EPS颗粒混合轻量土动力变形特性离散元分析  

Discrete Element Analysis on Dynamic Deformation Characteristics of Light Weight Soil Mixed with EPS Particles

作　　者：兰鑫 侯天顺[1] 杨艳[1] 张亚飞[1] LAN Xin;HOU Tian-shun;YANG Yan;ZHANG Ya-fei(College of Water Resources and Architectural Engineering,Northwest A&F University,Yangling 712100,China)

机构地区：[1]西北农林科技大学水利与建筑工程学院,陕西杨凌712100

出　　处：《土木工程与管理学报》2020年第3期147-154,共8页Journal of Civil Engineering and Management

基　　金：国家自然科学基金(51509211);中国博士后基金(2016M602863);陕西省留学人员科技活动择优资助项目(2018031);陕西省社会发展科技攻关项目(2015SF260);陕西省博士后基金项目(2017BSHYDZZ50);杨凌示范区科技计划项目(2016GY-01);西北农林科技大学国际科技合作基金项目(A213021602);西北农林科技大学外国文教专家项目(A213021803)。

摘　　要：为探究EPS颗粒混合轻量土的动力变形机理,通过对轻量土进行室内动三轴试验,并利用三维离散元软件PFC3D建立相应数值模型,得到宏观滞回曲线和细观参数影响规律、颗粒间接触力和位移场分布图。研究结果表明:EPS颗粒混合轻量土的动应力–动应变关系曲线具有应变硬化特性和应变累积性;摩擦系数和接触黏结强度主要控制破坏强度,刚度比控制初始弹性模量。试样加载过程中,随着荷载逐级递增,颗粒间接触力整体增大,按颗粒间接触力大小排列为:土颗粒–土颗粒>土颗粒–EPS颗粒>EPS颗粒–EPS颗粒;两端颗粒在竖直方向上向中部运动,中部颗粒在水平方向上向外围运动;由于阻尼效应,中部颗粒的位移相对于两端颗粒具有"滞后性",且宏观上表现为试样整体被压缩。In order to explore the dynamic deformation mechanism of EPS particles light weight soil,the indoor dynamic triaxial tests are carried out,and the numerical models are established by three-dimensional discrete element software(PFC3D).The macro hysteresis curves,micro parameter influence laws,distribution maps of contact force among particles and distribution maps of displacement field are obtained.The results show that the dynamic stress-strain curves of EPS particles light weight soil have strain hardening characteristics and strain accumulation characteristics.The failure strength is mainly controlled by friction coefficient and the contact bond strength,and the initial elastic modulus is controlled by the stiffness ratio.During the loading process,the contact force among particles increases with the increasing of loads gradually.The order of interaction force among particles is as followed:soil particles-soil particles>soil particles-EPS particles>EPS particles-EPS particles.The particles at both ends move to the middle in the vertical direction and the particles in the middle move outward in the horizontal direction.Due to the damping effect,the displacement of the particles in the middle part is“hysteretic”compared with the particles at both ends,and it shows that the samples are compressed.

关 键 词：轻量土 动力变形特性 离散元数值模拟 滞回曲线 骨干曲线 细观分析 

分 类 号：TU411.8[建筑科学—岩土工程]