暴雨作用下黑岱沟露天煤矿排土场土壤侵蚀泥沙来源解译

Characteristics and source analysis of erosion sediment in dump of open pit coal mine based on REE tracing

排土场是人为扰动下形成的巨型松散堆垫地貌,具有物质条件复杂、边坡松散和平台紧实等特点。为揭示排土场土壤侵蚀规律,选取内蒙古胜利黑岱沟露天煤矿东排土场为研究对象,建立排土场室内模型(二阶),采用人工模拟降雨与稳定性REE示踪技术相结合的方法研究了暴雨作用下排土场模型不同平台和边坡土壤侵蚀规律,解译了排土场模型侵蚀泥沙来源。结果表明:排土场模型的径流率和产沙率的变化曲线相似,表现为随降雨时间的延长先增加后平稳波动的趋势;总径流量和总产沙量随降雨时间的延长而增加,总径流量Z和总产沙量Y与降雨历时X之间具有较好的幂函数关系。90 mm/h雨强次降雨条件下,排土场模型第1阶边坡的产沙贡献率在90%左右,是排土场模型侵蚀泥沙的主要来源;120 mm/h雨强次降雨条件下,排土场模型第1阶边坡的产沙贡献率在70%左右,第1阶平台的产沙贡献率在20%左右,侵蚀泥沙主要来自边坡;150 mm/h雨强次降雨条件下,第1阶边坡和第1阶平台产沙贡献率在30%~50%波动,第2阶边坡产沙贡献率从降雨初期10%逐渐稳定增加到25%,第1阶平台和边坡是主要的产沙贡献区,第2阶边坡是重要的产沙贡献区。排土场平台和边坡的土壤侵蚀量和贡献率均随着雨强的增大而增大。

Mine dump is a huge loose cushion landform formed by human disturbance,which has the characteristics of complex material,loose slope and compact platform.In order to reveal the soil erosion law of the dump,the East dump of Heidaigou open pit coal mine in Shengli was selected as the research object,and the indoor model(second-order)of the dump was established.The soil erosion law of different platforms and slopes of the dump model under rainstorm was studied by using the method of artificial rainfall simulation and stability REE tracer technology,and the source of erosion sediment of the dump model was interpreted.The results show that:The runoff and sediment yield curves of the dump model were similar,showing a trend of first increasing and then stable fluctuation with the extension of rainfall time.The total runoff and sediment yield increased with the extension of rainfall time,and there was a good power function relationship between the total runoff Z and sediment yield Y and the rainfall duration X.Under the condition of 90 mm/h heavy rainfall,the contribution rate of sediment yield of the first slope of the dump model was about 90%,which was the main source of erosion sediment.Under the condition of 120 mm/h heavy rainfall,the contribution rate of sediment yield of the first slope of the dump model was about 70%,and that of the first terrace was about 20%,which was the main source of erosion sediment.The first stage platform was an important source of erosion sediment.Under the condition of 150 mm/h heavy rainfall,the contribution rate of sediment yield of the first slope and the first platform fluctuated between 30%and 50%,and the contribution rate of sediment yield of the second slope increased steadily from about 10%in the early stage of rainfall to about 25%.The first platform and slope were the main contribution area of sediment yield,and the second slope was an important contribution area.With the increase of rainfall intensity,the soil erosion of the dump model was stronger,and the contribution rate of sediment yield of the dump high-level platform and slope was greater.