Study On Monitoring And Information Feedback During The Construction Of Soft Rock Tunnel With A Large Section

With the rapid development of the high-speed railway in China, the constructionof tunnel becomes much faster and larger, which means, various weak and unstablestrata will be crossed and the problem of construction in weak strata has been a hotresearch field recently. To construct safely and gain a high quality, one of the effectiveprinciples should be diligent measurement. With a combination of acquiring andanalyzing the information that shows the overall stability of the tunnel surroundingrock, the dynamic changes of a tunnel excavation process can be truly effected.Therefore, to carry out the research in this area has a wide range of practical value andpromotion prospects. Monitoring and information feedback during the construction ofsoft rock tunnel with a large section will be studied, which is based on the project ofTaoshuping Exit at Lanyu High-speed Railway in this thesis, including the following:First, in this paper, extrusion deformation of the tunnel face is monitored, on thebasis of the common measurement about tunnel deformation, the stress of supportingstructure, and the surrounding rock pressure. Through the analysis of the monitoringdata, the change rule of vault settlement, clearance convergence deformationconstraints, extrusion deformation and stress of surrounding rock will be understood,the mechanical behavior of supporting structure and its security will be analyzed, all ofwhich will provide a theoretical basis for the design and construction of tunnel.In addition, a numerical simulation model is built for tunnel excavation accordingto current construction. With the comparison between model results and fieldmonitoring data, Displacement, stress and plastic zone of surrounding rock andsupporting structure internal force is analyzed. At the same time, the danger area andsensitive area are predicted during tunnel excavation. The results show: The stressstate of such as arch crown, arch sides, and arch springing is typical when compared with the whole tunnel surrounding rock. It means, to determine the stability of thetunnel surrounding rock, it is very significant to monitor the surrounding stability ofthe above key points.Besides, the effect of advance pre-reinforcement parameters on the deformationof surrounding rock after excavation is also studied in this paper. Also, after thevariation of the settlement displacement of arch crown, the convergence displacementof side wall and deformation displacement of the tunnel face is investigated under thecondition of different pile diameter pile length, elastic modulus and installation density,the best combination of parameters is determined.