深埋地下洞室层状岩体卸荷时效孕灾机理研究

Focused on the phenomena of time-dependent deformation and failure of the unloading surrounding rock due to excavations of layered rock mass in deep underground cavern, as well as the consequent identification and mechanical characterization of time-dependent disaster inducing mechanism of layered rock mass, this project plans to take some deep underground caverns with the development of layered rock mass as background, such as Xianglushan tunnel of central Yunnan province water diversion project. The comprehensive research approaches, including a series of macro-mesoscopic mechanical testing, on-site dynamic measurement as well as information interpretation, and numerical simulation, etc., are used to reveal time-dependent disaster inducing the mechanical characteristics and laws for the time-dependent damage evolution of the layered rock mass in underground cavern at great depth. Then, the correlation effect of high in situ stress-bedrock-stratigraphic structure, disaster generation process, influencing factors and their correlations for the process of time-dependent disaster of the layered rock mass in deep underground cavern can be identified. The macro - mesoscopic mechanism of time-dependent disaster generation of the unloading surrounding rock in deeply buried underground cavern can be interpreted. Afterwards, a time-dependent mechanical model reflecting the mechanism of damage evolution and layer structure effect of the unloading layered rock mass under high in situ stress could be established. On the basis, a numerical simulation method for describing the time-dependent disaster evolution process of the surrounding rock for layered rock mass in deep underground cavern is presented. Therefore, important theoretical and application basis for the development and enrichment of theory of deep rock mechanics, as well as the process control and safety analysis of the layered rock mass in underground cavern at great depth in China can be obtained.

针对深埋层状岩体地下洞室围岩开挖卸荷时效变形破坏现象及由此带来的层状岩体卸荷时效孕灾机理识别和力学表征问题，拟以滇中引水香炉山隧洞等深埋层状岩体洞室为依托，通过开展一系列宏细观时效力学试验、现场动态量测及信息解译、数值模拟等多尺度多手段研究，揭示深埋洞室层状岩体卸荷时效孕灾的力学特征与时效破裂损伤演化规律，识别深埋洞室层状岩体卸荷时效孕灾过程中高应力-母岩-层面结构相关作用效应、孕育条件、影响因素及其相关关系，阐释深埋层状岩体地下洞室围岩卸荷时效灾变孕育的宏细观演化机理，建立反映高应力作用下层状岩体卸荷损伤演化作用机理和层面结构效应的时效力学模型，提出描述深埋层状岩体地下洞室围岩时效孕灾演化过程的数值模拟方法，为丰富并推动深部岩石力学理论发展，以及为深埋层状岩体地下洞室围岩卸荷孕灾过程控制与安全分析等提供理论依据和应用基础。

针对深埋层状岩体地下洞室围岩开挖卸荷时效变形破坏现象及由此带来的层状岩体卸荷时效孕灾机理识别和力学表征问题，通过室内试验、现场量测、数值模拟、理论研究，获得了影响层状岩体地下洞室围岩变形破坏的主控因素是层面产状及与洞轴线的相对关系，解译了应力-岩体结构耦合作用对深埋洞室围岩变形破坏模式的显著影响特征，识别了层状岩体地下洞室围岩变形破裂呈现明显的层面结构有向性、非对称性和时效性，从宏细观上揭示了层状岩体卸荷时效破裂规律及其应力强度比诱导效应、围压抑制效应、层面结构控制效应以及均质度影响效应；在细观方面，建立了描述基岩细观颗粒非均质胶结特性和时效破裂特征的WLPB模型以及描述层面节理细观非均质黏结特性的WSJ模型，提出了非均质层状岩体时效破裂细观力学数值模拟方法；在宏观方面，建立了基于莫尔库伦参数的层状岩体横观各向同性强度准则，提出了表征卸荷损伤演化作用机理和层面结构效应的层状岩体遍布节理黏弹塑性模型，发展了描述深埋层状岩体地下洞室围岩变形破坏时效演化过程的数值模拟方法，初步形成深埋层状岩体地下洞室围岩卸荷时效分析理论方法，在引汉济渭秦岭输水隧洞等工程中进行了初步应用和验证，为深埋层状岩体地下洞室围岩卸荷时效孕灾过程控制提供理论依据和技术支撑。