【摘要】 以Hardin-Drnevich模型的双曲骨架曲线为基础,采用Masing准则构造其滞回圈,形成小应变土体动力耗散函数。然后从热力学基本定律出发,分析其对应的屈服面及能量耗散特性。发现筑坝堆石类无黏性材料的动力特性存在2个阈值应变,定义为第一和第二阈值应变。两个阈值应变将土体动力特性分成3段。当土体的动应变小于第一阈值应变时,土体屈服为常摩擦系数的摩擦耗散控制;当土体动应变介于第一、第二阈值应变之间时,土体屈服为变摩擦系数的摩擦耗散控制;当土体动应变大于第二阈值应变时,土体屈服除摩擦机制外还存在剪胀等土体结构改变的效应。土体的2个阈值应变主要受最大动剪切模量系数及指数控制,无黏性土的摩擦角对其也有一定影响。两个阈值应变均随最大动剪切模量系数及指数的增大而减小。更多还原

【Abstract】 Based on the hyperbolic skeleton curve of Hardin-Drnevich,small strain dynamic dissipation function was formulated by adopting the Masing rule.Then the corresponding yield surface and energy dissipation characteristics were analyzed.It was indicated that there existed two threshold strains which were defined as the first threshold strain and the second threshold strain respectively for dynamic characteristics of non-cohesive rockfill material.The two threshold strains divided the soil dynamic characteristics into three sections.When the dynamic strain is below the first threshold strain,the yield of soil was controlled by friction dissipation of the constant friction coefficient.When the dynamic strain was between the two threshold strains,the yield of soil was controlled by that of the variable friction coefficient.However,when the dynamic strain was bigger than the second threshold strain,the dilatancy-related structural variation was shown.The two threshold strains decreased when the maximum dynamic shear modulus coefficient and exponent increased.In addition,the friction angle of cohesionless soil would also influence them to some extent.更多还原