Theoretical And Experimental Study On Multilayer Geotextile Prevention Potential Collapse Of Karst Roadbed

Karst landform has a wide distribution in China, ground subsidence caused by karst cave roof instability has a progressive and sudden. In recent years, increasing number of reports of ground subsidence resulting in embankment instability and casualties. If the karst region highway does not take a scientific concealed cave prevention measures, it will face a lot of potential risk. Geotextile protection of karst collapse is an economical, practical and efficient engineering control measures. Multilayer geotextile reinforcement of this paper is not only able to increase prevention karst roadbed collapse of security, and can effectively control land subsidence caused by karst collapse, enhance driving comfort in the way the premise of ensuring safety.On the basis of theoretical research, designed a large proportion of 1:5 model test, combined with a new geogrid deformation test methods, do research in deformation and load characteristics of the multilayer geotextile reinforcement and soil arching effect, and based on the experimental results forming a new design method of multilayer geotextile reinforcemet.Experimental data obtained earth pressure data, geogrid deflection data and the strain data of geogrid in the middle position. Study results 1) the bottom geogrid load and y/b fitting formula,2) load transfer coefficient in the multilayer geotextile reinforcement,3) the critical height of soil arching effect in model test,4) the evolution of soil arching effect in geotextile reinforced model test,5) the load transfer from soil arching to multilayer geotextile.Multilayer geotextile reinforcement is divided into bottom geogrid and upper geogrid will help analyze the working mechanism of multilayer geotextile reinforced. In this paper, the relationship with the parabolic fit bottom geogrid load and y/b, and the load transfer parameters can provide new design ideas. Analysis of the load transfer from soil arching to multilayer geotextile, reveals the reason of multilayer geotextile reinforcement on the control of collapse settlement better than a single layer of geotextile reinforcement.