Study On Stress Characteristics And Seismic Stability Of Composite Liner Interface In Gully Landfill Site

With the advancement of urbanization in China,the production of Municipal Solid Waste(MSW)has increased dramatically,it seriously affects the living environment and health of urban residents.Sanitary landfill is the main method currently used to treat MSW.Composite lining systems usually consist of geosynthetics and compacted clay,which is a common anti-seepage structure system in modern landfill projects.Because of its low shear strength at the interface of geosynthetics,it is easy to become weak in landfill instability.In recent years,earthquakes have occurred frequently,and landfill instability has occurred in various countries around the world.Once the landfill is unstable,the toxic and hazardous substances in the landfill will seriously pollute the surrounding environment and cause heavy losses to the surrounding residents.In view of this,this paper studies the stress characteristics and seismic stability of the composite lining of the trench type landfill.The main research contents and main achievements are as follows:(1)The composite lining large triaxial test under consolidation and drainage conditions was carried out using a DJSZ-150 large-scale triaxial tester.Based on a large number of triaxial tests,the stress characteristics of the composite lining under consolidation and drainage conditions were studied in depth.It is found that the ultimate failure interface of the composite lining of multi-layer geosynthetics is not fixed at a certain interface,but will change from one interface to the other with the change of the buried slope ratio of the geosynthetic material.It is possible that both interfaces have extreme damage at the same time in the range.(2)Using FLAC^3Dsoftware to simulate and analyze the force characteristics of the composite lining in the large triaxial test,and verify the correctness of the model and parameters;use the validated mathematical model to analyze the mechanical characteristics of the composite lining under different working conditions,and explore the interface failure mechanism of composite lining and its influencing factors.(3)Considering the translational failure of the landfill along the bottom of the composite liner system,as the normal stress increases the failure surface transfer,the five-wedge analysis model of the landfill is established,and the quasi-static equilibrium analysis is performed on each wedge.A balance equation is established to solve the safety factor of the sliding of the landfill along the bottom composite lining under earthquake action.