http://yetl.yabesh.ir/yetl1/handle/yetl/18996 Mon, 27 Apr 2026 16:02:14 GMT 2026-04-27T16:02:14Z http://localhost:80/yetl1/bitstream/id/184286/ http://yetl.yabesh.ir/yetl1/handle/yetl/18996 http://yetl.yabesh.ir/yetl1/handle/yetl/4310098 Numerical Study of the Failure Process of Stone Column Groups in Soft Soil in Response to Rigid Loading Based on the DEM-FDM Coupled Model Xin Tan; Mengfei Luo; Xin Yin; Zhengbo Hu; Yuxuan Jin; Changfu Chen Compared with isolated stone columns, a group of stone columns exhibits a much more complicated failure mechanism because of the complicated interactions between the respective columns and the surrounding soil under various loadings, as well as the influence of the relevant geometries. Here, a numerical study based on the discrete-element method and finite-difference method coupled model was conducted to simulate the complete load-bearing process of stone column groups and to better understand the deformation and failure mechanisms of stone column groups in soft soil in response to rigid loading. The load settlement curves for the columns, soil, and loading plate were determined as the displacement and stress evolution. Moreover, the shear strain distribution indicating the ground failure mode during the complete loading process was visualized. Parametric studies considered the influences of the column arrangement, the soil strength, and various stiffnesses. The bearing capacity of individual columns within a stone column group varies due to the differing stress states of the surrounding soil. Edge columns typically fail first, thus transferring load to the internal columns. With a smaller number of columns, transferred loads can trigger internal column failures, resulting in overall instability of the column group. The strength and stiffness of the surrounding soil govern the stone column–bearing capacity. However, existing bearing capacity formulas primarily rely on soil strength parameters, ignoring the significance of soil stiffness. Wed, 01 Jan 2025 00:00:00 GMT http://yetl.yabesh.ir/yetl1/handle/yetl/4310098 2025-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4310087 Theoretical and Experimental Study on Elastic–Plastic–Sliding Load Transfer Model for Pile Tip and Pile Side Postgrouting Piles Jiaqi Zhang; Cheng Zhao; Chunfeng Zhao; Yue Wu An elastic–plastic–sliding trilinear load transfer model is established for grouted piles. This model summarizes the resistance–displacement relationships at both the side and tip of the pile, describing the transition from elastic to plastic to sliding behavior, to effectively capture the hardening, softening, and elastic-perfectly plastic characteristics of shear stress that are beyond the capabilities of current models. Postgrouting improvement in the shear performance at the pile–soil interface is represented by an increase in the stiffness of the elastic segment and the ultimate resistance value. A model test is conducted on pile tip and pile side grouted piles, whose resistance–displacement relationships are fitted, and the load–settlement curves are predicted using the proposed model. The results indicate that pile–soil grouting at both the tip and side demonstrates superior effects in improving the bearing characteristics compared to a single grouting method under the same grouting volume. The prediction error for the ultimate bearing capacity of the model piles ranges from −7.7% to 3.2%. Furthermore, the applicability of the elastic–plastic–slip model has been demonstrated by two case studies. Compared to the hyperbolic and Boxlucas1 models, the proposed model provides more accurate predictions of the stiffness in the initial elastic segment of the pile top load–displacement curves, which is crucial for the settlement calculation of pile foundations in engineering projects. Additionally, the prediction error of this model for ultimate bearing capacity is smaller compared to the two nonlinear models. Wed, 01 Jan 2025 00:00:00 GMT http://yetl.yabesh.ir/yetl1/handle/yetl/4310087 2025-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4310076 Thermodynamic Model for Sand-Incorporating Morphology Yang Xiao; Fang Liang; Zhichao Zhang; Hao Cui; Hanlong Liu Particle shape, size, and size distribution (gradation) significantly influence the mechanical response of granular soils. This research introduces a thermodynamic model based on granular thermodynamics theory, validated by predicting triaxial shearing tests of packed glass beads and crushed glass assemblies. The model reveals the microscopic mechanisms influencing granular system behavior by incorporating particle shape and size factors into both the elasticity and plasticity. The state-dependent hyperelasticity extended from Hertzian contact theory clarifies how particle morphology affects the mechanical behavior of granular soil, emphasizing how particle shape determines stacking structure. Variations in particle shape significantly affect the mechanical response of granular systems to changes in particle size and size distribution. Irregular particles show heightened particle-size sensitivity of the strength and energy dissipation in a granular system. Elevated confining pressures mitigate the influence of particle size and reduce the kinetic granular fluctuation described by the concept of granular temperature. In conclusion, integrating particle morphology into the thermodynamic framework provides a deeper understanding of granular soil behavior, offering insights for optimizing material design and application in engineering fields. Wed, 01 Jan 2025 00:00:00 GMT http://yetl.yabesh.ir/yetl1/handle/yetl/4310076 2025-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4310065 Failure of Ring Foundations on Soft Clay Reinforced with an Annular Stone Column Sudipto Mukherjee; Jyant Kumar The pressure–settlement response of ring foundations placed on soft clay and reinforced with an annular stone column was determined both experimentally and numerically. The mean diameters of the ring footing and the stone column were kept equal. The experimental work was carried out based on a series of small-scale model tests. The concrete ring footing was tested by placing it on soft clay with and without an annular stone column. The numerical assessment was based on: (i) an axisymmetric linearly elastic–perfectly plastic finite-element (FE) analysis for both associated and nonassociated flow rule materials; and (ii) an axisymmetric FE limit analysis (FELA) for the explicit determination of the collapse loads for an associated flow rule material. From the model tests, it was revealed that the employment of the stone column increased the bearing capacity of the ring foundations to almost double its magnitude. Employment of the stone column also led to a decrease in the magnitude of the footing settlement. When the inner portion of the ring footing was left unfilled, the footing was found to tilt. This footing tilt was avoidable by filling the inner hollow portion of the ring footing with a compacted soil mass, which also led to a marginal increase in the bearing capacity. The results obtained from the FE analysis compared reasonably well with the corresponding experimental data. The failure loads for an associated flow rule material from the FELA and FE analysis compare well with each other. Wed, 01 Jan 2025 00:00:00 GMT http://yetl.yabesh.ir/yetl1/handle/yetl/4310065 2025-01-01T00:00:00Z