摘要
传统的岩石唯像蠕变模型忽略了岩石内在细观结构的时效损伤演化机制,无法从深层次上揭示复杂工程条件下岩石蠕变特性和时效破裂机理。基于连续介质力学理论,提出了一种表征真实岩石介质的宏-细观双尺度概念模型;依据细观尺度下微裂纹瞬时扩展和亚临界扩展的物理机制,运用损伤力学与断裂力学理论,建立了基于微裂纹演化的岩石细观蠕变损伤本构方程及破裂准则;采用Matlab软件编程将该细观模型嵌入到Comsol宏观有限元模型中,实现了一种能够模拟岩石蠕变损伤与破裂演化全过程的数值方法。在此基础上,利用建立的数值方法对双轴压缩条件下岩石蠕变过程进行了数值模拟,模拟结果很好地表征了岩石典型的3阶段蠕变特征,并以一种物理真实、可视化的方式深入地揭示了岩石从细观时效损伤演化至宏观破裂的全过程。
The traditional phenomenological creep models,which ignore the physical mechanisms of time-dependent fracturing in rocks,are not adequate to replicate the realistic creep behavior of rocks under complex loadings. In this study,a dual-scale model was proposed to represent the realistic rock medium in the framework of continuum mechanics. In addition,based on the mechanisms of time-independent and time-dependent growth of microcracks,the theories of damage mechanics and fracture mechanics were employed to develop the micro-crack based damage constitutive equations and failure criterion at the micro-scale. The obtained governing equations were programmed with Matlab and Comsol,which are capable of capturing the time-dependent damage and failure process of rocks. Furthermore,a bi-axial compressive creep test was performed and the numerical results show that the proposed model replicates the typical tri-modal creep behavior and the time-dependent fracturing in rocks. The proposed model provides a useful approach to further investigate the long-term stability of rock engineering and to predict the geological disasters.
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2015年第6期1276-1283,共8页
Journal of China Coal Society
基金
国家重点基础研究发展计划(973)资助项目(2014CB046905)
国家自然科学基金资助项目(51274191
51404245)
关键词
微裂纹扩展
蠕变
损伤演化
破裂
宏-细观模型
micro-crack propagation
creep
damage evolution
failure
macro-microscale model
