jacobs pilot geotechnical s ite inves t igation san francisco… · 2018. 10. 24. · san...

JACOBS

PILOT GEOTECHNICAL SITE INVESTIGATION

SAN FRANCISCO, CALIFORNIA

Fugro Document No. 04.72170066 Appendix E

JACOBS PILOT GEOTECHNICAL SITE INVESTIGATION SAN FRANCISCO, CALIFORNIA

Fugro Document No. 04.72170066-PR-002(V2) Appendix E of 7

E.5 STRAIN-CONTROLLED UNDRAINED CYCLIC DIRECT SIMPLE SHEAR TESTS

Table E.5: Summary of Strain-Controlled Undrained Cyclic Direct Simple Shear Test Results

Boring Sample Depth

(ft)

Estimated In-Situ Vertical

Effective Stress, σ𝒗𝒗𝒗𝒗′ (ksf)

Lab Vertical Effective

Consolidation Stress, σ𝒗𝒗𝒗𝒗′ (ksf)

Lab OCR

Water Content

as Trimmed

(%)

Water Content

at σ𝒗𝒗𝒗𝒗′ (%)

Number of

Loading Cycles,

N

Average Shear Strain

Amplitude, ±γ (%)

Shear Modulus at N=1 (ksf)

Shear Modulus at N=30

(ksf)

Material Damping Ratio at

N=2 (%)

B-L-001 S-11 55.8 3.80 8.17 1.4 36.3 27.4 30 0.12 558.3 536.8 4.7

B-L-001 S-11 55.8 3.80 8.17 1.4 36.3 27.4 30 1.07 229.2 144.9 16.6

B-L-001 S-11 55.9 3.80 8.17 1.4 35.2 28.7 30 0.40 400.8 401.9 12.7

B-L-001 S-11 55.9 3.80 8.17 1.4 35.2 28.7 30 3.12 105.1 40.5 21.8

B-L-001 S-11 56.5 3.83 11.44 1.0 34.6 29.3 30 0.12 614.4 574.0 6.7

B-L-001 S-11 56.5 3.83 11.44 1.0 34.6 29.3 30 1.09 240.8 169.3 16.8

B-L-001 S-11 56.7 3.83 11.44 1.0 38.8 30.6 30 0.35 479.1 428.0 8.8

B-L-001 S-11 56.7 3.83 11.44 1.0 38.8 30.6 30 3.05 120.6 53.3 20.2

B-M-001 S-13 60.6 2.48 4.92 1.5 51.9 39.2 30 0.09 700.3 641.1 8.0

B-M-001 S-13 60.6 2.48 4.92 1.5 51.9 39.2 30 0.90 205.8 147.0 18.7

B-M-001 S-13 61.1 2.51 7.38 1.0 50.0 38.5 30 0.09 777.0 710.1 11.3

B-M-001 S-13 61.1 2.51 7.38 1.0 50.0 38.5 30 0.90 213.2 156.4 20.5

B-M-001 S-13 61.3 2.51 4.92 1.5 56.9 42.2 30 0.27 482.2 400.1 12.7

B-M-001 S-13 61.3 2.51 4.92 1.5 56.9 42.2 30 2.70 89.0 44.0 25.0

JACOBS




JACOBS




CYCLIC DSS PROPERTIES TESTOCR = 1 - Cyclic Rate: 1.0 Hz - Sequence 1 of 2

Sample: S-11a - Depth: 56.50 ftBoring B-L-001

0

100

200

300

400

500

600

700

1 10 100

Shea

r Mod

ulus

-G

(ksf

)

0

1

2

3

4

5

6

7

8

1 10 100

Dam

ping

(%)

Number of Cycles, N

'v,c = 11.440 ksfcy = 0.122 %

JACOBS





Sample: S-11a - Depth: 56.50 ftBoring B-L-001

0

50

100

150

200

250

300

1 10 100

Shea

r Mod

ulus

-G

(ksf

)

0

5

10

15

20

25

1 10 100

Dam

ping

(%)

Number of Cycles, N

'v,c = 11.440 ksfcy = 1.087 %

JACOBS





Sample: S-11b - Depth: 56.65 ftBoring B-L-001

0

100

200

300

400

500

600

1 10 100

Shea

r Mod

ulus

-G

(ksf

)

0

2

4

6

8

10

12

1 10 100

Dam

ping

(%)

Number of Cycles, N

'v,c = 11.440 ksfcy = 0.353 %

JACOBS





Sample: S-11b - Depth: 56.65 ftBoring B-L-001

0

20

40

60

80

100

120

140

1 10 100

Shea

r Mod

ulus

-G

(ksf

)

0

5

10

15

20

25

30

1 10 100

Dam

ping

(%)

Number of Cycles, N

'v,c = 11.440 ksfcy = 3.054 %

JACOBS




CYCLIC DSS PROPERTIES TESTOCR = 1.4 - Cyclic Rate: 1.0 Hz - Sequence 1 of 2

Sample: S-11d - Depth: 55.75 ftBoring B-L-001

0

100

200

300

400

500

600

1 10 100

Shea

r Mod

ulus

-G

(ksf

)

0

1

2

3

4

5

6

1 10 100

Dam

ping

(%)

Number of Cycles, N

'v,c = 8.170 ksfcy = 0.124 %

JACOBS





Sample: S-11d - Depth: 55.75 ftBoring B-L-001

0

50

100

150

200

250

1 10 100

Shea

r Mod

ulus

-G

(ksf

)

0

2

4

6

8

10

12

14

16

18

20

1 10 100

Dam

ping

(%)

Number of Cycles, N

'v,c = 8.170 ksfcy = 1.071 %

JACOBS





Sample: S-11e - Depth: 55.90 ftBoring B-L-001

0

50

100

150

200

250

300

350

400

450

1 10 100

Shea

r Mod

ulus

-G

(ksf

)

0

2

4

6

8

10

12

14

16

1 10 100

Dam

ping

(%)

Number of Cycles, N

'v,c = 8.170 ksfcy = 0.397 %

JACOBS





Sample: S-11e - Depth: 55.90 ftBoring B-L-001

0

20

40

60

80

100

120

1 10 100

Shea

r Mod

ulus

-G

(ksf

)

0

5

10

15

20

25

30

1 10 100

Dam

ping

(%)

Number of Cycles, N

'v,c = 8.170 ksfcy = 3.118 %

JACOBS





Sample: S-13a - Depth: 61.10 ftBoring B-M-001

0

100

200

300

400

500

600

700

800

900

1 10 100

Shea

r Mod

ulus

-G

(ksf

)

0

2

4

6

8

10

12

14

16

1 10 100

Dam

ping

(%)

Number of Cycles, N

'v,c = 7.380 ksfcy = 0.095 %

JACOBS





Sample: S-13a - Depth: 61.10 ftBoring B-M-001

0

50

100

150

200

250

1 10 100

Shea

r Mod

ulus

-G

(ksf

)

0

5

10

15

20

25

30

1 10 100

Dam

ping

(%)

Number of Cycles, N

'v,c = 7.380 ksfcy = 0.897 %

JACOBS





Sample: S-13b - Depth: 61.25 ftBoring B-M-001

0

100

200

300

400

500

600

1 10 100

Shea

r Mod

ulus

-G

(ksf

)

0

2

4

6

8

10

12

14

16

1 10 100

Dam

ping

(%)

Number of Cycles, N

'v,c = 4.920 ksfcy = 0.271 %

JACOBS





Sample: S-13b - Depth: 61.25 ftBoring B-M-001

0

10

20

30

40

50

60

70

80

90

100

1 10 100

Shea

r Mod

ulus

-G

(ksf

)

0

5

10

15

20

25

30

35

1 10 100

Dam

ping

(%)

Number of Cycles, N

'v,c = 4.920 ksfcy = 2.704 %

JACOBS





Sample: S-13d - Depth: 60.55 ftBoring B-M-001

0

100

200

300

400

500

600

700

800

1 10 100

Shea

r Mod

ulus

-G

(ksf

)

0

1

2

3

4

5

6

7

8

9

10

1 10 100

Dam

ping

(%)

Number of Cycles, N

'v,c = 4.920 ksfcy = 0.093 %

JACOBS





Sample: S-13d - Depth: 60.55 ftBoring B-M-001

0

50

100

150

200

250

1 10 100

Shea

r Mod

ulus

-G

(ksf

)

0

5

10

15

20

25

1 10 100

Dam

ping

(%)

Number of Cycles, N

'v,c = 4.920 ksfcy = 0.897 %


Fugro Document No. 04.72170066-PR-002(V2) Appendix E Page 7 of 7

E.6 RESONANT COLUMN TESTS

Table E.6: Summary of Resonant Column Test Results

Boring Sample Depth (ft)

Estimated In-Situ Vertical

Effective Stress, σ𝒗𝒗𝒗𝒗′ (ksf)

Initial Water

Content (%)

Stage

Lab Mean Effective

Consolidation Stress, σ𝒗𝒗𝒄𝒄𝒄𝒄𝒄𝒄′ (ksf)

Void Ratio at σ𝒗𝒗𝒄𝒄𝒄𝒄𝒄𝒄′

Water content at

σ𝒗𝒗𝒄𝒄𝒄𝒄𝒄𝒄′

Shear Modulus at Small Shear Strain

Amplitude, 𝑮𝑮𝒎𝒎𝒎𝒎𝒎𝒎 (ksf)

B-L-001 S-11 56.4 3.82 39.5

1 1.48 0.98 35.7 685.51

2 2.97 0.92 33.5 1041.68

3 5.95 0.87 31.8 1722.27

B-M-001 S-13 61.0 2.50 49.8

1 0.91 1.40 50.8 473.41

2 1.81 1.36 49.3 650.82

3 3.64 1.21 43.8 1071.70

JACOBS




RESONANT COLUMN TESTThree Stages of Isotropic Consolidation - OCR = 1

Sample: S-11c Depth: 56.35 ftBoring B-L-001

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.0E-04 1.0E-03 1.0E-02 1.0E-01 1.0E+00 1.0E+01

Nor

mal

ized

She

ar M

odul

us, G

/Gm

ax

Shear Strain Amplitude, cy %)

Seq. 1

Seq. 2

Seq. 3

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

1.0E-04 1.0E-03 1.0E-02 1.0E-01 1.0E+00 1.0E+01

Dam

ping

, %

)


Seq. 1

Seq. 2

Seq. 3

JACOBS




RESONANT COLUMN TESTThree Stages of Isotropic Consolidation - OCR = 1

Sample: S-13c Depth: 60.95 ftBoring B-M-001

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.0E-04 1.0E-03 1.0E-02 1.0E-01 1.0E+00 1.0E+01

Nor

mal

ized

She

ar M

odul

us, G

/Gm

ax


Seq. 1

Seq. 2

Seq. 3

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

1.0E-04 1.0E-03 1.0E-02 1.0E-01 1.0E+00 1.0E+01

Dam

ping

, %

)


Seq. 1

Seq. 2

Seq. 3


Fugro Document No. 04.72170066-PR-002(V2) Appendix F

F. DATA INTERPRETATION PRESENTATION SLIDES (9/13/2018)

Pilot site investigation data interpretation

September 13, 2018

Preliminary data interpretation for pilot site investigation presented to the Port and Seismic Peer Review Panel on 9/13/2018.

2

Outline of presentation

• Sample quality

• Strength– Monotonic (DSS, FVT, CPT)

– Cyclic

– Rate effects

– Sensitivity

• Shear strain dependent modulus and material damping

• Liquefaction assessment for sandy seams at Pier 3

3

Sample quality

4

Sample quality criteria

• Reconsolidation strain (Terzaghi et al. (1996))• / (Lunne et al. 1997)• Work-based framework (DeJong et al. 2018)

5

Sample quality

• Sample quality similar to that achieved for historic projects (piston samplers) in the project vicinity.

• Better sample quality for marine boring (greater OCR, lower confinement).

All data points for the pilot study (B-L-001 and B-M-001) are Otserberg piston samples.Lunne et al. 1997 e/eo criteria: VGE = Very good to excellent; GF = Good to fair; P = Poor; VP = Very Poor.

6

Sample quality (work-based framework)

• Work-based framework (DeJong et al. 2018) indicates better sample quality (relative to / ) for samples from the land boring and is less dependent on OCR and depth.

Lunne et al. 1997 e/eo criteria: VGE = Very good to excellent; GF = Good to fair; P = Poor; VP = Very Poor.

7

Strength

8

Monotonic strength (lab measurements)

• Undrained monotonic DSS tests results are consistent and follow empirical stress normalization relationships.

9

Normalized monotonic DSS stress-strain response

• Softening in DSS tests was significantly less than measured (at much high shear strains) during field vane testing (sensitivities of ~3-5).

10

Virgin and postcyclic monotonic DSS

• Strength loss due to generation of excess pore pressure during cyclic loading.

11

Monotonic strength (in-situ and lab measurements)

Vane correction ( ) and based on DSSm tests. Bjerrum correction shown for reference.= , ; = 0.85= 12.5 (marine) and 13.5 (land)

Greater strength for land boring (larger confinement) and greater strength ratio for the marine boring (greater OCRs).

12

Cyclic strength

• Stress-controlled cyclic DSS tests were performed at 1 Hz loading frequency.

• Good agreement with empirical expectation for sedimentary clays.

13

Effect of strain rate on undrained shear strength

• Cyclic and monotonic DSS data consistent with approximately 10% increase in undrained strength per log cyclic increase in shear strain rate.

Rate effects are consistent with empirical expectation for sedimentary clays (indicating consistency between DSS tests performed on different devices and at different rates).

14

FVT interpretation

25 revolutions

Slide added after 9/13/2018 presentation to provide clarification for interpretation of peak, residual and remolded field vane shear strengths.

15

Sensitivity

• Sleeve friction is approximately equal to remolded strength (FVT data not corrected)

• Ns = 6-9 roughly captures range of measured sensitivities

Lunne et al. (1997) suggest Ns = 6 to 9 represents the likely range of data.

16

Small-strain shear modulus

• Resonant column measurements are generally consistent with in-situ shear wave velocity measurements near the Ferry Building.

Resonant column test data are for isotropic consolidation conditions.

17

Modulus reduction and damping

• Data from pilot study consistent with relationships used for BART SFTS (based on data from Bay Bridge and SFO).

18

Liquefaction of sandy seams

19


20


21

Liquefaction susceptibility

Boulanger and Idriss (2004)Bray and Sancio (2006)

22


Negligible susceptibility (Ic, PI)

FSliq < 0.35 for all considered events(43, 225, and 1000 year return periods)

23

Summary

• Sample quality for the pilot study is consistent with piston samplers for historic projects in the project vicinity.

• Strength– A FVT correction of =0.85 gives good agreement with monotonic DSS test results

– Nkt = 12.5 (marine) and 13.5 (land) give good agreement with monotonic DSS test results

– Monotonic and cyclic DSS tests results consistent with empirical rate effects for sedimentary clays

• Pilot data consistent with BART SFTS modulus reduction and damping curves• Liquefaction of sandy seams

– Continuous seam at ~ - 55 ft elevation negligible susceptibility to liquefaction (Ic, PI)

– Sandy soil at ~-40 ft elevation (C-M-001) expected to liquefy in all events considered (43, 225, and 1000 year return periods)

jacobs pilot geotechnical s ite inves t igation san francisco… · 2018. 10. 24. · san...

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