戈壁风沙流结构特性及其意义  

STRUCTURAL CHARACTERISTICS OF GOBI SAND-DRIFT AND ITS SIGNIFICANCE

作　　者：屈建军[1] 黄宁[2] 拓万全[1] 雷加强[3] 董治宝[1] 刘贤万[1] 薛娴[1] 俎瑞平[1] 张克存[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所沙漠与沙漠化重点实验室,甘肃兰州730000 [2]兰州大学物理学院力学系,甘肃兰州730000 [3]中国科学院新疆生态与地理研究所,新疆乌鲁木齐830011

出　　处：《地球科学进展》2005年第1期19-23,共5页Advances in Earth Science

基　　金：国家重点基础研究发展规划项目"重大工程对风沙地貌发育过程的影响研究"(编号:G1999043505);国家自然科学基金项目"库姆塔格沙漠羽毛状沙丘形成发育过程研究"(编号:49971013)资助.

摘　　要：通过砾质戈壁风沙流野外实测数据的分析以及风洞模拟实验研究发现:戈壁风沙流结构具有与沙漠风沙流完全不同的风沙流特征,戈壁风沙地表的粗糙度随风速的增大而增加,其表面风沙流输沙量高度分布表现出独特的"象鼻"效应,在一定高度处呈现最大值,并随风速的增加而增高。该"象鼻"效应导致戈壁风沙流结构特征值λ远大于1,不论风速多大,风沙流都处于未饱和状态的非堆积搬运状态。这种特殊性质比较清楚地解释了敦煌莫高窟千年来不被沙山埋没的谜底。并且在风沙防治工程实践中,采用砾石压沙措施,构造类似与砾质戈壁的下垫面,人工促使风沙流结构呈现"象鼻"形状,可使防沙工程达到理想的输导作用。By field measurement and wind tunnel simulation on sand-drift of Gobi, this paper draws the following conclusions: ① The wind-drift structure of Gobi has the feature which is different from that of mobile sand. The roughness of Gobi surface increases with wind velocity. With height increasing, the sand transport rate of Gobi surface takes on unique effect of elephant nose, that is, the sand transport rate comes to a maximum value in certain height and this height increasing with wind velocity. ② The elephant nose effect leads to the characteristic value of sand-drift in Gobi (λ)being more than 1 at all times. This indicates that the Gobi sand-drift is belonging to the unsaturated and non-accumulating state, however how great the wind velocity is. ③ The elephant nose effect of Gobi sand-drift can also answer the question why the Mogao Grottoes can not be buried by sands during more than 1000 years. ④ Therefore, in the practice of protecting sand damages, we can use gravels to cover mobile sand surface to form an underlying surface like Gobi, and making sands pass over it freely.

关 键 词：戈壁 风沙流结构 输沙量高度分布 “象鼻”效应 粒度高度分异 风沙实验 

分 类 号：P512[天文地球—地质学]