The maximum and minimum unit weights of a granular soil are 117.1 lb/ft3 and 91.0 lb/ft3, respectively. Gs 5 2.65. What would be the relative density of the same sand compacted to a void ratio of 0.625?

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Problem 1.9 The maximum and minimum void ratios for a sand are 0.805 and 0.501 respectively. The field density test performed on the same soil has given the following results: 3 p= 1.81 Mg/m², w = 12.7%. Assume G₁ = 2.65. Compute the density index.

a) What are the typical permeability values for clay and sand, respectively? Discuss how the pore pressure in these soils would respond to loading, make use of schematic drawings when needed. b) A sample of silty clay is compacted into a mould 150 mm in diameter and 120 mm high. The mass of soil is 3.527 kg which reduces to 2.594 kg after drying in an oven. Calculate the bulk unit weight of the soil sample. Assuming the specific gravity of the soil grains, Gs = 2.72, calculate the degree of saturation and voids ratio of the soll. c) A site investigation is carried out in Northampton Square for a proposed five storey building. The ground is found to comprise 2 m of coarse gravel overlying London Clay. The gravel has a Gs = 2.65 and a specific volume of 1.573. The clay has a bulk unit weight = 17.9 kN/m³ and a coefficient of earth pressure, Ko= 1.1. The water table is at a depth of 2 m below the ground surface (i.e. level with the top of the London Clay strata). Calculate the vertical…