Study On Stability Of Tunnel Through Ancient Landslide

Along with the strong development of highway construction,the new tunnels willbe inevitable through the ancient land-slide.In this case, Stability is the overall stabilitywhich contains both the stability of the tunnel artificial constructions and tunnelsurrounding rock in which the mountain or slope. Analysis of the stability of the casenot only has a very important significance to the protection of the safety of tunnels andslope, but also has great reference value to similar projects at the same time. In thisPaper, study the disease and deformation by field measurement and numericalsimulation analysis based on the tunnel, which relies on an actual engineering of Shanxiprovince, through the ancient landslide, set a comprehensive analysis of the tunnelconstruction risk analysis model, the main contents and results are as follows:①Take the analysis of the performance characteristics of the development ofancient landslides and tunnel disease by making a survey of engineering geologicaldata;②By means of field measurement, taking an analysis of the deformation of thetunnel construction process as well as the tunnel disease, and drawn the change situationof the stability of the process, which from the tunnel construction to the tunnel diseaseappears. While the appearing of the tunnel disease, cracks, due to the release of stressand deformation energy, the tunnel is under critical state;③The numerical simulation analysis of the change of the displacement field、stressand strain fields in the tunnel construction process, show the reason of the ancientlandslide resurrection is the excavation of right tunnel, and come to the main factors tostudy of tunnel and slope stability those are the size of the area, the displacementmutation, the top of the tunnel, the distribution of the stress concentration region of thehorizontal direction and the vertical direction, equivalent plastic strain distribution whilethe right tunnel excavation but not add support. Meanwhile, according to thedistribution of the shear stress and shear strain, the start position of destruction as wellas possible destruction region can be determined.④The result of comparative analysis of field data and numerical results tells thatsubsidence of the tunnel slope surface near the free surface、invert deformation anddisplacement of tunnel arch waist in horizontal direction could be the signs oflandslides. ⑤By numerical simulation analysis of tunnel reinforcement conditions and slopestability, proved the composite reinforcement may increase the slope stability further.Therefore certain reinforcement measures are required on the middle rock area, andright tunnel to the area between the ancient slip surfaceto fully protect the stability oftunnel and slope, because of the exiting of the ancient slip surface.⑥During tunnel construction risk analysis, set a risk analysis model that based onthe priority of project duration, the duration loss rating score greater than the economicloss, and several control measures that respond to the risk factors are suggested.