Influencing Factors And Disposal Technology Of Silt Clay Tunnel Slope Stability

With the rapid development of highway construction in our country,tunnel crossing slopes have become an unavoidable problem in the process of engineering construction.Insufficient support strength will not only cause slope instability,but also affect the stability of the artificial structure of the tunnel.Disasters such as deformation and damage of steel arches,sprayed concrete cracking and tunnel collapse will cause engineering accidents and cause unnecessary economic losses.Therefore,slope stability analysis is of great significance for ensuring the safety of slopes and tunnels,and can provide an absolute theoretical basis for similar projects.In this paper,the slope of the Nanshao ? tunnel of Jianrong Highway in Guizhou is used as an engineering background.The technical methods of indoor soil moisture content test,shear test,theoretical derivation,on-site monitoring,on-site measurement,and finite element numerical simulation are used to analyze tunnel deformation and to open comprehensive analysis of slope stability,the main research contents and results are as follows:(1)The indoor moisture content and soil shear tests of silty clay at the entrance of the tunnel are performed to obtain the shear strength parameters of the soil under different moisture content,which provides data support for numerical simulation calculation.The laws of change between shear strength parameters and moisture content,as well as the laws of difference between soil failure forms and moisture content are analyzed.(2)The influence of the slope angle on slope stability is investigated by numerical simulation.It is found that there is a clear linear relationship between slope safety factor and slope angle logarithm.By comparing the relationship between the slope safety factor and the moisture content at different slope angles,the corresponding critical moisture content at different slope angles is obtained.By establishing a slope tunnel excavation model,the internal relationship between the tunnel excavation position,tunnel deformation and slope stability are analyzed,and the critical value of tunnel deformation when slope failure occurs.(3)The vertical pressure calculation formula of a single-hole biased tunnel in the code was improved,and the calculation method of surrounding rock stress in the form of the quadratic parabola was deduced.The reliability of the accuracy of the calculation method was verified by numerical simulation results.(4)Based on the results of numerical simulations,the changes in slope stability and deformation under different reinforcement treatment conditions are analyzed.Combined with field monitoring data,it is proved that the combined reinforcement measures are more favorable for slope stability and deformation control based on a single solution.At the same time,it can also ensure the security and stability of the tunnel.