摘要
为更好地从细观角度探究砂的变形破坏规律,对比不同围压加载方式下离散元三轴试验模型的有效性。采用颗粒流软件(PFC),考虑刚性和柔性两种围压加载方式,对不同密实度的HST95砂土试样建立离散元三轴试验,并结合相关室内三轴试验结果,讨论两种围压加载方式下砂土试样的力学特性、变形特性和剪切破坏过程。研究结果表明:柔性围压加载条件下模拟效果更好,且对于相对密实度越大的试样,柔性围压加载方式优于刚性围压加载方式:与室内试验结果相比,柔性围压加载下的应力应变结果误差均在10%以内,刚性围压加载结果误差在7%~53%范围内;30%密实度与70%密实度试样在刚性围压加载下,20%轴向应变时体积应变分别约为室内试验结果的0.6倍和1.1倍,且大剪切应变下试样体积缩小与实际不符。柔性围压加载下两种密实度试样的体积应变误差在1%以内;柔性围压加载下的试样可以更好地还原侧向鼓胀变形下的剪切破坏特征,并揭示剪切带的形成发展过程。
To better explore the deformation and failure law of sand from a mesoscopic perspective,this paper compares the effectiveness of discrete element triaxial test models under different confining pressure loading modes.Particle flow software(PFC)was used to establish discrete element triaxial tests for HST95 sand samples in different relative densities considering rigid and flexible confining pressure loading modes.Combined with the relevant laboratory triaxial test results,the mechanical characteristics,deformation characteristics and shear failure process of sand samples under two confining pressure loading methods are discussed.The results show that the simulation effect is better under the condition of flexible confining pressure loading mode.The higher the relative density of the sample,the better the flexible confining pressure loading mode than the rigid confining pressure loading mode:compared with the laboratory test results,the errors of stress-strain results under flexible and rigid confining pressure loading modes are within 10%and within the range of 7%~53%,respectively.For the sand in 30%and 70%relative density,the volumetric strain at 20%axial strain is about 0.6 times and 1.1 times of the laboratory test results for the samples under the rigid confining pressure loading mode,and the reduction of the volume under large shear strain is inconsistent with the actual situation.While the errors of the volumetric strain of the two samples under flexible confining pressure loading mode are within 1%.Further,the samples under the flexible confining pressure loading mode can better reproduce the shear failure characteristics of lateral bulging deformation and reveal the formation and development of the shear band.
作者
陈爱平
刘凯文
邱睿哲
熊志鹏
蔡志清
CHEN Aiping;LIU Kaiwen;QIU Ruizhe;XIONG Zhipeng;CAI Zhiqing(School of Rail Transit,Chengdu Vocational&Technical College of Industry,Chengdu 610218,China;MOE Key Laboratory of High-speed Railway Engineering,Southwest Jiaotong University,Chengdu 610031,China;School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;Guiyang Zhongtian Rock&Soil Engineering Co.,Ltd.,Guiyang 550001,China)
出处
《铁道标准设计》
北大核心
2024年第1期58-64,共7页
Railway Standard Design
基金
国家自然科学基金项目(52078427,51608461)。
关键词
三轴试验
颗粒流
加载方式
砂土试样
力学特性
triaxial test
particle flow code
loading mode
sand sample
mechanical properties
作者简介
陈爱平(1972-),男,讲师,1994年毕业于西南交通大学地下工程与隧道工程专业,工学学士,主要从事铁路路基工程相关教学研究工作,E-mail:11757832@qq.com;通信作者:刘凯文(1985-),男,副教授,博士生导师,2015年博士毕业于加拿大女王大学,主要从事路基工程研究工作wenliu@swjtu.edu.cn。
