关键词: 腾格里沙漠, 风沙流场, 最大可能合成输沙强度, 合成输沙方向, 防护体系

Abstract: Shapotou section of Baotou-Lanzhou Railway is the longest section of railway traversing moving dunes and suffered from very severe blown sand harms. The stable and effective protection system has always been regarded and recognized by people for 45 years since it was built. The former 23 years sand control practice and the later 22 years monitoring demonstrated that: ①These region exists a relative stable sandflow field and has three different wind directions, namely main wind direction W-NNW, sub-main wind directions NE-E and WSW-S. This kind of sandflow filed is the main factor shaping the configuration of reticulate dunes and harming railway with obviously seasonal changes. ②The moving process of sand dunes is manifested as that the main girder of reticulate dune sways along the main wind direction, with a slow forward speed of 2~5 m·a^-1. The most direct reason of forming wind-sand harm is the rapidly moving of sub-girder of reticulate dune, with an average moving speed of 0.527 m·a-1 during the 22 years. ③Theoretically, the forward moving sand body latently menaces the protection system and may forms a high sand bank at former sand-fixed belt and then buries the protection system. However, as the protection system being built and gradually being improved, the characteristics of sandflow field will be altered and the direction of sand-blown activity and its intensity also will be controlled.

Key words: Tengger Desert, sand-flow field, the most possible synthetic sand transport intensity, synthetic direction of sand transport, protection system