Research Into The Deformation Control Of Tunnel Slope Covered With Colluvial Soil And Technolog For Entrance Excavation

The slope at tunnel entrance often located in the area that geological conditions is poor, and often accompanied by various unfavorable factors to slope stability such as high slope, bias, and shallow buried. This condition lead to the stability of slope getting worse, at the same time, with the influence of the construction, the slope sliding at tunnel entrance occurred frequently, which threating the builder’s safety and hinder tunnel construction. So that how to construct the tunnel entrance safety tend to be the difficulty in the tunnel engineering. Two key points are important to ensure the safety of the tunnel entrance construct that the stability of the slope at tunnel entrance and the stability of tunnel entrance. Therefore, the research of mutual influence between slope stability and tunnel stability is very important. This paper based on Xiangshan tunnel of Mazhu expressway, and researched the aforementioned problems according numerical simulation and monitoring data. The research results are as follows:Established 3D finite element models of tunnel entrance, and analyzed the displacement, stress and strain’s change trend of slope at tunnel entrance. Then, summarized the change rule of slope’s displacement and stress, and gave the location of landslide occurred. On the basis of this, proposed optimizing scheme of tunnel entrance construction.Analyzed the impact generate by different tunnel excavation processes on stability of slope at tunnel entrance. Summarized the advantages and defects of different excavation processes and concluded the application conditions of every excavation process and the problems needed to pay attention. The result could provide the theory basis for adopting reasonable excavation process.Estimated the stability of slope at tunnel entrance according analyzed the monitoring data. And summarized the change law of displacement. Proved the rationality of the optimized scheme. At the same time, confirm the accuracy of the numerical simulation through the comparison between the measured data and simulated data. And provide the basis for the interpretation of numerical simulation data.