Research on Supporting Design of the Ultra-large and Complicated Foundation Pit in the Western Square of Hangzhou Eastern Railway Station

摘要

The engineering is located at the Eastern New Town of Hangzhou City, Zhejiang Province, The foundation pit has a large plane size (635 x 216m), and the excavation depth is 14.900m～15.600m.Within the excavation range, the foundation has high water level and strong permeability.The tunnel shield sections of 1# subway line and 4# subway line of Hangzhou go through below the basement of the square and are only 6m (the smallest distance) away from the foundation pit bottom.In addition, the project construction period is tight, environment and operating conditions are complicated.In this Paper, overview and characteristics of the foundation pit engineering, enclosure measures and design scheme, technical measures for protecting the shield tunnel during soil unloading in large Zone and dewatering process, field monitoring data and so on are described in details to provide design reference for similar engineering.