Failure Mechanism And Reinforcement Measure Research Of Broken Rock Tunnel Face

With the rapid development of mountainous expressway, the number of broken rock tunnel is increasing, broken rock tunnel face destruction caused by landslides, cave-disasters have occurred in engineering practice. The broken rock tunnel construction is often the emphasis and difficulty in the construction process of building. Taking the Han Jieling tunnel project of Yan Ru highway as background, through a combination of on-site research, theory analysis, numerical simulation method to make a study of the failure mechanism and control measures of broken rock tunnel face.(1) Using the upper bound limit analysis to derive the minimum active supporting force to maintain a stable working face considering the pore water pressure. Based on MATLAB software platform for the preparation of a non-linear optimization program, to make a analysis of pore water pressure effect on the stability of broken rock tunnel face.(2)Based on the numerical simulation method, considering the failure modes, failure location and a variety of influencing factors, to make a analysis of the failure mechanism of the broken rock tunnel face.(3) Combined with the results of numerical analysis, and in accordance with the measurement results of the on-site monitoring to discuss the failure characteristics, failure mode of the Han Jieling broken rock tunnel face; Thus, the combination of hydro-geological conditions and construction of the tunnel project, geological conditions, the tunnel footage, tunnel depth, tunnel face, form and size, to make a in-depth analysis of the destruction influencing factors of broken rock tunnel face in order to provide the strengthening technology basis for the tunnel face destruction.(4)It is discussed that the control methods of weak and broken rock tunnel face deformation and failure from the two aspects of the construction method and support measures, combined with the engineering characteristics of Han Jieling tunnel, using the numerical simulation comparative analysis of the tunnel face destruction control measures and further to be optimized of the tunnel construction process and support parameters. (5) According to the impact of groundwater flow on the tunnel face destruction, to discuss the causes of small groups of gushing wate of broken rock tunnel and treatment measures.