Abstract:

Soil erosion in mining area is a major problem for the ecological security, especially in Loess Plateau. Non-conservation managing practices have further aggravated the situation, especially in new dump slope, which are affected by the highest rates of soil erosion among mining area. Therefore, it is necessary to find a right managing model for the environment restoration of mining area. The one-year dump slopes were selected to evaluate rill erosion. Two managing models were applied to these one-year slopes of opencast coal mine in Inner Mongolia Erdos Yongli. Type A was Salix Psammophila Checkerboard mixed Astragalus adsurgens and type B was Salix Psammophila Checkerboard. In order to easily test the effect of A and B, a bare lope was regarded as a contrast (CK). The experiment included five sample sites: two A, two B, and a CK. Results showed that: rill density, degree of rill dissection, and rill width-depth ratio showed the trend of declining-rising-declining with increasing slope length on CK, but steadily rising on A, rising-declining on B; The rill erosion amount of CK increased rapidly 8 m interval, and reached 283.73 kg; the total rill erosion amount of A and B decreased 46.36% and 35.09% compared to CK. Therefore, A type decreased rill erosion due to the function of Astragalus adsurgens; The accumulation of rill erosion changed with the increase of slope length, and the relationships among them was exponential function of CK, and power function of A and B; the effect of control rill erosion was not different between 75% coverage and 45% coverage before 14 m. The 75% coverage was more effective than 45% between 14~20 m, and the rill erosion amount decreased 53.32%~61.49%. However, the effective control on erosion was within 20 m. This study may provide some scientific basis for the management of dump slope and the ecological security of mining area.

Key words: Opencast mining area, Dump slope, Rill erosion, Astragalus adsurgens, Salix Psammophila Checkerboard

摘要：

露天煤矿新建排土场边坡土质疏松，细沟侵蚀强烈。本文通过野外实地调查，以裸坡为对照，对内蒙古永利煤矿排土场边坡2种不同治理模式（A模式-沙柳方格+沙打旺（Salix Psammophila Checkerboard +Astragalus adsurgens），B模式-沙柳方格）下边坡的细沟侵蚀特征进行了研究。结果表明：裸坡细沟侵蚀总量为283.73 kg，A和B治理模式下边坡的细沟侵蚀总量较裸坡减少46.36%和35.09%。细沟密度、割裂度和宽深比从坡顶至坡脚的变化趋势，在裸坡上表现为减小-增大-减小，而在A模式治理的边坡上均为缓慢增大，在B模式治理的边坡上均为先增大后减小。距坡顶0~14 m处，75%和45%覆盖度沙打旺相比裸坡可使细沟侵蚀量降低37.29%~70.82%和43.10%~70.34%，二者控蚀效果基本相同；距坡顶14~20 m处，75%覆盖度坡面细沟侵蚀量较45%覆盖度减小53.32%~61.49%；距坡顶>20 m处，沙打旺不能有效控制细沟侵蚀。结果可为矿区生态环境安全与可持续发展提供科学依据。

关键词: 露天煤矿, 排土场边坡, 细沟侵蚀, 沙打旺, 沙柳方格