循环三轴颗粒流模拟中细观阻尼系数影响分析

Analysis on Impact of Meso-damping Coefficient in Simulation of Cyclic Triaxial Granular Flow

利用颗粒流软件PFC2D对粉土开展了基本力学特性模拟，并通过应变控制模式对粉土循环加载下动力性质进行了颗粒流模拟。随着颗粒流细观阻尼系数上升，滞回圈形态逐渐由狭长状趋于饱满，偏应力峰值也逐渐增大。当阻尼系数在0．5～0盘范围内，相同偏应变幅值条件下试样偏应力峰值近似成线性增长。但较高偏应变幅值水平下，细观阻尼系数对动力特性发展形式的影响较小。另外，采用能量分析对循环荷载在颗粒系统中能量耗散的限制性进行了说明，并推导了颗粒流中细观阻尼系数一定程度上决定了颗粒系统对外荷载作用所传递能量的耗散程度，从而直接影响到试样应力应变的发展规律。

The granular flow software PFC2 D is used to carry out the simulation of basic mechanical properties of silty soil. The granular flow simulation of dynamic properties of silty soil under cyclic loading is carried out by means of strain control mode. With the increase of the Meso-damping coefficient of granular flow, the pattern of hysteresis loop is gradually from the narrow long to plump, and the peak value of deviatoric stress is increased simultaneously. And with the same amplitude value of deviatoric strain and a damping coefficient in the range between 0.5 and 0.8, the peak value of deviatoric stress for test sample shows the approximate liner growth. But under the higher deviatoric strain amplitude level, the impact of the Meso-damping coefficient is smaller on the development of dynamic property. In addition, the energy analysis is used to explain the energy dissipation restriction of cyclic loading in the granular system. The Meso-damping coefficient of granular flow is derived to a certain extent to determine the dissipation degree of the energy transmitted by the external load of granular system so as directly to affect the development of stressand strain in the samples.