Excavation project-terzaghis method-bjerrum and eids method

Question

Question 1: An excavation project (B = L =20m) has soil profile shown in the figure where. c_w/s_u = 0.5 and γ_sat = 18 kN/m³.

A) Calculate the factor of safety (F_p) against push-in failure.

B) Calculate the factor of safety (F_b) against basal heave failure using the slip circle method.

C) Calculate the factor of safety (F_b) against basal heave failure using Terzaghi’s method.

D) Calculate the factor of safety (F_b) against basal heave failure using Bjerrum and Eid’s method.

E) Is it necessary to check sand boiling (Fs). If yes, calculate Fs using one dimension seepage method. If not, indicate your reason.

Question 2: A 2m×2m shallow foundation is shown as figure below. Calculate long-term and short-term bearing capacity (q_ult) using Terzaghi method.

γ_sat = 20 kN/m³
c’ = 5kPa
Φ’ = 25° 
cu = 30 kPa