A new solution for slope stability analysis, called Dual Grid Method, is originated. Dual Grid Method is essentially a combination of FEM and Rigid Limit Equilibrium Method. It treats slope grid as independent from mountain grid therefore potential slopes can be precisely simulated. The idea of virtual Gauss point is first brought forward as an interpolation strategy. Compared with traditional Rigid Limit Equilibrium Method, Dual Grid Method is able to take deformation compatibility of geotechnical materials into consideration. On the other hand, it outperforms Strength Reduction Method since it is insensitive to design of mesh. Besides, safety factors are attained once for all thereby to avoid repeated trial computation. In this paper, specific implementation procedures and numerical examples of Dual Grid Method are both presented.
Using Finite Element Method (FEM) to analyze slope stability has always been an essential issue. Researches on this topic can be categorized into two classes: one is to use overloading coefficient or strength reduction coefficient of the time when structure fails as slope safety factor. Of such methods, Strength Reduction Method is most known and has been widely used and variously developed in the past two decades. It was firstly originated by Zienkiwicz (1975) and afterwards developed by Naylar (1981), Donald and Giam (1988), Matsui & San (1992) and Griffiths (1999). Advantages of this method have been specifically discussed by Dawson et al (1999). However, it also has also some critical limitations, as already pointed out by Cheng (2007). Firstly, the Strength Reduction Method, by extension, methods of this first category, is sensitive to design of mesh and requires repeating calculation. And more importantly, one serious problem still lies in the bad computation convergence due to characteristics of geo-structures and geo-materials (Yang et al 2008).