Consolidation of Clay: Given Exercise Figure 7.4 and the accompanying information, what is the ultimate settlement in the clay under the applied load? Note: 1 ft = 0.3048 m; 62.4 lb/ft³ = 1 Mg/m³. Assuming the sand will not settle, determine the ulti- mate settlement in the clay using: Proceeding in steps: a. Determine the effective stress for the cross section prior to loading. Show the stresses at depth using an appropriate diagram. b. What is Ao' on the clay layer caused by the imposed load? (Hint: Calculate this for the center of the clay layer at 5.8 m [19 ft] deep.) (ft) 0 10(1+0) o' c. What is the value of eo based on the original poros- ity of the clay? d. How much settlement will occur in the clay? 5 H ΔΗ = -C log 1+- 1+% 16 22 P=125 tons Sand: Y = 105 lb/ft³ Silty sand: Ysat=127 lb/ft³ Clay: Ysat=121 lb/ft³ n = 0.629, C₁=0.82 GWT

Structural Analysis
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Chapter2: Loads On Structures
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**Consolidation of Clay:**

**Objective:**
Given Exercise Figure 7.4 and accompanying information, determine the ultimate settlement in the clay under the applied load. 

**Notes:**
- 1 ft = 0.3048 m
- 62.4 lb/ft³ = 1 Mg/m³

**Formula:**
Assuming the sand will not settle, the ultimate settlement in the clay can be calculated using the formula:

\[
\Delta H = \frac{H}{1 + e_0} C_c \log \left(1 + \frac{\Delta \sigma'}{\sigma'}\right)
\]

**Steps:**

a. **Effective Stress Determination:**
   - Determine the effective stress for the cross section prior to loading. Use an appropriate diagram to show stresses at depth.

b. **Calculate \(\Delta \sigma'\):**
   - Find the change in effective stress (\(\Delta \sigma'\)) on the clay layer caused by the imposed load. Calculate for the center of the clay layer at 5.8 m [19 ft] deep.

c. **Original Porosity (\(e_0\)):**
   - Determine \(e_0\) based on the original porosity of the clay.

d. **Settlement Calculation:**
   - Calculate how much settlement will occur in the clay.

**Exercise Figure 7.4: Explanation:**

The figure provides a cross-sectional view with the following layers:

- **0 to 5 ft:** Sand, dry unit weight \(\gamma_d = 105 \, \text{lb/ft}^3\)
- **5 to 16 ft:** Silty sand, saturated unit weight \(\gamma_{\text{sat}} = 127 \, \text{lb/ft}^3\), Groundwater Table (GWT) indicated at 5 ft
- **16 to 22 ft:** Clay, saturated unit weight \(\gamma_{\text{sat}} = 121 \, \text{lb/ft}^3\), with noted porosity (\(n = 0.629\)) and a compression index (\(C_c = 0.82\))

- **Load:** A point load of 125 tons is applied at the surface.

This setup is used to analyze the stress changes and resulting settlement in the clay layer.
Transcribed Image Text:**Consolidation of Clay:** **Objective:** Given Exercise Figure 7.4 and accompanying information, determine the ultimate settlement in the clay under the applied load. **Notes:** - 1 ft = 0.3048 m - 62.4 lb/ft³ = 1 Mg/m³ **Formula:** Assuming the sand will not settle, the ultimate settlement in the clay can be calculated using the formula: \[ \Delta H = \frac{H}{1 + e_0} C_c \log \left(1 + \frac{\Delta \sigma'}{\sigma'}\right) \] **Steps:** a. **Effective Stress Determination:** - Determine the effective stress for the cross section prior to loading. Use an appropriate diagram to show stresses at depth. b. **Calculate \(\Delta \sigma'\):** - Find the change in effective stress (\(\Delta \sigma'\)) on the clay layer caused by the imposed load. Calculate for the center of the clay layer at 5.8 m [19 ft] deep. c. **Original Porosity (\(e_0\)):** - Determine \(e_0\) based on the original porosity of the clay. d. **Settlement Calculation:** - Calculate how much settlement will occur in the clay. **Exercise Figure 7.4: Explanation:** The figure provides a cross-sectional view with the following layers: - **0 to 5 ft:** Sand, dry unit weight \(\gamma_d = 105 \, \text{lb/ft}^3\) - **5 to 16 ft:** Silty sand, saturated unit weight \(\gamma_{\text{sat}} = 127 \, \text{lb/ft}^3\), Groundwater Table (GWT) indicated at 5 ft - **16 to 22 ft:** Clay, saturated unit weight \(\gamma_{\text{sat}} = 121 \, \text{lb/ft}^3\), with noted porosity (\(n = 0.629\)) and a compression index (\(C_c = 0.82\)) - **Load:** A point load of 125 tons is applied at the surface. This setup is used to analyze the stress changes and resulting settlement in the clay layer.
Expert Solution
Step 1

Given,

Depth of clay layer, H= 6ft Porosity of clay,n=0.629Compression index, Cc=0.82Load acting at the top surface of soil,P =125tonsDry density of sand,γd=105lb/ft3Saturated density of silty sand,γsat=127lb/ft3Ground water table depth from surface = 5ft

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