Question

A clayey soil has a moisture content of 18%, a specific gravity of soil solids of 2.74, and a degree of saturation of 65%. The soil soaks up water during a rain event, and the degree of saturation increases to 85.2%. The change of the volume during the soakage is negligible. The new moisture content (in %) of the soil will be ......... (rounded off to 2 decimal places).

Hint:

To calculate moisture content changes in soils with varying degrees of saturation, use the relationship between moisture content, specific gravity, and saturation levels.

Answer 1

Given Data:

• Initial water content: \[ w_i = 18\% \]
• Initial degree of saturation: \[ S_i = 65\% \]
• Specific gravity: \[ G = 2.74 \]

Step 1: Calculate the Void Ratio \( e \)

The void ratio is given by:

\[ e = \frac{w_i G}{S_i} \]

Substituting the values:

\[ e = \frac{18 \times 2.74}{65} = 0.7587 \]

Step 2: Calculate the Water Content for \( S = 85.2\% \)

The water content at a new saturation level is given by:

\[ w = \frac{e S}{G} \]

Substituting the values:

\[ w = \frac{0.7587 \times 85.2}{2.74} = 23.59\% \]

Final Answer:

Correct Answer: \( \mathbf{23.59\%} \) (rounded to two decimal places).