What term describes the ratio of the volume of water to the total volume of void space?

The term that describes the ratio of the volume of water to the total volume of void space is correctly identified as the Degree of Saturation. This concept is crucial in geotechnical engineering and soil mechanics, where understanding the water content in soil can significantly influence its behavior and strength.

The Degree of Saturation specifically expresses how saturated a soil is with water. It is calculated using the formula:

Degree of Saturation (S) = (Volume of Water / Volume of Void Space) × 100%

This ratio provides essential insights into the soil's condition, helping engineers assess its properties in relation to drainage, stability, and load-bearing capacity. A higher degree of saturation indicates that more water occupies the void spaces, which can lead to reduced soil strength and increased pore pressure.

Understanding the Degree of Saturation is critical for engineers when designing foundations, slopes, and retaining structures, as it affects how the soil will behave under various loading and drainage conditions.