基于细观力学的脆性岩石长期蠕变失效研究  

Research on long-term creep failure of brittle rock based on micromechanics

作　　者：邵珠山[1] 李晓照[1] 

机构地区：[1]西安建筑科技大学土木工程学院,陕西西安710055

出　　处：《岩石力学与工程学报》2016年第A01期2644-2652,共9页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51375373);陕西省科技统筹创新工程计划项目(2013KTCQ01–16)~~

摘　　要：蠕变特性是评价岩石长期失效特性的重要依据。基于岩石细观力学模型及裂纹扩展法则,结合细观裂纹长度与宏观应变定义损伤之间的联系,建立细观裂纹扩展与宏观应变之间的关系,并给出岩石的应力–应变关系及三级蠕变演化表达式。研究岩石渐进失效过程中不同围压下的应力–应变关系,并分析分级加载下的蠕变演化规律,其结果与试验结果吻合较好,验证了提出的细观模型的合理性。然后,对不同常应力状态下的蠕变失效时间与稳态蠕变率进行研究,其结果对高地应力下地下支护结构的设计及服役寿命的评估具有重要指导意义。Creep property is an important basis for evaluating long-term failure of rocks. Based on the model of micromechanics and law of crack growth in brittle rocks, combining the definition of damage in micromechanical and macroscopic scale, the linkage between microcrack growth and macroscopic strain is established, and the theoretical expression of stress-strain relationship and three independent stages of creep are derived. Relationships between stress and strain under different confining pressures are studied and the creep properties under step axial loading are analyzed, which both agree well with the experimental results. The rationality of micromechanical model is verified by the experimental results. The creep failure time and steady-state creep rate are studied at different constant stress states, which provides the important help for the evaluation of service life and design of underground structure under high geostatic stresses.

关 键 词：岩石力学 脆性岩石 亚临界裂纹扩展 分级加载 蠕变 损伤 

分 类 号：TU45[建筑科学—岩土工程]