Numerical Analysis On Slope Excavation And Experimental Study On Reinforeced Slope Protection Applied In Expansive Soil District At Yun Gui Railway

China is one of those countries which have most widely distributed of the expansive soils and most seriously affected by the expansive soils disasters.Guangxi and Yunnan provinces are the most serious hazards areas by the expansive soils (rock) disasters in China,especially in Baise district,where the features of those expansive soils are extremely complex. In most time it would damage the expensive soil slopes.There is no uniform opinion on the expansive soil slope failure mechanism,supporting structure design and calculation.We study waterproofing and drainage system of roadbed (slope),flexible retaining effect in the expansion soil area through research, field investigating, field monitoring, theoretical analysis, numerical simulation and other methods base on projects supported by Railway Ministry:"Research on the key technology of expensive soil area at Yun Gui Railway"(2010G016-B)and National Natural Science Foundation "Evaluation method on dynamic stability of high-speed railway roadbed for long-time"(51278499).The main contents of the research are as follows:(1)Indoor data survey was conducted on geological data research along the Yungui railway,detailed engineering geological of expansive area from Nanning to Baise has been described. And a series of laboratory experiments were done to verify the survey(2)Through comprehensive research of treatment about Waterproofing and drainage in expansive soil roadbed (slope),we analysis the mechanism of water damage and make a brief introduction of commonly treatment on slope in expansive soil area.(3)Study stability and the stress change of slope in the excavation process through the simulation of expansive soil slope.We study the stability, stress characteristics of expansive soil slope under the residual strength, through the simulation of the completed slope with rainfall.Provides referrence for those slope excavations in expansive soil area.(4)We get the data of vertical stress changes,tensile force changes, soil moisture changes of geo-grid reinforced supporting structure under the rainfall condition by buried earth pressure cells,the flexible displacement meters and humidity sensors in geo-grid reinforced earth retaining wall.The result can indict the reinforce effect of geo-grid reinforced soil retaining wall.