含水率对非饱和土剪切破坏行为影响细观研究  

Microscopic Study on the Influence of Moisture Content on the Shear Failure Behavior of Unsaturated Soil

作　　者：陈铭潇 尹超 韩炳鑫 孟维庆 王伟 CHEN Mingxiao;YIN Chao;HAN Bingxin;MENG Weiqing;WANG Wei(School of Civil Engineering,Shiiazhuang Tiedao University,Shijiazhuang 050043,China;Key Laboratory of the Ministry of Education for Road and Railway Engineering Safety Assurance,Shijiazhuang Tiedao University,Shijiazhuang 050043,China)

机构地区：[1]石家庄铁道大学土木工程学院,河北石家庄050043 [2]石家庄铁道大学道路与铁道工程安全保障省部共建教育部重点实验室,河北石家庄050043

出　　处：《石家庄铁道大学学报（自然科学版）》2024年第3期91-97,共7页Journal of Shijiazhuang Tiedao University(Natural Science Edition)

基　　金：国家自然科学基金(52308511)。

摘　　要：含水率是决定非饱和土抗剪强度的重要因素.利用室内直剪试验及PFC3D模拟,对一定含水率(16%~24%)非饱和土直剪破坏过程中的演化机制进行研究.试验结果表明,当法向应力等其他条件不变时,非饱和土抗剪强度及黏聚力随含水率提升均逐渐减小;相同条件下,层面区域颗粒发生滚动和滑移的数量随含水率提升而增多,当非饱和土含水率达到24%时剪切带宽度在(17~19)d50之间,为16%含水率非饱和土剪切带宽的1.63倍;含水率对非饱和土黏结破坏数量与总黏结量的比值影响较大,且此影响与剪切带的形成及演化具有同步性.该研究可在非饱和土宏观直剪试验中较为精准地展现细观破坏特征,并为岩土力学仿真提供可供参考的依据.The moisture content is an important factor determining the shear strength of unsaturated soil.The indoor direct shear tests and PFC3D simulations were used to study the evolution mechanism of direct sheal failure in unsaturated soil with a certain moisture content(16%~24%).The experimental results show that when other conditions such as normal stress remain unchanged,the shear strength and cohesion of unsaturated soil gradually decrease with the increase of water content;Under the same conditions,the number of particles rolling and sliding in the layer area increases with the increase of moisture content,When the moisture content of unsaturated soil reaches 24%,the shear band width is between(17~19)d50,which is 1.63 times that ol unsaturated soil with 16%moisture content:The moisture content has a significant impact on the ratio of the number of bond failures in unsaturated soil to the total bond content,and this elect is synchronous with the for.mation and evolution of shear bands.This study can better reproduce the microscopic failure characteristics in macroscopic direct shear tests and provide reference basis for geotechnical simulation.

关 键 词：非饱和土 含水率 离散元法 直剪试验 细观机制 

分 类 号：TU442[建筑科学—岩土工程]