Excavation in the dry

Excavation in the dry is earthwork carried out behind a watertight enclosure that has been pumped out, so the soil is removed by land plant rather than by dredging underwater. In port construction it is used to build lock chambers, dry docks, immersed-tunnel casting basins, and quay foundations inside a cofferdam or a bunded and dewatered area. The enclosure is formed by sheet piles, diaphragm walls, or earth bunds, with well-point or deep-well dewatering holding the groundwater below the dig. Working dry gives tighter control of levels, compaction, and concrete placement than wet dredging, at the cost of the temporary works and the pumping needed to keep the excavation dry.