What is critical to evaluate before excavating cohesive soil?

When planning an excavation in cohesive soil, evaluating multiple factors is vital to ensuring safety and structural integrity. Each aspect—water content, moisture saturation, and stability of faces—plays a crucial role in determining how the soil will behave under excavation conditions.

Water content refers to the amount of water present in the soil. In cohesive soils, like clays, this can significantly affect strength and cohesion. When the water content is too high, the soil can become unstable and prone to sliding or collapse.

Moisture saturation is closely related to water content but focuses specifically on how saturated the soil is. High saturation indicates that the soil might lose its load-bearing capacity and become more fluid, increasing risks during excavation.

Stability of faces pertains to the physical integrity of the walls created by excavation. Proper assessment is necessary to ensure that these faces can withstand their own weight and any external pressures without failing.

Since all these factors contribute to the overall assessment of risk and stability in cohesive soils, evaluating them together ensures a comprehensive understanding of the excavation site's conditions, which is essential for safe excavation practices. Hence, the choice that includes all these critical elements is the most valid approach.