Numerical Simulation Research On Response Rule Of Wind-blown Sand Flow To Zhunger-shuozhou Railway Cutting And Effect Of Windbreak And Sand Fixation Measures

In this paper,based on measured data of cuttings of DK168+300-DK168+449.1 and DK161+897-DK162+073 in zhunger-shuozhou railway,the process of wind-blown sand flow through the cuttings and Windbreak and sand fixation measures are simulated based on fluent,parameters of cutting depth and slope are used to study the distribution of the flow field around the cutting,the effect of sand fixation measures and sand resistance-fixation measures is evaluated,providing the numerical simulation of the qualitative and quantitative basis on the background of setting up reasonable protective measures in different cutting area,providing supplement and further study for field actual measurement results,it has a very important significance for the design of protection measures and operation of the railway safety in cutting area.The main research results are:(1)The process of wind-blown sand flow through a section of the flat bed will be added-supersaturation-reduction-stabilization.The volume fraction of sand decreases along the height when the sand flow is stable,and it decreases from the exponential law in the height of 8cm.The effect of wind speed on the volume fraction of sand is that the larger the wind speed is,the larger the volume fraction of sand is at the same height.(2)The existence of cutting will change the distribution of the flow field around the cutting,forming a low-speed region in the cutting.The deeper of cutting is,the larger of low velocity area,sediment accumulation and sand accumulation area.The greater the slope,the smaller of low velocity area,sediment accumulation and sand accumulation area.(3)Sand fixation measures reduce the wind speed near the surface to achieve the effect of windbreak and sand fixation,the larger surface roughness value is,the better effect of windbreak and sand fixation.(4)The setting of the sand barrier fence change the flow field distribution,and the low velocity zone is formed in the vicinity of the windward side and the rear area of the sand barrier fence,sand deposited in those area to achieve the effect of sand resistance.(5)The combination of resistance and fixation measures has a better effect of sand fixation than the simple sand resistance measures,the larger surface roughness value is,the better protective effect of the combination of resistance and fixation measures.(6)The comparison between field measured datas and numerical simulation results shows that the numerical cutting model is reliable.