A deposit of dean sand has unit weight equal to 22 kN/m ³ . The relative density increases approximately linearly from 60% at the surface of the deposit to 75% at a depth of 10 m. K ₀ is 0.45 for this deposit. The sand can be assumed to have φ = 30°, Q = 10 and R _Q = 1.

Calculate and plot the values of φ _p under triaxial and plane-strain compression conditions between 0 and 10 m depth assuming σ’ _c = σ’ _m . Consider the water table to be very deep (deeper than 10 m).