Study On The Effect Of Windbreak And Sand Fixation Measures At DK3 60+200 Of Lin-Ce Railway

As one of the countries and regions with largest sand desert in the world,over 3000km long railway has been constructed in windy desert area in China,which has made significant contribution on accelerating the economic development in remote area,strengthening national unity and national defence.Due to the considerable effects of wind-sand disaster on safety operation of railway in windy desert area,examining the efficiencies of the treatments for minimizing the influences of windy sand disaster is essential and crucial to guarantee the safety of railway operation in windy desert area.This thesis investigates the performance of wind prevention and sand fixation measures on Lin-Ce railway DK360+200,employing field experiment and numerical simulation with Fluent.Main research results are showed as follows:(1)Having analysed the variation of cumulative percentage of sand mass with changing the height,it is found that sands are moved slightly above the ground by wind.Therefore,good prevention effects can be achieved when the height of sand barriers are set between 20cm to 30cm.(2)At the investigation point,the barrier effect of nylon mesh barrier is enhanced as the number of tunnels increases.The sand barrier effect of high vertical sand barrier decreases with the increase of barrier distance.(3)The integrated protection system shows a remarkable protection effect at the research point,with 99%amount reduction for sand discharge than the controlled area.(4)The most active period of wind-sand interaction at the research point is between March and May which experiences a strong wind environment.Wind erosion is the main wind-sand reaction and sand mass are delivered to the south of southeast.(5)According to the simulation by Fluent,the results show that high upright sand barrier has a better resisting performance and when the height is 2m,barriers show the best effect with an over 70%decrease of the wind speed.It is also found that the faster the wind speed in controlled area is,the larger reduction of wind speed happens.Also,when the height is over 6m,the profile curve of wind speed at experiment point is highly similar to that in controlled area,which shows that high upright sand barrier has limited influence on profile curve of wind speed.(6)The efficiencies of sand barriers are examined by numerical simulation under the strong wind condition.The results show that when the wind speed is lOm/s and 20m/s respectively,high vertical sand barrier and nylon grid sand barrier have a certain sand blocking effect.When wind speed is 30m/s,the effect of sand blocking of high vertical sand barrier decreases rapidly,and nylon net sand barrier still has better sand blocking effect.