What could cause excavation conditions to deteriorate through slumping?

Slumping in excavation sites primarily occurs due to increased moisture content in the soil, making it more prone to instability. Rain or surface water can saturate the soil, reducing its cohesion and increasing the likelihood of movement. When water seeps into the ground, it can cause the soil to lose its structural integrity, leading to slumping where material shifts down the slope.

In contrast, high temperatures might dry out the soil but do not typically contribute to slumping conditions. Heavy machinery use can create vibration and disturbance, which may impact stability, but it is not a direct cause of slumping related to moisture. Wind erosion primarily affects loose soil on the surface but does not directly influence deeper excavation stability in the same manner as moisture does. Therefore, rain or surface water is the most significant factor leading to deteriorating excavation conditions through slumping.