Research And Application Of New Construction Method In Soft Surrounding Rock Tunnel

With the development of the inter-city rail transit and urban rail transit, the way which goes through the underground is often used, when the line through the city doesn’t occupy the earth resources and reduces noise. Then the complex dynamics of urban underground geological conditions, the particularity of the ground environment, facing the, the shallowness of the tunnel buried have been met, these problems have brought a big difficulty to the tunnel construction in city, especially, in the soft rock tunnel. The paper has compared the CD, CRD, and the new labor law, which has been used in range of 1, 2 shaft of soft rock tunnel of intercity rail in GuanHui, then finished the followed job.(1) By analysis of the field data and the well-known examples of soft rock tunnel, the characteristics of the soft rock tunnel rock deformation and failure were summarized.(2) Simulating the process of the three engineering methods through the software named MIDAS/GTS to analyze the vault settlement to the direction of Y, the tunnel surrounding the displacement in the X direction, the influence in plastic zone and initial support structure(arch and anchor), we can get that the CD construction method is not suitable for the construction of the section of soft rock tunnel. Although C RD, the new labor law can make construction satisfied, the problems that vault settlement vary widely and the stress concentrate have still been faced.(3) Comparing the numerical simulation results and experimental data of the three construction methods, we can see that the simulation results of the surrounding rock deformation and the trend of the experimental data are in line with the law of surrounding rock deformation, and it will lead the construction.(4) By achieving the result which is point to getting curve fitting between the measured data vault settlement and surrounding displacement, we can get that the surrounding rock deformation is stable after the CRD and the new labor law has been used.(5) In order to use the CRD and the new labor law better and safer, the technical measures and management measures which can fix the settlement and the stress concentration and reduce the construction safety hazards should be carried out, for example, the full- face grouting, changing excavation methods, vertical supporting.