摘要
古尔班通古特沙漠是我国第二大沙漠 ,沙丘类型以固定和半固定纵向沙垄为主。垄间和坡中下部沙面较为稳定 ,仅在沙垄顶部存在 10～ 4 0m宽度不等的流动带 ,风沙活动规律独特。近年来在沙漠腹地修筑的公路、引水渠等线形工程 ,不可避免地造成沙垄切割和保护层破坏 ,所引发的工程安全问题引起了人们的普遍关注。通过风况分析和实地观测 ,对沙漠腹地风沙活动特征进行了初步研究 ,同时对线形工程风沙危害进行监测 ,在此基础上提出现有防护体系存在的主要问题与对策。
Gurbantonggut Desert, located in Junggar Basin in north Xinjiang, with an area of 48 000 km2, is the second largest desert in China. It is comprised mainly of fixed and semi-fixed longitudinal dunes. In recent years, many linear engineering projects have been constructed across the longitudinal dunes. This has disturbed the sand surface and blown sand now threatens the projects. This paper has analyzed wind data and sand movement to investigate the patterns of blown sand motion on the dune surface and discussed its threat to linear engineering projects. Affected by the west current and Mongolian high pressure, the preliminary wind directions are NE and NW, and their strong period is from April to July. The resultant wind-blown sand route in Cainan is N-S. From the bottom to the top of dune, there is a change of sand activity from weak to strong. In a 24 hour sampling period our research showed that the sand transport rate at the crest is 2000 times greater than that in the interdune. The pattern of blown sand motion on longitudinal dune surface is characterised by erosion on the windward slope and deposition on the leeward slope. Sand particles on the top of the longitudinal dune are transported alternately from side to side, while moving forward along the ridge from north to south. The base of the dune remains unchanged. Without a protection system the linear engineering projects face the direct effect of sand erosion and deposition. This usually occurs when the cutting heads of the dunes move from north to south and bury the projects. Protection using only a straw barrier system (checker boards) on the disturbed face was largely ineffectual because sand moving along the top of the dune rapidly buried the protective system. Fill from the excavation of the longitudinal dune was placed on the interdune area, leading to the formation of a small but relatively steep sand slope. Although, the fill area was fixed with check boards the steepness of the man-made slope means that this surface is prone to erosion from the dominant northerly winds. The key point of protection should be the cutting head of the longitudinal dune. On the one hand, the high barrier system should be set up on top of dune in order to decrease the wind velocity and block the blown-sand. On the other hand, straw-check board should cover a significant area along the active belt and decrease the sand source. In the interdune area a gently sloping face should be created on the sand fill. Revegetation should be implemented after establishing the mechanical protection system.
出处
《干旱区地理》
CSCD
北大核心
2003年第2期143-149,共7页
Arid Land Geography
基金
国家重点基础研究发展规划项目 (G19990 43 5 0 4)
中科院"西部之光"人才培养计划 ( 2 0 0 3 2 0 5 7)资助
关键词
古尔班通古特沙漠
沙丘
沙垄
风沙活动规律
引水渠
风沙危害
Gurbantonggut Desert
pattern of blown sand motion
linear engineering projects
wind sand disasters
