水力强耦合作用下深部隧洞围岩裂隙演化及突水机理研究

The mechanism of progressive failure and buckling damage of deep rock mass under high in-situ stress and seepage pressure is complex, which leading to significant water burst disaster. Further study on fracture evolution and water burst mechanism of deep rock mass under hydro-mechanical coupling will be conducted in this project with combination methods of experimental investigation, theoretical analysis and numerical simulation. Firstly, in the meso-scale, the failure test of samples will be carried out to study the interaction between fracture evolution and seepage progression, and the mechanism of water burst channels formation. Furthermore, large-scale model test will be conducted to study the progressive evolution mechanism of seepage-damage and to reveal the mechanism of buckling damage of rock mass. Based on the experimental results, the precursor characteristics for different stage of water burst disaster will be presented. The theoretical model will be built for rock mass under intense hydro-mechanical coupling and for water burst. The criterion will also be proposed for the buckling damage. Based on the theoretical model, the FEM software will be developed to simulate the fracture evolution and rock mass failure process. Finally, evaluation methodology and technological means will be obtained for the prediction of water burst of deep tunnels.

高应力强渗压条件下的深部隧洞围岩渐进破坏过程和失稳机理异常复杂，由此诱发的突水灾害问题日益突出。本项目采用试验研究、理论分析和数值模拟相结合的方法，从宏细观角度研究水力强耦合作用下深部隧洞围岩裂隙演化及突水机理。从细观尺度出发，开展高应力强渗压条件下裂隙岩体破坏试块试验，分析裂纹扩展与渗流过程的互馈作用机制，揭示突水通道的形成机理及主控因素；从宏观尺度出发，开展深部隧洞开挖模型试验，分析岩体结构渗流-损伤的演化累进机制，揭示开挖扰动条件下突水灾变演化及岩体结构失稳的突变机理。基于水岩互馈演化机理，提出突水灾害不同阶段的前兆表征；建立水力强耦合条件下裂隙岩体宏细观跨尺度破坏本构模型及基于突变理论的非线性突水模型，提出深部隧洞突水及岩体结构失稳判据。基于理论模型，开发可反映水力强耦合作用下岩体裂隙演化及结构失稳过程的有限元程序，形成深部隧洞突水灾害预测预警的评价方法和技术手段。

本项目针对水力强耦合条件下深部隧洞隔水岩体裂隙演化和岩体失稳导致的突水灾害问题，采用现场调研、室内试验、模型试验、数值模拟等多种手段进行了研究。通过对国内外大量突涌水灾害案例的研究，揭示了深部隧洞突水判别的围岩赋存特征。将突涌水分为隔水岩体破坏突涌水和充填渗透失稳突涌水。分析了深部隧洞裂隙岩体突涌水特征及其成因，总结了隔水岩体破坏致灾规律。进行了不同水压下预埋单裂隙试件的单轴压缩试验，研究了三维裂隙起裂扩展模式。研制了一种可视化模拟隔水岩体破裂突水的试验装置。并利用该装置进行了隔水岩体破裂突水模拟试验。分析了水力强耦合作用下岩体裂纹起裂和扩展规律，以及裂纹扩展和渗流过程的相互作用机制。研制了“高地应力-高渗压隧道突水模型试验系统”。并利用该系统进行了“隧道掌子面前方隔水岩体破裂突水”和“隧道顶部隔水岩体破裂突水”模型试验，针对相应工况进行了数值模拟分析。分别研究了高水压充填型溶洞对隧道开挖的影响以及隔水岩体破裂突水前兆信息，建立了深部隧洞突水及岩体结构整体失稳的判据。揭示了隔水岩体破裂突水通道的形成过程及其影响因素，获得了开挖扰动作用下深部岩体结构失稳及突水致灾机理。开发了隧道突涌水融合预警软件，并与隧道突涌水远程监控与预警分析系统衔接。形成了水力强耦合作用下深部隧洞突水灾害预测预警的评价方法与技术手段。