Average Stress Increase in Clay Layer Under Square Foundation

Lect. 8 - 16:

A $(1.83\text{ m} \times 1.83\text{ m})$ foundation shown in figure below. Using the procedure outlined in Section 8.9, determine the average stress increase in the clay layer below the center of the foundation due to the net foundation load of $500\text{ kN}$. Use the common corner, Eq. (8.25).

SOLUTION:

[Visual Content Includes]:

- Net load: $500\text{ kN}$

- Footing dimensions: $1.83\text{ m} \times 1.83\text{ m}$

- First layer: Sand, depth $1.52\text{ m}$, $\gamma = 15.7\text{ kN/m}^3$

- Water table (GWT) at boundary.

- Second layer: Sand, depth $1.22\text{ m}$, $\gamma_{sat} = 19.24\text{ kN/m}^3$

- Third layer: Clay, depth $3.05\text{ m}$, $\gamma_{sat} = 19.24\text{ kN/m}^3$, $e_0 = 0.8$, $C_c = 0.25$, $C_s = 0.06$, Preconsolidation pressure $= 100\text{ kN/m}^2$

This question includes visual content: A cross-sectional diagram of a soil profile with a foundation. A square footing of size $1.83\text{ m} \times 1.83\text{ m}$ is buried $1.52\text{ m}$ deep in a sand layer with unit weight $\gamma = 15.7\text{ kN/m}^3$. A net load of $500\text{ kN}$ is applied through a column. Below the footing base, there is a second sand layer, $1.22\text{ m}$ thick, which is saturated ($\gamma_{sat} = 19.24\text{ kN/m}^3$) with the Groundwater Table (GWT) at the footing base level. Below this sand layer is a $3.05\text{ m}$ thick clay layer with the following properties: $\gamma_{sat} = 19.24\text{ kN/m}^3$, $e_0 = 0.8$, $C_c = 0.25$, $C_s = 0.06$, and a preconsolidation pressure of $100\text{ kN/m}^2$.