摘要
本文基于离散单元法,研究了轴压和围压共同作用下的压缩实验中循环荷载对颗粒材料力学行为的影响.在PFC2D中建立了离散颗粒模型,并开发了相应程序以实现其数值模拟,重点关注了循环荷载条件下颗粒材料组构各向异性、应力应变曲线及剪胀性的演化规律.数值结果表明,加载阶段垂直方向组构各向异性变化增强,卸载阶段水平方向组构各向异性增强,且随着循环次数的增加,水平方向组构各向异性变化强于垂直方向组构各向异性.循环过程产生的塑性滞回环的第1次与第2次循环有明显的差别,循环次数越多,滞回环区别越小,近乎重合.随着围压的增加,积应变增加,且体积应变-轴向应变曲线随循环次数的增加更快趋近于重合.
The mechanical behavior of granular materials under cyclic loading is investigated in this paper based on discrete element method.The compression test with axial pressure and confine pressure is simulated by user defined programs on PFC2 Dplatform to focus on the evolution of fabric anisotropy,stress-strain relationship and dilative response behavior of granular materials.The results from the simulations show that the induced fabric anisotropy in the vertical direction enhanced during loading.The induced fabric anisotropy in the horizontal direction enhanced during unloading.The induced fabric anisotropy in the horizontal increased more obvious than in the vertical direction for cyclic loading.Hysteresis loop,generated for the cyclic loading,has obvious difference between the first cyclic loading and the second time.During the subsequent loading and unloading cycles,the change of hysteresis loop becomes smaller,almost overlapping.Both volumetric strain increases and volumetric strain-axial strain curve tends to overlapping faster with the increase of confine pressure.
出处
《宁夏大学学报（自然科学版）》
CAS
2015年第4期341-345,共5页
Journal of Ningxia University(Natural Science Edition)
基金
国家自然科学基金资助项目(11372230)
关键词
颗粒材料
离散单元法
循环荷载
组构各向异性
granular material
discrete element method
cyclic loading
fabric anisotropy
