This work aims to experimentally investigate the failure mechanism and the spatiotemporal evolution of permeability in the fissured rock-like specimens under the coupled hydromechanical conditions. The different factors on the coupled hydromechanical loading/unloading failure mechanism are investigated. The experimental results of 3-D internal fracture morphology obtained from the X-ray CT scanning system coupled with 3-D reconstruction techniques indicate that the initial unloading state promotes the nucleation of the secondary cracks at the low internal hydraulic pressures. The nucleation of secondary cracks is inhibited when the hydraulic pressure of the fluid-injection is high. Furthermore, the quantitative relationships among the 3-D fractal dimensions, mechanical strengths and permeability are constructed to discover the coupled hydromechanical unloading failure mechanism. The coupled hydromechanical prepeak unloading failure mechanism summarized in this work provides the deep insights in the underground engineering.

这项工作旨在通过实验研究在耦合流体力学条件下裂隙岩石样件的破坏机制和渗透率的时空演变。研究了影响耦合流体力学加载/卸载失效机制的不同因素。X 射线 CT 扫描系统结合 3-D 重建技术获得的 3-D 内部裂缝形态的实验结果表明，初始卸载状态促进了低内部水压下二次裂缝的形核。当流体注入的液压压力高时，二次裂纹的形核被抑制。此外，3-D 分形维数之间的定量关系，构造机械强度和渗透性以发现耦合的流体力学卸载失效机制。在这项工作中总结的耦合流体力学峰前卸载破坏机制为地下工程提供了深刻的见解。