What does the symbol 'CL' represent in soil classification?

• A. Silt with low plasticity
• B. Clay with low plasticity
• C. Plastic silts
• D. Clay with high plasticity

Answer: (B)

The symbol 'CL' in soil classification specifically denotes 'Clay with low plasticity.' This classification is part of the Unified Soil Classification System (USCS), which categorizes soil based on its physical properties, particularly particle size, consistency, and plasticity.

In this system, 'C' indicates clay, which is characterized by its ability to retain water and its fine particle size. The 'L' signifies that this particular type of clay has low plasticity, meaning that it will not undergo significant changes in its consistency or behavior under varying moisture conditions compared to clays with higher plasticity. This is particularly important in civil engineering and construction because soil with lower plasticity is often more stable and less prone to issues like swelling or shrinkage when wet or dry.

Understanding this classification helps engineers and geotechnical professionals to predict how the soil will behave under loads and environmental changes, thereby influencing the design and stability of structures built on or within that soil.