Stress measurement and stability analysis of support system of large-span underground space

Monitoring and measurement are necessary procedures in the design and construction of tunnel when using new Austrian tunneling method (NATM). Combined with the pressures on the supporting system and with monitoring of stress and pressure in the large-span underground space of Jiaochangkou-Xinshancun line of Chongqing Light Railway, the experimental results are analyzed and the undetermined laws are disclosed such as pressure of initial supporting I-steel, axial stress of bolt, shotconcrete stress, contacting pressure between shotconcrete and surrounding rocks, supporting pressure of temporary I-steel, contacting pressure of shotconcrete and the secondary lining, and stress of steel of the secondary lining. The methods of choosing the supporting system and structural parameters, the excavation methods of underground space, and the measuring methods and testing methods, are proposed. The stability of supporting system and safety of the structure are determined, and the achieved results can provide references to the information construction in engineering practice.