Question

Q1: for the soil profile in the figure, the surcharge was replaced by a rigid square 2 m footing of 2 2m and loading of 200 kN/m from the N.G.L, after two at dept h of 2m 2m Sand months of surcharge application, estimate the total settlement of the footing, knowing that "q" of the surcharge is 250 kN/m average N of the sand layer is 30, the Poisson ratio in saturated soils is: 0.5, the modulus of elasticity of the clay is: 40 4 m 2.80' misec - 0 26 mday Clay 2 C 0.38 m'day Yelay 19.5kN/m3, yclay2 21kN/m, and 0.8, Cclay1-0.9 and eclay2 0.95. Sand..i.. 2: if the loading profile is applied on deep soil layer, what will be the total settlement? 3: What will be the changes in footing settlement if: 1) water table changes; 2) coefficient of permeability changes? Table 9.2 2 L/B LB-5 4 0.73 0.82 1.00 1.22 circle 10

Answer 1

66 2 180 132 KN/m2 10 20ox C2t6)C246) 12 205125 o 8.06 mm mon th NOTES

Ss冫 10 0.028m of-28mm. 12 - 0 056 m o 5.6 mm Ss = 33.6mm, ague, fotal attilomint S 15:36 + 48.01+ 3.3-6

Ans 2) If the loading profile is applied to deep soil layer ,

Immediate settlement will same = 15.36 mm

settlement due to primary consolidation will also same = 48.01 mm

Secondary settlement = 5.6 mm

Total settlement = 96 mm

Ans 3a) If water table changes then effective stresses will change and hence if water table decrease settlement decreases and when water table increase settlement increase.Also, water table effects bearing capacity of soil and hence affects settlement.

Ans 3b) When coefficient of permeability increase void ratio increase and hence settlement decreases. Similarly when permeability decrease ,settlement increase.