为解决架空线和地下线等复杂环境条件下基坑施工的难题，以南昌市红谷隧道东岸双线并行明挖基坑为例，探讨低净空条件下采用反循环钻机进行钻孔咬合桩施工的方法。利用混凝土支撑作为悬吊梁悬吊保护横穿基坑的地下电缆，基坑内采用逆作法施作工字钢喷射混凝土支护。在基坑外斜向交叉打设高压旋喷桩加固110 kV电缆包封处一定深度的地层，在基坑内电缆底部竖向施工高压旋喷桩止水帷幕至岩面封堵地下水，并在基坑围护结构连接处施作应急降水井。根据施工结果可知： 1）采用高压旋喷桩可以有效避免基坑不同形式围护结构的连接处出现渗漏水现象； 2）在基坑围护结构未封闭处的下游设置止水帷幕可以起到有效的止水作用。

The bored secant pile constructed by backcycling drilling machine under low clearance is discussed by taking the opencut foundation pits on double lines of Honggu Immersed Tunnel in Nanchang for example. The underground cable crossing the foundation pits is protected by concrete support; and the Ishaped steel and shotcrete support is constructed by topdown method. The ground around 110 kV cable is consolidated by highpressure jet grouting pile out of foundation pit; and the water curtain is constructed by vertical highpressure jet grouting pile under cable in foundation pit to stop the water and the emergency dewatering well at connecting point between retaining walls is constructed. Finally, the foundation pits have been successfully and safely constructed under complex conditions.