surcharge

In the construction context, surcharge is where you place more of something than is natural; for example, they will add 20 feet of stone over a construction site to "surcharge" the soil underneath from the weight. This is a common term for adding more weight to the edge of an excavation where there was no weight before. These additional vertical loads or weights placed on the ground surface near an excavation can include spoil piles, equipment, vehicles, or other materials. The closer a surcharge load is to the edge of the excavation, the greater the potential for destabilizing the soil and causing a cave-in.