Construction Method Research About Soft And Broken Rock Of Shallow Metro Station Tunnel With Large Span

When building big-span metro tunnels in complex geological environment, such as the existence of large buildings, it is a need to control surrounding rock deformation and surface subsidence to ensure the safety problem of building (structure) and surrounding the tunnels. Therefore, it is a must to take safe and reasonable construction procedure. Based on the station tunnel in XingGongJie,Dalian,the study researches on constructing shallow large-span tunnel is in weak surrounding rock, and the results have theoretical and practical value.After studying job practice of shallow large-span tunnel and engineering projects at home and abroad, we reach advantages and disadvantages of all kinds of construction methods. Based on the the project as an example,we compares the advantages and disadvantages of a variety of construction methods.The paper’s main research contents are:(1)We forecast the rock’s shear strength and modulus of deformation.(2)We study the reasonable construction scheme of shallow buried tunnel with large section under the conditions that soft and broken surrounding rock and upper-soft lower-hard ground.(3)We analys the monitoring data of the tunnel construction.The main results are as follows:1, Through to the rock point load test and analyze the characteristics of the structural plane and the joint surface,We obtain the rock uniaxial compressive strength and geological strength index. Finally We get the rock’s shear strength and modulus of deformation by using the empirical formula.2, We use numerical method to imitate double side heading and micro-step tunneling method, CRD method. We also analyse displacement of surrounding rock and primary support system, stress, distortion of tunnel sidewall and internal force of double primary support system. It is found that double side heading and micro-step tunneling method is suitable for shallow large-span station tunnel in weak surrounding rock in XingGongJie,Dalin.3,By analyzing the monitoring measurement of station tunnel using the method of double side excavation,it is also found that Dalian XingGongJie Street Station Tunnel with Twin-Side heading excavation method is reasonable and feasible construction method.