In soil classification, what does the symbol 'G' indicate?

• A. Gravel
• B. Clay
• C. Organic silt or clay
• D. Silty-gravel

Answer: (A)

In the context of soil classification, the symbol 'G' specifically denotes gravel. This is part of the Unified Soil Classification System (USCS), a widely used classification framework that distinguishes soils based on their physical properties such as grain size, consistency, and plasticity. The classification of gravels includes both fine gravel (with smaller particle sizes) and coarse gravel (with larger particle sizes), usually defined by a specific range in terms of sieve mesh size.

Gravel is significant in soil mechanics as it influences drainage characteristics and load-bearing capacity. It possesses high permeability which is essential in applications where water drainage is necessary. Understanding these classifications helps engineers and geologists select appropriate materials for construction and evaluate soil behavior under load.

In this context, while the other options relate to different soil types (like clay, organic silt or clay, and silty-gravel), they do not pertain to the 'G' classification, making 'G' specifically indicative of gravel within this system.