| With the rapid development of our country’s economy, urbanization has entered a stage of rapid development, ground traffic has also been a rapid increase, traffic congestion has become more serious. Nowadays, development and utilization of the underground space dominated mainly in tunnel which has been developed as a solution to three major crises:urban resources, population, environment. The attendant problem is rock stability after tunnel excavation, in this study, the finite difference analysis software FLAC3D is used to simulate the stress and displacement of the rock after tunnel excavation. In the numerical model calculations, linear elastic material is used for the concrete lining, the Mohr-Coulomb elastic-plastic model is used for soil.Firstly, this paper base on the long tou ling tunnel in the dongzhi country, and use different tunnel excavation methods:CRD excavation, bench excavation, full section excavation to analyze the rock stability. The following conclusions are drawn by analyzing the results:(1) The vault and arch bottom’s displacements have a larger subsidence after the tunnel excavation, the hance appears the stress concentration, and lining makes the rock stress get some relief. (2) By the CRD excavation, the rock displacement is much smaller, and more safer. (3) The surface subsidence trough shape after tunnel excavation like the reversed normal distribution curve. (4) With the increase of soil depth, the rock displacement become more larger. Secondly, analyze the impact of various factors on the stability of surrounding rock structure, study the the structural stability of surrounding rock about the split Tunnel excavation. Finally, describes the tunnel construction process safety precautions and control measures in many ways. The conclusions obtained from this study merit attention in assessing the tunnel excavation on adjacent pile foundation in engineering project. |
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