In regards to trench excavations, tills with low moisture content would be most similar to which material?

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

Answer: (B)

Moisture content changes how trench soils behave: cohesive soils tend to hold together and resist shear, while non-cohesive soils cave more easily. Tills with low moisture act like cohesive soils because the clay fraction in the till holds particles together, increasing cohesion and shear strength. That behavior is most like clay, which forms stable, stick-together faces in trenches and often requires methods suited to cohesive soils, such as careful shoring or bracing. Non-cohesive materials like sand or gravel don’t stick together in the same way and would cave differently, while silt is less cohesive than clay and behaves differently under trenching conditions.