Research On The Slope Stability Of The Shallow Unsymmetrical Loading Neighborhood Tunnel Entrance

With the further implementation of great western development strategy. During the high grade highway construction process of tunnel project, it is easy to cause the tunnel accidents in the shallow unsymmetrical loading neighborhood tunnel due to the topography and geomorphology, engineering geology condition, hydrology geology condition and man-made factors. As the safe stability of the tunnel entrance slope is the the key for a smooth project, so people pay more and more attention to the slope stability of tunnel entrance. This paper combines Zuan Qianmen tunnel in Shanxi Province,and takes it as the engineering background. Based on a large number of reading references, monitoring results of theoretical analysis and numerical simulation analysis, also with the research and discusses this type slope stability at tunnel entrance in the construction situation,we do the research and results are as following:①Generalized the internal and external factors that affect slope stability at the tunnel entrance ;Get a further conclusion of the slope wreck mode and wreck mechanism .②According to Zuan Qianmen tunnel in XinBao highway engineering practice, based on the analysis of monitoring measuring results, summarizes stability variation of shallow bias tunnel, lists and analyses the actual disasters phenomenon during project.③Make use of Midas/GTS to analysis the slope stability of shallow unsymmetrical loading neighborhood tunnel entrance section under the conditions of specific rock. With numerical simulation method different construction methods, different hole depth and different slope shallow buried, calculate the safety factor under various slope condition , and assess the slope stability integratively.④Based on Zuan Qianmen tunnel monitoring analysis of the measured results, and summarizes when shallow unsymmetrical loading tunnel hole construction to the influence degree of slope stability. Analyses the reasons of the actual engineering disasters.Based on the usage of the numerical simulation software, simulate the 3D dynamic construction of tunnel entrance slope, deeply analyzes and summarizes the scope of slope tunnel boundary displacement and surrounding rock mechanics properties, and analyses the tunnel construction of the slope in the process, it is concluded that the time-space effect methhod tunnel excavation scope of slope stability of the hole edge the influence degree. Analysis of numerical simulation of the slope displacement and construction procedures of slope and tunnels relation curves, the numerical simulation results and control the distribution characteristics of plastic, calculates the hole slope safety coefficient of drilling,supply a quantitative judgment. For the stability of the tunnel entrance.⑤Combining with Zuan Qianmen tunnel monitoring and 3D numerical simulation analysis results, comparing the deformation characteristics of the large deformation disasters actual engineering slope and simulated deformation, with the specific reason for the slope disaster, provide certain reference for Slope stability assessment of similar phenomena and disaster analysis.