粗粒土三轴试验数值模拟与试样颗粒初始架构初探

试样颗粒初始架构是粗粒土室内三轴试验中一个难以人为控制的因素。基于元胞自动机方法,结合粗粒土的室内三轴试验开发了能制备不同颗粒初始架构粗粒土试样的HHC-CA模型,该模型制备的粗粒土试样表征了粗粒土各粒组分布的不均匀性和随机性,再借助FLAC3D进行粗粒土三轴数值模拟试验,并探讨了试样剪切带内的砾石含量和试样砾石含量对内摩擦角的影响。数值模拟结果表明,同一粒径级配下,粗粒土的内摩擦角值与剪切带内的砾石含量呈增函数关系;试样砾石含量的增加可能会出现内摩擦角减小的现象,但同一粒径级配下的内摩擦角均值随试样砾石含量的增加而明显增大。

Numerical simulation triaxial tests for coarse-grained soil and preliminary study of initial fabric of sample grain

The initial fabric of sample grain is a hard artificial controlling factor in the laboratory triaxial tests of coarse-grained soil. Based on cellular automata method, combining the laboratory triaxial tests of coarse-grained soil developed the HHC-CA model which generated the coarse-grained soil samples of different initial fabrics of grain to characterize the heterogeneous and random distribution of coarse-grained soil grain group. Then by means of the fast lagrangian analysis of continua in three dimensions (FLAC3D), conducting triaxial numerical simulation tests of coarse-grained soil and discussing the relationship between the gravel contents of sample shear band and samples and internal friction angle. Numerical simulation results indicate that the relationship between internal friction angle of coarse-grained soil and gravel contents of samples shear band were increasing function in the same size grading. According to the increasing of samples gravel contents, the internal friction angle might reduce, but the mean internal friction angle significantly increases with the increment of samples gravel contents.