Lem $4(20$ Points$)$

in excavation will be made for a ten storey $1525m$ building. Temporary support of earth pressure and water pressure will be made by deep secant cantilever pile wall. The gross pressure due to dead and live loads of the structure and weight of the raft is $130$kPa $($assume that it is uniform$).$

a$)$ What is net foundation pressure at the end of construction but before the void space between the pile wall and the building has not been filled, and there is no water inside the foundation pit yet $($water level at the base level$)($GWT position $1).$

b$)$ What is net foundation pressure long after the completion of the building, i$.$e$.$ water level is inside the pile wall and the backfill between the building and the pile wall is placed $($GWT position $2).$ What is the factor of safety against uplift?