轴向荷载下岩石剪切破坏时效损伤蠕变模型研究

岩石蠕变滑移失稳是诱发断裂滑移型岩爆的主要原因之一,为了揭示岩石蠕变失稳过程的力学响应特征,文中通过理论分析和试验研究,分析了岩石剪切滑移失稳过程的蠕变增长模式和力学响应特征,建立了轴向荷载作用下的岩石剪切破坏时效损伤蠕变模型。研究结果表明:该模型可以很好地描述岩石剪切滑移失稳过程的蠕变演化特征,也能够表征岩石不同蠕变演化阶段的力学响应差异;在轴向荷载作用下,岩石剪切滑移失稳过程具有明显的阶段化特征,存在典型的减速蠕变阶段、等速蠕变阶段和加速蠕变阶段;岩石蠕变增长速率受弹性模量和黏性系数等影响,也受时效损伤效应影响,尤其对于加速蠕变阶段影响显著,这是造成岩石非线性加速蠕变失稳的原因之一。

Study on Time-dependent Damage Creep Model of Rock Shear Failure under Compression

The creep sliding instability of rocks is one of the main reasons for inducing fault-slip rockburst. For revealingthe mechanical response characteristics of the creep sliding instability process of rocks,the creep growth mode and failure evolution characteristics of rocks shear-slip instability process was analyzed clearly by theoretical analysis and experimental verification. Subsequently,a time-dependent damage creep model was established for the shear-slip failure of rocks and verified bythe previous test. The results demonstrated that the time-dependent damage creep model can be used to describe the creep evolution characteristics of rocks shear slip instability under compression, and it can also better characterize the mechanicalresponses of different creep stages for rocks failure. The shear creep failure process of rocks had obvious stage characteristics,and there existed deceleration creep modes,constant velocity creep modes and accelerated creep modes. The creep growth rateof rocks was affected by its elastic modulus and viscosity coefficient,and it was also affected by its time-dependent damageeffect,especially at the accelerated creep stage,which was also one of the main inducements for rocks nonlinear accelerationinstability.