煤炭开采过程中会形成平台岩土紧实、边坡高陡松散的排土场，是露天煤矿土壤侵蚀最为严重的区域。排土场紧实平台的汇流作用是坡面径流侵蚀的主要动力，平台前缘出现的土体裂缝更是为地表径流涌入排土场提供优先路径，极大程度地增加排土场崩塌、滑坡、泥石流等水土流失灾害发生的可能性。研究降雨和微地形对排土场平台-边坡系统土壤侵蚀的作用机制可为露天煤矿排土场水土流失防治提供科学依据。本文以内蒙古锡林郭勒盟锡林浩特市大唐国际胜利东二号露天煤矿南排土场为研究对象，利用相似模拟原理和土体裂缝等效模型建立排土场平台-边坡室内模型，采用人工模拟降雨试验研究不同降雨强度（90、120、150 mm/h）和土体裂缝深度（5、10、15、20 cm）条件下排土场平台-边坡系统土壤侵蚀演变过程、产流产沙特征和侵蚀沟形态特征。结果表明：排土场平台-边坡系统土壤侵蚀演变过程分为土壤溅蚀与面蚀、裂缝充水与坍塌、细沟侵蚀、裂缝贯穿、坡肩垮塌和稳定阶段6个阶段，土壤侵蚀过程是水力侵蚀和重力侵蚀共同作用的结果。当裂缝深度为5、10、15、20 cm时，排土场径流量依次为23.41、58.70、35.24、75.95 L，侵蚀量依次为3.79、19.66、23.01、34.57 kg；随着降雨强度的增大，径流量和侵蚀量均增大；当降雨强度为90 mm/h、裂缝深度为10 cm时，排土场在侵蚀前期形成泥流，其含沙量高达1.03 kg/L。排土场平台-边坡系统径流量和侵蚀量是土体裂缝和降雨强度共同作用的结果，其交互作用与径流量和侵蚀量达到显著和极显著水平。不同降雨强度和裂缝深度条件下，各时段土壤侵蚀量依次为对照的1.94~4.56、2.07~63.19、4.98~34.54、5.84~53.98、6.31~74.64、38.78~176.25倍，呈现多峰多谷的变化规律。随着降雨强度和裂缝深度的增大，排土场侵蚀沟数量减少，侵蚀沟长度、宽度和深度增大，溯源侵蚀越严重。

The dump,with the compact rock platform and high steep loose slope,which is formed during coal mining,is the most serious area of soil erosion in a surface coal mine.The confluence of compact platform is the main driving force for the erosion of slope in the dump,and the ground fissures at the front edge of the platform provide a preferential path for surface runoff to flow into the dump.These greatly increase the possibility of soil and water loss disasters such as collapse,landslide,and debris flow in the dump.Studying the mechanism of rainfall and micro-topography on the soil erosion of platform-slope system of dump can provide a scientific basis for the prevention and control of soil erosion in a surface coal mine dump.Taking the south dump of the Shengli Dong No.2 open-pit coal mine of Datang international power generation company in Xilinhot City,Xilingol League,Inner Mongolia as the research object,establishing an indoor model using similarity simulation principle and equivalent model of ground fissures,the evolution process of soil erosion,runoff and sediment yield characteristics and morphological characteristics of erosion ditch under different rainfall intensities(90,120,150 mm/h) and ground fissure depths (5,10,15,20 cm) were studied using simulated rainfall experiment.The results indicate that the soil erosion evolution process of platform-slope system of dump was divided into six stages:soil splash erosion and surface erosion,water filling and collapse of ground fissures,rill erosion,ground fissures through,slope shoulder collapse,and stable stage.The soil erosion process was the result of water erosion and gravity erosion.The runoff was 23.41,58.70,35.24 and 75.95 L with the ground fissure deep of 5,10,15 and 20 cm,and the corresponding erosion was 3.79,19.66,23.01 and 34.57 kg.The runoff and erosion increased with the increase of rainfall intensity.Mud flow was formed in the early stage of soil erosion process,and the sediment concentration was 1.03 kg/L under 90 mm/h rainfall intensity and 10 cm ground fissure depth.The runoff and erosion of platform-slope system of dump were the result of the joint action of ground fissure and rainfall intensity.The interactions of ground fissure and rainfall intensity have a significant relationship with runoff,and have an extremely significant relationship with erosion.The erosion with each period was 1.94-4.56,2.07-63.19,4.98-34.54,5.84-53.98,6.31-74.64 and 38.78-176.25 times of the control under different rainfall intensities and ground fissure depths,and the erosion presented continuously multi-peak multi-valleys.With the increase of rainfall intensity and ground fissure depth,the number of erosion gullies decreased,their length,width and depth increased,and the head cut erosion became more serious.

1 材料与方法

   1.1 研究区概况

   1.2 研究方法

2 结果与分析

   2.1 排土场平台-边坡系统侵蚀演变过程

   2.2 排土场平台-边坡系统产流产沙特征

   2.3 降雨强度和土体裂缝对排土场平台-边坡系统土壤侵蚀的影响

   2.4 排土场平台-边坡系统侵蚀沟形态特征

3 讨论

   3.1 排土场平台-边坡系统土壤侵蚀的特殊性

   3.2 降雨和微地形对排土场平台-边坡系统土壤侵蚀的作用机制

4 结论