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从Ramberg-Osgood模型的骨架曲线和滞回曲线出发,假定塑性中心的移动为直线,构造土体动力耗散函数,从热力学基本定律出发研究了土体动力耗散特性及动力变形机理.提出了反映筑坝堆石料动力特性的第1阈值应变和第2阈值应变,两个阈值应变主要受最大动剪切模量系数、指数及无黏性土的内摩擦角的影响.第1和第2阈值应变间屈服面的摩擦系数研究表明,当应力点沿滞回圈运动时,不同点的耗能机制随动应变水平的增大而差别变大;屈服面首先在摩擦系数小时发生弯曲,土体动力过程中发生间歇剪缩;当动应变继续增大,剪缩与剪胀同时发生.
Based on the skeleton curve and hysteretic curve of Ramberg-Osgood model, assuming that the movement of plasticity center is a straight line and the dynamic dissipation function of soil is constructed, the dynamic dissipation characteristics and dynamic deformation mechanism of soil are studied based on the basic laws of thermodynamics. The first threshold strain and the second threshold strain, which reflect the dynamic characteristics of damped rockfill material, are mainly affected by the coefficient of maximum dynamic shear modulus, index and the internal friction angle of non-cohesive soil. The first and second The research on the friction coefficient of the yield surface between the threshold and the strain shows that when the stress moves along the hysteresis loop, the energy dissipation mechanisms at different points vary with the increase of the dynamic strain level. The yield surface first bends when the friction coefficient is small, Intermittent shear shrinkage occurs in the dynamic process of the body; when the dynamic strain continues to increase, shear shrinkage and dilatancy occur simultaneously.