Southern Reinforcement Project: Underground Transmission Line
Challenges Solved
An unusually complex electric line reinforcement project in southern New Jersey required installation of a 500-foot long trenchless crossing 30 feet below a lake and highway ramp. The challenging soil conditions consisted of loose fill and soft clay deposits. The optimal 48-inch diameter micro-tunnel profile was in the soft clay. MRCE designed an interlocking steel sheet pile cofferdam with tremie concrete plug for groundwater cut-off. The tremie plug gave the contractor significant cost savings. MRCE also designed and installed an instrumentation and monitoring program to verify that adjacent utilities, roadways and existing structures were not damaged by the trenchless micro-tunneling operation.