基于非饱和大孔隙流双重介质模型的浸水边坡水力响应数值模拟

受地形限制，大量公路、铁路等常出现沿库与沿河线，水位变化是引起库岸滑坡的重要因素。目前边坡渗流研究多集中在非饱和均匀流，对大孔隙边坡非平衡流方面研究仍显滞后。为此，以福建省某一典型库区边坡为例，对比了水位上升时考虑非饱和渗流和非饱和大孔隙流时边坡水分场和稳定系数随时间的变化规律，并分析了水位上升速率（v）、大孔隙域水力传导系数（Ksf）、两域交界处水力传导系数（Ksa）、土粒中心至大孔隙边界距离（a）、大孔隙体积占比（wf）等对大孔隙边坡稳定系数的影响规律及权重。研究结果表明：水位上升中，非饱和渗流下边坡内部基质域含水率明显小于非饱和大孔隙渗流下边坡内部基质域含水率。非饱和渗流条件下边坡浅层向内的水力坡度明显大于非饱和大孔隙流边坡且大孔隙边坡中相同位置基质域含水率远大于大孔隙域（最大达18.9倍）。两种渗流工况下，边坡稳定系数随水位上升均呈现先减小后增大的趋势，并于同一水位（在最高蓄水位高程的一半附近）同时达到最小值。相同渗流工况下，且考虑非饱和大孔隙渗流边坡比考虑非饱和渗流边坡稳定系数更小。增加v、Ksf、a、wf或减少Ksa，坡内两域间水分交换减弱，水分将快速运移至坡体深处，引起地下水位上升，促使边坡稳定性最大降幅达17.7％。v、Ksf和wf对边坡稳定影响占权重较大且相当，Ksa和a所占权重较小且约为前者一半。

Numerical Simulation of Hydraulic Response of Immersed Slope Based on Dual-permeability Model of Unsaturated Macropore Flow

Restricted by terrain, a large number of roads and railways often appear along the reservoir line and along the river line, and water level changes are an important factor causing landslides on the reservoir bank. At present, the research on slope seepage mostly focuses on the unsaturated uniform flow, and the research on the non-equilibrium flow of macropore slope is still lagging behind. Therefore, the stability factor of unsaturated seepage and unsaturated macropore flow slope is analyzed, and the influence law of the factors including water level rise rate(v), hydraulic conductivity in macropores (Ksf), hydraulic conductivity of the matrix-fracture interface(Ksa), the equivalent diffusion distance between two domains(a) and the volumetric fraction of macropore domain(wf) on the stabilization of slope were analyzed by macropore flow model. The results show that the water content in the matrix area of the slope is close to saturation in the unsaturated macropore flow, and the water content in the matrix domain is obviously less than the water content in the matrix domain of the slope under unsaturated macroporous seepage with rise of the water level. The hydraulic gradient of the shallow inward slope is obviously larger than that of the unsaturated large pore flow slope under unsaturated seepage. The moisture content in the matrix domain is much larger than that in the macropore domain(up to 18.9 times) at the same location due to the permeability coefficient of matrix domain is much smaller than that of macroporous domain. The stability factor of reservoir bank slope decreases first and then increases with the increase of reservoir water level, and it reach the minimum at the same water level(close to the height of the highest storage level) at the same time. Under the same seepage conditions, the stability of unsaturated macropore flow is weaker than that of unsaturated seepage. Reducing Ksf, a, wf or increasing Ksa makes the water exchange between the two regions slow, the moisture rapidly migrate to the depth of the slope, and causes the groundwater level to rise, and the maximum decrease of slope stability is 17.7%. The influence of v, Ksf and wf on slope stability is relatively large and equivalent, while Ksa and a are relatively small and about half of the former.