qb Pred. Qs Pred. Qb

Meas. Total Meas. Shaft Meas. Base

5/13/2013

9

GT Friction Shaft C2:  d = 2.5' by L = 55'

0

10

20

30

40

50

60

0 100 200 300 400 500 600

Axial Load, Q (tons)

Dep

th (

feet

)

25 tons

50 tons

75 tons

100 tons

150 tons

200 tons

300 tons

350 tons

450 tons

500 tons

Base

LOAD Q

Axial Load Transfer Distribution

BASE

Elastic Continuum Response ‐ Shaft C2

0

50

100

150

200

0 1000 2000 3000 4000 5000 6000

Axial Load, Q (kN)

Top

Def

lect

ion,

wt (m

m)

Qtotal = Qs + Qb Pred. Qs Pred. Qb

Meas. Total Meas. Shaft Meas. Base

Cone Penetration Tests (CPT) at GT West Campus

0

2

4

6

8

10

12

14

16

18

20

0 2 4 6 8 10

De

pth

(m

)

qt (MPa)

0

2

4

6

8

10

12

14

16

18

20

0 100 200 300

fs (kPa)

0

2

4

6

8

10

12

14

16

18

20

0 1 2 3 4 5 6

FR = fs/qt (%)

qt

fs

Continuous Readings at20 mm/s

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

• Cell Prepartion Tube

• Central Payment Tool

• Certified Proctology Technologist

• 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

ADSC Load Test at West GT Campus

0

2

4

6

8

10

12

14

20 30 40 50 60

Effective Stress Friction Angle, ' (deg)

Dep

th (

met

ers)

CPT qc(K&M'90)

TriaxialTests

GT Load Test ProgramADSC‐FHWA‐ASCE

McKinney Drilling

Long Foundation

Georgia Tech

ADSC

FHWA

Russo Corporation

Georgia DOT

Law Engineering‐MACTEC‐AMEC

Golder Associates

GeoSyntec Consultants

Johnson Drilling

AT&E (QORE)

Dames & Moore (URS)

CH2M‐Hill

Coastal Caisson

Allied Fence Company

Chatham Brothers 

McLean‐Behm

R.H. Harris Inc.

Stan Agee Company

Thomas Concrete Inc.

Vulcan Materials

ATEC Consultants (ATC)

Georgia Power

Tensar Corporation

Turner Engineering

W.T. Mayfield & Sons

Brainerd‐Kilman

5/13/2013

10

CPT‐SPT Trend in Piedmont Residuum

0

2

4

6

8

10

12

14

16

0 10 20 30 40Penetration Value

DEP

TH (met

ers)

SPT-N (bpf)

CPT: 3 qt (MPa)

qt (bars)  3.3 N

CPT‐SPT Interrelationship in Piedmont 

GeorgiaAlabama

qt/N

60(atm

/bpf)     

Kulhawy & Mayne 1990

Mean Grain Size, D50 (mm)

CPT‐DMT Interrelationships in Piedmont 0 0

10000 50000

0

10000

20000

30000

40000

50000

0 2000 4000 6000 8000 10000

CPT Tip Stress, qt (kPa)

DM

T M

od

ulu

s, E

D

(kP

a) GA

AL

NC

ED = 5 qt

Opelika National GeotechnicalExperimentation Site, Alabama

Preconsolidation Stress from ConsolidometerPiedmont Silt, Opelika, Alabama (Mayne & Brown 2003)

?

Generalized Pc' Method for CPT in all soils

10

100

1000

10000

10 100 1000 10000 100000

Net Cone Resistance, qt - vo (kPa)

Ap

par

ent

Yie

ld S

tres

s,

p' (

kP

a)

General Trend:

p' = 0.33(qt-vo)m

Intact clays: m = 1.00 Organic clays: m = 0.90Silts: m = 0.85

Silty Sands: m = 0.80Clean Sands: m = 0.72

pp m1atm

mvotp )100/()q(33.0'

Amherst, MAWashington 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

5/13/2013

11

Apparent OCR Profiles at Opelika

0

1

2

3

4

5

6

7

8

9

10

11

12

0 1 2 3 4 5 6 7 8 9 10

Yield Stress Ratio, YSR

Oedometer

Groundwater Lowered to 20 m

Disturbed sample

CPTU

0

1

2

3

4

5

6

7

8

9

10

11

12

0 100 200 300 400

Apparent Yield Stress, y' (kPa)

Dep

th (

met

ers)

silts:  p' = 0.33(qtnet)0.85 (0.1∙atm) 0.15

Cone Trucks at Opelika NGES

A.P. Van Den Berg (Morris Shea) Hogentogler (Williams Earth Sciences)

Fugro Geosciences Pagani Rig  (WPC) GeoStar (Georgia Tech)

Dielectric Piezocone Sounding at Opelika

Digital Oscilloscope

Control Panel

Nitrogen Tank

0

5

10

15

20

25

30

35

0 10 20qt (MPa)

De

pth

BG

S (

m)

0

5

10

15

20

25

30

35

0 300 600fs (kPa)

0

5

10

15

20

25

30

35

-100 200 500u2 (kPa)

0

5

10

15

20

25

30

35

0.5 1DEM, e

60o

qc

fs

u2

DEM

Piezocone Response in the Piedmont

0

1

2

3

4

5

6

7

8

9

10

0 2 4 6 8 10

Depth (meters)

Cone Tip Resistanceqt (MPa)

0

1

2

3

4

5

6

7

8

9

10

0 100 200 300 400

Sleeve Frictionfs (kPa)

0

1

2

3

4

5

6

7

8

9

10

-100 0 100 200

Porewater Pressureu2 (kPa)

0

1

2

3

4

5

6

7

8

9

10

0 500 1000 1500

Porewater Pressureu1 (kPa)

qt

u1

u2

fs

Height ofCapillarity

Piezo‐Dissipation in Piedmont ResiduumLAB 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

5/13/2013

12

CPTu in Piedmont PWR‐ Atlanta, GA

SPTN6023

34

71

34

56

67

50/6"

50/6"

50/2"

50/3"

0

2

4

6

8

10

12

14

0 10 20 30 40 50 60

qT (MPa)

Dep

th (

m)

0 0.2 0.4 0.6 0.8 1

fs (MPa)

-0.1 -0.05 0 0.05 0.1

u2 (MPa)

Partially‐

Weathered 

Rock 

(gneiss)

Saprolite

(hard fine 

sandy silt)

Residuum:

silty fine

sand 

Combo CPT‐Drill Rig

CPTDrill/SPT

SCPTU in Piedmont residual siltsWinston‐Salem, NC

Geotechnics 2013 in the Piedmont

More Measurements

is

More Better

Mas Mejor

Seismic Piezocone (SCPTu)Piedmont silts in Marietta, GA

Tip Resistance

0

2

4

6

8

10

12

14

16

18

20

22

24

0 10 20 30

qT (MPa)

Dep

th (

m)

Sleeve Friction

0 200 400 600

fs (kPa)

Porewater Pressure

-100 0 100 200

u2 (kPa)

Shear Wave Velocity

0 100 200 300 400 500

Vs (m/s)

Vs

fs

u2

qt

u0

Ken Stokoe2004 Sowers

Lecture

In‐Situ QA/QC Testing for Dynamic Compaction 

Hartsfield Airport Runway 5

5/13/2013

13

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

Equivalent Modulus for Static Loading

Gmax = t Vs2

t = t/g

Emax = 2Gmax(1+)

Modulus Reduction from Laboratory Data

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Mobilized Strength, /max or q/qmax

Mo

du

lus

Red

uct

ion

, G/G

max

or

E/E

max

NC S.L.B. Sand

OC S.L.B. Sand

Hamaoka Sand

Hamaoka Sand

Toyoura Sand e = 0.67

Toyoura Sand e = 0.83

Ham River Sand

Ticino Sand

Kentucky Clayey Sand

Kaolin

Kiyohoro Silty Clay

Pisa Clay

Fujinomori Clay

Pietrafitta Clay

Thanet Clay

London Clay

Vallericca Clay

= 1/FS

Open Dots = DrainedClosed Dots= Undrained

Resonant Column Torsional Shear Triaxial Shear with 

local strain measurements

Modulus Reduction Scheme (Fahey & Carter 1993)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Mobilized Stress Level, q/qmax

Mo

du

lus

Red

uct

ion

, E

/Em

ax

g = 1.0

g = 0.4

g = 0.3

g = 0.2

Note: f = 1

gqqfEE )/(1/ maxmax

= 1/FS

Equivalent Modulus for Static Monotonic Loading

• Initial Stiffness from Shear Wave Velocity (Vs)

Shear Modulus: Gmax =  Vs2

Young's Modulus: Emax = 2 Gmax(1+)       0.20 at small strains

• Modified Hyperbola for Modulus Reduction (Fahey 

& Carter, 1993; Mayne 2007):  E/Emax = 1 – (Q/Qult)g

• Factor of Safety, FS = Qult /Q

• For uncemented, unstructured soils:   g  0.3

Randolph Compressible PilesL

ptt Ed

IPw

:]1[

d

L

L

Lx

)tanh(

)1(

811)1(41

d

L

L

Lx E

)tanh(4

)1(

43

[2] Ip = x1/x3

The proportion of load transferred from the top to base:

[3] Pb/Pt = x2/x3

The proportion of load carried in side shear is:

[4] Ps/Pt = 1 - Pb/Pt

The displacement at the pile toe/base is given by:

[5] wb = wt/cosh(L)

[6] = db/d = eta factor (Note: db = base diameter, so that = 1 for straight shaft piles)[7] = EsL/Eb = xi factor (Note: = 1 for floating pile; < 1 for end-bearing pile)[8] E = Esm/EsL = rho term. The parameter can be evaluated from: E = ½(1+Es0/EsL). [9] = 2(1+)Ep/EsL = lambda factor[10] = ln{[0.25 + (2.5 E(1- ) - 0.25)] (2L/d)} = zeta factor[11] L = 2(2/)0.5 (L/d) = mu factor

)cosh(

1

)1(

42 L

x

Es = Equivalent Elastic

Soil Modulus

AXIAL PILEDISPLACEMENTS

LengthL

Diameter dEso(surface)

EsM (mid-length)

EsL (along side at tip/toe/base)

Eb (base geomaterialModulus of layer 2)

sL

tt Ed

IPw

Pt Where Ip = displacementInfluence factor fromelastic continuum theory

z = Depth

Soil Layer 1

Soil or Rock Layer 2

5/13/2013

14

Drilled Shaft C2, Georgia Tech, Atlanta

0

10

20

30

40

50

60

0 1000 2000 3000 4000

Axial Load, Q (MN)

Top

Def

lect

ion,

wt (m

m)

Qtotal = Qs + Qb Pred. Qs Pred. Qb

Meas. Total Meas. Shaft Meas. Base

D = 0.76mL = 16.9 m

Opelika NGES

Mean SCPTu ProfilesOpelika NGES, Alabama

Load Tests: Opelika, Alabama (Brown 2002)

0

5

10

15

20

25

30

0 1 2 3

Axial Load, Q (MN)To

p Def

lect

ion

(mm)

Qtotal = Qs + Qb

Pred. Qs

Pred. Qb

Meas. Total

Meas. Shaft

Meas. Base

Drilled Shaft No. 01(cased)d = 0.91 mL = 11.0 m

Q (total)

Q shaft

Q base

Drilled Shaft Load Tests: Opelika, Alabama (Brown 2002)

4 Drilled Shafts d = 0.91 mL = 11.0 m

Q (total)

Q shaft

Q base

0

20

40

60

80

100

120

0 1000 2000 3000 4000

Dis

pla

cem

ent,

s (

mm

)

Applied Load, Q (kN)

Opelika NGES

Shaft S02

Shaft S04

Shaft S07

Shaft S09

Load Test at I‐85 Bridge, Coweta County, GA

GDOT Drilled Shaft Load Test: 

D = 0.91 mL = 20.1 m 

Load TestDirected byMike O'Neill

5/13/2013

15

SCPTu at I‐85 Bridge, Newnan, GA

0

2

4

6

8

10

12

14

16

18

0 2 4 6 8

qT (MPa)

De

pth

(m

)

0

2

4

6

8

10

12

14

16

18

0 100 200 300

fs (kPa) Ub (kPa)

0

2

4

6

8

10

12

14

16

18

-100 0 100 200

0

2

4

6

8

10

12

14

16

18

0 100 200 300 400

Vs (m/s)

Axial Load Response of Coweta Shaft

0

10

20

30

40

50

0 2000 4000 6000 8000

Axial Load, Q (kN)

Top

Def

lect

ion,

wt (m

m) Qtotal = Qs + Qb

Pred. Qs

Pred. Qb

Meas. Total

Meas. Shaft

Meas. Base

RHYMESWITHORANGEby Hilary Price

Rock → Stone →  Sand  = Formation of Residuum  

Saprolitic

Class “A” Prediction of Axial Pile ResponseJackson County, Georgia

Gmax from SCPTu for dynamically‐loaded block foundations

Switched to driven 273 mm diameter closed‐ended steel pipe piles:  8 < L < 18 m.

CPT qt, fs and u2 used for axial capacity and Vs for initial stiffness.  

Turbine Foundations,Plant Dahlberg Power StationSouthern Companies

Courtesy Marty Meeks

Seismic Piezocone Sounding, Jackson County, GA Axial Pile Response from SCPTu, Jackson County, GA

Driven Steel Pipe Pile No. P22 (L = 9.45 m)

0

2

4

6

8

10

12

14

0 200 400 600 800 1000 1200

Axial Load, Q (kN)

Def

lect

ion,

w t

(m

m)

Predicted by SCPTuin Advance

Measured

5/13/2013

16

Axial Pile Response from SCPTu, Jackson County, GA

Driven Steel Pipe Pile No. P33 (L = 17.8 m)

0

2

4

6

8

10

12

14

0 200 400 600 800 1000 1200

Axial Load, Q (kN)

Def

lect

ion,

w t

(m

m)

Predicted in advance from SCPTU data

Measured from Load Test

92

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

www.statnamiceurope.com

Reaction FrameDead Weight

Osterberg CellStatnamic Load Testwww.fhwa.dot.gov

Pile Load Tests

GDOT Viaduct at International Boulevard near CNN, Atlanta

Drilled Shaft Load Test

by multi‐stage O‐Cells

GT Class “A” Prediction

March 2003

GDOT Load Test for Viaduct at CNN

2.9 m

11.8 m

6.2 m

d = 1.68 m

d = 1.59 m

d = 1.44 m

Residual Soils(ML/SM)

Partially-WeatheredRock (PWR)

Stage 1 O-cell

Stage 2 O-cell

Constructed Dimensionsof Drilled Shaft

Geotechnical Site CharacterizationGDOT ‐ International Blvd.

GDOT Viaduct at CNN-International Blvd

0

5

10

15

20

25

30

35

0 10 20 30 40 50 60 70 80 90 100 110 120

Equivalent N-value (bpf)

De

pth

(m

)

CPT equivalent N

ave CPT N

SPT N

Boring Log RecordB-5 Sta 30+306

Fill: silty sand

Brown-pink sandy SILT, v. stiff hard, soft

SAND, some silt, graymedium dense, dense

PARTIALLY-WEATHEREDROCK (sand, some silt) trace mica, dark gray to grayish brown

PARTIALLY-WEATHEREDROCK (sand, some silt) trace mica, gray to grayish white

SAND, some silt, gray

GT Seismic Piezocone Sounding (SCPTu)GDOT ‐ International Blvd.

Tip Resistance

0

2

4

6

8

10

12

14

16

18

20

22

0 10 20 30

qT (MPa)

Dep

th (

m)

Sleeve Friction

0 200 400 600 800

fs (kPa)

Porewater Pressure

-100 0 100 200

u2 (kPa)

Shear Wave velocity

0 100 200 300 400 500 600

Vs (m/s)

5/13/2013

17

Class A Prediction ‐ GDOT Bridge at CNN

GDOT International Blvd. at CNN

0

10

20

30

40

50

0 1 2 3 4 5 6 7 8 9 10 11 12

Axial Load, Q (kN)

Top

Def

lect

ion,

wt (m

m)

Qt Predicted

O-cell top down

O-cell Creep Limit

(MN)

O‐cell load tests in Piedmont rocksDrilled shafts ‐ Lawrenceville, GA (2011)

Axial Pile Capacity:  Qtotal = Qsides + Qbase

Qt

Qs = ∫ fp dAs

Qb =  qb ∙ Ab

unit sidefriction, fp

unit base resistance, qb

Geomaterial

Fred Kulhawy(2005 Sowers Lecture

Unit Side Friction in Drilled Shafts(Kulhawy and Phoon 1993)

0.1

1

10

100

0.1 1 10 100 1000

Unit Side resistan

ce, f

p/

atm

TC equivalent shear strength,  su/atm or   ½ qu/atm

Clay

Shale & Mudstone

Sandstone & Limestone

=  321

SOILS

IGM

ROCKS

Unit Side Friction in the PiedmontDrilled Shafts in Residuum, PWR, and Rock

0.1

1

10

100

0.1 1 10 100 1000

Unit Side resistan

ce, f

p/

atm

TC equivalent shear strength,  su/atm or   ½ qu/atm

Lawrenceville O‐Cells

ADSC at GT

Opelika NGES

SILTS

Open Symbols (Kulhawy & Phoon, 1993)

PWR

O‐Cell Elastic Solution

01

1

111o1s

1

r

L2

wrG

P

P  = applied force

L = pile length

ro = pile radius

Ep = pile modulus

Gs = soil side shear modulus

=  Poisson's ratio of soil

2o

2

222o2s

2

r

L2

)1(

4

wrG

P

Rigid pile or plate under compression loading

Rigid pile shaft under upward loadingupper

segment

lower segment

O‐Cell

w  = pile displacement

l = 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]}  = magic radius

P1 = P2

Diameterd1 = 2r1LengthL1

Diameterd2 = 2r2LengthL2

5/13/2013

18

O‐cell tests ‐ ADSC/ASCE Lawrenceville, GA

‐1.0

‐0.5

0.0

0.5

1.0

1.5

2.0

0 1000 2000 3000 4000 5000 6000

Displacement, w (inches)

Applied Load, Q (tons)

Upper Segment Base Response

Elastic Pred Upward Elastic Down Pred

‐1.0

‐0.5

0.0

0.5

1.0

1.5

2.0

2.5

0 200 400 600 800 1000 1200

Displacement, w (inches)

Applied Load, Q (tons)

Upper Segment Base Response

Elastic Pred Upward Elastic Down Pred

E' = 3500 tsf E' = 1050 tsf

Test Shaft 1 in Rock Test Shaft 2 in PWR

Application of Randolph Elastic SolutionRecommendations toGeotechnical Practice

Site Characterizationin the Piedmont

FIRMCLAY

DIRECT‐PUSH TECHNOLOGY

SDMTàVp

Vstflexp1p0

NON‐INVASIVE GEOPHYSICS

(Resistivity, Radar, Conductivity)

SCPTùVs  fst50u2qt

DENSESAND

loosesand

softclay

Direct Push Borehole MethodsContinuous Push Sampling  Steel mandrel with inner plastic lining (d = 35 to 70 mm) Hydraulic and/or percussive push in 3‐m strokes

www.geoprobe.com www.ams‐samplers. com boartlongyear.com

Sonic Drilling Vibrations at resonant frequency of drill pipe Fast and continuous sampling of soil and rock

Calibration of SPT Energy ‐ Auto Hammers

Manufacturer Type ID No. Mean Energy Ratio (%) Reference

Diedrich D‐120 ID 26 46 UDOTDiedrich D‐50 321870551 56 GRLCME 850 ID 21 62.7 UDOTBK‐81 w/ AW‐J rods B2 68.6 ASCEMobile B‐80 ID 18 70.4 UDOTSK w/ CME hammer B6 72.9 ASCEDiedrich D50 UF5 76 UFCME 55 UF2 78.4 FDOTCME 850 296002 79 GRLCME 45 UF1 80.7 UFCME 85 UF4 81.2 UFCME 75 w/ AW‐J rods A3 81.4 ASCECME 75 UF3 83.1 UFCME 750 ID 4 86.6 UDOTMobile B‐57 DR‐35 93 GRLCME 75 rig ID 10 94.6 UDOT

Factorof 2.1

O‐cell load tests in Piedmont rocksDrilled shafts ‐ Lawrenceville, GA (2011)

5/13/2013

19

Methods for Rating Rock Masses

Core Recovery (CR) Rock Quality Designation (RQD); Deere et al. (1966) Rock Mass Rating (RMR);  Bieniawski (1976, 1989) Q‐System by NGI;  Barton et al. (1976, 1991) Geological Strength Index (GSI); Hoek (1995, 2009)

Uniaxial Compressive Strength, qu Rock Quality Designation (RQD) Spacing of Joints Condition of joints and/or infilling Groundwater conditions

Rock Mass Rating (RMR)

Dick Goodman3rd Sowers

Lecture

Shear Wave Velocity Profile in Piedmont VC Summer Power Station, South Carolina

Intact Rock

CR   =  98 ‐ 100%

RQD = 97 ‐ 100%

Vs = 10,100 fps = 3078 m/s

qu = 25 ksi =  170 MPa

t = 180 pcf = 28 kN/m3

Shear Wave, Vs (fps) Shear Wave, Vs (fps)

Elevation (feet msl)

Vs from suspension logging in boreholes

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

Combined MASW Arrays for 2DMapping Subsurface Heterogeneity

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

Dep

th (m)

courtesy:  Illmar Weemees ‐ ConeTec

ReMi Mapping of Subsurface Geomaterials(Cha, Kang, and Jo, 2006: Exploration Geophysics)

ReMi = Reflection Microtremors(passive Rayleigh wave survey)

Geotechnics 2013 in the Piedmont

• Beyond conventional SPT and PMT, showed advent and value of DMT, CPT, + SCPTu, SDMT

• Elastic continuum solution for pile foundations

Static top down loading

Bi‐directional O‐cell load tests

• Fundamental soil stiffness:  Gmax = Vs2

• Presented case studies in Piedmont

• Use of Rock Mass Rating (RMR) 

• Recommended more use of geophysics for site characterization, particularly Vs profiling  

5/13/2013

20

thanks