乌玛高速公路中卫段风沙环境及输移规律
王金国1, 安志山2,3, 张克存2, 屈建军2, 何明珠2

(1.宁夏交投工程建设管理有限公司, 银川 750000; 2.中国科学院 西北生态环境资源研究院 沙漠与沙漠化重点实验室 敦煌戈壁荒漠生态与环境研究站, 兰州 730000; 3.中国科学院大学, 北京 100049)

乌玛高速公路; 输沙势; 粒度特征; 风沙流

Surface Sand Grain Characteristics Along Zhongwei Section of Wuhai-Maqin Highway
WANG Jinguo1, AN Zhishan2,3, ZHANG Kecun2, QU Jianjun2, HE Mingzhu2

(1.Ningxia Investment Engineering Construction Management Company, Yinchuan 750000, China; 2.Dunhuang Gobi and Desert Research Station, Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; 3.University of Chinese Academy of Sciences, Beijing 100049, China)

Wuhai-Maqin Highway; drift potential; particle size characteristics; sand flow structure

备注

作为宁夏自治区南北向交通运输通道,乌玛高速公路对于带动区域经济发展有着重要意义。为保证公路正常运行,该文采用野外定位监测和室内分析方法,揭示了公路沿线风沙活动规律。结果表明:(1)区域0～5 m/s等级的风速频次占全年风速的90.45%,起沙风向主要集中在西北、东和偏南方向,合成输沙方向为偏东南方向; 研究区输沙势小于200 VU,属于低风能环境。(2)沿乌玛高速公路自东北向西南方向,所有样品均以细沙和中沙为主,粒径范围集中在1.0～2.76 Φ。除5号采样点20 cm,50 cm和100 cm深度沉积物的百分含量分布曲线呈双峰态,其余样品全部为单峰态,表明研究区域表层沉积物经过了充分分选。随着深度的增加,不同粒径范围百分含量的变化规律并非十分明显,即区域风能环境比较稳定。(3)所有样品分选性较好或很好,偏度为正偏或极正偏,粒径偏粗。(4)区域内风沙流主要集中在30 cm以下,占总输沙量的89.46%,地表0～20 cm高度内的输沙量占总输沙量的63.81%。基于防护体系走向与区域合成输沙方向垂直时可取得较好防护效益,建议乌玛高速防护体系走向设计为东北—西南,且固沙措施的高度不低于20 cm。
As an important north-south traffic channel in the Ningxia Autonomous Region, the Wuhai-Maqin highway is of great significance for driving economic development in the autonomous region and transportation pressure in the environmental region. Through field investigation and sampling, combining with indoor analysis experiments, the distribution characteristics of surface sand particles along the Tengger Desert section of Wuhai-Maqin highway were studied. The results show that:(1)the frequency of wind speed of 0～5 m/s level in the area accounted for 90.45% of the annual wind speed; the winds of sand blowing mainly concentrated in the northwest, east and south directions, the direction of sand transport was combined, and the synthetic transport potential was in the southeast direction; the area where the transport potential was less than 200 VU belonged to a low wind energy environment;(2)from northeast to southwest, the particle size range of all samples concentrated in 1.0～2.76 Φ, and mainly belonged to fine sand and medium sand; except for the No.5 plot, the cumulative frequency distribution curves of the sediments at the depths of 20 cm, 50 cm and 100 cm were bimodal, and the rest of the samples were all unimodal, indicating that the sediments had been fully sorted, and sedimentary environment was dominated by the early two groups of dominant wind directions;(3)with the increase of depth, the change of percentage content in different particle size ranges was not very obvious, and the sorting performance was good or very good, the skewness was positive or extremely positive;(4)the sand flow in the area mainly concentrated below 30 cm, accounting for 89.46% of the total sediment transport, and the sediment transport within the height of 0～20 cm on the surface accounted for 63.81% of the total sediment transport. The direction of the Wuhai-Maqin Highway protection system should be northeast-southwest which is perpendicular to the direction of the regional synthetic sand transport. It is suggested that the height of the sand fixation measures should not be less than 20 cm.