A water tower is constructed on a circular raft 4 m in diameter at a depth of 2 m below the ground surface in sand having bulk unit weight of 18 kN/m. The gross pressure at the base of the raft is 150 kN/m. What will be the increase in vertical stress at a point 3 m beneath the centre of the raft?

Compute the increase in the stress at point A when two line loads of value 90 kN/m and 325 kN/m act on the soil surface at a distance of 4 m between them. Also, the point A is 3 m below the surface and at horizontal distance of 2.5 m from the second line load.

Note:hand written solution should be avoided.

Referring to Figure Q2 (a), the vertical stress increase at point A is 25 kN/m2due to application of line loads q1 and q2. Determine the magnitude of q2.

A level ground surface exists in an area where soil in the underlying stratum has a wet unit weight of 19 kN/m3. The vertical pressure at any depth represents the major principal stress. The vertical pressure (stress) is the product of the soil unit weight and depth. The lateral pressure at a corresponding depth is 0.45 times the vertical pressure and represents the minor principal stress. (a) Determine the principal stresses acting at a depth 4 m below the surface, and draw the Mohr’s circle for the condition. (b) What is the maximum shear stress acting at this depth?

2. Find the induced stress at point B at depth 20 ft below the surface. The bearing pressure on the area is 400 psf. 40 ft 35 ft 70 ft