The liquid limit and plastic limit of a cohesive soil are determined in a laboratory as 40% and 20% respectively. What is the plasticity index of the soil?

A soil yields a maximum dry density of 1.6 g/cm3 at an optimum moisture content (OMC) of 18% during a standard Proctor test. If the specific gravity G = 2.62, find the void ratio and degree of saturation.

A stratified soil deposit consists of three layers with permeabilities k1 = k, k2 = 2k, and k3 = 3k, and thickness values H1 = h, H2 = 2h, and H3 = 3h respectively. Find the ratio of equivalent permeability in the horizontal direction to that in the vertical direction (kH / kV).