Numerical Simulation Study On The Mechanism Of Mechanical Sand Barrie

With the intensification of land desertification in recent years,the wind-blown sand flow has caused serious damage to farmland,transportation,and residential areas.In the struggle between mankind and desertification,scientists and engineers did a lot of work.They explored and proposed a number of effective measures to prevent desert expansion.However,the improvement and optimization of these engineering measures are mainly based on experience and lack of in-depth theoretical support at present.Therefore,this paper uses advanced numerical methods to conduct in-depth research on two types of sand resistance and fixation engineering measures: wind-break wall and straw checkerboard barrier,which are currently widely used and have achieved remarkable results.The main research contents are as follows:1)Reviewed the current numerical model for wind-blown sand flow,analyzed and selected a mathematical model that is reasonable and easy to use.A mathematical model for the two-dimensional sand-Gobi collision process applied to the Gobi surface was proposed through model simplification and empirical adjustment.Based on this,the numerical simulation of the wind-sand flow on a flat sand/Gobi surface is carried out,and the results are compared with the wind tunnel experiments to verify the reliability of the wind-blown sand flow calculation model.2)The numerical simulation of the wind-blown sand flow around the railway subgrade,the railway subgrade with wind wall,and the improvement of the wind subsidence around the railway subgrade with different underlying surfaces in sand and Gobi are carried out.The wind speed,horizontal/vertical transport rate flux,particle velocity,particle size,etc.were obtained under different wind speeds and different roadbed patterns.The sand-resistance mechanism and the cause of sand accumulation on the backside of the wind-break wall were analyzed.3)Simulate the wind-blown sand flow around straw checkerboard barriers,and some results are verified with wind tunnel experiments.By analyzing the flow,vertical and lateral sand transport rates,the effect of straw checkerboard barriers on sand resistance and fixation was evaluated,and the cause of the formation of unique erosion pattern inside the straw checkerboard barriers were discussed.Through the analysis of the sand particle size,it was found that the resistance and fixation effect of the straw checkerboard barriers on large particles is better than that of small particles.