Consolidation and Slope Stability Study of Embankment Made of Ash Fill Supported by Hybrid Stone Columns: 3D Numerical Investigation

Abstract

AbstractThe consolidation and slope stability analysis of the ash fill dykes and embankments in the vicinity of thermal power stations (TPS) is still posing a challenge to the TPS management and governments. An attempt was made to study the ash fill dykes supported by the hybrid stone columns using 3D numerical analysis. This paper deals with studies conducted on the ash fill dyke (embankment) that the slope angle is 2 h:1v, underneath slow consolidated and highly compressible soils. Four cases were investigated, firstly simple ash dyke under the compressible stratified layers (clay and ash fill). The remaining three cases are the dykes supported by the conventional stone columns (CSCs), vertically encased stone columns (VEG) and hybrid confined stone columns (HC). The dissipate pore water pressure, the degree of consolidation and settlement with the effect of time were calculated. The embankments supported by the CSC, VEG and HC cases are displaying promising results. Slope stability analysis was conducted on four cases, under long-term steady-state seepage condition factor of safety determined. The embankment rested on the soil modified/ reinforced with the granular columns without and with encasement the factor of safety improved by 60%. This hybrid lateral confinement using the high tensile stiffness geotextile could be recommended for strengthening the ash dykes/embankment rested on the highly compressible, slow consolidation and high water table regions to enhance the better engineering properties and stable constructions.KeywordsStone columnsDegree of consolidationSlope stabilityHybrid confined columnsFEM