Water actuated down-the-hole hammer drilling techniques were used to install grout holes to depths as great as 348 feet for a full-depth grout curtain around the perimeter of the planned concrete-lined wet well gate shaft on the Thornton Composite Reservoir Project. Initial grout mixes and grout curtain closure were determined based on the results of water pressure tests. Grout takes ranged from 4 to 900 gallons per stage. Once installed, the grout curtain allowed excavation and construction of the wet well to proceed without interruption. Throughout the project, water inflows were maintained well below the total specified value of 30 gpm.
展开▼
