Research On Laboratory Shear Tests Of Geosynthetics And The Application In MSW Landfill

With the widely applications of geosynthetics,the interface shear characters are regarded as increasingly importanct by engineers.Meanwhile,increasing needs and requests of interface shear tests in laboratory are being asked.Because the frictional characters are so important that it could directly affect the factor of safety and effectiveness of system.In this thesis,a series of research work,which is about the interface shear test of geosynthetics and the application of test results in municipal solid waste landfill,is as follows:(1)This paper manufactures a simple tilt table device to measure the frictional characters between three different HDPE(High-Density Polyethylene) geomembranes and sand, geotextile and woven geocomposite.The test results are presented in this paper.(2)This paper also develops a direct shear device to research the frictional characters of the same materials.The results are analysed to discover the frictional characters and influence factors.(3)Then, this paper presents the comparision of the two kinds of lab tests,including the differences of test results and application range of the them.(4)Finally,the test results are applied in the lining system and capping system of Laogang MSW landfill of Shanghai.This paper calculates the safety factors with different parameters and different methods.Through inducing and summarizing the rusults of tests and calculates,we get some valuable conclusions as follows:(1)The frictional characters of geosynthetic interface is influenced by surface feature of planner materials.In a general way,roughness of test interface is the most important factor.(2)There are much influence factors of interface frictional characters, including sample scales and normal stresses.As to tilt table test and direct shear test,the rules of influence factors are much different.(3)The comparision of the test results shows that the interface shear stress is different due to different test methods.lt presents that test results of direct shear device is less than that of tilt table device.(4)When analysis different parts of MSW landfill,it is important to choose appropriate parameters and methods,due to the system directions and upper stresses.