In soil classification, which symbol indicates silty sand?

• A. SM
• B. SP
• C. GC
• D. O

Answer: (A)

The symbol that indicates silty sand in soil classification is SM. This designation comes from the Unified Soil Classification System (USCS), which categorizes soils based on their physical properties.

In this system, the first letter represents the main soil type, with "S" denoting sand. The second letter indicates the type of finer material present, and "M" signifies that the soil contains silt. Therefore, the combination "SM" specifies a soil that is primarily sandy but contains a significant amount of silt, making it silty sand.

This classification is crucial in geotechnical engineering and construction as it provides valuable information about the soil's behavior, strength, and suitability for various engineering applications. Understanding the specific classifications helps engineers make informed decisions regarding foundation design, drainage, and overall site development.