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采用离散单元法软件PFC2D模拟了大量砂土试样双轴试验,分析了砂土剪切带形成机理及发展过程,并通过研究试样剪切带内外应力-应变关系及孔隙比、平均接触数及配位数等参数的变化情况,研究了带内外宏微观性质的差异。研究表明:砂土剪切带的形成过程即为试样内部应变局部化过程,也为试样内部平均转动率(aver-aged pure rotation rate,APR)的局部化;剪切带开始形成点也为试样剪缩、剪胀分界点;剪切带内外各宏微观参数变化规律上存在明显的差异,主要表现为近剪切带位置土体及带内土表现为应变软化现象,而距带中心较远土体应力应变关系曲线出现’回滞圈’现象;带内变形量明显大于带外,且带内较带外松散。
The discrete element method software PFC2D was used to simulate the biaxial tests of a large number of sand samples. The formation mechanism and development process of sand shear zone were analyzed. The stress-strain relationship and the ratio of void to the average number of contacts And coordination number and other parameters of changes in the macro and micro-band with the nature of the difference. The results show that the formation process of sand shear zone is the process of local strain localization and the localization of aver-aged pure rotation rate (APR). The shear band begins to form a point There is a clear difference between the macro and micro parameters of the shear band in the shear band, which is mainly manifested as the phenomenon of strain softening in the near-shear zone soil and in the in-band soil, while the distance zone The phenomenon of “hysteresis loop” appeared in the stress-strain curve of the soil far away from the center. The deformation in the belt was obviously larger than that in the belt, and the belt was more loosely out of band.