Abstract:

In slope stability analyses, the failure surface is often assumed to be predefined as a persistent fat or circular concave plane and the slide resistance along the plane is evaluated. Though this procedure gives the safety factor based on the limit equilibrium theory, the existence of such plane is highly unlikely, and a complex interaction between pre-existing flaws, stress concentration and resulting crack generation, these are not modeled. The development of advanced numerical methods is the key issues of importance. This paper attempts to develop a numerical procedure providing means to analyze the kinetic failure process and the state of stability using a discrete approach. The ground is modeled with an assembly of mass points connected by a pair of springs, normal and tangential direction and the translational motion of each mass point is calculated by solving the equation of motion. The stress state is evaluated on each mass point.

1 Introduction

Slope instability occurs in many parts of urban and rural areas and causes damages to housing, roads, railways and other facilities. Slope engineering has always involved some form of risk management and this has led to the process of the identification and the characterization of the potential slope failure together with evaluation of their frequency of occurrence. An essential part of the hazard (slope failure) identification is the prediction in terms of the character of failure (type, volume), the post-failure motion (travel distance, velocity) and the state of activity (Fell, et al. 2008). The literatures of slope stability analysis using the limit equilibrium method (LEM) and the finite element method (FEM) were reviewed by Duncan (1996), and a number of valuable lessons concerning the advantages and limitations of the methods for use in engineering problems were presented. Jing and Hudson (2002) presented a review of the techniques, advances problems and future development directions in numerical modeling for rock mechanics and rock engineering. The expanded version of the brief review was presented by Jing (2003) and he has suggested that computer methods available can be still inadequate when facing the challenge of practical problems, especially when representation of rock fracture systems and fracture behavior are a pre-condition for successful modeling. Despite of all the advances in both continuum and discrete approaches, the development of advanced numerical methods is the key issues of importance. This paper attempts to develop a numerical procedure providing means to analyze the kinetic failure process and the state of stability as a function of a trial gravitational acceleration to a lattice spring model. This procedure is also able to explain a possible depth and volume of failure at the site.

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