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超声波波速作为一种无损检测手段,对岩石、岩体工程的损伤和破裂过程预测有一定的意义。从声波波速的角度出发,测试无受力和受力状态下干燥、饱水裂隙片岩的纵波波速,研究饱水天然裂隙片岩的波速特性及在压缩全过程中波速随应变的变化规律,探讨超声波特性与岩石损伤和失稳、破坏间的关系。研究结果表明:在未受力条件下,饱水试件比干燥试件的波速有明显的增加,平行裂隙波速V‖饱水前后的增量在0.928%~15.357%范围内,垂直裂隙波速V⊥饱水前后的增量在20.042%~113.362%范围内,饱水前后波速的变化呈现出一定的分散性;垂直裂隙的波速V⊥比平行裂隙上的波速V‖受水的影响明显,垂直裂隙方向上的岩石饱水波速较天然波速增加均在2倍以上,而平行裂隙上饱水岩石的波速变化小,岩石各向异性弱化。在压缩过程中,干燥和饱水裂隙片岩垂直裂隙方向波速V⊥在压密及线弹性阶段均表现出非线性的特性,在应力峰值点,岩石超声波波速急剧降低,岩石裂隙扩展明显。相比于垂直裂隙方向声波的变化,平行裂隙方向的波速V‖只有在峰值应力处,波速有个跌落,但饱水状态下V‖表现出一定波动性。
As a kind of non-destructive testing method, ultrasonic wave velocity has certain significance to the prediction of the damage and rupture process of rock and rock mass engineering. From the point of view of sonic wave velocity, the longitudinal wave velocity of dry and saturated fractured schist in unstressed and stressed state was tested. The wave velocity characteristics of saturated fractured schist and the variation of wave velocity with strain during the whole compression process were studied. Characteristics and rock damage and instability, destruction of the relationship between. The results show that under the unstressed condition, the velocity of the saturated specimen increases obviously compared with that of the dried specimen, the increment of the parallel fracture before and after the V‖ saturation is in the range of 0.928% -15.357%, and the vertical fracture velocity V The variation of wave velocity before and after saturated water shows a certain dispersion in the range of 20.042% -113.362% before and after the ⊥ saturation. The wave velocity V⊥ of the vertical fracture is significantly affected by water than the wave velocity V∥ of the parallel fracture, The saturated wave velocity of rock in the crack direction is more than twice that of the natural wave velocity, while the change of the wave velocity of the saturated rock on the parallel crack is small and the rock anisotropy is weakened. During compression, the wave velocity V⊥ in the direction perpendicular to the fracture of the dry and saturated fractured schist shows nonlinear behavior in the compressive and linear elastic phases. At the peak of the stress, the ultrasonic wave velocity of the rock decreases sharply and the fracture of the rock expands obviously. Compared with the change of acoustic wave in the direction perpendicular to the fracture, the wave velocity V‖ in the direction parallel to the fracture has a drop in the wave velocity only at the peak stress, but V‖ shows some volatility in the saturated state.