基于流固耦合的充水采空区渗流模型

Seepage Model of Water-Filled Goaf Based on Fluid-Solid Interaction

为研究潜水面升降对充水采空区渗透系数的影响,根据立方定律推导以应变为参数的3个渗透主方向上的等效渗透系数,通过FISH函数完善FLAC_(3D)的非饱和渗流计算功能,基于FLAC_(3D)的流固耦合计算模式,对采动岩体的等效连续介质流固耦合模型非饱和单元进行修正,实现充水采空区渗流场与应力场的模拟计算.通过主渗透系数比与1差值的绝对值反映渗流场对应力场的影响程度,对比模型修正前后矿柱中部单元的计算结果可知:该值随潜水面升高而增大;模型修正前渗流场对应力场的影响大于修正后;模型修正后最大和最小主应变的变化曲线在饱和度为1后出现拐点.因修正前渗流模型参数与饱和渗流参数相同,由此可验证修正后的模型更符合非饱和渗流理论.最后通过与实际工况中地下水渗流量的数据对比,验证了修正后的模型更符合实际.

In order to study the influence of the rise and fall of the water table on the permeability coefficients of the water-filled goaf,the equivalent permeability coefficients in three main permeability directions with strain as parameters were derived according to the cubic law.FISH function was used to improve the unsaturated seepage calculation function of FLAC_(3D)based on the fluid-solid coupling calculation model,and the unsaturated element of the equivalent continuous medium fluid-solid coupling model of mining rock mass was modified to realize the simulation calculation of the seepage field and stress field of water-filled goaf.The influence of the seepage field on the stress field was reflected by the absolute value of the difference between principal permeability coefficient ratio and 1.By comparing the calculation results of pillar central unit before and after model modification,it could be seen that:the value increases with the rise of the water table.The effect of seepage field on stress field before model modification is greater than that after model modification.After model modification,the maximum and minimum principal strain curves show an inflection point when the saturation is 1.Since the parameters of the seepage model before modification are the same as those of saturated seepage,it can be verified that the modified model is more consistent with the unsaturated seepage theory.Finally,by comparing the data of the groundwater seepage flow in actual working conditions,the modified model is verified to be more consistent with the reality.