一种确定裂隙非饱和水力参数的数值模拟法

根据裂隙面分形维数、裂隙面位错值和裂隙面上的面积接触率 ,用随机布朗函数生成裂隙的开度分布。基于裂隙局域为平行平板的假定 ,把裂隙面离散成许多等大小的正方形网格 ,对裂隙排水和吸水时的非饱和渗流过程进行了数值模拟。根据不同毛细压力下裂隙饱和度和非饱和渗透系数的模拟结果整理出了裂隙排水和吸水曲线 (即毛细压力 -饱和度的关系曲线 )以及减饱和、增饱和时的非饱和渗透系数 -毛细压力的关系曲线。模拟结果与试验结果的定性比较表明用本文方法来确定岩体裂隙非饱和水力参数是切实可行的。

A numerical simulation method to determine unsaturated hydraulic parameters of fracture

According to the fractal dimension, the disturbed distance between upper and lower fracture surfaces and the ratio of area contact (the proportion of contact area to whole area of fracture) of fracture, the random Brown Function is used to generate a rough walled fracture with position dependent aperture. Based on the parallel plate approximation for suitably small cell in the fracture plane, the fracture is divided into many equally spaced cells and numerical simulations are done for the process of unsaturated seepage flow during drainage and imbibition. In the light of the simulated results of water saturation and unsaturated permeability under different capillary pressure, drainage and imbibition curves are obtained and relationships between unsaturated permeability and capillary pressure during drainage and imbibition are also presented. The qualitative comparison of simulated results and experimental results shows that the method proposed in this paper is feasible and reliable to determine the unsaturated hydraulic parameters of rock fracture.