Study On The Surrounding Rock And Ground Deformation Laws Induced By Construction Of Metro Tunnels In Yue-Rong Area

It is of great significance and engineering application value to carry out research on surrounding rock and ground deformation induced by construction of subway tunnels in Xi'an loess area.This paper takes the tunnel engineering of Yuejiazhai-Rongjiazhai section of the Xi'an Metro Line No.5 project as the background and uses the methods of theoretical analysis,numerical simulation and on-site monitoring to carry out research work.The main contents and conclusions are as follows:(1)The characteristics of tunnel construction subway tunnel in Xi'an loess area and the surrounding rock and ground deformation induced by tunnel construction was analyzed.The main factors affecting the tunnel surrounding rock and ground deformation include the physical and mechanical properties of the soil,the buried depth and overburden ratio of the groundwater,the tunnel,the tunnel section geometry,excavation footage,construction methods,pre-support measures,primary lining and secondary lining,and construction management.(2)The internal force distribution model of the primary lining structure of the tunnel was established based on the load structure method.The distribution law of the internal force of the primary lining structure was given.Based on this result,the lining parameters of the tunnel were designed.(3)Kinds of three-dimensional calculation models for the tunneling project of Yuejiazhai-Rongjiazhai tunnel were established by using FLAC,including the CD method,CRD method,two side-wall pilot tunnel method,were built respectively.By analysing the laws of surface,dome and convergence induced by tunnel construction about different construction methods.The study showed that the reasonable construction scheme for the tunnel in this interval is the CRD method.(4)Developed a monitoring program for surrounding rock and surface deformation in the tunnel between Yuejiazhai and Rongjiazhai and carried out engineering practice.The engineering practice shows that the proposed CRD method construction scheme ensures that the settlement of the surface,the settlement of the surrounding rock dome,and the horizontal convergence amount meet the requirements for safe construction during the tunnel construction.The measured results are basically consistent with the results of numerical simulations.