Question

A 2 m wide square foundation is placed at a depth of 1.5 m in a very thick homogeneous sand deposit where qc = 10 MN/m2 , μs = 0.15 and  = 18.5 kN/m3 . The stress level at the foundation is 140 kN/m2 and the water table is currently at a depth of 1.5 m below the foundation. a. Using the theory of elasticity and Terzaghi’s theories, estimate the total elastic settlement at the centre of the foundation.

Answer 1

The stress level at the foundation in the image is 167.75 kN/m².

The stress level at the foundation in the image is 140 kN/m².

This can be calculated by using the following equation:

σ = q + γz

where:

σ is the stress level at the foundation (kN/m²)

q is the overburden pressure (kN/m²)

γ is the unit weight of the soil (kN/m³)

z is the depth of the foundation (m)

In this case, the overburden pressure is equal to the weight of the soil column above the foundation. This can be calculated by multiplying the unit weight of the soil by the depth of the foundation:

q = γz

q = 18.5 kN/m³ * 1.5 m

q = 27.75 kN/m²

Therefore, the stress level at the foundation is equal to the overburden pressure plus the applied load from the foundation:

σ = 27.75 kN/m² + 140 kN/m²

σ = 167.75 kN/m²

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