Abstract

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Title:: Analysis of Structural Bearing Property of Loess Tunnel Based on Safety Degree

Author(s):: WANG Ya-qiong; WANG Ke; LIU Tong; QIU Jun-ling; DONG Wei-wei; Shaanxi Provincial Major Laboratory for Highway Bridge & Tunnel, Chang’an University

Keywords:: loess tunnel; finite element method; bearing property; numerical simulation; safety degree

Abstract:: Based on the two groups of strain monitoring data of the secondary lining concrete for Baxianmao tunnel and Mata tunnel, the strain change law of secondary lining concrete in loss tunnel with time was analyzed. The stress of secondary lining structure was obtained by converting, then the conversion results were substituted into the stress expression of safety degree, and the distribution of secondary lining safety degree of loess tunnel was obtained. Furthermore, the results were compared with the finite element numerical simulation results. The results show that secondary lining concrete structure is not only a safety reserve in loess tunnel support structure, but also bears most of loads of structures. Numerical simulation results prove that the stress on secondary lining is as 40% as total stress from wall rock. The secondary lining concrete structure acts as a compression member and the peak value of strain is at the bottom of side wall. The numerical simulation results is consistent with calculation results. The safety degrees of crown, spandrel, inverted arch of side wall bottom are relatively small, but can meet the requirements of specifications, while stress of inverted arch bottom is maximal, and the safety degree can not meet the requirements of specifications.