黏质粉土地层中超浅埋暗挖地铁出入口地道施工技术

摘要

以郑州市某地铁车站出入口地道施工为实例,对黏质粉土地层中超浅埋暗挖地道采用交叉中隔墙法(简称CRD法)的施工过程进行了介绍,针对施工误差导致管棚下沉而部分失效的问题,提出了采用双排注浆小导管超前支护方案代替原设计的管棚加小导管的方法,并将开挖施工方案由单向开挖调整为从两侧向中间双向开挖.施工方案变更后,经过严密的施工监测和过程控制,地道最终顺利安全贯通,典型点位的沉降参数均满足规范要求,证明了该设计变更后超前支护方案的合理性与可行性.%Based on a practical tunnel construction of metro station entrance in Zhengzhou City,the CRD technology is briefly introduced which is used in the construction of supper shallow-buried excavation metro tunnel in the clayey silt layer.According to the problem of partial failures caused by pipe shed subside,a new advanced supporting plan is proposed,which uses double grouting small pipes to replace the original design of pipe shed plus small pipes,and adjusts accordingly the working process from unidirectional excavation to side excavation towards the middle.After the change of construction plan with strict inspection and process control,the tunnel is completed smoothly and safely in the end.The settlement parameters at typical spots have met the requirements of the metro code,that proves the rationality and feasibility of the advanced supporting plan after the design change.