Evaluation And Application Of Tunnel Slope Stability Based On Improved Variable Weight Equilibrium Function

The purpose of slope stability analysis is to study and grasp the state of slope safety and stability,and to deal with and remedy the landslide with the method of system optimization,which is one of the key fields of Geotechnical Engineering Research for a long time.During the excavation of the portal section,the supporting structure and dynamic load of the tunnel front slope are complex and have the characteristics of dynamic change.Numerical simulation analysis and on-site monitoring analysis are the common methods for its stability analysis.In this paper,xqxn of Xingquan railway of China Railway Fifth Group Co.,Ltd?3.Based on the deformation monitoring project of the front slope at the entrance of the buldeng Zhanwu tunnel,the safety factor of numerical simulation is combined with the field monitoring project,and the stability of the front slope during the excavation of the portal section is comprehensively evaluated based on the improved uncertainty comprehensive evaluation model.The main research contents and results are as follows:(1)Based on the simulated safety factor,the stability of the slope is analyzed,and the characteristic points of the early warning monitoring project are optimized.The results show that during the excavation of the portal section,the front slope is in a "potentially unstable" state during the excavation of the mileage section dk41 + 001-dk41 + 012,and the rest are in a "basically stable" state;the slope toe of the front slope and the left side of the frame beam are in an under supported state.(2)Based on the optimized feature points,the scheme of on-site monitoring of the front slope is supplemented and improved,and the stability of the front slope during the excavation of the portal section is analyzed based on the on-site monitoring data.The results show that: during the excavation of the portal,the front slope is safe as a whole,but the analysis results of the monitoring data are different;most of the monitoring maximum points are supplementary points,which shows that the selection of monitoring characteristic points based on numerical simulation is more reasonable.(3)A state variable weight equilibrium function based on the degree of unbalance is put forward,which is compared and analyzed by a case,and a comprehensive evaluation function model of the slope stability is constructed by combining TOPSIS and IFAHP.The results show that the balance function based on the degree of unbalance has a good corresponding relationship between the degree of variable weight adjustment and the degree of unbalance.(4)Based on the simulated safety factor,monitoring data and the comprehensive evaluation function model,the stability of the front slope during the excavation of the portal section of dengzhanwu tunnel is comprehensively evaluated and analyzed,and the relevant suggestions for the later construction,support and monitoring work are put forward.The research shows that: the dynamic change of the safety and stability of the front slope during the excavation of the portal section of dengzhanwu tunnel,when the excavation reaches dk41 + 005.5,i.e.10.5m away from the portal,the stability of the front slope is the lowest,which is in the "potential instability" state,as a whole,the front slope is relatively safe;in the comprehensive evaluation of the stability of the front slope,the variable weight is more conservative than the constant weight;based on the safety factor,monitoring data and improved variable weight The comprehensive evaluation result of the equilibrium function is reliable,which provides a reference for the safety and stability evaluation of similar engineering cases.