生态棒间隔距离对铁尾矿坡面减流减沙效应的影响

中国铁尾矿库的排放量大而综合利用率低，遗留下的铁尾矿库形成大面积裸露库面和边坡，易引发水土流失、边坡滑塌等危害。为明确边坡生态修复中生态棒拦挡措施的水土流失防治机理，该研究以张宣铁矿区尾矿库边坡为对象，采用人工模拟降雨，研究不同间隔生态棒拦挡措施的减流减沙效应。结果表明：坡度25°、30°，30~90 mm/h雨强下，1）不同间隔生态棒拦挡措施下初始产流时间较裸坡分别增加0.44%~57.76%、1.08%~39.14%，且随生态棒间隔、坡度、雨强的增大而减少；减流效应分别为8.92%~80.68%、12.67%~76.45%，随雨强增大而减小，30mm/h雨强下随生态棒间隔缩短呈增强趋势，60、90 mm/h雨强下无明显规律变化；径流流速削减效应分别为20.78%~55.12%、20.16%~41.44%，随生态棒间隔缩短呈增强趋势，随坡度增大而降低，同时0.67 m间隔削减坡面流速效应最佳；2）减沙效应分别为-127.47%~71.57%、-287.19%~62.01%，减沙效应弱于减流效应；3）30 mm/h雨强下累积径流量、侵蚀量随生态棒间隔的缩短而减少，60、90 mm/h雨强下规律不明显；且90 mm/h雨强下，坡度30°的累积侵蚀量显著大于坡度25°；4）对产流产沙指标进行Pearson相关分析，表明生态棒拦挡措施在坡面减流、削减流速方面发挥关键作用，雨强对产流产沙的影响处于主导地位，坡度处于辅助地位；5）建议坡度25°、30°，雨强30、90 mm/h时选择0.40 m生态棒间隔，雨强60 mm/h时选择1.00 m生态棒间隔。研究结果可为铁尾矿边坡生态修复中生态棒拦挡措施的科学应用提供参考依据。

Influence of ecobar spacing distance on flow and sand reduction of iron tailings slopes

Iron tailings ponds have been confined to large emissions and low utilization rates in recent years. A large area of exposed surface and slope can be found in the rest of the iron tailings ponds, leading to soil erosion and slope landslides. This study aims to clarify the erosion control mechanism of ecological bar barriers in slope ecological restoration. The slopes of the tailing pond were taken from the Zhangxuan Iron Mining District, Hebei Province, China. Artificial rainfall simulation was adopted to evaluate the flow and sand reduction of ecological bar barriers at different intervals. The test parameters were set as the slopes of 25° and 30° with the ecological rod spacing of 0.40-1.00 m in the rainfall intensity of 30-90 mm/h. The results show that: 1) The initial production time of ecological rod blocking increased by 0.44%-57.76% and 1.08%-39.14%, respectively, at different intervals, compared with the bare slopes, indicating the decrease with the increase of the ecological rod intervals, slopes, and rainfall intensity; The flow was reduced by 8.92%-80.68%, and 12.67%-76.45% with the increase of rainfall intensity. The trend was enhanced at the rain intensity of 30 mm/h with the shortening of the ecological bar interval. There was no outstanding variation in the rain intensity of 60 and 90 mm/h; The runoff flow rates were reduced by 20.78%-55.12%, and 20.16%-41.44%, respectively, with the increase of slope. While the 0.67 m interval was performed the best in the flow rate reduction of the slope; 2) The sand reduction was -127.47%-71.57% and -287.19%-62.01%, respectively. Furthermore, the sand reduction effect was weaker than the flow; 3) The cumulative volume of runoff and erosion decreased with the shortening of the ecobar interval under the rainfall intensity of 30 mm/h. There were no outstanding changes under the rainfall intensities of 60 and 90 mm/h. The cumulative erosion volume of slope 30° was much larger than that of slope 25° under the rainfall intensity of 90 mm/h; 4) Pearson correlation analysis was implemented on the indicators of streamflow and sand production. The ecological rod blocking was dominated to reduce the streamflow and cut the flow velocity on the slope. The dominant influencing factors on streamflow and sand production were the rainfall intensity, followed by the slope; 5) The ecological rod spacing of 0.40 m was recommended for the slopes with 25° and 30°, and the rainfall intensities of 30 and 90 mm/h. At the same time, 1.00 m ecological rod spacing was suitable for 60 mm/h rainfall intensity. The finding can provide a strong reference to apply the ecobar blocking in the ecological restoration of iron tailing slopes.