Multi Factor Stability Analysis And Reinforcement Research On Loess High Embankment Slope Of Tongding Expressway

With the development of western China,the scale of expressway construction is expanding increasingly.the loess slope safety is a prominent problem,especially the slope stability under the influence of rainfall or earthquake,which have attracted much attention from academic circles.In the background of taking the newly-built Tongwei-Dingxi Expressway subgrade slope,Firstly,the slope stability is evaluated by means of mutual verification between field monitoring and theoretical simulation results.Then,combined with the soil mechanics,the finite element,This paper studies the slope stability under rainfall,earthquake and rainfall coupling rainfall earthquake conditions.Finally,according to the mechanism of bolt reinforcement,the author analyzes the protective measures of bolt reinforcement slope.The main research contents of this paper are as follows:(1)According to the basic information of stratum lithology,meteorology and hydrology of K59+020～K59+155 section in Tongwei-Dingxi Expressway high-filled embankment slope,the author designs the slope monitoring scheme and carries out on-site monitoring;The on-site monitoring mainly analyzes the laws of slope deformation and deep horizontal displacement and infers the deformation characteristics and stability of slope after construction.(2)Based on the principle of finite element strength reduction method,The author uses Midas/GTS simulation software to study the stability(safety factor)of high-speed loess slope under design conditions.Then,In view of the selected three typical sections,the author studied the equivalent plastic strain,stress distribution and deformation characteristics of the model and analyzed the stress and deformation characteristics of the slope.After comparing the results of on-site monitoring with those of theoretical simulation,the stability state of slope is judged.(3)The author simulated and analyzed the stability and deformation characteristics of loess slope in the condition of rainfall,earthquake and rainfall-coupled earthquake,and then obtained the most unfavorable conditions affecting the stability and deformation of this kind of slope.(4)Based on the most unfavorable conditions of rainfall-coupled earthquake,The author systematically studies a variety of anchor reinforcement schemes,and gets the optimum reinforcement method,further obtains the quantitative relationship between the anchor reinforcement design index and the slope safety factor;the author verifies and analyzes the stress,strain and deformation characteristics of the loess high slope before and after reinforcement,so as to provide ideas and methods for the treatment of similar engineering emergencies.