采深对煤矿沉陷区坡面形态及侵蚀的影响分析

Analyzing the Effect of the Mining Depth on the Shape and Erosion of Surface Slope in Coal Mining Area

井下采煤产生的大范围岩移必然最终改变原有地表形态并影响坡面侵蚀特征及规律。该文从井下与地表相结合的新视角,结合彬长矿区水土流失特征和典型煤矿采矿条件,以采深、地表坡面坡度等因素为变量,构建了30个不同类型的数值模型,通过数值模拟方法研究并揭示井下采深对地表坡面形态及侵蚀的影响规律。结果表明:(1)随着采深的增加,地表坡面坡度增大幅度呈现减小的变化趋势。在相同采深条件下,坡度增大率与坡面自然坡度整体上呈负相关。(2)随着采深的增加,地表坡面坡长减小幅度呈现减小的变化趋势,且自然坡度越小,该变化趋势越明显。地表坡面坡长减小率与自然坡度随着采深的增加呈现先正相关后负相关的关系,自然坡度为26.57°是拐点。(3)采深的增加会削弱地表坡面产流产沙的强度增幅,缓解坡面侵蚀加剧的程度,这种效应在坡度较小的坡面更加显著。井下采煤引起地表坡面坡度的增大是产生这一规律的主因。

The strata movement caused by underground coal mining inevitably changes the original shape of land surface and has impact on the characteristics and law of the slope erosion.According to the typical mining conditions and the characteristics of the soil and water loss in Binchang coal mining area,30 different numerical models with mining depth,slope as variables were constructed,to study and reveal the law of the impact of the mining depth on the shape and erosion of surface slope by means of numerical simulation.Results showed that with the increase of mining depth,the increase degree of the surface slope presents a change trend of decrease.Under the same condition of mining depth,the increasing rate of slope and natural slope present a negative correlation.The decrease degree of the length of the surface slope presents a change trend of decrease with the increase of the mining depth;the smaller the natural slope is,the greater the surface slope length changes.With the increase of mining depth,the decrease rate of the surface slope length is positively correlated first and then negatively correlated with the natural slope.And the natural slope at 26.57 ° is the inflection point in this change process.The increase of mining depth can reduce the intensity of the runoff and sediment yield on the surface slope,relaxing the erosion of surface slope.And this effect is more obvious on the smaller natural slope.The increase of slope caused by underground coal mining is the main reason of the law.