富水砂卵石地层暗挖车站侧壁咬合桩止水关键技术

Key Technology about Side Wall Occluded Pile Water Stop of Underground Excavation Station in Water Rich Cobble Ground

随着我国城市轨道交通建设的快速发展和地下水严重短缺、保护地下水资源势在必行的环境下,暗挖地铁车站逐步采用止水施工。结合北京地铁某位于富水砂卵石地层的车站,研究了侧壁咬合桩素桩桩身材料选择、咬合桩实施期间导洞底板的破除和保护,采用有限元数值模拟分析了咬合桩钢筋混凝土桩与素桩的咬合可靠度和车站主体开挖期间咬合桩抵抗土压力及水压力的能力,并结合现场实施情况提出了咬合桩垂直度的控制措施,以实现咬合桩止水安全、可靠。

With the development of China’s urban rail transit construction and the serious shortage of groundwater,it’s impervative to protect groundwater resources.Water stop method is gradually adopted in underground excavation station construction.Combined with water rich cobble ground of Beijing subway station,body material selection of sidewall occlusive plain pile as well as the break and protection of the pilot tunnel bottom in the course are studied.By Finite Element Numeral Method,the occlusion reliability of reinforced concrete pile and plain pile and the resis-tance to soil pressure and water pressure during excavation of the occluded pile are simulated and analyzed.According to the site situation,the control measures of occlusive verticality are put forward so that it’s safe and reliable to achieve water stop of occluded piles.