Improving the Slope Stability of Municipal Solid Waste Dumps Using Reinforced Soil Berms: A Case Study

Abstract

The slope stability of an existing dump at Delhi has been analyzed for (a) dry waste, (b) with pore water pressure, and (c) with earthquake. The results show that existing slopes are just stable in the dry case and instability is triggered by development of pore water pressures due to infiltration in rainy season as well as by seismic forces. In order to stabilize the slope of the dumps, the traditional way is to flatten the slope by extending the toe of the slope outward in horizontal direction or by moving the crest inwards. This is not a feasible solution in Delhi where there is a scarcity of land and waste heights and volume are very large. The alternative considered in the paper is the construction of reinforced soil (RS) berm at the base of Municipal Solid Waste (MSW) dumps. A parametric study has been carried out considering the influence of the following factors (a) height of waste and (b) slope angle of waste for three cases viz., original slope, slope with 10 m high RS berm and slope with 20 m high RS berm. Apart from internal stability, the external stability of the complete system is analyzed using the limit equilibrium method of analysis. An optimum solution is suggested based on the results of the study. The study shows that RS berm offers a more acceptable solution for stabilizing the slopes of waste dumps where limited space is available beyond the toe of the existing dump.