中山大学学报（自然科学版）（中英文）2025，Vol.64Issue(3)：92-102,11.DOI:10.13471/j.cnki.acta.snus.ZR20240229
极端干湿交替作用下浅层黄土剪切强度特性对比
The shear strength characteristics of shallow loess under extreme dry-wet alternating
摘要
Abstract
Understanding the mechanical properties of loess under extreme dry-wet alternating climatic conditions is essential for analyzing and evaluating the stability of geological bodies.Focusing on the Q3 loess of a cutting slope in the Yan'an new area,we conducted repeated dry-wet cycle tests and direct shear tests of undisturbed and remolded loess to investigate how factors,such as dry-wet cycles,cycling path,amplitude,and normal pressure,affect loess'shear strength and its associated properties.The results indicate that the relationship curve between shear stress and shear displacement for dry-wet cycle loess,under different normal pressures,exhibits a strain-softening behavior;Furthermore,the peak characteristics of the curve gradually diminish as the number of dry-wet cycles increases.The shear strength attenuation of undisturbed loess during dry-wet cycles is more pronounced than that of remolded loess,with shear strength decreasing by 77.82%after three dry-wet cycles.Significant differences exist in both shear strength and its parameters in dry-wet cycle loess across high-and low-pressure conditions,with the low-pressure condition requiring careful consideration in direct shear tests.The shear strength parameter of loess declines rapidly with the increasing number of dry-wet cycles initially,then decreases slowly before stabilizing.Notably,the impact of dry-wet cycles on cohesion is greater than that on internal friction angle.Additionally,the shear strength parameter of loess is negatively correlated with the amplitude of dry-wet cycles,cohesion in high-pressure conditions and internal friction angle in low-pressure conditions showed more significant deterioration at larger dry-wet cycle amplitudes.The evolution of the deterioration curve for the loess shear strength parameter can be divided into three stages:a rapid growth stage(1-3 times),a slow growth stage(3-5 times),and a gradual stability stage(5-7 times),with over 78.77%occurring during the rapid growth stage.Based on the statistical analysis of the experimental data,we have established a predictive model for the absolute deterioration degree of cohesion and internal friction angle in dry-wet cycle loess.关键词
路堑边坡/浅层黄土/极端干湿交替作用/剪切强度/劣化模型Key words
cutting slope/shallow loess/extreme dry-wet alternating/shear strength/deterioration model分类
建筑与水利引用本文复制引用
邱明明,李晓敏..极端干湿交替作用下浅层黄土剪切强度特性对比[J].中山大学学报（自然科学版）（中英文）,2025,64(3):92-102,11.基金项目
陕西省教育厅服务地方专项计划(21JC035) （21JC035）
延安市重点研发计划(2019ZCSY-006) （2019ZCSY-006）
延安大学科研计划(2023KXJ-010,2021ZCQ011) （2023KXJ-010,2021ZCQ011）
