摘要
冻土的剪切破坏过程研究一直是寒区岩土力学领域的重要课题。本文采用离散元法中的平行黏结模型模拟冻土中冰的胶结作用,通过开展三轴压缩离散元数值试验研究了冻土的剪切破坏过程,并利用多因素方差分析探究了细观参数的敏感性。研究结果表明:离散元法可以较好地模拟冻结砂土的剪切破坏过程,数值模拟获得的应力-应变曲线与试验结果基本吻合;提出一种基于正态分布函数确定冻土剪切带宽度的方法,通过对不同工况下的冻土剪切带进行分析,发现随着温度的降低或围压的增加,剪切带宽度呈现出逐渐增宽的趋势;通过对线性组刚度、黏结组刚度、黏结组强度、摩擦系数等细观参数进行敏感性分析,发现黏结组强度和摩擦系数对冻土强度影响特别显著。相关研究可为后续开展基于离散元法的冻土力学性质研究提供一定的参考。
Research on the shear failure process of frozen soil has long been an important topic in geotechnical mechanics in cold regions.The instability of roads and slope failures in frozen soil regions are often accompa⁃nied by the progressive failure of frozen soil materials,highlighting the importance of in-depth research on the shear failure behavior of frozen soil.However,conventional triaxial tests face limitations in directly observing the shear failure process under loading.Consequently,the discrete element method(DEM)becomes essential for investigating the mechanical behavior of frozen soil from both macroscopic and microscopic perspectives.In this study,the parallel bond model in the DEM was used to simulate the bonding effect of ice in frozen soil,and a series of discrete element simulations of triaxial compression were conducted to investigate the shear failure process in frozen soil.Additionally,orthogonal experiments were used to study the influence of microscopic pa⁃rameters such as particle linear group stiffness,bond group stiffness,bond group strength,and friction coefficient on the strength of frozen soil.Multifactor variance analysis was used to explore the sensitivity of these mi⁃croscopic parameters.The results showed that:(1)Through discrete element simulation of triaxial compression tests on frozen sandy soil under different temperatures and confining pressures,it was found that the stress-strain curves obtained from the simulation closely matched the experimental results,enabling full simulation of the gen⁃eration,development,and formation of shear bands in frozen soil.(2)A method for determining the width of frozen soil shear bands based on normal distribution functions was proposed.By analyzing the shear bands of fro⁃zen sandy soil under different temperatures and confining pressures,it was found that within the experimental conditions of this study,temperature and confining pressure had little influence on the inclination angle of the shear bands.As the temperature decreased or the confining pressure increased,the width of the shear band showed a gradually widening trend.This was because the higher the strength of frozen sandy soil,the larger the plastic zone generated when the soil sample failed.(3)Through sensitivity analysis of the microscopic parame⁃ters in the discrete elements,it was found that when the temperature was relatively high,each microscopic pa⁃rameter had a significant influence on the strength of frozen soil,with the degree of significance ranked in the or⁃der of:bond strength>friction coefficient>bond stiffness>linear stiffness.When the temperature was relative⁃ly low,the bond strength and friction coefficient had a particularly significant influence on the strength of frozen soil,while the influence of bond stiffness and linear stiffness on frozen soil strength could be neglected.This study mainly explored the discrete element simulation of the triaxial shear failure process of frozen soil under spe⁃cific temperature and confining pressure conditions.In the future,more extensive experimental data will be used for numerical simulation to further verify the universality of the results.Meanwhile,the correlation between the sensitivity analysis results of discrete element microscopic parameters and the macro-and micro-mechanical mechanisms of frozen soil should be further explored.This study provides a valuable reference for conducting indepth research on the mechanical properties of frozen soil using DEM.
作者
王冬勇
周蕾
崔雯宇
齐吉琳
彭丽云
WANG Dongyong;ZHOU Lei;CUI Wenyu;QI Jilin;PENG Liyun(School of Civil and Transportation Engineering,Beijing University of Civil Engineering and Architecture,Beijing 100044,China;Beijing International Science and Technology Cooperation Base of Urban Transportation Infrastructure Construction,Beijing University of Civil Engineering and Architecture,Beijing 100044,China)
出处
《冰川冻土》
2025年第4期1024-1032,共9页
Journal of Glaciology and Geocryology
基金
国家自然科学基金项目(42372312,41972279,42172299)
北京建筑大学金字塔人才培养工程项目(JDYC20220807)资助。
关键词
冻结砂土
三轴试验
剪切破坏
离散元法
敏感性分析
frozen sandy soil
triaxial test
shear failure
discrete element method
sensitivity analysis
