Experimental and Numerical Investigations on a Stone Column in Sandy Ground Contains Clayey Lens

Bazazzadegan, Niyousha; Ganjian, Navid; Nazariafshar, Javad

doi:10.22059/ceij.2024.366034.1968

Experimental and Numerical Investigations on a Stone Column in Sandy Ground Contains Clayey Lens

Document Type : Research Papers

Authors

Niyousha Bazazzadegan ¹

Navid Ganjian ²

Javad Nazariafshar ²

¹ Ph.D. Candidate, Department of Civil Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.

² Assistant Professor, Department of Civil Engineering, Shahr-e-Qods Branch, Islamic Azad University, Tehran, Iran.

10.22059/ceij.2024.366034.1968

Abstract

Utilizing stone columns proves highly effective in altering the behavior of challenging ground conditions. The combined application of stone columns with surrounding reinforcement enhances the methods efficiency for layered ground formations. The current study investigates the effectiveness and behavior of unreinforced and geotextile-reinforced stone columns integrated into sandy ground containing a soft clayey lens. This problem was investigated employing a Frustum Confined Vessel (FCV) in physical models and using ABAQUS software in numerical analyses. The results of experimental tests, demonstrated that reducing soft lens thickness significantly augmented the bearing capacity of both unreinforced and geotextile-encased stone columns. As soft lens depth increased, both unreinforced and reinforced stone columns exhibited approximately 40% and 10% increases in bearing capacity, respectively. The results of numerical analysis showed that in the presence of soft lens, the change in the length of a stone column had no effect on the occurrence of bulging failure and decreasing placement level of the soft lens, increased the bulging failure occurrence proportional. On the other hand, increasing the thickness of the soft lens reduced the bearing capacity of the ordinary and reinforced stone column. The phenomenon of bulging can occur at the level of the lens placement and up to a depth of about 4 times the diameter of the ordinary column because of existence of a soft lens in a relatively loose sandy bed, while mechanism of failure is not bulging anymore if using encasement.

Keywords

Frustum Confined Vessel (FCV)

Stone Column

Bearing Capacity

Clayey Lens

ABAQUS

Reinforcement

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