Seepage Grid Method

In analysis of the stability and the stress state of rockmass, such as the stability of slope and embankment, seepage in fractured rock is often considered as the major factor and more and more attention is put on it. So further research is worth making on how to use effective numerical method to solve this problem.Element free Galerkin method(EFGM), similar to Finite element method, is a new numerical method developed recently. In EFGM, the shape function is constructed by moving least squares(MLS) to get a numerical solution for a partial differential equation and the control equation is derived from the weak form of variational equation . EFGM has many advantages: only nodal data are necessary, high accuracy can be achieved, problems involving moving boundary , large material distortion and structural deformation , etc.Moving 1 east s quares m ethod i s the m athematical b asis o f E FGM. T o use MLS, it is only necessary to construct an array of nodes in the domain under consideration. Just because of this, EFGM is completely free. Moving 1 east s quare i nterpolants do n ot p ass t hrough t he d ata because t he interpolation functions are not equal to unity at the nodes . So it is difficult to impose the essential boundary conditions and coupling EFGM to FEM method is used to solve this problem. EFGM-FEM coupling method, which is fit for analysis of seepage in fractured rock, can impose the essential boundary conditions easily, improve the accuracy of EFGM and solve problem of different materials.In this paper, EFGM-FEM coupling method is applied to solve seepage problem of fractured rock and a detail discuss is made about EFGM, EFGM-FEM coupling method, basic theory of seepage in fractured rock and numerical model. Then the corresponding compute program is developed and several examples are given. The results of examples arecompared with those of FEM to test the validity and reliability of the theory and m ethod i n this p aper. Some r elative i ssues w hich i nfluence the result are also discussed in this paper. Theory and numerical foundations are established for EFGM-FEM coupling method to solve realistic problems.