Construction method for reinforcing foundation pit of overpass rail transit

The invention relates to the technical field of upper-span rail transit foundation pit reinforcement construction, in particular to an upper-span rail transit foundation pit reinforcement construction method, which adopts a mode of combining MJS construction method piles and three-shaft mixing piles to greatly improve the construction speed and control the deformation of an existing subway tunnel within an allowable range. After construction parameters of the three-axis stirring piles and the MJS construction method piles are determined through experiments, foundation pit reinforcement construction is started, the three-axis stirring piles are constructed firstly for foundation pit reinforcement of the overpass rail transit, and then the MJS construction method piles are constructed after the three-axis stirring piles reach certain strength. 本发明涉及上跨轨道交通基坑加固施工的技术领域，特别是涉及一种上跨轨道交通基坑加固施工方法，其采用MJS工法桩和三轴搅拌桩相结合的方式能大大提高施工速度，同时控制既有地铁隧道变形在允许范围内；通过实验确定三轴搅拌桩及MJS工法桩施工参数后，开始基坑加固施工，上跨轨道交通基坑加固先施工三轴搅拌桩，待三轴搅拌桩达到一定强度后，再施工MJS工法桩