剪切波在堆石体中传播的细观数值模拟

摘要

The stochastic granular discontinuous deformation (SGDD) method was employed to simulate the bender element test. The characteristics of shear wave propagation were analyzed from two aspects of displacement evolution and frequency domain analysis. Different travel determination methods were compared in a biaxial compression test to determine the most precise method. Based on the selected method, the influences of the excitation frequency, excitation amplitude, inter-particle contact spring stiffness and confining pressure on shear wave velocity were further studied. The results indicate that the granular assembly acts as an obvious filter for the higher frequency components of the input signal. The cross-correlation method is adopted due to its high precision. The shear wave velocity decreases and then tends to converge with the increase of excitation amplitude, increases firstly and then remains stable with the increase of excitation frequency, and increases gradually with the increase of inter-particle contact spring stiffness and confining pressure.%采用随机颗粒不连续变形方法(SGDD),对堆石体二维弯曲元试验进行数值模拟,从位移演化和频域分析分析剪切波传播特性,并通过与双轴压缩试验结果对比选择合理的剪切波传播时间确定方法,研究激发频率、激发幅值、颗粒接触刚度以及围压等因素对剪切波速的影响.研究结果表明:堆石体对高频率剪切波信号具有明显的过滤作用;综合比较几种常见方法,采用互相关法确定剪切波传播时间的方法精确度最高;剪切波速随激发幅值的增加先减小后趋于收敛,随激发频率的增加先增大后保持稳定,随围压、颗粒接触刚度的增加而逐渐增大.