What is the symbol used to represent poorly graded sand without fines?

• A. SP
• B. S
• C. G
• D. M

Answer: (A)

The symbol used to represent poorly graded sand without fines is SP. In the Unified Soil Classification System (USCS), soil types are classified based on their grain size and distribution. Specifically, the "SP" designation indicates that the soil is composed predominantly of sand particles that are poorly graded, meaning the size distribution is relatively uniform with little variance in particle size. This classification is critical because it helps geotechnical engineers and soil scientists understand the behavior of the soil in construction and foundation applications.

In contrast, the other symbols represent different soil types or characteristics: "S" generally indicates sand without additional qualifiers, "G" is used for gravel, and "M" signifies silty soil. Understanding these classifications ensures proper soil management, construction planning, and assessment of the soil’s properties in engineering contexts.