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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。
The creep property is an important basis for evaluating the long-term failure characteristics of rock. Based on the mesomechanical model of rock and crack propagation law, the relationship between mesoscopic crack propagation and macroscopic strain is established based on the relationship between the mesoscopic crack length and the macro-strain defined damage. The stress-strain relationship of the rock is also given Grade creep evolution expression. The relationship between stress and strain under different confining pressures during rock asymptotic failure is studied. The creep evolution under different loading conditions is analyzed. The results are in good agreement with the experimental results, which proves the rationality of the proposed model. Then, the creep failure time and the steady state creep rate under different normal stress conditions are studied. The results have important guiding significance for the design of the subsurface support structure under high ground stress and the assessment of service life.