考虑应变率变化的岩石变形统计损伤模拟适用性分析

Applicability of statistical damage simulation method of deformation process for rock deformation process considering strain rate variation

针对应变率的变化影响岩石静动态变形破坏过程及其力学特性的特点,通过考虑应变率对岩石强度的影响,联系现有的静态岩石强度准则,建立能反映静动载荷条件下的岩石强度性质,且考虑应变率变化的岩石强度准则泛函式。基于本研究建立的强度准则泛函式,结合M-C强度准则和D-P强度准则,分别确定两种不同的岩石微元强度的合理度量方法,进而引入统计损伤理论,考虑岩石损伤阈值的影响,建立岩石静动态统计损伤本构模型,并提出静动态模型参数确定方法,从而建立考虑应变率变化的岩石变形过程模拟方法。通过与现有同类模型理论曲线以及相应试验曲线的比较分析得出:该模型不仅能模拟静载荷条件下的岩石变形过程,还能模拟动载荷条件下的岩石变形过程,适用于模拟不同应变率条件下的岩石变形破坏过程,且与试验曲线较为贴合。

According to the characteristics of static and dynamic deformation and failure process and mechanical properties of rock affected by the change of strain rate,by considering the effect of strain rate on rock strength,and connecting with the existing static rock strength criterion,the rock strength criterion functional is established,which can reflect the rock strength property under static and dynamic load and consider the change of strain rate.Then,based on the strength criterion functional established in this paper,combined with M-C strength criterion and D-P strength criterion,two different reasonable measures of rock microelement strength are determined.Then the statistical damage theory is introduced to consider the effect of damage threshold,and the static and dynamic statistical damage constitutive model of rock is established,the simulation method of rock deformation process considering the change of strain rate is established.Finally,it is concluded that the model can simulate not only the process of rock deformation under static load but also the process of rock deformation under dynamic load.It is suitable to simulate the deformation and failure process of rock under different strain rates,and is in good agreement with the test curve.