A clear dry sand sample is tested in direct shear test. The normal stress and the shear stress at failure are both equal to 120 kN/m². The angle of shearing resistance of the sand will be

Question

Question

This question was previously asked in

BPSC AE Paper 5 (Civil Engineering) 2019 Official Paper

Answer 1

Concept:

Shear stress of a soil sample is given by,

τ = c + σ tan ϕ

Where, τ = shear strength of soil

σ = normal stress of soil

c = cohesion

ϕ = angle of internal friction or shearing resistance

Calculation:

Dry sand sample, So, C = 0

σ = τ = 120 kN / m²

τ = 0 + σ tan ϕ ⇒ 120 = 120 tan ϕ

⇒ tan ϕ = 1

⇒ ϕ = 45°