岩石低周疲劳损伤模型与损伤变量表达方法

在岩石（体）工程领域，周期荷载作用下岩石的疲劳破坏特性与岩体的长期稳定性密切相关。针对目前对混凝土疲劳损伤研究较多，但对岩石疲劳损伤研究相对较少这一现状，运用损伤力学方法对以累积塑性应变表达的损伤变量进行了分析，指出了目前常用的以累积塑性应变表达的损伤变量表达式存在的理论上的缺点，建立了一种新的岩石疲劳损伤变量表达方法。为研究岩石在疲劳荷载作用下力学性能不断劣化的过程，从连续介质损伤力学的基本理论出发，分析岩石在疲劳荷载下的损伤发展和变形规律，并考虑岩石材料的硬化特性，推导了低周疲劳损伤演化方程，经低周疲劳试验数据分析，所建模型可以较好地反映岩石的疲劳损伤演化规律，可用于岩石在低周疲劳荷载作用下的有限元分析。

Low cycle fatigue damage model and damage variable expression of rock

In the realm of rock project, the fatigue failure characteristics of rock under cyclic load and long-term stability of rock mass are closely related. At present, researches for fatigue damage of concrete are more than that for rock, in view of this situation, using damage mechanics method, the fatigue damage variable expression based on accumulated plastic strain is analyzed; according to the theoretical shortcoming of the used damage variable expression based on accumulated plastic strain, a new rock damage variable expression method is established. At the same time, in order to study the deterioration process of rock mechanical performance under fatigue load, the damage development and deformation law of rock under fatigue load are analyzed according to continuum damage mechanics; and a low cycle fatigue damage evolution equation is deduced and established considering hardening characteristics of rock; the evolution equation reflects fatigue damage evolution rule of rock well after experimental confirmation, and it can be used for finite element analysis of rock under fatigue load.