岩石破坏过程中波速变化特征的试验研究

Experiment study on the law of wave velocity variation in the process of rock failure

在单轴阶段加载条件下,对取自闽南地区的闪长岩岩样进行了不同方向上纵波传播速度以及声发射活动的测试,并据此归纳总结出不同方向波速在岩石破裂过程中的变化规律。研究结果表明：微裂纹演化在方向上的不均匀导致波速变化特征的各向异性。对于平行于加载方向的波速,变化过程为压密应力（约0.2σc）前的非线性快速上升及该应力后的线性上升,岩石破裂前的波速降并不明显;而对于垂直于荷载方向的波速,变化过程则为在约（0.3-0.5）σc前的少量上升及该应力后的加速下降,岩石破裂前的波速降非常明显。

Under uniaxial multilevel loading conditions, the longitudinal wave velocities in different directions were measured as well as acoustic emission（AE） activities.The diorite specimens were taken from southern region of Fujian Province and according to the test the law of wave velocity variation in different directions in the process of rock failure is summarized.Experimental results show that inhomogeneous evolution of micro cracks on different directions leads to the anisotropy of wave velocities.For the wave velocity parallel to the loading direction,the change process was characterized by an initial quick,nonlinear rise below a critical stress （about 0.2σc）,followed by a more gradual line-ar increase above this critical stress,and the drop was not obvious when the rock was about to fracture.For the wave velocity perpendicular to the loading direction,the change process was characterized by a slightly rise below a critical stress （about 0.3-0.5σc）,followed by an accelerated decrease above this critical stress,and the drop was very obvi-ous when the rock was about to fracture.