静载荷与循环冲击组合作用下岩石损伤本构模型研究

建立合理的损伤本构模型，对研究岩石在静载荷与循环冲击组合作用下的动态力学性能具有重要的意义. 首先，基于静载荷与循环冲击组合作用下岩石的损伤累积演化模型，结合岩石弹性模量与累积损伤变量的关系，将循环冲击次数引入岩石损伤本构关系中. 接着，假设岩石微元体强度服从Weibull分布，将统计损伤模型和黏弹性模型相结合，并根据Drucker-Prager破坏准则，建立有轴压有围压时循环冲击作用下岩石的动态损伤本构模型.进而，利用岩石动静组合加载试验数据验证损伤本构模型的正确性和可行性. 最后，研究模型中参数对循环冲击过程中应力-应变曲线的影响规律.结果表明，建立的岩石损伤本构模型较好地与试验数据吻合，能较好地反映具有静载荷的岩石在循环冲击过程中的本构关系.岩石的弹性模量、黏性系数等参数对循环冲击时岩石的应力-应变曲线影响较大；而岩石的摩擦角和泊松比等对具有三维静载岩石的冲击疲劳应力-应变曲线影响较小. 循环冲击过程中，岩石的非均匀度逐渐增加. 研究结果有益于完善静载荷与循环冲击组合作用下岩石动态疲劳力学理论体系. 

Damage constitutive model of rock subjected to coupled static loadings and cyclic impacts

Establishing a suitable damage constitutive model of rock is of great significance to study the dy-namic mechanical characteristics of rock subjected to coupled static loadings and cyclic impacts. Firstly, the parameter of cyclic impact times was introduced to the damage constitutive relation of rock with the relation-ship between the elastic modulus of rock and the accumulative damage variable which based on the evolution model of damage accumulation of rock subjected to coupled static loadings and cyclic impacts. Secondly, com-bining the statistic damage model and visco-elastic model, a rock dynamic damage constitutive model was es-tablished under the axial pressure and the confining pressure and cyclic impacts based on the Drucker-Prager failure criterion with the assumption that the rock micro unit strength complied with the Weibull distribution. Then, the experimental data with coupled static and dynamic loadings on rock was used to verify the correct-ness and feasibility of the damage constitutive model. Finally, the influence law of parameters to the stress-strain curve was studied in the process of cycle impact in the model. The results show that there is a good co-herence between the established damage constitutive model of rock and the experimental data, which can also reflect a constitutive relation of rock subjected to coupled static loadings and cyclic impacts. The parameters of elastic modulus and viscosity coefficient of rock have a great influence on the stress-strain curve in the pro-cess of cycle impact, but the parameters of friction angle and Poissonˊs ratio of rock have little influence on the impact of fatigue stress-strain curve of rock which is under 3D static loadings. In the process of cycle im-pact, the non-uniformity of rock gradually increases. The results are beneficial to improve the dynamic fatigue mechanics theory system of rock subjected to coupled static loadings and cyclic impacts.