2(a) Two foundations are constructed as shown in Fig. Q.2a. The uniform load acting on the rectangular and the L-shaped foundations are 150 and 2Y0 kPa respectively. Ignoring the effect of the self-weight of the foundations, determine the increase in vertical stresses due to the two foundations at a depth 5 m directly below the foundation at (i) location A and, (ii)location B. (6 marks) 8 m Rect. Foundation 150 kPa (6 marks) where Y is the last L-shaped digit of your 2Y0 kPa student number Figure Q.2a (NTS) (b) A pad foundation of size 8m x 8m is constructed at a depth of 2m below surface in a layer of sand, which in turn is underlain by a layer of normally consolidated clay as shown in Figure Q.2b. The ground water level is at 4m below ground level. The foundation will exert a net increase in pressure of 300 kN/m² on the ground. The compression index (cc) is 0.3Y and the initial void ratio (eo) of the clay is 0.45 respectively, (where Y is the last digit of your student number). (i) Using a spread of the load of 2 vertical to 1 horizontal, estimate the ultimate consolidation settlement in the clay layer due to the foundation. (8 marks) (ii) What would be the total ultimate consolidation settlement if there is a further permanent draw down of ground water level of 2m due to a dewatering process in a nearby site? (5 marks) 4 m 2 m sand 300 kN/m² Y = 17 kN/m³ 3 m Yat=19 kN/m³ 2 m Normally consolidated clay at 18 kN/m³ Figure Q.2b (NTS)