Shear behaviors of core samples from a deep geothermal exploration well was investigated using direct shear tests. The fracturing process inside the intact rock samples during shear was monitored using acoustic emission (AE) technique. The results show that three shear stages including compaction, quasi-elastic and failure phases can be easily divided based on the shear stress-shear displacement or the cumulative AE parameters-shear displacement curves. Three characteristic stresses in terms of crack initiation stress, crack damage stress and peak strength are defined for intact rock samples undergoing shear. The crack initiation stress is about 0.80 times of the peak strength, and the crack damage stress is about 0.88 times of the peak strength. In addition, the different shear behaviors and AE characteristics between intact rocks and rock fractures are compared. AE events are scattered in the pre-peak stage but are localized around the fracture surface in the post-peak stage, while AE events are located along the shear zone in intact rock samples.

使用直接剪切试验研究了来自深部地热勘探井的岩心样品的剪切行为。使用声发射（AE）技术监测剪切过程中完整岩石样品内部的破裂过程。结果表明，基于剪切应力-剪切位移或累积AE参数-剪切位移曲线，可以轻松地将压实，准弹性和破坏三个阶段划分为剪切阶段。对于完整的受剪切岩石样品，定义了三个特征应力，分别是裂纹萌生应力，裂纹破坏应力和峰值强度。裂纹萌生应力约为峰值强度的0.80倍，裂纹破坏应力约为峰值强度的0.88倍。此外，比较了完整岩石与岩石裂缝之间的不同剪切行为和声发射特征。AE事件散布在峰前阶段，但在峰后阶段位于裂缝表面附近，而AE事件沿完整岩石样本中的剪切带分布。