FES Test 2 (5 Years Ago)

8/8/2019 FES Test 2 (5 Years Ago)

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Test 2

Foundation Engineering and Earth RetainingStructure

Name: :

ID No :



PART A; SHEAR STRENGTH OF SOIL

A.1 Identify tests that relevant in directly determining Coulomb’s strengthparameters.

[5 MARKS]

a. Direct Shear Test

UU

CU

CD

b. Triaxial TestUU

CU

CD

c. Unconfined Compression Test

d. Oedometer Test

f. Laboratory Vase Shear Test

g. Standard Penetration Test

h. Cone Penetration Testi. Dilatometer Test

j. Pressuremeter Test

k. Field Vane Shear Test

A.2 Identify tests that relevant in indirectly determining Coulomb’s strengthparameters.

[5 MARKS]


UU

CU

CD

b. Triaxial Test

UU

CU

CDc. Unconfined Compression Test

d. Oedometer Test

f. Laboratory Vase Shear Test

g. Standard Penetration Test

h. Cone Penetration Test



FIGURE QA3

A.3 Identify graph as results of soil testing in FIGURE QA3 for thefollowing test.

[5 MARKS]


UU

CU

CDb. Triaxial Test

UU

CU

CD

c. Unconfined Compression Test



A.4

Tick terms that relevant tosand

[5 MARKS

TERMS Tick terms that relevantto clay

[5 MARKS

1 Relative Density

2 Specific Gravity

3 Void Ratio

4 Water Content

5 Particle Shape

6 Liquid Limit

7 Plastic Limit

8 Plasticity Index

9 Coefficient of Uniformity

10 Dry Density

11 Coefficient of Curvature

12 Degree of Saturation

13 Compression Index

14 Swelling Index

15 Coefficient of Consolidation

16 Saturated Density

17 Shrinkage Limit

18 Undrained Cohesion

19 Consolidation

20 Time Rate of Consolidation

21 Degree of Consolidation

22 Consistency23 Elastic Settlement

24 Consolidation Settlement

24 Medium Density



PART B: COMPRESSIBILITY OF SOIL

Given a two-layer soil system with ground water level two meter below groundsurface. The water level will be lowered to the top of clay layer. You arerequested to assess the settlement on top of clay layer. The followingconsolidation settlement equation is given as below.

σ

σ∆+σ

+=∆

o

o

o

c H

e

C S log

1

C.1. Calculate effective pressure at point A:

a. Before lowering of ground water:

=vσ ___________ kN/m2

[1 MARKS] b. After lowering of ground water level

=vσ ___________ kN/m2

[1 MARKS]



PART C: EARTH RETAINING STRUCTURE

C.1 Steps to be taken to assess the stability of steel sheetpile penetrating into claylayer, retained horizontally by rock anchor, can best described as follow:

[5 MARKS]

a. 1. Check depth of embedment. Increase depth of embedment if required,

2. Determine earth pressure distribution,

3. Calculate passive and active forces,

4. Calculate point of inflection by rotational equilibrium,

5. Calculate anchor force by horizontal equilibrium equation,6. Check capacity of tie rod.

7. Check overall stability,

8. Check capacity of rock anchor,

b. 1. Check depth of embedment. Increase depth of embedment if required,

2. Determine earth pressure distribution,


4. Calculate point of inflection by rotational equilibrium,5. Calculate anchor force by horizontal equilibrium equation,

6. Check bearing capacity of sheetpile,


c. 1. Determine earth pressure distribution,


3. Calculate anchor force by horizontal equilibrium equation,

4. Check capacity of tie rod.5. Check bearing capacity of sheetpile,



d. 1. Determine earth pressure distribution,


3. Calculate point of inflection by rotational equilibrium,

4. Calculate anchor force by horizontal equilibrium equation,5. Check bearing capacity of sheetpile,



e. 1. Check depth of embedment. Increase depth of embedment if required,



C.2. For a anchored sheetpile shown in FIGURE D-Q2 below, L1 is 4.0 meter and L2 is 9 meter. The soil is sand throughout.

Calculate effective pressure distribution at the following points:

[3 MARKS]

a. Point A: =vσ ___________ kN/m2

b. Point B: =vσ ___________ kN/m2

c. Point C: =vσ ___________ kN/m2

C.3 Equation to obtained L3 is obtained by knowing the fact that active and passivepressure is equalizing. The correct equation to obtain L3 is:

[3 MARKS]

a.)(

3 D B

De D L

σ σ

σ

+=

b.)(

3

a p

D

K K L

−=γ

σ

D σ

P

A

Fl2

l1 A

C

D

B

L

L

De

Sand:γ =18kN/m

3

φ=35o

L

L

Water Table

X



e.)(

3 pa

D

K K L

−=γ

σ

C.4. Suppose that L3 is 2.0 meter and De is 5.0 meter, calculate the following:

[2 MARKS]

a. Active force, A = _________________ kN/m’

b. Passive force, P = _________________ kN/m’

c. Anchor force, F = _________________ kN/m’

C.5 The equilibrium equation to obtained L3 is

[2 MARKS]

a. 0)(3

24 =−+− X D L A

LP e

b. 0)3

1()( 432 =+−− L LPl X A

c. 0)3

2()( 432 =+−− L LPl X A

d. 0)(3

24 =+++− X D L A

LP e

e. 0)3

2()( 432 =++− L LPl X A

C.6 FIGURE 1 shows several possibility of earth pressure diagram (GROUP A)

based on type of soil being penetrated (sand or clay), type of flexible sheetpile in

GROUP B (cantilever sheetpile, anchored sheetpile and freestanding sheetpile).

Select the correct pairing of GROUP A and GROUP B

[5 MARKS]

a. (a-A), (b-E), (c-F), (d-D), (e-B), (f-C)

b. (a-E), (b-A), (c-B), (d-C), (e-F), (f-D)

c. (a-B), (b-F), (c-D), (d-A), (e-C), (f-E)

d. (a-F), (b-B), (c-D), (d-C), (e-E), (f-A)



C.7

Pick the earth retaining structure from the following list that you think for the: (a.

embankment, b. above surface excavation, and c. below surface excavation.

1. Gravity wall,2. Counterfort wall,3. Sheet pile wall with or without anchored,4. Braced excavation,5. Soil nailing,6. Diaphragm wall with or without anchored,7. Closely spaced bored pile with or without anchored,8. Reinforced wall

a. Two meter fill (or embankment).

[2 MARKS]

b. Six meter excavation at roadside.

[2 MARKS]

c. Fifteen meter excavation for basement.

[2 MARKS] d. Six meter excavation for basement.

[2 MARKS]

e. Eight meter fill for bridge abutment.

[2 MARKS]



PART D: FOUNDATION

D.1 Identify the type of foundation from the above figure.

[2 MARKS]

a.

b.

c.

d.

f.

1. Shallow Foundation

Background information

The following equation is a general bearing capacity equation that govern the shallow foundation:

γ γ γ F BN qN F cN q qccu2

1++=

Where:

a=?

d=?c=?



D.2

a. Given depth of embedment is 2 meter, width of the footing is 3 meter, unitweight of soil 15 kN/m

3, cohesion is 15 kN/m

2and friction angle is 35

o,

calculate the ultimate bearing capacity.

qu= _______________kN

[1 MARKS]

b. Given depth of embedment is 2 meter, width of the square footing is 3

meter, unit weight of soil 15 kN/m3, cohesion is 15 kN/m

2, friction angle is

35o, and the ground water table reaches the bottom of footing, calculate the

ultimate bearing capacity.

qu= _______________kN

[2 MARKS]

c. Given depth of embedment is 2 meter, width of the footing is 2 meter and

its length is 4.5 meter, unit weight of soil 15 kN/m3, cohesion is 15 kN/m

2,

friction angle is 35o, and the ground water table reaches the bottom of

footing, calculate the ultimate bearing capacity.

qu= _______________kN

[2 MARKS]

d. If the applied vertical load is 1.5 MN, depth of embedment is 1 meter, unit

weight of soil 15 kN/m3, cohesion is 20 kN/m

2, friction angle is 35

o, and

the ground water table reaches the bottom of footing, calculate the ultimate

bearing capacity.

qu= _______________kN

[5 MARKS]

f. If the applied vertical load is 1.5 MN and inclined 10o to the vertical,depth of embedment is 1 meter, unit weight of soil 15 kN/m

3, cohesion is

20 kN/m2, friction angle is 35

o, and the ground water table reaches the

bottom of footing, calculate the ultimate bearing capacity.

qu= _______________kN

[5 MARKS]



D.3

[5 MARKS]A pad foundation is place on a two-layer soil system with a weak soil layer

overlying a stronger soil layer. In your opinion which of the following statement

is the most correct statement to calculate the ultimate bearing capacity.

a. Use stronger soil strength parameter, 1,, 11 φ γ c , in the general bearing

capacity equation, included all possible correction factor, to calculate the

ultimate bearing capacity.

b. Use weak soil strength parameter, 222 ,, φ γ c , in the general bearingcapacity equation, included all possible correction factor, to calculate the

ultimate bearing capacity. This approach is a lower bound value.

c. Calculate the bearing capacity of both the weak and strong layer and take

the average as the ultimate bearing capacity of the two-layer system.

d. Calculate contribution of passive resistance and adhesion, which develop

within the stronger soil layer to the bearing capacity of weak layer.

f. Calculate the bearing capacity of both the weak and strong layer and take

the weighted average as the ultimate bearing capacity of the two-layer

system. Thickness of each layer is used as weighting factor.



A comparison is to be made between a pad foundation and a mat foundation.

Both are for a foundation of building with excavation for basement D below the

ground surface. The width of the building is W. Both the thickness of the pad

and mat are t.

D.4 Select from the following equations the ultimate bearing capacity of pad

foundation.

[2 MARKS]

a.γ γ γ γ F BN DN F cN q qccu

2

1++=

b.γ γ γ γ F BN tN F cN q qccu

2

1++=

c.γ γ γ γ F WN DN F cN q qccu

2

1++=

d.γ γ γ γ F WN tN F cN q qccu

2

1++=

f.γ γ γ F BN qtN F cN q qccu

2

1++=

D.5 Select from the following equations the ultimate bearing capacity of mat

foundation.

W W W

B B

D

t



b.γ γ γ γ F BN tN F cN q qccu

2

1++=

c.γ γ γ γ F WN DN F cN q qccu

2

1++=

d.γ γ γ γ F WN tN F cN q qccu

2

1++=

f.γ γ γ F BN qtN F cN q qccu

2

1++=

2. Pile Foundation

Background information

Given the following pile bearing capacity equation.

s

s

b

baF Q

F QQ +=

bbb q AQ = and ∑= pl f Q isis , hence,

s

iis

b

bba

F

pl f

F

q AQ

∑+=

Where:

sb F F , Factor of safety for base and friction resistance capacity,respectively

b A Area of base

bq Ultimate base pressure

='q N q

si f Friction of layer i

il Thickness of layer i

p Perimeter of pile

bq = ''qc N qcN +

'c N and 'q N = bearing capacity factorsFor clay:

usi c f α = ;

α is obtained from table or other resources,

uc is undrained strength

For sand:



Table 1: Bearing Capacity Equation

a.

sb

bqa

F

plllK llK

F

A N llQ

]tan)(5.0tan[)( 2222112111112211 δ γ γ δ γ γ γ +++

+=

b.

s

u

b

bqa

F

plllK lc

F

A N llQ

)tan)(5.0)()(22211212211 δ γ γ α γ γ ++

++

=

c.

s

uu

b

bua F

plclc

F

Ac

Q

)(9 222111 +

+=

d.

sb

bua

F

plllK llK

F

AcQ

)tan)(5.0tan(9 222211211111 δ γ γ δ γ +++=

e.

s

u

b

bu

a F

plllK lc

F

AcQ

)tan)(5.0(9 2222112111 δ γ γ +++=

D6 Given Table 1 and FIGURE 2, match pile condition in FIGURE 2 and pilebearing capacity equation in Table 1.

A. Equation ( ) from Table 1:

[1 MARKS]

B. Equation ( ) from Table 1:

[1 MARKS]

C. Equation ( ) from Table 1:

[1 MARKS]

D. Equation ( ) from Table 1:

[1 MARKS]

E. Equation ( ) from Table 1:

[1 MARKS]

F. Equation ( ) from Table 1:

[1 MARKS]



D.7 Figure below shows driven pile penetrating into highly overconsolidated clay

layer through two layers of medium dense sand. The thickness of Layer 1 and

Layer 2 are 5 meter and 6 meter respectively. The prestressed concrete pile has a

diameter of 600 mm.

a. Calculate overburden pressure at the bottom of the first layer (A) and agt

the top of the second layer (B), respectively

Answer:

At A: vσ =_________kN/m2

At B: vσ =_________kN/m2

[1 MARKS]

b. Determine the critical depth Dc

Answer:

Dc=__________m

[1 MARKS]

A

MediumSand

Highly OCClay

MediumSand

Bed Rock

l1

l2

Layer 1, γ 1=18kN/m3, φ1=30o

Layer 2, γ 2=18kN/m3, φ2=35o

cu=15kN/m2

B



d. Give your best estimate for coefficient of lateral pressure for driven

pile 1K and 2K . Remember, the coefficient of lateral earth pressure fordriven pile is larger than coefficient of lateral earth pressure at rest.

Answer:

K 1=__________

K 2=__________

[1 MARKS]

e. Pick bearing capacity equation that most relevant to the above problem.

Answer:

Equation:________

[1 MARKS]

f. Calculate the ultimate pile base capacity.

Answer:

Qb=__________kN

[1 MARKS]

g. Calculate friction resistance taking into account the “critical depth”.

Qs=__________kN

[1 MARKS]

h. Calculate friction resistance WITHOUT taking into account the “criticaldepth”.

Qs=__________kN

[1 MARKS]

i. If F b=3 and F s=2.5, calculate allowable bearing capacity

Answer:

Qa=__________kN

[1 MARKS]



19

FIGURE 1



20

FIGURE 2

FES Test 2 (5 Years Ago)

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