Prepared byJ. P. Singh & Associates

in association with

Mohamed Ashour, Ph.D., PE West Virginia University Tech

andGary Norris Ph.D., PE

University of Nevada, Reno

APRIL 3/4, 2006

Computer Program DFSAPDeep Foundation System Analysis Program

Based on Strain Wedge Method

Washington StateDepartment of Transportation

SOIL LIQUEFACTION AND

LATERAL SPREADING OF SOIL

Current Available Procedures That Assess the Pile/Shaft Behavior in Liquefied Soils (Using the Traditional P-y Curve):

1. Construction of the p-y curve of soft clay based on the residual strength of liquefied sand presented by Seed and Harder (1990)

2. The use of random Pmult < 1 to reduce the stiffness of the traditional p-y curve of sand

3. Reduce the unit weight of liquefied sand with the amount of Ru (Earthquake effect in the free-field ) and then build the traditional p-y curve of sand based on the new value of the sand unit weight. (proposed by Brown based on Cooper River Test)

0 4 8 12 16 20 24Equivalent Clean Sand SPT Blowcount, (N1)60-CS

0

400

800

1200

1600

2000

Res

idu

al U

nd

rain

ed

Sh

ear

Str

eng

th, S

r (p

sf)

E a rth q u a k e -In d u ce d L iq u efac tio n a n d S lid in g C a se H is to r ie s W h e reS P T D a ta & R es id u a l S tre n g th P a ra m e te rs H a v e b e e n M e asu re d

E a rth q u a k e -In d u ce d L iq u efac tio n a n d S lid in g C a se H is to r ie s W h e reS P T D a ta & R es id u a l S tre n g th P a ra m e te rs H a v e b e e n E s tim a ted

C o n stru c tio n -In d u c ed L iq u efa tio n a n d S lid in g C a se H is to rie s

L o w er S a n F ern a n d o D a m

Fig. 1 Corrected blowcount vs. residual strength (Seed and Harder, 1990)

Pile Deflection, y

Soi

l-P

ile

Rea

ctio

n, p

Upper Limit of Sr using soft clay p-y curve

Lower Limit of Sr

API Procedure

0 4 8 12 16 20 24Equivalent Clean Sand SPT Blowcount, (N1)60-CS

0

400

800

1200

1600

2000

Res

idu

al U

nd

rain

ed

Sh

ear

Str

eng

th, S

r (p

sf)

E a rth q u a k e -In d u ce d L iq u efac tio n a n d S lid in g C a se H is to r ie s W h e reS P T D a ta & R es id u a l S tre n g th P a ra m e te rs H a v e b e e n M e asu re d

E a rth q u a k e -In d u ce d L iq u efac tio n a n d S lid in g C a se H is to r ie s W h e reS P T D a ta & R es id u a l S tre n g th P a ra m e te rs H a v e b e e n E s tim a ted

C o n stru c tio n -In d u c ed L iq u efa tio n a n d S lid in g C a se H is to rie s

L o w er S a n F ern a n d o D a m

Corrected blowcount vs. residual strength, Sr (Seed and Harder, 1990)

Treasure Island Test Result (Rollins and Ashford)

P-Y Curve of Completely Liquefied Soil

19

Post-liquefaction stress-strain behavior of completely liquefied sand (uc = 3c and Ru =1)

Axial Strain,

Dev

iato

r S

tres

s,

dPost-liquefaction stress-strain behavior of partially liquefied sand (uc < 3c and. Ru <1)

xo

d = 2 Sr

Fig. 1 Subsequent undrained stress-strain behavior of sand that has experienced partial or complete liquefaction

d

E ffe c tiv e S tre ss P a th

p

q =

/

2

3 cc=

C yclic LoadingFailure

Enve

lope

3

rs

r

s

3 c

u c 3 c

A B

Fully Liquefied Soil (Ru =1)

Water Pressure in the Free- and Near-Field Due to the Earthquake Shaking and Equivalent Static Load from the Superstructure

p

dq

=

/ 2

Earthquake E ffectFailure Envelope

u c

3 cc

3 c

3 c

r, s

s

Partially Liquefied Soil (Ru < 1)

0 5 10 15 20U n d ra in e d Axia l S tra in , 1, %

0

100

200

300

400D

evi

ato

r S

tres

s,

d, k

Pa

0 5 10U n d ra in e d Axia l S tra in , 1, %

0

100

200

300

400

De

via

tor

Str

ess

, d, k

Pa

D r = 40%c = 100 kPa

cc = 0 kPa

50 = 0 .0035

D r = 19%c = 100 kPa

cc = 0 kPa

50 = 0 .005

PredictedM easured (Vaid & Thom as 1995)

P red ictedM easured (Vaid & Thom as 1995)

Post-liquefaction undrained stress-strain behavior of completely liquefied Fraser sand

Ru = 1Ru = 1

0 2 4 6 8U ndra ined Axia l S tra in, 1, %

0

200

400

600

De

via

tor

Str

ess,

d,

kP

a

D r = 40%c = 400 kPa

cc = 45 kPa

50 = 0 .0035

PredictedM easured (Vaid & Thom as 1995)

Ru = 0.88

Fig. 2Effect of Cyclic Loading upon Subsequent Undrained Stress-Strain Relationship for Sacramento River Sand (Dr = 40%) (Seed 1979)

0 1 0 2 0 3 0 4 0 5 0

A x ial S tr a in , 1, %

0

2

4

6

8

10D

evia

tor

Str

ess,

d,

kg/

cm2

0 1 0 2 0 3 0 4 0 5 0

- 2

- 1

0

1

Cha

nge

in P

orew

ater

Pre

ssur

e

u x

s, n

f, kg

/cm

2

0 1 0 2 0 3 0 4 0 5 0

A x ia l S tra in , 1 , %

Initia l S tatic Loading

A fter 9 C yclesC SR of 0 .18 P roduced ru = 1

In itia l S ta tic Loading

100% R esidual Porew ater P ressure A fter 9 C ycles,C SR of 0 .18

In itia l E ffective C onfin ing

P ressure = 1 kg/cm 2

Validation Example for Pile and Pile Group in Liquefiable soil profile

Treasure Island Test

Report, Chapter 6

TABLE I. SOIL PROPERTIES EMPLOYED IN THE SWM ANALYSIS FOR TREASURE ISLANDTEST

Soil LayerThick. (m)

Soil Type Unit Weight, (kN/m3)

(N1)60 φ(degree)

ε50

%*Su

kN/m2

0.5 Brown, loose sand (SP) 18.0 16 33 0.45

4.0 Brown, loose sand (SP) 8.0 11 31 0.6

3.7 Gray clay (CL) 7.0 4 1.5 20

4.5 Gray, loose sand (SP) 7.0 5 28 1.0

5.5 Gray clay (CL) 7.0 4 1.5 20

* Undrained shear strength

Peak Ground Acceleration (amax) = 0.1 gEarthquake Magnitude = 6.5 Induced Porewater Pressure Ratio (ru) = 0.9 - 1.0

Soil Profile and Properties at the Treasure Island Test

Shaft Width

x x

Longitudinal Steel

Steel ShellS

oil-

Pil

e R

eact

ion,

p

Pile Deflection, y

Treasure Island Test Result (Rollins and Ashford)

Upper Limit of Sr using soft clay p-y curve

Lower Limit of Sr API Procedure

P ile H ead E levation ( 0 .00 )P o

M o = 0 .0

A xia l Load= 0.0

D iam eter of P ile

Pile

Le

ngt

h =

20

.0 ft

Thickness of Layer # 2

Thickness of Layer # 3

W ater Tab le

SA

ND

CL

AY

G round Surface1.0 m

4.0

m4.

0 m

0 .61 m

Layer th ickness = 4.0 mE ffective un it w e ight = 8 .0 kN /m 3

E ffective fric tion ang le = 31.0o

50 = 0 .006, (N 1)60 = 11

Layer th ickness = 3.7 mE ffective un it w e igh t = 7 .0 kN /m 3

E ffective fric tion ang le = 24 o o r 0 .0 (defau lt)(S u)Top =20 kN /m 2, (S u)B o ttom =20 kN /m 2

50 =0 .015

CL

AY

SA

ND

4.5

m7.

5 m

0 .5 m

Thickness of Layer # 4

Layer th ickness = 5.0 mE ffective un it w e ight =7 .0 kN /m 3

E ffective fric tion ang le =28.0o

50 = 0 .01, (N 1)60 = 9

Layer th ickness = 5.5 mE ffective un it w e igh t = 7 .0 kN /m 3

E ffective fric tion ang le = 24 o o r 0 .0 (defau lt)(S u)Top =20 kN /m 2, (S u)B o ttom =20 kN /m 2

50 =0 .015

Thickness of Layer # 5

Thickness of Layer # 1

Layer th ickness =0.5 mE ffective un it w e igh t = 18.0 kN /m 3

E ffective fric tion ang le =33.0o

50 = 0 .0045, (N 1)60 = 16

% of fines= 5%

% of fines= 10%

T-Shell

P eak G round Acceleration (a m ax) = 0 .1gM agnitude o f E arthquake = 6 .5N o la tera l spreadingFree- and N ear-fie ld excess porew ater pressure e ffectA ssum e sand grains Subangular

Shaft SectionN um bers of shaft segm ents =1Segm ent length = 20 mShaft d iam eter = 0 .61mSteel shell th ickness = 9 .5 m mfy o f the stee l shell = 420000 kN /m 2

fc o f concrete = 34444 kN /m 2

fy o f the stee l bars = 420000 kN /m 2

R atio of S teel bars (A s/A c)= 2%R atio of Transversesteel = 0.3%

Shaft W idth

x x

Longitud ina l S tee l

TREASURE ISLAND TEST

O b se rv ed

P red ic ted

0 5 0 1 0 0 1 5 0 2 0 0 2 5 0P ile -H ead D e flec tio n , Y o , m m

0

40

80

120

160P

ile-

Hea

d L

oad,

Po,

kN C IS S , 0 .3 2 4 m

E I = 4 4 5 1 5 k N -m 2

N o -L iq u efac tio nP o st-L iq u e fac tio n

(u x s , ff + u x s , n f)

0 5 0 1 0 0 1 5 0 2 0 0 2 5 0P ile-H ead D ef lectio n , Y o , m m

0

40

80

120P

ile-

Hea

d L

oad,

Po,

kN H -P ile , 0 .3 1 0 m

E I = 4 9 0 0 0 k N -m 2

O b se rv ed

P red ic ted

No-

Liq

uefa

c tio

n

P o st-L iq u e fac tio n

(u x s , ff + u x s , n f)

0 100 200 300 400Pile-Head Deflection, Yo, mm

0

100

200

300

400

500P

ile-

Hea

d L

oad,

Po,

kN

CISS, 0.61 mEI = 448320 kN-m2

ObservedPredicted (SWM)Predicted (Com624)

No-

Liqu

efac

tion

Post-Liquefaction (uxs, ff + uxs, nf)

0 4 0 8 0 1 2 0 1 6 0 2 0 00

40

80

120

160

200

Pile-

Hea

d L

oad,

Po,

kN

0

100

200

300

400

500

Pil

e-H

ead

Loa

d, P

o, k

N

Pile-Head Response (Yo vs. Po) for 0.61-m Diameter CISS at Treasure Island Test.

0 40 80 120P ile Latera l D eflection, y (m m )

0

10

20

30

40

50p

(kN

/m)

M easured P red icted (SW M odel)

API (Pmult = 0.3)

p-y Curve at 1.5 m Below Ground (0.61-m Diameter CISS )

0 40 80 120 160P ile Latera l D eflection, y (m m )

0

20

40

60

80p

(kN

/m)

M easured P red icted (SW M odel)

0.2 m Below Ground

0 40 80 120P ile Latera l D eflection, y (m m )

0

10

20

30

40

50

p (

kN/m

)

M easured P redicted (SW M odel)

1.5 m Below Ground

0 40 80 120P ile Latera l D eflection, y (m m )

0

10

20

30

40

50

p (k

N/m

)

M easured P red icted (SW M odel)

3.2 m Below Ground

p-y Curve of 0.61-m Diameter CISS in Liquefied Soil. (Treasure Island, After Rollins et al. 2005)

p-y Curve Empirical Formula in Liquefied Sandby Rollins et al. 2005

p(d=324 mm) = A(By)C for Dr = 50%

where:

A = 3 x 10-7 (z+1)6.05, B = 2.8 (z+1)0.11

C = 2.85(z+1)-0.41 z is depth in (m)

y is lateral deflection (mm)

pmultiplier = 3.81 ln d + 5.6

p = p (d=324 mm) x pmultiplier

Pile-Head Response (Yo vs. Po) for an Isolated 0.324-m Diameter CISS at Treasure Island Test.

Curve # 1

Curve # 2Pile

Loa

d (

kN

)

Deflection at Load Point (mm)

0 25 50 75 100 125 150P ile Latera l D eflection, y (m m )

0

5

10

15

20

25

p (k

N/m

)

D epth o f p-y C urve Be low G round0.3 m1.3 m2.3 m

p-y Curve of 0.324-m Diameter CISS in Liquefied Soil (Treasure Island)

Responses of Individual Piles in a 3 x 3 Pile Group in Non-Liquefied Soil Profile at the Treasure Island Test (Rollins et al. 2005a)

Pile-Head Response (Yg vs. Pg) for a 3 x 3 CISS Pile Group(0.324-m Diameter) at Treasure Island Test. (After Rollins et al. 2005)

Deflection at Load Point (mm)

Pile

Loa

d (

kN

)

Curve # 1

Curve # 2

Curve # 1

Curve # 2

0 25 50 75 100P ile Latera l D eflection, y (m m )

0

2

4

6

8

10

p (k

N/m

)

D epth o f p-y C urve Be low G round0.3 m1.3 m2.3 m

AB, C

E

p-y Curve of a 3 x 3 Pile Group in Liquefied Soil (Treasure Island, 0.324-m CISS)

Lateral Soil Spread

Bartlett and Youd, 1995 (Current Practice)

SOIL LATERAL SPREADING CHALLANGES:

• Mobilized Driving Lateral Forces Acting on Piles and Generated by Crust Layer(s)

• Varying Strength of Liquefied Soil(s)

• Amount of Soil Lateral Displacement

Stress-Strain Behavior of Fully Liquefied SandAxial Strain,

Dev

iato

r S

tres

s,

dxo

Soil Lateral Displacement (Xo)in DFSAP

(Ishihara)

Po

Mo

Axial Load

Liquefiable Soil

Clay

y

p

y

p

Clay

1.2 m

p

y

Phase I Phase IIPo

Mo

Axial Load

Liquefiable Soil

Clay

y

p

y

p

Clay

1.2 m

p

y

Po

Mo

Axial Load

Po

Mo

Axial Load

Liquefiable SoilLiquefiable Soil

Clay

y

p

y

p

Clay

1.2 m

p

y

p

y

Phase I Phase II

Shaft Diameter

Shaft Cross Section Liquefied Soil

Soil Flow Around

LATERAL SOIL SPREAD

P ile H ead E levation ( 0 .00 )

Po

Axia l Load

S oil Layer # 1(N onliquefied)

Soil Layer # 2(Com pletely L iquefied)

S oil Layer # 3(N onliquefied)

G round Surface

y s1

y s

y s1

y

p

y sy

p

y

p

y s1 = E ffec t o f la te ra l sp re a dy s= S o il la te ra l sp re ad

1 6

1 2

8

4

0

Dep

th (

m)

0 400 800

M om ent (kN -m )

Pile head load = 100 kNPile head moment = 316 kN-m

No-LiquefactionLiquefactionLiquefaction + Lateral Spread

Lateral Spread ProblemPile Cross-Section # 1

Ben

ding

Stif

fnes

s, E

I, k

N-m

2

Bending Moment, M, kN-m

0

500000

1000000

1500000

2000000

2500000

3000000

0 500 1000 1500 2000 2500 3000

1 6

1 2

8

4

0

Dep

th (

m)

-20 0 20 40 60 80D eflection (m m )

Pile head load = 100 kNPile head moment = 316 kN-m

No-LiquefactionLiquefactionLiquefaction + Lateral Spread

Hokkaido Island Test (Ashford et al. 2006, ASCE J.)LATERAL SOIL SPREAD, TEST 1

Hokkaido Island Test (Ashford et al. 2006)LATERAL SOIL SPREAD

Peak Ground Acceleration (amax) = 0.4 gEarthquake Magnitude = 6.0 Induced Porewater Pressure Ratio (ru) = 1.0

TABLE I. SOIL PROPERTIES EMPLOYED IN DFSAP FOR HOKKAIDO ISLAND TESTSoil LayerThick. (m)

Soil Type Unit Weight, (kN/m3)

(N1)60 φ(degree)

ε50

%*Su

kN/m2

1.0 Loose sand (SM) 18.0 8 30 1.0

3.0 Loose sand (SM)) 8.0 8 30 1.0

3.5 Soft clay (CL) 7.0 4 1.5 20

1 Med. dense sand 9.0 5 33 0.8

5 Very dense gravel 10.0 > 50 45 0.1

-200 0 200 400 600

12

8

4

0

0 200 400 600

12

8

4

0

DFSAP

0.314-m-Diameter Steel Pipe Pile

Hokkaido Island Test (Ashford et al. 2006, ASCE J.)LATERAL SOIL SPREAD, ISOLATED FREE-HEAD PILE

-400 -200 0 200 400 600

Shear Force, kN

1 2

8

4

0

Dep

th, m DFSAP

Hokkaido Island Test (Ashford et al. 2006, ASCE J.)LATERAL SOIL SPREAD, ISOLATED FREE-HEAD PILE

0 0.2 0.4 0.6 0.8 1W ater P ressure R atio , ru

1 2

8

4

0

Dep

th, m

-200 0 200 400 600

8

4

0

Rotation = 1 Deg.(Not fully fixed)

Hokkaido Island Test (Ashford et al. 2006, ASCE J.)2 X 2 FIXED-HEAD PILE GROUP WITH CAP

0 200 400 600

12

8

4

0

DFSAP

Steel Pipe Pile

Dense Sand

Loose Sand

Clay = 6 kN/m3, Dr = 21-35% = 30o, 50= 0.01

= 7 kN/m3, Dr = 69-83% = 36o, 50= 0.004

Cu= 44 kPa = 16 kN/m3

14.39.22.24.60.0511.1723.5

Pile Cap Length (m)

Pile Cap

Width (m)

Pile Cap

Height (m)

Pile Spacing

(m)

Wall Thick.

(m)

Diameter

(m)

Pile Length

(m)

UC Davis, Centrifuge Test(Brandenberg and Boulanger, 2004)

UC Davis, Centrifuge Test on 2 x 3 Fixed-Head Pile Group(After Brandenberg and Boulanger, 2004)

-100 0 100 200 300 400P ile Latera l D eflection, y (m m )

2 5

2 0

1 5

1 0

5

0

Dep

th (

m)

M easured C om puted

Pile Displacement

-12000 -8000 -4000 0 4000 8000 12000M om ent, kN -m

2 5

2 0

1 5

1 0

5

0

Dep

th (

m)

M easured C om puted

Bending Moment

amax = 0.67 g Magnitude = 6.5

0 100 200 300 400 500Shaft D eflection, y, m m

0

40

80

120

160

Soi

l-Sha

ft R

eact

ion,

p, k

N-m

Depth of p-y Curves1 m2 m4 m6 m8 m

p-y Curves at Different Depths for a Lateral Soil Spreading Case (UC Davis Test, amax = 0.3g)

Input Data

1. Shaft/Pile Properties• Shaft length and diameter• Shaft-head location above ground• Moment and axial load at shaft head• Type of the shaft cross-section and material

• Uniaxial fc28 of concrete• Percentage of rebars• Percentage of horizontal steel• Thickness of steel shell (if any)• Fy of steel (nonlinear modeling)

Input Data (Continue)

2. Soil properties:• Thickness of soil layer of soil layer• Effective unit weight of soil ()• Normal strain of sand at 50% strength, 50%

Uniformity coefficient (Cu)• Angle of internal friction, (Sand)• Undrained shear strength, Su (Clay)

• Relative density (Dr)• Percentage of fines (passing from sieve # 200)• Sand grain roundness parameter ()

3. Earthquake• Magnitude, M• Peak ground acceleration, amax

QUESTIONS ????•