TBM动力扰动下防突结构渐进性破坏规律与突涌水演化机理

Deep-buried long tunnel is a major and difficult project for national infrastructure construction. How to ensure the safety of TBM machine passing through the high risk area of water inrush is a major issue in any projects that need to be solved. At present, the prevention and control of water inrush disasters in TBM construction tunnel is under a passive situation for a long time. The essential reason that why it is difficult to take the initiative in preventing and controlling water inrush is because the complex dynamic catastrophe mechanical mechanism is not clear. Methods such as literature review, case study, theoretical analysis, laboratory test, numerical simulation, and so on will be adopted in this project, to systematically launch the research of water inrush mechanism under failure of the water inrush prevention structures in TBM construction. First of all, according to the macroscopic geological analysis and the case study, the typical geological structure of the rock mass which has the ability to prevent water inrush will be studied; the main controlling factor of the failure on water inrush prevention structures in TBM construction will be determined; the pattern of the disaster and the characteristics of the catastrophe will be put forward. Secondly, the regulations of internal cracks in water contained rock samples from initiation, extension and passing through under the effect of disc cutter will be studied, and the fracture mechanism of rock mass under the effect of disc cutter will be revealed. Finally, under the TBM dynamic disturbance, the extension and passing through of the internal cracks in the water inrush prevention structures will be proposed, as well as the dynamic characteristics and the induced conditions of water inrush channel will be proposed; gradual failure laws of the water inrush prevention structures and the evolution mechanism of sudden water inrush under the dynamic disturbance from TBM and the effect of penetrating and weakening of water will be revealed. The research results truly have important scientific significance and engineering application value for the prevention and control of major water damage in underground engineering.

深长隧道（洞）是国家基础设施建设的重难点工程，如何保障TBM安全穿越突涌水高风险区成为工程中亟待解决的重大难题。目前TBM施工隧道（洞）突涌水灾害长期处于被动防治的局面，难以主动防控的根本原因在于复杂动力灾变力学机制不清。本项目采用文献查阅、案例调研、理论分析、室内试验和数值模拟等手段，系统开展TBM施工防突结构破坏突水机理研究。首先，通过宏观地质分析及案例调研，研究防突岩体的典型结构特征，确定TBM施工防突结构破坏突涌水主控因素，提出典型致灾模式；其次，研究滚刀作用下含水岩样内部裂隙萌生-扩展-贯通规律，建立滚刀破岩数值模型，揭示TBM滚刀作用下岩石的破裂机理；最后，提出TBM持续动力扰动下防突结构内部裂隙扩展、贯通与突水通道形成的动力特征与诱发条件，揭示TBM动力扰动与渗透弱化作用下防突结构的渐进破坏规律与突水演化机理。研究成果对于地下工程重大水害防治具有重要的科学意义与工程应用价值。

随着国家“十三五”规划与“一带一路”战略的实施，交通、水利水电等重大基础设施建设达到了空前规模。工程建设逐渐向地质、地形条件极端复杂的山区与富水地区转移，深长隧道成为交通基础设施的关键节点和重点工程。TBM凭借其施工效率高、安全、经济等优势，逐渐成为深长隧道施工的首要选择，如何保障TBM安全穿越突涌水高风险区成为深长隧道工程中亟待解决的重大难题。.本项目系统开展TBM施工防突结构破坏突涌水机理研究。首先，揭示防突结构的典型地质构造特征，明确防突结构破坏突涌水的致灾模式；其次，研究滚刀和岩体的相互作用机制，提出动力扰动下突水通道形成的诱发条件；最后，揭示防突结构渐进性破坏的演化规律及突涌水机理，做到突涌水发生条件及灾变模式的科学评估。.取得的成果如下：总结了岩溶管道型、充水溶洞型、断层型与裂隙型四种突涌水灾害源的赋存规律与灾变特征，针对前两种突涌水灾害源的精细探查难题，开展了昏暗环境钻孔真彩摄像分辨率优化与充水环境激光扫描衰减特性试验研究，将突水划分为充填结构渗透失稳突水和裂隙渐近性破坏突水两种致灾模式。开展了在不同节理倾角和间距条件下破岩加载模拟，将双滚刀破岩过程分为三个阶段：挤压阶段、起裂阶段和破碎阶段，揭示了不同角度、不同间距和不同方向力三种因素对滚刀破岩的作用机理。基于离散元方法模拟了TBM掘进过程，研究了掘进过程中围岩的扰动受力与位移变形规律。基于自主研制的微型全断面隧道硬岩掘进试验系统，开展了TBM施工引发突涌水模型试验，重点分析了TBM突涌水过程中防突岩体的多物理场演化规律，揭示了TBM动力扰动与渗透弱化作用下防突结构渐进破坏规律与突涌水机理。项目研究成果有利于推动实现TBM施工重大突水灾害的有效主动防控，降低TBM施工风险，尤其对保障隧道突水高风险段的TBM安全掘进，具有十分重要的理论价值与研究意义。