Determine the Excavation of soil

Excavation of soil in open well foundations is done  by dredging with grab buckets or similar equipment. The volume of excavated soil always exceeds the volume of the embedded portion of the well foundation, because the soil outside the cutting edge tends to flow into the excavation. In granular soils, the excess may be 100 per cent of the volume displaced. Grab buckets do not reach the area near and below the cutting edge; therefore, divers may be required to remove the soil under the cutting edge by hand if the soil does not flow into the excavation.