砂土微宏观性质相依关系研究

Research on relationships between microscopic and macroscopic properties of sand

为了研究砂土微观力学性质,采用了离散单元法对砂土进行三轴试验模拟,并引入抗转动模型来表征砂土颗粒的抗转动效应。通过对选取的不同法向接触刚度、刚度比、颗粒内摩擦角、滚动刚度系数以及塑性弯矩系数进行三轴排水数值试验,得到了砂土不同微观参数与其宏观力学性质的对应关系。试验结果表明:法向接触刚度对砂土弹性模量影响显著,并呈现正相关线性关系;刚度比与砂土泊松比呈现较为显著的负相关线性关系;颗粒内摩擦角对砂土宏观内摩擦角影响显著,滚动刚度系数影响砂土残余强度,塑性弯矩系数主要影响峰值强度。

To investigate the microscopic mechanical properties of sand, a series of consolidated drained triaxial test is performed via discrete element method. In addition, the rolling resistance contact model is added into simulations. Five different microscopic parameters are discussed, namely, the normal contact stiffness, the stiffness ratio, the internal friction angle, the coefficient of rolling stiffness, as well as the coefficient of plastic moment. Finally, the relationship between microscopic parameters and macroscopic properties of sand is obtained. The results show that the normal contact stiffness shows a positive linear correlation with the Young’s Modulus, and the stiffness ratio shows a negative linear correlation with the Possion’s ratio, and the internal friction angle has a significant influence on friction angle; the coefficient of rolling resistance is chosen to control the residual strength; the coefficient of plastic moment play a major role in peak stress.