The Classification And Stability Evaluation Of Tunnel Surrounding Rock

With the rapid development of our country’s economy, infrastructure, especially the traffic infrastructure construction is in constant acceleration, also along with the rapid development of highway construction, highway tunnel, especially long tunnel is more and more. In the process of the excavation of tunnel,the rock mass stress will be redistribution within a certain range around the tunnel.When the distribution of stress exceeds the limit of the surrounding rock strength, will certainly to cause the deformation and failure of surrounding rocks. Therefore, the stability analysis of surrounding rock is closely related to highway tunnel construction and operation safety, is a significant research content.In this paper, with Jin haihu tunnel project as the background. The tunnel surrounding rock classification and study of the stability of surrounding rock By adopting the combination of qualitative quantitative method, the main contents and conclusions are as follows.1.The grey theory of grey clustering method, geological mechanics of rock mass, the RMR method, the BQ method were used to the tunnel surrounding rock classification in this paper. Surrounding rock of Jin haihu tunnel is divided into Ⅲ, Ⅳ, Ⅴ level, among them, Ⅲ class surrounding rock a total length of 100 m, accounting for 42.2% of the total length, Ⅳ class surrounding rock a total length of 80 m, accounting for 33.7% of the total length, Ⅴ class surrounding rock a total length of 57 m, accounting for 24.1% of the total length.2. The stability evaluation of surrounding rock was analysised by adopting the combination of engineering geological evaluation and numerical analysis. First, the surrounding rock deformation mechanism and factors affecting the stability of surrounding rock were analyzed and discussed by engineering geological evaluation. Puts forward the main mechanism of deformation and failure for Jin haihu tunnel is controlled by strength- stress, and then combining to the reality of Jin haihu tunnel project, comprehensive evaluation that the stability of surrounding rock ability of level Ⅲ section is better, the stability of surrounding rock ability level Ⅳ section is general,the stability of surrounding rock ability level Ⅴ section is poor.3.Using COMSOL Multiphysics numerical analysis software respectively establish level Ⅲ, Ⅳ, Ⅴsection two-dimensional model of surrounding rock of the tunnel. To study stress and displacement distribution laws of surrounding rock in different section of the tunnel surrounding rock after excavation. According to the results of numerical simulation to evaluate the stability of surrounding rock.4.According to the simulation results to analyze the stability of surrounding rock, and points out that the weak position of the corresponding section of surrounding rock. The last, puts forward Suggestions for tunnel construction and surrounding rock deformation control. It has a certain guiding significance for the stability of surrounding rock and construction safety in the process of tunnel construction.