Study On The Influence Of Lining Cracks On Tunnel Stability And Its Remediation Technology

With the construction of a large number of tunnels,China’s total tunnel has been ranked in the forefront of the world.However,in the construction and operation process,the tunnel lining is often accompanied by some disease defects;such as void,cracks,leaking water,lining thickness is insufficient,hemp and so on.Among them,the crack is a common disease,appeared in the tunnel lining,always threaten the safe operation of the tunnel.However,the impact of different cracks on the tunnel,and some harmful,and some harm is small,and some even on the tunnel without harm.How to judge this phenomenon,the need for specific analysis of the tunnel cracks.Lining cracks in a variety of forms,and therefore its classification is also varied.This paper will analyze the cracks of tunnel lining with the hydrological and geological conditions,topography and construction methods of Jiangxi Province,and the classification of tunnel lining is analyzed.Jiangxi is mostly sandstone geology,and sandstone rheological characteristics are obvious.When the internal force of the lining caused by the creep of the surrounding rock exceeds the strength of the concrete,the lining will produce secondary cracks.Secondary cracks and the original cracks are different,mostly in the unstable state,continuous development,the stability of the tunnel has a huge impact.In this paper,the samples of typical sandstones in Jiangxi Province are selected,the relevant mechanics experiments of sandstone are carried out,and the creep curves of sandstone are analyzed to determine the empirical constitutive model and creep mechanics model of sandstone.ABAQUS finite element software was used to simulate the stability of tunnel lining under the creep of surrounding rock,and the weakness of tunnel lining was analyzed(ie,it was easy to crack).Based on the extended finite element theory and cohesive technique,ABAQUS is used to analyze the secondary cracks in different positions and different angles(at a certain angle with the tunnel axis),and the crack propagation process under the action of creep.And summarizes the law of the expansion of lining of different lining,which provides the basis for the remediation of cracks.