Slope Stability Analysis by Swedish Slip Circle Method Using C-Programming

Abstract

The side slopes of an earthen dam should be safe against shear failure. Out of the various methods of stability analysis of slopes, “Swedish Slip Circle Method” is commonly used in practice. Here in the Swedish circle method, potential failure surface is assumed to be cylindrical in shape (i.e., circular in cross section). After determining the actuating and resisting forces for assumed failure surface, the factor of safety is calculated. The slope is considered safe if the minimum factor of safety is greater than the specified value. This paper aims at presenting the procedure for determination of factor of safety using C-program. The program helps to calculate normal component (N) and tangential component (T) at a faster rate as compared to graphical method. With the use of co-ordinate system for determination of normal and tangential components, the program results in a very accurate value which will otherwise be approximate, if calculated by graphical method. The program also displays N-plot, T-plot and U-plot which are important features of rectangular plot method.  Another important feature of the program is the graphical representation of cross section of the dam along with assumed slip surface and number of slices with different forces acting on them. This paper aims at comparing the value of factor of safety obtained by graphical method with that obtained by C-program. With this computational approach, the obtained factor of safety is more accurate than that obtained by conventional graphical method.

Keywords: N-plot and T-plot, factor of safety, rectangular plot method, normal and tangential components, slope stability, graphical method