Foundation pit flooring below groundwater level builds floor above ground water level for progressive lowering using in-floor passages for excavator tools and sub-floor spoil removal.

摘要

The floor of the foundation pit or sluice etc is produced above ground or in a pit above groundwater level and only then lowered to end point by the use of passages in the floor to take extractor tools used to remove the sub-floor material up and back through the floor passages for surfacing. The spoil can be removed through passages other than those used for the extractor tools and the ground below the floor can also be flushed out by water jets. During or before sinking, the floor sides are walled thus preventing groundwater breaking through onto the pit floor. The floor can also be sunk by loading it with ballast and again the pit floor can be made up of separate parts to be lowered separately and joined at bottom point to complete an over-size foundation pit floor.