Slope Stability Analysis And Evaluation Of Road Cut Slope In Case Of Goro To Abagada Road, Adama

Abstract

Slope failures are among the common geo-environmental natural hazards in the hilly and mountainous terrain of the world causing damages to human life and destruction of infrastructures. In Ethiopia, the demand for the construction of infrastructures especially highway and railways are increased to connect the developmental centers. However, the failure of roadside slopes formed due to the difficulty of geographical locations is the major difficulty for this development. As a result, a comprehensive site-specific investigation about destabilizing agents and suitable selection of slope profile is needed during design. Hence, this study was emphasized on the stability analysis and performance evaluation of slope profiles (single slope, multi-slope, and benched slope). The analysis was conducted for static and dynamic loading conditions using limit equilibrium (slide software) and finite element method (Plaxis software). The analysis results in selected critical sections show that the slope is marginally stable with FS varying from 1.2 to 1.5 in static condition and unstable with FS below 1 in dynamic condition. From the comparison of analysis methods, the finite element method provides more valuable information about the failure surface of a slope than limit equilibrium analysis. Performance evaluation of geometric profiles shows that geometric modification provides better and economical slope stability. Benching provides significant stability for cut slope (i.e. the use of 2m and 3m bench improves the factor of safety by 7.5% and 12% from single slope profile). The method is more effective in steep slopes. Similarly, the use of a multi slope profile improves the stability of slope in stratified soil with varied strength. The performance is more significant when it is used in combination with benches. The study also recommends drainage control and slope reinforcement as a remedial measure for cut slope.