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

• A. Organic silt-clay of low plasticity
• B. Organic clay of high plasticity
• C. Clay with low plasticity
• D. Plastic silts

Answer: (B)

The symbol 'OH' in soil classification specifically refers to organic clays with high plasticity. This classification is part of the Unified Soil Classification System (USCS), which categorizes soils based on their grain size and plasticity characteristics.

Organic clays contain significant amounts of organic matter, which contributes to their high plasticity. This means they can undergo considerable deformation without breaking, a trait that is essential to recognize in various engineering and construction contexts. The classification helps engineers and geologists determine the suitability of the soil for construction projects, as high plasticity can affect drainage, stability, and load-bearing capacities.

In contrast, other classifications like 'OL' would refer to organic silts of low plasticity, or 'CL' would refer to clays with low plasticity. Each of these symbols denotes distinct types of soil with varying properties, which are critical for understanding the performance of soil in engineering applications.