花岗岩颗粒流模型循环压缩作用下能量特征分析

为分析花岗岩颗粒流模型循环作用下的能量特征，基于花岗岩单轴压缩试验得到的应力应变曲线，完成了PFC3D数值试验的参数标定，探讨了不同循环次数下数值试件内部总能量、弹性应变能和耗散能的变化规律，建立了一定循环次数下耗散能随应力变化的演化方程。研究结果表明:在数值试件加载至破坏过程中，这些能量参数以应力应变曲线峰值点为分界，峰前的总能量、弹性应变能和耗散能随应力呈非线性增长，总能量增长速率最快，弹性能次之，耗散能最慢；至峰值点附近时弹性应变能达到储能极限，增速降为0；峰后则表现为弹性应变能急剧释放，耗散能随裂纹发展而快速增加，能量急剧释放是导致岩石灾变破坏的主要原因。提出的基于材料阻尼理论的耗散能演化方程，计算结果和试验数据对比表明其可以较好地反映一定循环次数下耗散能随应力变化的特征。

Analysis on energy characteristics of granite particle flow model under cyclic compression

In order to analyze the energy characteristics of granite particle flow model under the cyclic action,based on the stress strain curves obtained from uniaxial compression tests of granite,the parameters of PFC3D numerical test were calibrated,then the variation rules of total energy,elastic strain energy and dissipated energy in the numerical specimens under different numbers of cycles were discussed,and the evolution equation of dissipated energy varying with stress under a certain number of cycles was established.The results showed that in the process of loading and failure of numerical specimens,the above energy parameters were divided by the peak point of stress strain curve.The total energy,elastic strain energy and dissipated energy before the peak increased nonlinearly with stress,and the growth rate of total energy was the fastest,followed by the elastic energy,and that of dissipated energy was the slowest.Around the peak point,the elastic strain energy reached the energy storage limit,and the growth rate decreased to 0.After the peak,the elastic strain energy released rapidly,and the dissipated energy increased rapidly with the development of cracks.The rapid release of energy was the main cause of rock catastrophic failure.An evolution equation of dissipated energy based on the material damping theory was proposed,and the comparison between calculated results and experimental data showed that it could reflect the characteristic of dissipated energy varying with stress under a certain number of cycles well.