典型草原煤矿排土场边坡不同治理措施次降雨水蚀过程分析

以典型草原露天煤矿的排土场边坡为研究对象，利用野外原位径流小区观测设施研究了不同治理措施条件下排土场边坡次降雨的产流、产沙规律。结果表明:在边坡治理初期，首次降雨的土壤侵蚀产沙量均较大，达到中度以上的侵蚀强度，其中铺设植生带措施次降雨产沙量最大，为6 469 t/km²，生态袋一字型布设措施产沙量最小，为2 543 t/km²，分别是裸地产沙量5 640 t/km²的1.15倍和0.45倍；随治理恢复年限的增加，恢复第3年时，生态袋一字型治理措施（生物+工程措施）的年径流量比沙地柏+绣线菊灌丛恢复7 a（纯生物措施）的年径流量小；当边坡治理措施的植被盖度 > 35%时，各治理措施的产沙量均小于未治理裸地的产沙量，且雨强越大，生物+工程治理措施的阻沙能力越明显；生态袋一字型布设措施年土壤侵蚀量由治理当年的5 179 t/（km²·a）下降到治理第3年的1 260.35 t/（km²·a），减少75.7%。因此，在草原矿区的排土场边坡采取生物与工程相结合的治理措施明显优于单纯的生物治理措施，可有效控制排土场边坡的水土流失。

Analysis on Water Erosion Process Caused by Secondly Rainfall Under Different Slope Treatment Measures at Dump Site in Typical Steppe

At the beginning of the vegetation restoration,the slope erosion can reach up to moderate level due to the runoff generated by the first rainfall.In such condition,the sediment yield caused by secondly rainfall is 6 469 t/km2 in vegetation zone,which is 1.15 times of bare land (5 640 t/km2);however,the sediment yield under the measure of the eco-bag with'-'type is just 45.1％ of the bare land.With the increase of restoration duration,the eco-bag with'-'type which is combined by biological and engineering measures is better than biological measures.For instance,in the third year,the annual runoff depth is less than that under the seven years of Sabina vulgaris + Spiraea sp.which is completely biological measure.When the vegetation coverage is more than 35 ％,the sediment yields in different treatment measures are less than those in the bare land;and with the increase of the rainfall intensity,the sediment control capacity of the combina tion of biological and engineering measures is better.Soil erosion amount under the measure of the eco-bag with ‘— ’ type can decrease by from 5 179 t/(km2 · a) (the first year) to 1 260.35 t/(km2 · a) (the third year),the reduction is just 75.7％.In conclusion,combination of biological and engineering measures in the dump slope can control erosion effectively.