Earth slopes stabilization is one of the main issues in geotechnical engineering. The use of Stone Columns is one of the approaches for properly increasing the safety factor of earth slopes of the soil embankments. Furthermore, it is economically efficient and is easy in implementation. The present paper aims at an experimental comparison of the Ordinary Stone Column (OSC) and Rigid Stone Column (RSC) behaviors in sandy slopes. These tasks were carried out by constructing an embankment sandy slope, and then, saturating it with rain and, finally, loading increment. The experimental results of laboratory modeling have been also verified through the three-dimensional finite difference method. Laboratory modeling and numerical analyses results showed that the existence of rigid Stone Column in the middle of the slope (as the optimal placement location) enhances the sandy slope stability up to 1. 36 times compared with a slope reinforced by Ordinary Stone Columns.

1. Introduction: Stone Columns are one of effective methods of confronting liquefaction in saturated sands. The main objectives of this method is to increase soil strength and pore water drainage rate in surrounding soils, considering higher permeability of Stone Column materials. Different researchers have studied the effects of using Stone Columns on reducing liquefaction potential. Generally, these studies can be classified as numerical and experimental studies. Considering the fact that interactions between Stone Column and soil are tridimensional, the aim of present study is numerical investigation of application of current method in decreasing liquefaction potential...

Installing Stone Columns in the ground is an effective improvement technique to increase the load bearing capacity and reduce the consolidation settlement of the loose or weak cohesive soils. In addition to the increase in the bearing capacity and reduction in the settlement, Stone Columns can accelerate the dissipation rate of the excess pore water pressure generated by the surcharge, which expedites the ground improvement procedure. Due to these advantages, this technique has been widely used to improve the mechanical properties of the soft and problematic soils. In this study, the behavior of Stone Columns in saturated soft grounds are studied using Finite Element (FE) numerical method. For this purpose, a three-dimensional (3D) FE model of the Stone Column-improved ground is built considering the nonlinear behavior of the soil and Stone Columns. This model considers the effect of consolidation, and its accuracy is verified using the unit cell concept and the results of a real ground improvement project in Iran. In addition, a parametric study is performed using the verified FE model to investigate the effect of different material and geometric characteristics of the Stone Columns on the behavior of improved ground. At the end, the efficacy of the Stone Column method is compared to that of deep soil mixing (DSM) ground improvement technic.

Among all of the slope stability methods, use of Stone Columns and geosynthetic elements can be a good way for stabilizing. One of the efficient ways in order to reinforce earth slopes is Geogrid Encased Stone Column (GESC). This technique can dramatically increase bearing capacity and decrease settlement rate. The aim of this paper is experimentally to investigate a comparison between the behavior of Ordinary Stone Column (OSC) and GESC for reinforcing of sand slopes. The slope was constructed using raining technique and reinforced using GESC. The slope saturated through precipitation and loading procedure applied. The obtained results compared and verified with 3D Finite Difference Method (3DFDM). Both experimental and numerical analyses indicated that location of GESC in middle of the slope increases the bearing capacity of slope crown 2. 17 times than OSC.

Among all methods for ground improvement, Stone Columns have become more popular recently, owing to their simple construction and plentiful availability of raw materials. However, in relatively softer soils, Ordinary Stone Columns (OSCs) experience significant bulging owing to the minimal confinement offered by the surrounding soil. This necessitates the introduction of reinforcements in the Stone Column, to enhance their strength in such circumstances. The subject of this investigation was the assessment of the behavior of horizontally reinforced Stone Columns (HRSCs), introduced in layered soil, under the raft foundation. The soil material included was idealised using an isotropic linearly elastic fully plastic model with a Mohr-Coulomb failure criterion. There are a total of six separate factors required by the Mohr-Coulomb criterion. These include cohesion (c), the soil's dry unit weight (γd), the Poisson ratio (μ), the angle of internal friction (φ), the angle of dilatancy (ψ), and the Young's modulus of elasticity (E). At the very beginning, the load-settlement response of unreinforced soil was evaluated followed by a comparative study between square and triangular arrangements of Stone Columns, at different spacings, under the raft, to arrive at the configuration that encounters minimal settlements and lateral deformations. Furthermore, circular discs of suitable geogrid material were introduced along the length of the Stone Column. The elastic behaviour of geogrids is governed by two properties: tensile modulus and yield strength. The load-settlement behavior and lateral deformations of the resulting reinforced Stone Columns, with OSCs were compared. Furthermore, the spacing between the circular discs of geogrids was kept at D/2, D, 2D, and 3D, where D is the diameter of the Stone Column. According to the findings of an investigation conducted using FEM software, the performance of a granular pile group that is laid out in the shape of a triangle encounters much less lateral deformation and settlement than the square arrangement. The results also show that the performance of HRSCs was way better than those of OSCs, under the same in-situ soil conditions.