An Experimental Investigation on the Load Settlement and the Bulging Behaviour of Stone Columns Placed on Highly Palstic Clays

Abstract

Background: Stone columns are used to increase bearing capacity, improve the drainage conditions, reduce foundation settlements, improve slope stability, reduce seismic subsidence, and reduce lateral spreading and liquefaction potential, control the deformation and accelerate consolidation, permit construction on loose/weak soil fills. Statistical Analysis: When a stone column is placed on high plastic clays, the load carrying capacity of the stone column would vary depending upon various parameters. This experimental investigation was performed to check the ultimate load carrying capacity and the bulging failure of stone columns with varying Length to Diameter (L/D) ratio of the stone column, Consistency Index (IC) and the Liquid Limit (LL) of the soil on which the stone column is resting by conducting various tests like CBR test. Findings: After conducting the tests it is found that the ultimate load carrying capacity of the stone column increases up to a certain L/D ratio, beyond that value there would be no further increase in ultimate capacity. The Vertical extent of Bulging (BV) is mainly influenced by L/D ratio and the lateral extent of Bulging (BL) is predominantly influenced by IC. The results thus obtained from the present investigation will be helpful in finding the failures in stone columns by varying the load acting on it and also to check the load carrying capacity of stone columns with other parameters with respect to the L/D ratio. Improvements: As bulging failure is considered to be the predominant type of failure for stone columns especially in clayey soils, an attempt can be made to see that the length of stone column doesn't exceed 2-3 times of its diameter beyond which the bulging would surely happen.