Research On The Slop Stability And Numberical Analysis At The Tunnel Entrance

With the development of social economic, the investment of infrastructure construction is greatly enlarged. As an important part of infrastructure construction of traffic, tunnel engineering pay an important role in road and railway project. Also, tunnel engineering is closely related with slope, especially mountain tunnel of high-speed railway, disaster, such as landslides, falling off, the collapse of slope deformation and failure, is extremely easy induced at tunnel entrance section, as the result of the wide span and complex techniques. Therefore , study on the stability of tunnel slope is very important. In addition, roadbed slope researches has developed rapidly, but slope of tunnel entrance is always not considered as an independent part for design, especially excavation under the dynamic load of blasting, stability characteristics and design methods of tunnel entrance slope is still lack of in-depth systematic study, such as Gaoyangzhai tunnel slope falling breaking vehicle case in Yiwan railway . Therefore, how to analysis and evaluate of tunnel slope stability, propose reasonable design, develop effective measures, has a very important theoretical and practical significance.This thesis based on the Bai longba tunnel slope of Yi wan railway, which does an extensive investigation and research on relevant topics, depthly discuss slope stability analysis methods and calculation theories, summarizes basic factors of the slope stability, study failure mechanism of the slope, proposes basic failure modes of slope and analysis the five stages of slope failure. By a reference to many documents, proposes failure criterion of slope deformation. Then, FLAC method and its advantage for the analysis of slope stability are introduced.Finally, the slope stability in natural state is analyzed by the method of stereographic. In addition, selecting reasonable physical and mechanical parameters of rock mass, without taking into account and consider blasting under the conditions of dynamic load, setting up two-dimensional model, carries out the tunnel slope stability through FLAC program. In order to verify its accuracy, applies limit equilibrium method to analyze under the same conditions. The results of two methods are very anastomosis and in accordance with actual situation. It has an important guide significance for design and construction of tunnel engineering, aslo it can be referred in the design, construction and research of similar tunnel engineering in future.