基于FLAC^(3D)的饱和-非饱和渗流分析

Saturated-unsaturated seepage analysis based on FLAC^(3D)

当使用基于有限差分法的FLAC3D计算渗流场时,自由面位置过高,非饱和区渗透系数被定义成常数,这与实际情况不符。运用变单元渗透系数法,对其进行二次开发,并提出了修正的变单元渗透系数法,对非饱和区的渗透系数进行较为严格的理论修正,得出准确的连续光滑的自由面,求解出饱和-非饱和渗流场。利用有限元法与该方法进行对比,论证了该方法的可行性和有效性。提出了附着接触面的方法,解决了三维复杂边界中寻找溢出点的困难;并以实际的三维复杂工程为例,计算了某边坡的渗流场分布情况,经验证,结果准确。研究成果对研究饱和-非饱和渗流以及该软件中与渗流有关的计算具有有指导意义。

When using FLAC3D which based on finite difference method（FDM） to calculate the seepage,the seepage surface is higher than the real situation＇s and the permeability of unsaturated zone is a constant which is defined by mistakes.An adjusting element permeability method is used to develop the program secondly,and the modified adjusting element permeability method is proposed to correct the permeability of unsaturated zone strictly.After calculation,the exact continuous smooth seepage surface and saturated-unsaturated seepage are obtained.The FEM is used to analyze the seepage contrastively,and the feasibility and effectiveness of the method are validated.The method of attaching interface to downstream side is proposed to solve the problem in which the seepage points are hard to obtain on complicated three-dimensional boundary;then a three-dimensional complicated example is given to calculate the seepage field distribution of a slope;the result is accurate after verifications.The research results are helpful to guide the analysis of saturated-unsaturated seepage and the calculation related to seepage in the program.