Applicability Analysis of Stone Column Against Liquefaction Under Repeated Dynamic Events

Abstract

AbstractIn the event of sudden earthquakes, loose sandy soil loses its shear strength tremendously due to the generation of excess pore water pressure causing liquefaction. Due to soil liquefaction, the infrastructures’ foundation becomes unstable, thereby causing threats to its structural stability. Hence the application of suitable ground improvement methods becomes necessary for improving the liquefaction susceptibility of sandy soils. Ground reinforcement using the stone column proves to be an efficient reinforcement technique for improving liquefaction resistance of sandy soils. In this study, the stone column improvement technique was evaluated experimentally under repeated acceleration loading events. The experiments were carried out in a tank of dimension 1.4 m × 1.0 m × 1.0 m, placed over a uniaxial shaking table. A saturated sand bed having 40% relative density was prepared and tested under repeated acceleration loading of 0.3 g and 0.4 g at 5 Hz Frequency sequentially. A comparative analysis between untreated virgin sand bed and stone column treated ground was performed for performance assessment. The liquefaction assessment parameters such as generation and dissipation of pore water pressures, foundation settlement and soil displacement were monitored and compared. The results showed that there is a significant reduction in the excess pore water pressure generation even at repeated acceleration loading for the stone column stabilized bed. The test results concluded that soil densification and drainage are the key features in the liquefaction mitigation system to enhance the safety of foundation structures in seismic-prone areas.KeywordsLiquefactionSoil improvementStone columnPore water pressureSettlement