Study On Stability Of Embankment Slope Of Gobi Desert Soil Forhigh-speed Railway

In this paper, the filler of the typical representative of subgrade construction in Xinjiang is as the research object for the second double-track in Lanzhou-Xinjiang railway.The stability of embankment slope of Gobi desert soil is studied through the theoretical analysis, laboratory test, and numerical simulation methods.The main research results can be summarized as:(1) The grading of the filler is good or not,which is mainly controlled by the curvature coefficient, and meeting the requirements of the curvature coefficient is or not,which is mainly decided by the content of the filler granules.There is a relationship between the maximum dry density and optimum moisture content of the filler and its particles content.(2) Improving the compaction coefficient can increase the cohesion c value and internal friction Angle φ value to improve the stability of slope.The effect that the moisture content affects the shear strength index of the filler is different. The cohesion c value firstly increases, then it decreases along with the moisture content increasing. But the internal friction Angle φ value is decreased continuously along with the moisture content increasing;(3) It is a great practical significance that improving the compaction coefficient of the filler can improve the effect of compression index and the compression feature; The compression modulus of the filler shows a trend of increase, and a good compression feature can be gained under the condition of repeated loading.(4) When the filler is in unsaturated condition, the gravel sand and the fine gravel soil in the Gobi region are used for filling embankment slope, which can meet the requirements of high-speed railway specification;In the engineering of the height H≤8m of embankment slope for high-speed railway in the Gobi region,the slope with1:1.5can satisfy the requirement of engineering practice when the filler is under unsaturated condition.(5) The rainfall has a great influence on the stability of slope.After the rainfall infiltrating,the safety factor of slope firstly increases, then it decreases with the increase of moisture content of the filler. When the moisture content of the filler in drying or the optimum water content nearly,the slope stability is better.When the moisture content of the filler is close to the saturation moisture content, its safety coefficient of the value being far less than specification requirements reduces sharply, and its stability is poor;When the shallow soil is saturated, the slip failure phenomenon of the shallow slope collapses easily,and the parts of slip failure takes place in the different parts of embankment slope. (6) Elastic modulus, length of reinforced material, and layer spacing of the geogrid reinforced slope all have a certain influence to the horizontal maximum displacement of the slope,but the effect is small to its the maximum shear strain and the safety factor.In addition, there is an obvious effect that the shallow reinforcement of geogrid reinforced slope can improve the performance and enhance the slope stability.(7) Slope protection can greatly improve the slope stability.Compared with without any protective measures, the horizontal maximum displacement of the slope in slope protection measures is largely reduced,and the safety coefficient is improved greatly.(8) In contrast,the stability of embankment slope of Gobi desert soil is poorer under without any reinforcement or protective measures;The stability of embankment slope is greatly improved under the reinforcement or slope protective measures, and both the effect improved is similar.The stability of embankment slope is the best under the comprehensive measures of the reinforcement and slope protective working together.