What does the symbol 'CH' signify in soil types?

• A. Clay with high plasticity
• B. Liquid limit above 50
• C. Organic clay of high plasticity
• D. Peat and highly organic soil

Answer: (A)

The symbol 'CH' in soil classification refers specifically to clay with high plasticity. This is a designation used in the Unified Soil Classification System (USCS), where 'C' indicates clay, and 'H' denotes high plasticity. Soil with high plasticity can deform significantly under stress and retains water well, making it crucial in engineering projects. High plasticity clays typically have a liquid limit greater than 50, which relates to the second choice, but the definition is more focused on the classification that primarily uses 'CH' to designate the plasticity characteristics of clay. Understanding this classification helps engineers and geotechnical professionals assess soil behavior under various load conditions, water interactions, and construction implications. The other options reference different soil types or characteristics that do not apply specifically to the 'CH' designation.