细粒含量对砾性土路基劣化及静力剪切特性影响  

Influences of fines content on strength deterioration and static shear characteristics of gravelly soil subgrade

作　　者：张涛艺 王家全[1,2,3] 林志南 唐毅[1,2,3] ZHANG Tao-yi;WANG Jia-quan;LIN Zhi-nan;TANG Yi(College of Civil and Architectural Engineering,Guangxi University of Science and Technology,Liuzhou,Guangxi 545006,China;Guangxi Zhuang Autonomous Region Engineering Research Center of Geotechnical Disaster and Ecological Control,Guangxi University of Science and Technology,Liuzhou,Guangxi 545006,China;Guangxi University Key Laboratory of Disaster Prevention and Mitigation and Prestress Technology,Guangxi University of Science and Technology,Liuzhou,Guangxi 545006,China)

机构地区：[1]广西科技大学土木建筑工程学院,广西柳州545006 [2]广西科技大学广西壮族自治区岩土灾变与生态治理工程研究中心,广西柳州545006 [3]广西科技大学广西高校防灾减灾与预应力技术重点实验室,广西柳州545006

出　　处：《岩土力学》2025年第4期1141-1152,共12页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.52468047);广西自然科学基金重点项目(No.2022GXNSFDA035081);广西高等学校高水平创新团队及卓越学者计划项目(桂教人才[2020]6号);广西科技大学研究生教育创新计划(No.GKYC202463);广西高校中青年教师科研基础能力提升项目(No.2020KY08026)。

摘　　要：针对细粒影响砾性土路基静力特性研究的不足,利用GDS三轴测试系统,开展了不同细粒含量和不同有效围压条件下的饱和砾性土固结排水三轴剪切试验,探究了细粒含量对砾性土静力剪切特性的影响。结果表明:(1)随着细粒含量的增加,应力-应变曲线的发展模式由应变软化转为应变硬化,存在细粒含量Fc=15%的临界阈值;(2)细粒的加入导致砾性土的主应力比、脆性指标、峰值强度、黏聚力和内摩擦角下降,而劣化指标上升,其中峰值强度和黏聚力劣化指标与细粒含量的关系可用二次函数描述,内摩擦角劣化指标则可通过三次函数描述;(3)随着细粒含量的增加,临界状态参数下降,有效应力路径呈现折返性,应力路径变短并向左偏移;(4)细粒的加入导致割线模量下降,体积应变-轴向应变曲线由剪缩-剪胀模式变为剪缩模式。Given the insufficiency in research on the mechanism of fine particle impact on gravelly soil subgrade deterioration,a series of saturated gravelly soil consolidated drained triaxial shear tests was conducted using the GDS triaxial testing system under varying fines contents and effective confining pressures to investigate the effect of fine particle contamination on the static shear characteristics of gravelly soil.The results indicate that:(1)As the fines content increases,the stress-strain curve development pattern transitions from strain softening to strain hardening,with a critical threshold at a fines content of Fc=15%.(2)The addition of fine particles leads to a decrease in the principal stress ratio,brittleness index,peak strength,cohesion,and internal friction angle of the gravelly soil,while the degradation indices increase.The relationship between the degradation indices of peak strength and cohesion and fines content can be described by quadratic functions,and the degradation index of the internal friction angle by a cubic function.(3)With increasing fines content,critical state parameters decrease.The effective stress path shows retracing behavior,becomes shorter,and shifts to the left.(4)The addition of fine particles results in a decrease in the secant modulus,and the volumetric strain-axial strain curve changes from contractive-dilative to purely contractive.

关 键 词：细粒含量 砾性土 三轴试验 力学特性 劣化机制 

分 类 号：TU452[建筑科学—岩土工程]