Unsuitable soil can be recognized by what phenomenon when equipment runs over it?

Pumping occurs when unsuitable soil experiences excessive deformation under load, particularly when heavy equipment passes over it. This phenomenon is characterized by the soil's inability to adequately support the weight, leading to a temporary expulsion of water from the soil matrix. As the equipment moves, the soil can effectively "pump" water from beneath the surface, causing a sensation of instability and a visible change in the surface condition. This indicates that the soil lacks the required bearing capacity or is too saturated, making it unsuitable for construction or excavation work.

Recognizing pumping can help assess the soil's condition and determine whether additional testing or preparation is necessary before proceeding with excavation or grading activities. Understanding soil behavior under load conditions is crucial for ensuring the stability and safety of construction operations.