【摘要】 围压卸载路径对于地下工程开挖过程围岩稳定性有着重要的影响.微裂纹扩展对深部地下工程中脆性围岩流变失效有着重要的意义.本文通过耦合翼型裂纹模型、裂纹扩展法则及一个裂纹长度与应变关系,提出了一个宏细观力学模型.其中裂纹长度与应变关系通过宏细观损伤联系得到.然后,将一个围压卸载路径函数引入该宏细观力学模型,理论分析了围压卸载路径对裂纹扩展作用下下的脆性岩石流变特性的影响.通过围压分级卸载试验结果验证了本文理论模型的合理性.并分析了模型参数对围压卸载下流变失效特性影响.研究了围压卸载后,继续加载时机及加载大小对流变特性影响.其对脆性围岩深大地下工程设计及施工提供了一定的理论基础.更多还原

【Abstract】 The unloading path of confining pressure has an important influence on the stability of surrounding rock during underground excavation.Microcrack growth has a great significance for the rheological failure of brittle surrounding rock in deep underground.Coupling the wing crack model,the crack growth law and the crack growth-strain relation,a macro-micro mechanical model was proposed.The crack growth-strain relation was established by the correlation of micromechanical and macroscopic damage.A stress path function of unloading for confining pressure was implemented in the macro-micro model.The rheological behaviors caused by microcracks growth were studied under the unloading of confining pressure.Rationality of the suggested model was verified by the rheological experimental results under step unloading of confining pressure.Influences of model parameters on rheological failure under unloading of confining pressure were analyzed.Influences of loading time and size on rheological failure after unloading of confining pressure were also studied.The studies provide a theoretical help for design and construction of deep underground engineering.更多还原