塔里木沙漠公路风沙危害评估指标体系

ASSESSMENT INDICATORS OF DRIFTING SAND HAZARD ALONG TARIM DESERT HIGHWAY, XINJIANG

本文通过对塔里木沙漠公路沿线风沙危害环境的综合分析，提出了沙漠公路风沙危害程度的评估指标和评估方法，并对不同程度公路沙害的空间分布特征作出概括。

Tarim Desert Highway, with a length of 522 km, passes through the hinterland of Takli- makan Desert, the second largest shifting-sand desert in the world. It suffers from serious drift- ing sand hazard due to the complx aeolian landform, extremely arid climate and frequent occur- rance of sand-raising wind. In this paper, the hazard along the highway passing through the shifting-sand field is assessed by following steps: Firstly, 5 main factors affecting.drifting sand hazard along the highway are determined with comprehensive analyses of natural environment and human activities. They include: (1) frequent occurrance of sand-raising winds, which is a dynamical factor of drifting sand; (2) sand source, which are the material sources for forming drifting sand hazard; (3) land form, which leads to the difference of wind intensity from the different parts of the compound dunes; (4) cross section construction of the highway; and (5) structure and arrangement of sand- control system. It is emphasized that the drifting sand hazard is caused by natural factors and influ- enced by human activities. Secondly, the whole highway is divided into 250 sections, the basic units of the assess- ment based on the data collection in the field and analysis on the occurrance of drifting sand hazard. According to the indicators mentioned above and using fuzzy mathematics, the assessed results are obtained, which show that 41 sections (45. 6 km long in total), 73 sections (118. 2km long), 53 sections (76.8km long) and 83 sections (187.1km long) suffer from the extremely serious, serious, moderate and slight drifting sand hazard respectively. Lastly, the spatial distribution of drifting sand hazard is discussed. The highway passes through 5 morphological units. Drifting sand hazard is serious in unit 1 and 3, moderate in unit 4, and slight in unit 2 and 5. The forms of drifting sand hazard are different from different parts of compound dunes. With the highway passing through from the top of dunes to the lower land, drifting sand hazard varies from serious to slight. Human factors, such as construction of the highway and arrangement of sand-control system, affect the spatial distribution of drifting sand hazard.