大理岩加卸荷破坏过程的能量演化特征分析

根据大理岩加荷破坏与卸荷破坏试验结果，研究大理岩不同应力路径下的破坏特征和能量演化规律。结果表明，常规三轴破坏岩样吸收总能量 高于单轴压缩吸收总能量，峰值强度后常规三轴弹性应变能释放比单轴缓慢，储能极限高于单轴压缩的储能极限。随着卸荷初始围压升高，岩样峰值强度和峰值应变增大，破坏形式由张拉–剪切破坏向剪切破坏过渡，岩样在峰值强度处吸收的总能量 和弹性能 增大，耗散能 却没有明显变化，围压对峰值强度处的 和 无明显影响。卸荷速度增大，岩样峰值强度和峰值应变减小，破坏形式由剪切破坏向张拉–剪切破坏过渡，岩样在峰值点处吸收的总能量 和弹性能 减小，耗散能 却没有明显变化，卸荷速度对 和 无明显影响。加荷与卸荷2种应力路径下，岩样在到达峰值强度时所吸收的总能量和储能极限都与峰值强度呈线性关系。

ANALYSIS OF MARBLE FAILURE ENERGY EVOLUTION UNDER LOADING AND UNLOADING CONDITIONS

According to the results of marble loading and unloading tests，marble failure characteristics and energy evolution under different stress paths are studied. Results show that the absorbed total energy of conventional triaxial compression is higher than that of uniaxial compression. The release velocity of elastic strain energy under conventional triaxial compression is slower than that of uniaxial compression after peak strength. The energy storage limit of conventional triaxial compression is higher than that of uniaxial compression. The peak strength and peak strain increase with the initial confining pressure increasing. Marble failure mode transfers from tension-shear failure to shear failure. The absorbed total energy and elastic energy increase. But the dissipated energy has no significant change. Confining pressure has no significant effect on the rate of and . The peak strength and peak strain decrease with the unloading velocity increasing. Marble failure mode transfers from shear failure to tension-shear failure. The absorbed total energy and elastic energy decrease. But the dissipated energy has no significant change. Unloading velocity has no significant effect on the rate of and . The absorbed total energy and peak strength are in a linear relationship. The energy storage limit and peak strength are also in a linear relationship.