深埋隧洞高压隐伏水体突灾细观水岩耦合机理研究

Damage caused by the gush of concealed water is one of the major disasters in the deep underground engineering, yet the mechanism of the induction of these disasters is still unclear, especially the study on the meso-scopic mechanism of water-rock coupling deformation and failure is still to be further consolidated. Based on a supporting tunnel engineering, application of indoor test, theoretical analysis and the mesoscopic numerical analysis are combined together in the project to study the evolution law of concealed water gushing in time and space at mesoscopic level, in order to reveal the mechanism of the induction of disaster. Firstly, on account of the characteristic that the dynamic evolution of crack groundwater migration which is likely induced by buried tunnel driving, through the development of wide rough fracture high-speed non-Darcy seepage test and theoretical study, as well as improvement and unity of Darcy - non-Darcy equation, obtain the dynamic evolution law of buried tunnel crack groundwater. Secondly, damage rate parameter was introduced in particle bonding model to establish the microscomic FBPM model equivalent to rock fracture. Wedge splitting test was carried out based on FBPM model, in comparison with the laboratory test, fractal dimension rate and constant injury rate were combined to consummate the model. Finally, unified Darcy and non-Darcy equation was implanted into CFD to consummate and construct the CFD-PFC analysis platform for coupling of water and rock to realize the microscopic dynamic study on the process of concealed water gushing and the mechanism of the disaster was also revealed. The results of this research are anticipated to offer valuable references for the prevention of disasters caused by the gush of concealed water with high pressure.

隐伏水体突出致灾是深部地下工程中的重大灾害之一,其灾变诱发机制尚不明确，特别是水岩耦合变形破坏细观机理的动态研究有待进一步深入。本项目结合依托工程，应用室内试验、理论分析及细观数值分析相结合的手段，从细观尺度深入研究隐伏水体突出的时空演化规律和诱灾机理。首先基于深埋隧洞掘进可能诱发裂隙中地下水运移动态演化的特性，通过开展宽大粗糙裂隙高速非达西渗流试验及理论研究，完善统一的达西-非达西方程，获取深埋隧洞裂隙地下水动态演化规律；其次，在颗粒粘结模型中引入损伤速率参量，建立与岩石断裂损伤等效的细观FBPM模型，基于FBPM开展楔形劈裂数值试验, 获取裂纹扩展分维数，通过相应室内试验验证，率定损伤速率完善模型；最后，将达西-非达西方程植入CFD，通过构建CFD-PFC水岩细观耦合分析平台，实现隐伏水体突出致灾演化过程的细观动态研究，揭示其灾变机理，研究成果可为隐伏水体突出致灾的预防提供重科学依据。

隐伏水体突出致灾是深部地下工程中的重大灾害之一，其灾变诱发机制尚不明确，特别是水岩耦合变形破坏细观机理的动态研究有待进一步深入。本项目结合依托工程，应用室内试验、理论分析及细观数值分析相结合的手段，从细观尺度深入研究隐伏水体突出的时空演化规律和诱灾机理。.首先设计符合不同节理粗糙度的拟岩体粗糙单裂隙试件，研制高速非达西渗流试验装置。开展粗糙单裂隙非达西渗流室内物理试验，探讨粗糙裂隙高速非达西渗流的演化规律及运动特征。基于VB构建CFD-PFC水岩耦合分析平台模拟岩体水力劈裂，引入FBPM模型，通过比对室内试验与细观数值仿真试验，验证该耦合平台，并基于此开展不同应力状态下裂纹的起裂、扩展细观研究。 实现隐伏水体突出致灾演化过程的细观动态研究。.通过开展实验，得到了非达西影响系数关于裂隙隙宽和节理粗糙度系数之间的经验关系式，实现定量的描述岩体裂隙粗糙程度和隙宽大小对裂隙水流运动非达西运动特性的影响；研发了PFC-CFD联合分析平台，通过仿真模拟室内厚壁圆筒水力劈裂试验，并与室内试验结果进行了对比和研究，验证PFC-CFD耦合分析平台，表明其用于水力劈裂的研究是有效可行的，为水力劈裂的研究和设计建立了一种新方法。.通过课题研究，创新性地提出孔隙网格剖分渗流模型，并基于法向及切向积分方案，获取细观水岩耦合力，作为岩体裂纹渐进扩展的驱动力，结合FBPM模型开展水岩耦合细观机理研究，实现将PFC非连续方法应用于连续岩体开裂过程细观动态模拟。PFC-CFD联合求解法可以获取临界突水距离或临界水压力。本课题的开展可为洞室开挖可能出现的岩体崩塌及突水、涌水提供实时预报，为科学预报及有效防治突涌提供理论依据。