ESTABLISHMENT OF READILY MATHEMATICAL FORMULATION FOR THE EVALUATION OF SLOPE STABILITY IN EARTH-FILL DAMS

Abstract

ABSTRACT

The assessment of slope stability has been considered to be one of the most common issues to deal with by geotechnical engineers. This is due to the amount of destruction that can be brought up by the slope failure of soil masses to roads, railways, and earth dams, for example. Therefore, the stability of soil mass slopes must be carefully analysed prior to, during and after the construction of such a structure. Depending on the importance of slope stability problem, a number of alternative methods have been proposed for the evaluation of slope safety. These can generally be divided into two main types: limit equilibrium methods and finite element methods. In limit equilibrium methods (LEM), the soil mass is subdivided into a set of slices with straight base where each slice must fulfil the equilibrium conditions of forces and/or moments. LEM’s have three main limitations: 1) slope discontinuity between adjacent slices; 2) unequal inter-slice forces; and 3) the requirement of determining base slope for each individual slice. Accordingly, a large number of slices are needed to accurately represent the curved slip surface, which is computationally time consuming. The purpose of this study is to develop a mathematical approach that addresses the aforementioned issues and best represents the curved slip surface. A fast and accurate mathematical formulation that uses the principle of infinitesimal strips was developed. The new formulation only dependent on the geometrics of slip surface, which are readily available once the slip surface is assumed, eliminated the need of slicing, and satisfied the base slope and inter-slice force continuities. Compared with different sets of slices, the new formulation outperformed the ordinary method of slices in terms of accuracy and efficiency.