Dewatering & Groundwater Control
A system of ejector wells installed to maintain groundwater below subgrade level for excavation and construction of a rock-filled buttress to improve the factor of safety of the dam. Five deep wells were also installed to relieve artesian pressure.
Dewatering wells in the area of a surface depression on the side of an earthen dam to provide additional information regarding the location of possible piping paths through the dam core, followed by a program of low mobility grouting to locate and seal the paths.
Design and installation of a system of shallow penetrating wells within tight, steel sheeting excavation support to provide dry subgrade while minimizing off-site groundwater drawdown during cut-and-cover construction of a 2,900-foot long depressed roadway adjacent to a canal.
Deep well dewatering to draw groundwater below the floor level of a dry dock to reduce buoyancy, maintain structural integrity, and control water infiltration during dock wall and floor rehabilitation.
Freezing of more than 135 vertical feet of sand and mudstone overburden to ensure completely dry and stable excavation during construction of an elevator shaft for transportation of museum visitors 650 feet below ground.
Ground freezing of varying depths of overburden for excavation support and groundwater control at five shaft locations to aid construction of deep vertical access shafts connecting to the new water tunnel 500+ feet below ground.
Ground freezing of more than 100 feet of saturated soils to facilitate sinking of a mine shaft, 32 feet in excavated diameter, through the overburden and underlying rock to a depth of 550 feet below ground surface.
Ground freezing for excavation support and groundwater control to aid installation of six CSO shafts to depths of up to 175 feet. Permeation grouting was performed at one shaft to close anomalous “windows” in the frozen wall that occurred as a result of unanticipated subsurface conditions.
Multi-system project involving a micropile foundation system, wellpoint dewatering and installation of an earth support system to allow excavation of a below-grade wheel truing facility housing heavy machinery at PANYNJ’s Harrison, NJ location.
Ejector wells installed to draw groundwater to top of rock at 85 feet below grade to aid underpinning of, and excavation below, two existing subway tubes for new cut-and-cover tunnel construction.
Multi-system project involving wellpoint dewatering to draw groundwater below excavation subgrade, installation of 6,700 square feet of tied back, temporary beam and lagging excavation support, and treatment of low levels of contaminants present in the groundwater.
Deep well dewatering to draw groundwater down below new elevator pit subgrade, coupled with permeation grouting to stabilize the sandy soils prior to excavation.
Wellpoint dewatering to lower groundwater levels below excavation subgrade and installation of a tied back, beam and lagging system to support a slope cut up to 27 feet deep to create space for a 51,000 square foot library addition.
Deep well dewatering to depths of 190 feet to drain and stabilize granular deposits in advance of SEM tunneling.
Deep well dewatering to lower groundwater below core foundation subgrade for dam replacement.
Injection of a balanced stable cement-based grout through a single line of grout holes to reduce the permeability of the weathered rock upstream of the dam spillway and eliminate leakage potential prior to spillway expansion.
Urethane grouting to control water groundwater leakage into the damaged WTC “bathtub” through slurry wall panel joints and tieback penetrations.
Permeation grouting to seal excavation support interfaces, close gaps and joints, and create a bulkhead around an existing subway structure to ensure a watertight work shaft.
Installation of a deep well system, an eductor system, and tied back soldier pile and lagging support systems to facilitate construction of a new RCC structure at the toe of an existing dam.