调水工程深埋输水隧洞围岩时效大变形孕灾机理及安全控制

Large time-dependent deformation for surrounding rock is a kind of major engineering disaster, which is a threat to construction and long-term operation safety of deep tunnels in water conveyance projects. This project plans to take some major water conveyance projects as background, such as Hanjiang river to Weihe river water diversion project and central Yunnan province water diversion project. The comprehensive research approaches, including field tests, laboratory tests, in-situ dynamic test and monitoring analysis, numerical simulation, theoretical analysis, practical application and verification are conducted. Then, disaster generation process, condition and evolution mechanism of large time-dependent deformation for surrounding rock of deep tunnels can be identified based on effect caused by the ratio of strength to stress, coupling effect of stress and structure, and interaction effect of water and rock. The interaction mechanism among energy-absorbing bolt, grouting and surrounding rock, as well as the effect of anchor reinforcing effect can be revealed. Afterwards, HM coupling laws for the evolution of surrounding rock and lining structure bearing behavior can be interpreted. Unloading induced time dependent degradation mechanical model reflecting the coupling mechanism mentioned above could be established. Continuous-discontinuous analysis method for large time-dependent deformation of surrounding rock and the evolution of surrounding rock and lining structure bearing behavior under HM coupling effect can be developed. On the basis, safety control standards and long-term safety control theory for the evolution of surrounding rock and lining structure bearing behavior under effect of multi-field forcescan be proposed. Therefore, important theoretical and technical guidance for optimal design, construction safety and long-term operation of deep tunnels of water conveyance projects and other related projects in China can be obtained.

围岩时效大变形是调水工程深埋输水隧洞建设中危及隧洞施工及长期运营安全的重大工程灾害之一。本项目拟以引汉济渭、滇中引水等调水工程深埋输水隧洞为依托和示范，综合采用室内和现场试验、原位动态测试与监测分析、数值模拟、理论分析以及工程应用验证等方法和手段，识别基于应力强度比效应、应力-结构耦合效应以及水-岩作用效应的深埋隧洞围岩时效大变形的孕育过程、孕灾条件及演化机理，揭示吸能锚杆-注浆-围岩的相互作用机制及锚注加固效应，解译围岩-衬砌结构协同承载性状演化的HM耦合作用规律，建立反映上述耦合作用机制的岩体卸荷时效劣化力学模型，发展HM耦合作用下围岩时效大变形及围岩-衬砌结构协同承载性状演化的连续-非连续分析方法，提出多场力作用下围岩-衬砌结构协同承载性状演化的安全控制标准和长期安全控制理论，为我国调水工程和其他相关工程深埋隧洞的优化设计、安全施工和长期运营提供理论和技术支撑。

调水工程深埋输水隧洞围岩时效大变形孕灾机理及安全控制是尚未解决的前沿课题。为此，项目组采用室内外试验、原位动态测试与监测、理论分析及数值模拟等开展研究工作，揭示了深埋隧洞围岩时效大变形孕育过程、灾变规律及宏细观演化机制，获得了影响岩体卸荷时效变形的应力强度比效应、应力-结构耦合效应、水-岩作用效应，发现了围岩相对变形量与强度应力比呈幂函数型反比关系且存在发生大变形的门槛值，提出了挤压型围岩大变形孕灾条件与判别方法。建立了适用于岩石卸荷特性和水弱化作用的非线性流变模型以及考虑岩体结构效应的遍布节理黏弹塑性模型，构建了非均质岩体时效破裂细观力学模型以及平行粘结水弱化细观接触模型，提出了非均质岩体细观时效数值模拟方法，开发了岩体工程长期稳定性细观力学模拟系统。研发了适应于围岩时效大变形的独立覆盖新型数值流形法，提出了基于三维块体切割和新型数值流形法的裂隙-孔隙双重介质渗流-应力耦合计算方法。研发了适应于围岩大变形的吸能让压新型锚杆模拟方法，提出了不良地质体围岩灌浆方法以及松弛区围岩精细控制灌浆补强技术，建立了考虑裂隙产状的岩体注浆时空扩散模型理论，揭示了吸能锚杆-注浆-围岩的相互作用机制及锚注加固效应。获得了隧洞衬砌混凝土结构力学响应特征及材料时效劣化规律，建立衬砌混凝土性能时效劣化模型。研发了可考虑围岩压力和外水压力的围岩-衬砌结构联合承载仿真实验装置，提出了围岩和衬砌结构渗流-应力-损伤耦合计算方法以及连续-非连续分析方法，揭示了围岩-衬砌结构协同承载的水-力耦合作用机制。提出了围岩-衬砌结构协同承载体系长期安全的均匀设计-响应面-有限元时变可靠度评价方法，建立了围岩衬砌性状演化的安全控制指标及控制标准。上述理论方法在引汉济渭等5个重大引调水工程中得以应用，在相关理论方法及测试方法和试验设备上有新突破，为我国引调水工程等深埋隧洞的优化设计和长期运营提供理论和技术支撑。