零距离下穿既有短桩地铁车站关键技术研究

The Key Technology of Undercrossing Existing Short Pile Station at Zero Distance

新建地铁车站采用暗挖法零距离下穿既有短桩地铁车站施工时,由于既有短桩地铁车站预留桩长不足,其设计难度和安全风险较大。以南京地铁5号线上海路站为例,采用MIDAS进行数值模拟分析,提出零距离下穿既有短桩地铁车站的关键技术,即采用多台阶分部开挖和车站结构逆做相结合的设计方法,通过多台阶开挖和支撑解决既有车站短桩承载力不足的问题,同时,对预留短桩采用墙包柱的处理方案,确保下穿既有车站结构的安全。

When a new subway station undercrosses an existing station at zero distance, as the insufficient pile length of the existing station, the new one is exposed to both design difficulty and infrastructure security risk. In order to solve this problem, this paper utilized numerical simulation analysis by MIDAS, proposed key technology of undercrossing existing short pile station at zero distance.Adopting the design method of multi-sequences excavation and reverse construction method, we solved the problem of insufficient bearing capacity of the existing station. And adopting reserved short piles with a treatment of encasing column in wall, we ensured the safety of the existing station infrastructure.