EL-SHOROUK ACADEMY GEO-TECHNICAL ENG. (1) Civil Eng. Dep. Sheet No. 6 2 nd Year 2013-2014

Sheet-6

1- A flexible load area Figure (1) is 2mx3m in plan and carries a uniformly

distributed load of 21.0t/m2. Estimate the immediate (elastic) settlement below the

center & corner of the loaded area if :

a. Assume Df = 0 & H = ∞.

b. Assume Df = 0 & H = 4 m.

2- Refer to Figure (2) a footing that is 3.30m x 2.3m in plan is resting on sand

deposit. The net load per unit area at the level of the foundation (qn) is

1.50Kg/cm2. For the sand, µ= 0.30, Es = 225Kg/cm2, Df = 2.00m, H = 10m.

Assume that the foundation is rigid, determine the elastic settlement that the

foundation would undergo. Ignore the effect of the depth of embedment.

3- The stratification at a site consists of the following :

*- From 0.0 to -3.50 m: silty sand (ɣb=1.50t/m3, ɣsat=1.80t/m3)

*- From -3.50 m to -9.50m: {soft clay(N/C), L.L=70%, natural moisture content

=40%, specific gravity=2.72t/m3, and coefficient of consolidation 5 m2/year}

*- From -9.50 m: medium sand

*- Water Level at (-1.00m)

A tank (25 x 45) is supported at level (-2.50) and exerted foundation pressure of

15.0t/m2.Determine:

a- The initial void ratio and saturated density of clay soil.

b- The maximum differential settlement due to consolidation of the clay layer

4- Calculate time of 6cm settlement of double drainage clay layer with thickness

H=6.00m. Given that: mv=0.025Cm2/Kg ∆σ =12.0t/m2

Cv = 3.60x10-9 cm2/Sec

5- Given Cv =0.025cm2/min , Sf =8.00cm , thickness of clay layer=3m, drainage from

one side. Find:

a- Time of 50% consolidation

b- Time for 2.50cm Settlement

c- Settlement in one year

6- Fig.3 Showing Soil Properties, Calculate:

a- Estimate settlement at point a (Center)

b- Estimate settlement at point b

c- Time for 2.00cm Settlement at point b

d- Settlement at point a at the time calculated above

7- Fig.4 Illustrate data of soil properties, if water table lowered to (-6.00) find

a- Settlement of clay layer

b- time of 90% degree of consolidation

8- Referring to Fig.5 Calculate:

a- Maximum differential settlement below the building

b- Time of 50% consolidation

c- Differential settlement for villa due to construction of tall building

9- The stratification at a site consists of the following :

*- From 0.0 to -8.0 m: medium dense sand

*- From -8.0 m to -20.0m: normally consolidated soft clay

*- From 20.0 m: sandstone

The clay layer has a void ratio of 1.20, a moisture content of 45%, a compression

index of 0.30 and a coefficient of consolidation of 4m2/year. The original water table

is at -2.0 m from ground surface. If the water table is lowered by, 4.0 m (to -6.0 m)

determine the expected settlement due to consolidation of clay and time required to

reach 90% consolidation

Good Luck

Dr- Ezzat Abdel-Rahiem

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