干湿循环条件下含软弱夹层矿山边坡降雨渗流特性研究

为了研究软弱夹层在干湿循环条件下的渗透性变化对边坡整体降雨渗流特性产生的影响,结合现场实际利用Geostudio有限元软件建立概化模型,模拟了不同干湿循环次数下边坡的降雨渗流,揭示了不同循环次数下边坡体内孔隙水压力的变化规律。结果表明,在初始状态下由于软弱夹层的弱透水性雨水很难侵入软弱夹层以及下部灰岩,软弱夹层及下部灰岩孔隙水压力几乎没有变化；干湿循环后软弱夹层渗透系数的变大导致其不能作为隔水层阻碍雨水的向下入侵,随着循环次数的增加软弱夹层和下部灰岩受到雨水的浸润,孔隙水压力变大且由于软弱夹层和灰岩的雨水排出能力远小于上部区域,雨水无法及时排出,在边坡体后缘形成的高孔隙水压力区域面积远大于初始状态,雨水入侵对边坡整体稳定性的影响更大。研究结果可为同类型矿山边坡防护提供参考。

Study on rainfall seepage characteristics of mine slope with weak interlayer under dry and wet cycle

For the influence of the permeability change of weak interlayer on the overall rainfall seepage characteristics of slope under the condition of wet and dry cycles, an generalized model was established by using Geostudio finite element software combined with the field practice to simulate the rainfall seepage under different times of wet and dry cycles, and the variation rule of pore water pressure under different times of wet and dry cycles was revealed. The results show that in the initial state, the pore water pressure of the soft interlayer and the lower limestone has little change because the weak permeable rain water of the soft interlayer is difficult to invade the soft interlayer and the lower limestone. As the permeability coefficient of the weak interlayer increases after the dry-wet cycle, it cannot be used as a water-insulating layer to prevent the downward intrusion of rainwater. With the increase of cycle times, the weak interlayer and the lower limestone are infiltrated by rainwater, and the pore water pressure increases. As the rainwater discharge capacity of the weak interlayer and limestone is much smaller than that of the upper area, the rainwater cannot be discharged in time. The area of high pore water pressure zone formed at the back edge of the slope body is much larger than the initial state, and the rain water has a greater impact on the overall stability of the slope. The research results can provide reference for slope protection in the same type of mine.