A rectangular foundation 4 m × 6 m (Figure P7.20) trans- mits a stress of 100 kPa on the surface of a soil deposit. Plot the distribution of increases of vertical stresses with depth under points A, B, and C up to a depth of 20 m. At what depth is the increase in vertical stress below A less than 10% of the surface stress? B 6 m -2 m- A 2 m -4 m E

A rectangular foundation 6 x 3m carries a uniform pressure of 300 kN/m2 near the surface of a soil mass. Determine the vertical stress at a depth of 3m below a point (A) on the centre line 1.5m outside the long edge of the foundation, as shown below. 3.0 m 1.5 m 6.0 m 300 kN/m² A

A square footing is loaded as shown in Figure 05.13. The center of the base of footing is at coordinate (0, 0, 0). Determine the increase in vertical stress at a point whose coordinate is (3, 0, 4) using pressure isobars based on Boussinesq equation for square footings shown in Figure 05.7. O O O 10.215 O 10.512 10.125 10.251 P = 900 KN #7 2 m Figure 05.13

Q. 12 A soil profile at a certain location is as shown in figure. A rigid circular foundation of 4 m diameter rests on the sand. The contact pressure at the underside of the foundation is 230 kN/m?. The average coefficient of compressibility of the clay is 0.65 × 10-3 m2/kN for the stress range encountered. The ultimate settlement of the foundation assuming 45° load distribution

Two foundations are located next to each other as follows. Determine the stress increase on a horizontal plane (i.e. - the increase in vertical stress) beneath Point A at a depth of 3 m below the ground surface. The foundations are bearing on the ground surface. 3 m- +2.5 m -6 m 5 m A O= 90 kPa = 120 kPa 6 m