What is represented by the symbol 'M' in soil classification?

• A. Silt
• B. Clay
• C. Sand
• D. Gravel

Answer: (A)

The symbol 'M' in soil classification actually represents silt. Silt is a particle size that falls between sand and clay, typically characterized by its smooth texture and small particle size, which ranges from 0.002 mm to 0.075 mm in diameter. In the Unified Soil Classification System (USCS), soil types are denoted by letters, where 'M' indicates that the soil contains significant amounts of silt in its composition.

In the context of the other classifications, 'C' represents clay, 'S' is for sand, and 'G' stands for gravel. Each of these materials has distinct physical properties that influence their behavior in civil engineering and construction applications, but 'M' specifically denotes silt based on its particle size and characteristics. Understanding these classifications is essential for soil testing and determining the suitability of soils for various construction purposes.