Study On The Compaction Control And Slope Stability Of Aeolian Sand Subgrade

Aeolian sand distributes widely in China,and the high-quality subgrade filling is relatively scarce in these areas.It is necessary to use aeolian sand as subgrade filling.However,the special subgrade filling for aeolian sand is still unclear in the specification,which causes various problems in the filling of the subgrade with aeolian sand,including the determination of the maximum dry density,the compaction process,the test methods of compaction quality and the stability of the subgrade slope.In view of this,this paper systematically studies the above problems based on practical engineering.The main research contents are as follows:(1)Under the condition of insufficient local water resources,combined with the compaction characteristics of aeolian sand and the test of test section,it is feasible to use natural water content aeolian sand to fill subgrade.(2)By comparing the dry density of indoor compaction test with that of vibration test,the maximum dry density obtained by the optimum compaction method is the largest.A method of determining the maximum dry density of aeolian sand by the optimum compaction method is proposed.Combining with the test of aeolian sand subgrade test section,the compaction parameters of aeolian sand subgrade compacted by crawler bulldozer are recommended.The compactness detection method of aeolian sand subgrade based on dynamic deformation modulus is studied,and the conversion equation of dynamic deformation modulus and compaction degree is given,and the calculated value of the equation fits well with the experimental value.By means of adopting the transient Rayleigh wave method combined with the detection of compaction degree,through a large number of detection,the compaction degree detection effect is better,indicating that the transient Rayleigh wave method is suitable for the detection of the compaction quality of aeolian sand subgrade.(3)The finite element analysis model of aeolian sand subgrade slope is established,and the factors affecting the stability of aeolian sand subgrade are analyzed by using the strength reduction method of finite element.It is concluded that the stability of aeolian sand subgrade is improved by the reduction of subgrade height,the slowdown of slope gradient,the increase of the width of surrounding soil and the increase of friction angle in aeolian sand.The material properties of the surrounding soil have little effect on the stability of the aeolian sand subgrade.At the same time,the response surface method is used to establish the prediction model of the stability of the surrounding aeolian sand subgrade.(4)The causes for analyzing the erosion of aeolian sand subgrade is found that the physical properties of aeolian sand itself are the direct cause of the erosion of the broken surface.After the program comparison,the planting rate of plants with ice grass and caragana and straw curtains is the highest.The ecological protection measures of straw curtains have the characteristics of good effect,low cost,easy construction and good management,and are suitable for aeolian sand slope.