Soil mechanics terminology — the ratio of the weight of a given volume of soil solids to the weight of an equal volume of distilled water at the same temperature is known as:

Introduction / Context:
Specific gravity of soil solids (Gs) is a cornerstone property used in almost every phase-relationship calculation in geotechnical engineering. It allows conversion between mass/weight and volume for the solids phase and is essential in determinations of unit weights, void ratio, and saturation when combined with water content data. Understanding what Gs represents avoids confusion with other volumetric ratios like porosity and void ratio.

Given Data / Assumptions:

• The comparison is between equal volumes: one of soil solids and one of distilled water.
• Temperature is the same for both, typically 20 °C, because water density varies with temperature.
• Only soil solids are considered (voids and moisture are excluded from the solids volume).

Concept / Approach:

Specific gravity of soil solids is defined by Gs = Ws / Ww for equal volumes, where Ws is the weight of soil solids occupying a reference volume and Ww is the weight of water occupying the same volume. For most mineral soils, Gs ranges from about 2.60 to 2.75, with quartz-rich soils near 2.65. Higher Gs values may indicate heavy minerals; lower values can indicate organics or porous lightweight constituents.

Step-by-Step Solution:

Verification / Alternative check:

Laboratory methods such as the pycnometer test determine Gs by replacing the unknown solid volume with water and applying mass balances. Cross-checks with known mineralogy (e.g., silica content) can validate expected ranges.

Why Other Options Are Wrong:

Porosity is Vv/V (voids to total). Void ratio is Vv/Vs (voids to solids). Water content is mass of water to mass of dry solids. Degree of saturation is volume of water to volume of voids. None of these compare equal volumes of solids and water by weight.

Common Pitfalls:

Including pore water or air in the solids volume; ignoring temperature control for water density; confusing Gs with unit weight ratios.

Final Answer:

specific gravity