The New Jersey Department of Transportation solicited a request for proposal for a design-construct bid to extend the Atlantic City Expressway to the marina district and Brigantine. This would service a developing area for casino construction as well as greatly improve access to the beachfront towns north of Atlantic City. The preliminary proposal required approximately 0.8 km (0.5 mi) of four-lane roadway to go underground, eliminating traffic noise, and to pass under US-30. The prime and specialist contractors, in concert with intuitive engineering support, developed an in situ installation of a subgrade bottom-strut bracing system for a cut-and-cover tunnel installation. This concept offered many advantages, including months of schedule savings, reduced sheet-pile cost, and much-reduced wall-anchoring requirements. To economically install this bottom strut, the new system of SuperJet grouting was used. This grouting system offers several key advancements over conventional jet grouting and allows the construction of columns up to 5 m (16 ft) in diameter. This new technology, the method of installation, difficulties overcome, and the quality-assurance and quality-control elements of this portion of the project are presented. Future applications are also proposed.
Evaluation of Ground Properties in Deep Soil Improvement Method and its Application to Construction Automatization
