Land reshaping method of imitating natural geomorphology for open-pit mine dump in eastern grassland area of China
LI Shuzhi1 ,GUO Xiaoli1 ,LI Xueliang1 ,SUN Zhongxiang1 ,YAN Jiancheng2,3
东部草原区是我国以露天开采为主的大型煤电基地,由于其生态环境脆弱,露天矿排土场边坡易失稳引发滑坡、沉陷、崩塌问题,因此开展排土场边坡整形对保护草原生态环境、减少水土流失具有重要意义。为探索更加科学、合理的露天矿排土场边坡整形方法,采用归一化植被指数(Normalized Difference Vegetation Index,NDVI)、边坡稳定性分析评价比较了宝日希勒露天矿外排土场台阶式、仿自然地貌的斜坡式和波浪式3种边坡整形方法的效果。结果表明:① 不同整形边坡的NDVI指数表现为波浪式(NDVI=0.551)>斜坡式(NDVI=0.475)>台阶式(NDVI=0.340),但均小于周围自然地貌(NDVI=0.657),波浪式整形边坡植物生长状况优于斜坡式和台阶式整形边坡;② 在同一整形边坡,高台阶的植被覆盖度低于低台阶(覆盖度650 m平台>660 m平台>670 m平台),低台阶边坡水土流失量小于高台阶;③ 边坡稳定性与坡角大致呈负相关关系,不同整形边坡的稳定性为波浪式(F=2.711)>斜坡式(F=2.513)>台阶式(F=1.073),波浪式、斜坡式边坡都处于稳定状态,台阶式边坡滑坡状态处于基本稳定状态;④ 3种整形边坡的NDVI值与稳定系数存在正相关关系,植被覆盖度越高边坡稳定性越高。宝日希勒露天矿外排土场仿自然地貌的波浪式整形边坡水土保持性能和边坡稳定性最好。
The eastern grassland area is a large-scale coal-fired power base dominated by open-pit mining in China. Due to its fragile ecological environment,the slope of the dumping site in open-pit mining is prone to landslide,subsid- ence and collapse. Therefore,the slope shape of dump is of significance to the protection of ecological environment and the sustainable development of mining industry. In order to explore a more scientific method for the slope shaping of open-pit dump,in this study,a normalized difference vegetation index (NDVI) and slope stability analysis are used to compare the effects of three slope shaping methods ( step type,slope type and wave type,which the wave type and slope type are designed by imitating natural landform) in the external dumping site of the Baori Hiller open-pit mine. The results show that ① the NDVI index of different shaped slope is wave type (NDVI = 0. 551) >slope type (NDVI = 0. 475) >step type (NDVI = 0. 340),but all of them are smaller than that of the surrounding natural topography,the plant growth of wave shaped slope is better than that of slope and step shaped slope;② the high step plant coverage is low. On the low step (650 m platform >660 m platform >670 m platform),the water loss of the low step slope is less than that of the high step;③ the slope stability is negatively correlated with the slope angle,and the stability of differ- ent shaping slopes is realized as wave slope type slope (F = 2. 711) >Slope type (F = 2. 513) >step type (F = 1. 073), the wave type and slope type slope are all within the safe range,and the step slope landslide is basically stable;④ the NDVI and stability coefficient of three types of slope shape have the same trend,the higher the vegetation coverage,the higher the slope stability. The wave-shaped shaping method of the natural dump of the excavation field outside the Bao- ri Hiller open-pit mine has the best effect.
eastern grassland area;dump slope;natural topography shaping;normalized vegetation index;stability safe- ty factor
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会