利用迭代思想标定砂土三轴试验宏-细观参数

To calibrate triaxial test macro-meso parameters of sand by iterative thought

为提高离散元中三轴试验宏-细观参数标定工作效率,提出一种新的方法——迭代标定法.利用fish语言编写程序在PFC^(3D)中实现了三轴试验的数值模拟.基于接触黏结模型对砂土三轴试验进行模拟,验证了迭代标定法的有效性.结果表明:颗粒刚度大小和颗粒刚度比都会影响偏应力的大小;颗粒法向刚度会影响初始杨氏模量;细观摩擦系数对偏应力的影响程度取决于模型围压的大小;黏结强度对接触黏结模型的应力应变曲线形态影响较小,但对平行黏结模型的应力应变曲线形态有较大影响.迭代标定法可以有效标定宏-细观参数,减少"试参数"过程.

To improve the efficiency of the macro-meso parameters calibration of the triaxial test in the DEM,a new method,iterative calibration,is proposed. By using a fish language program,the numerical simulation of the triaxial test in the PFC^(3D) software is achieved. Based on the contact bond model,the triaxial test of sand is simulated,and the validity of the iterative calibration method is verified. The calibration proves that both the size of the particle stiffness and the ratio of the particle stiffness affect the size of the partial stress,particle normal stiffness affect the initial Young's modulus,the effect of the friction coefficient on the partial stress is depended on the size of the confining pressure,and the bond strength has little influence on the stress-strain curve of the contact bond model,but huge influence on the parallel bond model. It is concluded that the iterative calibration method can effectively calibrate macro-meso parameters and reduce the 'test parameter'process.