Study On Efficiency Of Wind-erosion Control Of The Mechanical Sand-barriers At The Qinghai-Tibet Railway

It is more than a little important to use a pure preventing-and-binding mechanical sand-prevention engineering system at Qinghai-Tibet railway, which also is known as a typical alpine railway without irrigation conditions. This article discusses sand-preventing efficiency of different mechanical measures at a couple of typical sections (South Mountain DK887, Cuona Lake DK1562 and the Xining-Geerm section J01 716+200). We can evaluate sand-preventing efficiency of mechanical measures at Qinghai-Tibet railway by comparing benefit differences of semi-buried checkerboard sand-barriers of different specifications and materials (stone checkerboard, plastic net checkerboard, straw checkerboard and clay checkerboard) and analyzing wind erosion on roadbed at DK878. Evaluation mainly contains three methods, the first one is analyzing erosion-and-deposition intensity and sand-surface stability of each checkerboard with erosion-controlling formula, the second one is analyzing sand-collecting volume ratio and percentage of proximate and stable concave surfaces accounting for total concave surfaces according to sand cross-section data, the last one is analyzing wind erosion on roadbed with survey pins method. We could obtain conclusions as follows:1. The mean sand-buried depth at measurement zones all basically close to or above 8cm, and the mean sand-buried depths of the second measurement are all above that of the first measurement, as well as the erosion-and-deposition coefficients are all less than the first measurement.2. All of the longitudinal sand shapes are relatively stable, the percent that proximate and stable concave surfaces accounting for total concave surfaces has increased lead to a conclusion that lateral sand shapes of the second measurement are all stabler than that of the first measurement.3. Apart from checkerboard 2 of the first measurement at DK887 showing wind-erosion, all other checkerboards of different measurement zones present deposition, and all the calculating-collecting-volume ratios are basically above 10%.4. Regardless of undercutting, undulation or relatively stable checkerboards, they are all presenting a trend to more stable checkerboards.Analysis results show that stone checkerboards at South Mountain DK887 and Cuona Lake DK1562, plastic net checkerboards, straw checkerboards and clay checkerboards at the Xining-Geerm section J01 716+200 gradually present sand-controlling efficiency with time increases. It also shows that it is effective and feasible to analyze each checkerboard with erosion-controlling formula and analyze sand-collecting volume ratio as well as percentage of proximate and stable concave surfaces accounting for total concave surfaces according to sand cross-section data. All of those different mechanical measures present a prominent effect on wind-preventing and sand-binding to protect the Qinghai-Tibet railway from sand disaster.