岩石的损伤软化对应力波传播的影响

针对不含水干岩弹塑性变形的基本特征，考虑岩石的剪胀效应和软化效应，并根据岩石不同变形阶段的特点，给出了不同的屈服面形式和损伤演化方程，建立了岩石的弹塑性连续损伤本构模型．在此基础上研究了一维应变波在岩石介质中的传播规律，揭示了应力波在岩石类脆性损伤软化材料的传播过程中，损伤软化使得材料分为损伤演化区和完全破坏区，应力平台在两区交界面处产生凹陷．这一不稳定的凹陷在传播过程中逐渐消失，因而应力波传播在损伤的作用下经历了一个从不稳定到稳定的演化过程．

The Influence on Stress Wave Propagation by the Damage Softening of Rock

Based on the analysis of elastic plastic deformation of dry rock, a continuous damaged constitutive model of the rock is described and developed. The damage evolution equations and yield functions in the model are established on the basis of different deformation behaviours, and both the effects of distortional dilation and damage softening are also included. One dimensional strain waves in the rock induced by a rectangular impulsive loading are simulated by numerical computation. The results reveal the main characteristics of wave patterns for the softening rocks with continuous damaged constitutive relation. It is indicated that the materials are divided into two parts: damage evolution region and complete destroyed region, a stress falling is induced by damage softening at the connection of these two parts. This unstable falling will disappear during the propagation process. It is concluded that there is a process from unstable to stable for stress wave propagation in the rock with the development of the damage.