关键词: 半隐蔽格状沙障, 稳定凹曲面, 防护效益

Abstract: The semi-buried checkerboard sand-barrier mainly made from wheat straw or rolled reed, is an economic, effective and widespread-used method of sand fixation (stabilization) in China. It can stabilize the shifting sand by increasing the roughness height of underlaying surface, decreasing the wind velocity near the ground surface and thus weakening the intensity of sand transportation. Due to the eddy action of airflow, the sand in sand-barriers can reach a state of equilibrium between erosion and accumulation, and finally form a stable concave surface. These regular-arrayed surfaces in sand-barriers have a lift force effect, which causes unsaturated sand flow pass it over totally. This is the key mechanics of sand protecting of checkerboard sand-barriers. The tests in Shapotou show all of 1 m×1 m, 1.5 m×1.5 m and 2 m×2 m girds have marked function to sand-protecting, whereas the sand-protecting efficiency of 0.5 m×0.5 m checkerboard sand-barriers is not ideal as the two formers, they lost their function of sand-protecting soon after being buried. Moreover, the making of 0.5 m×0.5 m sand-barriers wastes a lot of manpower and materials. In addition to dimension of sand-barriers, the topographic location has also a direct effect on sand-protecting efficiency. So in order to evaluate the integrated sand-protecting efficiency of sand-barriers objectively, both the wind field characteristics of investigated area and the function of sand-fence must be considered simultaneously. Recently, we used some new techniques and materials (such as nylon, polyester and plastic net) to sand protecting, and obtained some fruits during tests. These measures cannot only provide the material sources to sand protecting, but also extend their operational life span.

Key words: semi-buried checkerboard sand-barriers, stable concave surface, sand-protecting efficiency