Which factor contributes to soil instability during excavation?

Soil type and moisture content are critical factors that contribute significantly to soil instability during excavation. Different soil types, such as clay, sand, or silt, exhibit varying behaviors under stress and changing conditions. For example, clay can retain water, becoming soft and unstable when saturated, while sandy soils may shift and collapse when dry due to their granular structure.

Moisture content also plays a vital role; when soil becomes too wet, it may lose its load-bearing capacity. Conversely, dry soil may become loose and susceptible to erosion. Recognizing the impact of these factors is essential for maintaining safety during excavation activities, as they can influence the likelihood of landslides, collapses, or other hazardous situations. Effective excavation planning includes assessing soil type and moisture to mitigate risks associated with instability.