| The terrain in the central and western regions of China is complex,and landslide geological disasters occur frequently.The requirements of railway smoothness and curvature make the line often cross complex mountains in the form of tunnels to form a tunnel-slope system.Its stability and protection technology have always been a hot issue in the field of railway engineering.At the same time,the influence of dynamic and static loads of heavy haul trains on the stability of tunnel-slope system is unknown.Therefore,it is of great practical significance and scientific value to study the stability and control method of tunnel-slope under train load.In this thesis,the tunnel-slope system is taken as the research object,and the stability and control methods of the tunnel-slope system are studied by means of theoretical analysis,three-dimensional numerical simulation,model test and correlation analysis.Based on the disaster-causing factors and failure modes of the tunnel-slope system,a three-dimensional tunnel-slope simulation model was constructed.The spatial and temporal distribution of displacement and stress of the tunnel-slope was analyzed,and the sensitivity of each factor was analyzed.The overall stability of the tunnel-slope system before and after anti-slide pile reinforcement was studied,and the model test was carried out to verify the accuracy of the numerical simulation results.The stability of the tunnel-slope system under train load was compared and analyzed by applying moving load to simulate the train running process.The main research contents and conclusions are as follows:(1)Through literature research,seven factors affecting the stability of tunnel-slope system are summarized : rock mass structure,rock characteristics,topography,groundwater,engineering excavation,slope foot and earthquake action;the failure modes of tunnel-slope system are summarized : collapse failure,surrounding rock sliding failure,local collapse failure,wedge failure,surface spalling and accumulation failure,and the applicability of anti-slide piles as tunnel-slope protection measures is analyzed.(2)The three-dimensional simulation model of tunnel-slope-anti-slide pile is constructed to study the spatial distribution of mechanical properties such as lining displacement and stress under different spacing of anti-slide piles and different horizontal spacing of anti-slide piles and tunnels.Considering the influence of antislide piles on the surface and deep displacement of the slope,the optimal reinforcement scheme with horizontal spacing of 12.5 m and pile spacing of 3.75 m is obtained.(3)Through the indoor test,the similar soil ratio of the slope body is obtained,and the tunnel-slope orthogonal system model test is designed.The bending moment value of the anti-slide pile obtained by the test is basically consistent with the bending moment value obtained by the numerical simulation.The deformation of the outer side of the lining is convex in the middle and concave on both sides,indicating that the deformation of the tunnel vault and arch bottom is the largest,and the deformation of the left and right-side walls is the smallest.At the same time,the accuracy of the threedimensional numerical simulation results is verified.(4)The stability of tunnel-slope system and the model test of anti-slide pile reinforcement are designed.Based on the similarity principle,the similar materials of simulated slope rock mass are configured.The stress and deformation characteristics of anti-slide pile and tunnel during the test are compared and analyzed.The test results show that the bending moment value above the sliding zone of anti-slide pile is greater than that below the sliding zone,and the bending moment direction is opposite.The deformation of tunnel vault and arch bottom is the largest,and the deformation of left and right-side walls is the smallest.The overall deformation of lining is convex in the middle and concave on both sides.The bending moment value of anti-slide pile and tunnel displacement deformation are in good agreement with the numerical simulation results.(5)Based on the grey correlation method,the sensitivity analysis of rock mass parameters and pile spacing to slope displacement and acceleration in the tunnel-slope system reinforced by anti-slide piles was carried out.The experimental model was constructed by orthogonal test method,and the correlation between various factors and slope spatial displacement and acceleration field under train load was analyzed.The sensitivity relationship is: anti-slide pile spacing > moving load size > elastic modulus >damping. |
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