深长岩溶隧道突水灾变动力学演化机理及最小防突厚度研究

Long-deep tunnel is always surrounded by complex geological-mechanical environment with high geo-stress, high water pressure, strong karst and construction disturbance. The dynamic evolution mechanism of water inrush places an important role in disaster warning and control. In the actual researches on the disaster mechanism of water inrush, the understanding of dynamic disaster mechanism is very limited induced by outer disturbance of explosion, excavating and other forces, which directly lead to problems of engineering application for the critical criterion and the minimum against-inrush thickness for water inrush. The research method of this project was presented with the combination of laboratory experiment, numerical simulation, physical model test and theoretical analysis. Mechanism characteristics and hydraulics characteristics of disaster-causing construct, as well as damnification mechanism of surrounding rock were investigated under the action of construction disturbance, and water inrush mode, the occurrence condition and the main control parameters for long-deep tunnel were put forward. Failure stability of protective rock for water inrush induced by gradual destruction and its evolvement regularity were studied, and movement characteristics for different stages of water inrush and discrimination method of mechanics for disaster-induced conditions were brought forward. Dynamic characteristics of water inrush and disaster evolution were studied for digging the trigger mechanism and critical point of water inrush under the action of construction disturbance. The analysis method of the critical criterion and the minimum against-inrush thickness of protective rock for water inrush were established. The study method and the final results of this program could provide scientific basis and theoretical foundation for study on comprehensive prediction, early warning and process control of water inrush for long-deep tunnel.

深长岩溶隧道处于"高地应力、高渗透水压、强岩溶和施工扰动"的复杂地质力学环境中，突水的动力学演化机理是事关灾害控制及预警的关键科学问题。但在目前的突水致灾机理研究中，因对爆破、开挖等外力扰动诱发突水的动力灾变机制认识不清，致使建立的临突判据和最小防突厚度难以应用于工程实践。本课题拟采用室内岩样试验、数值模拟、物理模型试验和理论分析相结合的研究方法，研究工程扰动下致灾构造的力学特性、水力学特性及附近围岩的损伤演化机制，提出深长岩溶隧道的突水模式及其发生条件和主控因素；研究防突岩体渐进损伤失稳与演化规律，提出突水不同阶段的运动特征和灾变启动条件的力学判别方法；研究突水的动力学特征与灾变演化过程，揭示施工扰动下突水灾变失稳的触发机制、临界点，建立突水临界判据及其防突岩体最小安全厚度分析方法。项目研究方法和最终成果可为深长岩溶隧道突水的综合预测、预警以及过程控制提供科学依据和理论基础。

本项目以深长岩溶隧道突水灾害为研究对象，以防突岩体的渐进性破坏为突破口，采用工程调研、统计分析、室内试验、数值模拟和理论分析相结合的方法，研究开挖扰动条件下隧道突水的动力学演化机理。分析深长岩溶隧道的突水模式及其发生条件，并自主开发了地下工程重大灾害案例库，建立了突水影响因素层次结构模型，提出了隧道突水的主控因素。研发了三套隧道突水突泥模拟试验装置，分别开展了开挖扰动下高地应力高水压隧道突水模型试验、不同防突厚度岩体的可视化突水模型试验和地下水渗流下隧道突水突泥模型试验，模拟了突水灾变演化过程，揭示了突水不同阶段的动力学特征与防突岩体的渐进失稳破坏机制。通过数值模拟，从宏观角度揭示了开挖扰动对隧道突水的影响规律；从微观角度，建立了固、液和气的三相耦合数值模型，研究了突水过程中岩溶管道充填物的水分运移特征。考虑开挖扰动损伤影响系数，提出了防突岩体最小安全厚度计算方法。最后，针对岩溶隧道突水风险评估过程中存在的模糊性和随机性问题，建立了基于集对分析（SPA）的风险预警模型，实现了岩溶隧道突水风险的综合预测、预警。本项目圆满完成了研究目标，达到了预期效果，具体量化指标如下：发表学术论文23篇（SCI检索9篇，EI检索10篇），出版学术专著1部，授权发明专利4项，实用新型专利3项。申请并公开发明专利2项。获中国公路学会科学技术奖二等奖1项，山东省科技进步三等奖1项，徐州市自然科学优秀学术论文二等奖1项。培养博士生1人，硕士生2人。