| The PLA is a kind of biodegradable fibre. It can break into CO2 and H2O under the soil microorganism work. This paper takes the PLA fabric introduced from TORAY. JP as the study object. From 2007 to 2009, we choose 3 experimental areas in the Ulan Buh desert and the Mu Us Sandy land. By using the indoor experiment and outdoor observation methods, the construction & desining way, combating desertification effects and the material degradable characters of the PLA sand barrier have been studied in this paper. Meanwhile, the porpularization and application foreground also been discussed. The mainly conclusions are as follows:(1) The construction method which using the PVC tube + scissors is very convenient and efficient. Both the weather and site conditions have strong influence on PLA sand barrier construction. The soil moisure can influence the construction speed and the slope grade can influence the sand barrier stability. The checkerboard sand barrier is better than the stripped sand barrier. It can improve the sand-leaking phenomenon if the materials were seethed and the basic index will be changed. Improved materials almost have no influence on the construction speed.(2) PLA sand barrier which set by the traditional style can take a good combat effect. a. the wind speed profile shows special"S"changing rule in the PLA sand barrier. The PLA sand barrier also can influence near surface sand flux structure and can reduce the wind speed, increase the roughness rate and improve the surface erosion and deposition situation. b. this kind of sand barrier can promote revegetation and all of the sand barrier size, the slope position, the barrier body perfection degree and the plant have important influence. c. slope position have notable effect on surface soil water content in the sand barrier. There are no differences among different size and the PLA sand barrier is helpful to enhance the deep layer soil's moisure and it has the thermostatic effect for deep soil. When the sand barrier set 1 year, the soil mechnical character hasn't notable changes and it is similar with the straw sand barrier. But the quickly nutrient content changes more.(3) The PLA sand barrier has many kinds of configuration for its strong maneuverability. The best configuration for stabilize the crescent dune is 1m×1m small size in the bottom and the below of the slope, 1.5m×1m in the middle and the long side is perpendicular to the mainly wind direction, the up of the slope is 2m×2m size. PLA sand barrier affluence and sediment transport effect shows quickly and remarkable, so it have big potential in the wind power combat desertification area.(4) When the PLA fabric are used in the sandy land as sand barrier material, its mechanical character is influenced by the wind and sand activity mostly, and the illumination and soil water content also can effect it. After the barrier set 1.5 years later, the fiber average molecular weight has a small decline and its surface keep well. This material can degradable rapidly in the hot and humid environment. And the higher temperature has, the faster degradable speed is. The material in the sand is degraded faster than which on the sand surface. Soil water content has notable influence on the materials degradable and the higher water content has, the faster degradable speed is. The material on the sand surface is degraded faster than which in the sand. Different soil type has different influence on the material degradable.(5) Compared with the straw sand barrier and the Salix psammophila C. sand barrier, PLA sand barrier material cost too much and it has a lower expense for transportation and construction. Its life is longer and without maintenance cost. So by integrated analyzation, PLA sand barrier has prodigious development potential and widely popularization and application foreground.
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