An exploratory drill hole was made in a saturated stiff clay having a water content of 32%. It was observed that the sand layer underlying the clay was under artesian pressure water in the drill hole rose to a height of 4 m. above the top of the sand layer. If an open excavation is to be made in the clay. ground surface exploratory drill hole Šaturated clay. 8m =32% G=2.70 4m- B. Sand 3m. a) Determirne the void ratio of clay. b) Determine the saturated unit weight of clay. c) How deep can the excavation proceed before the bottom of the saturated clay heaves or when its effective stress is zero.

0.50 m. 1.50 m 1.50 m. 0.50 m² N B D 2.00 m F E

PROBLEM SOLVING Analyze this problem and complete the level note with customary arithmetic check. 8.89 3.46 7.75 1.83 BM No. 4 10.34 1.37 9-7 (H)2.64 TP, 2.178.57 (H) 8.56 [11.14 TP, 1-89 CH) BM No. 3 elevation 441.72 ft

Please answer 15.2