浅埋深砂砾岩堆积层隧洞穿路穿沟施工技术措施

Construction Measures for Shallow Tunnel Crossing and Trenching in Glutenite Accumulation Layer

某工程放空洞下穿公路和天然沟渠,渗水量约40 m^(3)/h~60m^(3)/h,且属于浅埋深隧洞,埋深21~23m,该段隧洞主要围岩为砂砾岩堆积层,开挖过程中隧洞成型和安全稳定性较差。通过隧洞上下游帷幕灌浆、洞顶沟渠流水引排,洞内自进式超前管棚、自进式中空锚杆、三台阶预留核心土法开挖、开挖6m及时跟进一期混凝土的施工技术措施,安全顺利完成该段隧洞开挖支护施工。

A project emptying tunnel passes through highway and natural ditch with seepage volume of about 40 m^(3)/h-60 m^(3)/h.It is a shallow tunnel with buried depth of 21-23 M.The main surrounding rock of this tunnel is gravel accumulation layer,which has poor shaping and safety stability during excavation.Through a series of construction technical measures,such as curtain grouting at the upstream and downstream of the tunnel,water diversion of the channel at the top of the tunnel,self-propelled and advanced pipe shed in the tunnel,self-propelled hollow anchor rod,excavation of three-step reserved core soil method,excavation of 6m and timely follow-up of Phase I concrete,the excavation support construction of this section of tunnel is completed safely and smoothly.