内排土场边坡近自然重塑渗流及孔隙水压力特征研究

Research on seepage and pore water pressure characteristics of internal dump near-natural remodeling

为研究我国东部草原区某露天矿边坡在近自然修复模式下的渗流及孔隙水压力特征,以GEO软件中SEEP/W模块为父项,拟合SLOPE/W模块对该矿区强降雨条件下的边坡抗侵蚀特征,渗流路径变化情况以及孔隙水压力重分布情况进行模拟分析。结果表明:对原内排土场边坡进行反S型重塑后,边坡抗侵蚀特性提升明显,单台阶上部及下部区域台阶坡面角降低,区域内径流流速下降,降雨入渗程度增加;受坡面形态改变影响,原内排土场边坡各级台阶坡面处均出现水流渗出现象,水土流失程度较高;重塑后,15 m及20 m台阶重塑模型渗流密集程度增加,内排土场坡面未表现出明显出水现象;边坡顶部孔隙水压力实现重分布,负孔隙水压力分布范围增加,过渡区域面积较为均匀,有效缓解了因不同岩层渗透系数差异性而导致的边坡上部岩层局部积水现象。

In order to study the characteristics of seepage and pore water pressure of an open-pit mine slope in the grassland area of eastern China under the near-natural restoration mode, this paper takes the SEEP/W module in GEO software as the parent item and fits the SLOPE/W module to simulate and analyze the characteristics of slope resistance to hydraulic erosion, the change of seepage path and the redistribution of pore water pressure under the condition of heavy rainfall in the mining area. The results show that after the anti-S-type reconstruction of the original internal dump slope, the resistance to hydraulic erosion of the slope is significantly improved, the slope angle of the upper and lower steps of a single step is reduced, the flow velocity of regional inner diameter flow is reduced, and the degree of rainfall infiltration is increased. Affected by the change of slope surface shape,water seepage occurs at all levels of the slope of the original inner dump slope, and the degree of water loss and soil erosion is high. After remolding, the seepage density of 15 m and 20 m bench remolding models increased, and there was no obvious water outflow on the slope of inner waste dump. The pore water pressure at the top of the slope is redistributed, the distribution range of negative pore water pressure is increased, and the area of the transition area is relatively uniform, which effectively alleviates the local ponding phenomenon in the upper rock stratum of the slope caused by the difference of permeability coefficient of different rock strata.