卸载下岩石裂隙扩展机制及破坏前兆特征的并行模拟与物理试验研究

地下洞室与高陡边坡失稳灾害问题，都与开挖卸载诱发岩体裂隙扩展失稳相关，而通常在加载条件下的研究结果，难以解释卸载下岩体裂隙扩展导致的破坏机理，因此卸载下岩体破坏前兆规律研究更具挑战性。本项目首先开展物理力学试验，借助声发射仪、红外热像仪捕捉裂隙岩体破坏的声发射与温度场演化信息，研究复杂卸载下岩体裂隙扩展贯通机制和力学响应。其次，通过考虑卸载路径和残余变形，建立高性能并行模拟方法，模拟裂隙岩体破坏的应力变形场。然后，综合分析岩体裂纹扩展模式与形态、声发射突变、温度场异常、应力积累与释放的时空演化关系，建立温度场、应力场、声发射序列、断裂模式之间的内在联系，避免单一观测手段的局限性，揭示基于多物理场参量的断裂失稳前兆信息规律。最后，依托地下洞室工程，建立相似物理模型与数值模型，通过加卸载试验研究围岩裂隙方向、初始地应力和卸载强度对裂隙开裂与扩展的影响，为地下工程岩体稳定性分析提供依据。

Instability analysis of underground caverns and high-steep slopes are related to rock mass crack propagation induced by excavation and unloading. However, it is difficult to explain the failure mechanism caused by crack propagation under unloading using results obtained under loading, so the precursory information of rock mass crack propagation and failure is more complex. Firstly, physical and mechanical experiments will be carried out in this project. Acoustic emission (AE) and temperature field evolution information of fracture rock mass are captured by acoustic emission (AE) technique and infrared thermal imager, and the fracture propagation mechanism and mechanical response of rock mass under complex unloading will be studied. Secondly, by considering the unloading stress path and residual deformation, a high performance parallel simulation method will be established to simulate the stress and deformation field of the rock mass. Then, the spatio-temporal evolution relationship between crack propagation mode and morphology, abrupt change of acoustic emission, abnormal temperature field, stress accumulation and release will be comprehensively analyzed, and the intrinsic relationship among temperature field, stress field, acoustic emission sequence and fracture mode will be established, so as to avoid the limitation of single observation method and reveal the precursory rule of rock mass based on multi-physical field parameters. Finally, according to an underground cavern engineering, a similar physical model and related numerical model will be established, and the influence of surrounding rock fracture direction, initial in-situ stress and unloading strength on crack cracking and propagation will be studied through loading and unloading test, which provides a basis for underground engineering and stability analysis of rock mass.