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Marina Coastal Expressway is designed to enhance the transportation system for Marina Bay Development. MCE 485 is a 700m long, dual 5 lane undersea vehicular tunnel expressway. Kiso-Jiban is engaged by Penta Ocean Construction Co. Ltd. to provide geotechnical design service of temporary retaining wall system for tunnel box excavation. Double layer of tubular pipe pile wall with 1400mm diameter and four layer of strut are proposed to support the 20m depth excavation (measured from sea level). This is because the tubular pipe pile wall could provide a robust support system for excavation and yet it could be easily dismantle after the completion of project. Besides, with proper connection and additive, the double layer tubular wall could effectively serve as a water proof barrier to cater a favorable environment for tunnel construction. In order to provide a safe and economical design, the temporary retaining system is separate into several sections in FEM analysis. This is to ensure the variation of site topography, regional geological condition and proposed expressway alignment are properly considered and simulate in modeling. Besides, Kiso-Jiban also involve in soil investigation for this project.

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