黏质黄土地层高铁隧道变形控制基准研究

Study on Deformation Control Datum of High-Speed Railway Tunnel in Cohesive Loess Stratum

黄土隧道具有埋深浅、开挖时变形量大、稳定性差的问题,下穿既有建构筑物时,给地表建构筑物的安全带来巨大的影响,需保证开挖过程中变形在规范规定的范围内。针对黏质黄土地层高铁隧道开挖过程中的拱顶及地表变形规律进行分析,结合现场实测数据的分析,得出黏质黄土地层中隧道的沉降量与埋深及开挖方法有直接关系,相同的埋深下地表沉降与拱顶沉降有着显著的线性关系,其比值与施工方法的相关性不大。进一步得出了基于地表沉降控制要求的黏质黄土地层高铁隧道施工变形控制基准:S_(v)=[δ]/i_(H),可供类似工程进行变形控制提供依据。

Loess tunnel has the problems of shallow buried,large deformation during excavation and poor stability.When the loess tunnel passes through the existing buildings,it will bring great influences on the safety of the surface buildings,it’s in urgent need to ensure that the deformation in the excavation process chanegs within the scope specified in the specification.The deformation law of vault and ground surface in the process of high-speed railway tunnel excavation in clay loess stratum are analyzed.Combined with the analysis of field measured data,it is concluded that the settlement of tunnel in clay loess stratum is directly related to the buried depth and excavation method.There is a significant linear relationship between the surface settlement and the arch crown settlement under the same buried depth,and the ratio has little correlation with the construction method.The deformation control datum of high-speed railway tunnel construction in clay loess stratum is obtained based on the requirements of surface settlement control:S_(v)=[δ]/i_(H).It can be used as a reference for deformation control of similar projects.