甘肃北山地区花岗岩破坏过程能量聚集和耗散特征研究

Study on energy concentration and dissipation of Beishan granite in Gansu during failure process

  • 摘要: 对甘肃北山地区的花岗岩进行不同围压下三轴试验,通过轴向压力和横向变形联合控制加载过程,获得了不同围压下岩石全应力应变曲线,重点研究了岩石特征应力和不同阶段岩石能量变化特征。研究结果表明:随着围压的增加,特征应力线性增大,围压每增加1 MPa,启裂应力、损伤应力、峰值应力分别增加3.30 MPa、6.74 MPa、7.68 MPa;特征应力对应的总能量和弹性能均有较大幅度的增加,围压从2 MPa升高到30 MPa时,启裂应力、损伤应力和峰值应力对应的弹性能分别增加了5.2倍、5.8倍和5.1倍,启裂应力、损伤应力和峰值应力对应的总能量分别增加了4.9倍、5.7倍和4.7倍;各阶段耗散能增加量整体上随围压增大呈增加的趋势,且裂隙不稳定扩展阶段能量受围压影响更剧烈;定义峰值岩石储能系数,并分析储能系数对峰值岩石稳定状态的影响。

     

    Abstract: Servo test system was used to obtain stressstrain curves of Beishan granite under different confining pressure,and the loading process was jointly controlled by means of axial pressure and circumferential deformationVariation characteristics of energy and characteristic stress of Beishan granite were researchedCharacteristic stress are linear increase with confining pressure increasing,crack initiation stress,damage stress and peak strength increased 330 MPa,674 MPa,768 MPa respectively along with confining pressure increased 1 MPaTotal energy and elastic energy corresponding to characteristic stress are greatly increase with confining pressure increasingWhen confining pressure increased form 2 MPa to 30 MPa,elastic energy corresponding to initiation stress,damage stress and peak stress increased 52 times,58 times and 51 times respectively,corresponding total energy increased 49 times,57 times and 47 times respectivelyThe increment of dissipation energy increase with increasing of confining pressure,and energy at the crack unstable propagation stage was significant affected by confining pressureEnergy storage coefficient was defined to estimate rock stability around the peak strength,effect of stress state coefficient on energy storage was further analyzed

     

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