考虑时空效应的软弱围岩隧道施工失稳演化机理与控制理论

The weak surrounding rock tunnel has a remarkable time-space effect and easy to collapse. The study on the time-space effect of unstable weak surrounding rock tunnel construction is the theoretical basis to innovate a safe development model of weak surrounding rock tunnel and has great application value.This project aims to establish a analysis method of time-space effect which can unify the various grades of typical weak surrounding rock tunnel, including the grade IV, grade V and grade VI, reveal the law of time-space evolution while the construction is unstable, and propose the time-space quantitative control theory of the safety management in construction stage. Therefore, the key of safety control is to make clear the time-space effect mechanical model, instability mode and stability conditions of weak surrounding rock tunnel construction, that also exactly the scientific problems urge to be solved in the current construction of weak surrounding rock tunnel. This project intends to carry out further research, meanwhile, illustrate the time-space effect principle of instability and establish the time-space quantification control parameters of safety construction of weak surrounding rock tunnel for creep damage constitutive model, unstable time-space evolution mechanism, instability mode, instability comprehensive control index, quantitative method of control standard, multi-phase containment method during construction procedure and safety time-space quantification control of excavation and support etc.. Both making a breakthrough innovation in time-space effect design theory, time-space effect construction method and time-space effect security management of weak surrounding rock tunnel and solving the current prominent problem of the theoretical studies on time-space effect of weak surrounding rock tunnel fall behind the engineering practice have great theoretical significance and social significance.

软弱围岩隧道时空效应显著、易坍塌失稳，研究软弱围岩隧道施工失稳的时空效应，是创新软弱围岩隧道安全发展模式的理论基础，具有重要应用价值。本项目旨在建立IV、V、VI级软弱围岩隧道统一的时空效应分析方法、揭示软弱围岩隧道施工失稳的时空演化规律，提出软弱围岩隧道安全施工的时空量化控制理论。为此，明确软弱围岩隧道施工的时空效应模型、失稳模式及稳定条件，是当前软弱围岩隧道建设中亟待解决的科学问题。本项目拟针对软弱围岩隧道蠕变损伤本构模型、失稳时空演化机理、失稳控制指标、量化控制标准、施工安全多阶段控制方法、开挖支护安全时空量化控制等，开展系统深入的研究，阐明软弱围岩隧道施工失稳的时空效应原理，提出软弱围岩隧道施工过程安全管理的时空量化控制参数。在软弱围岩隧道时空效应设计理论、施工方法和安全控制方面取得创新突破，解决目前软弱围岩隧道时空效应理论研究滞后于工程实践的突出问题，具有重大的理论和社会意义。

软弱围岩隧道具有变形速度快、变形时间长、变形量大、扰动范围大、自稳能力差、压力增长快等特点，容易引发围岩大变形侵限、支护严重破裂、隧道坍塌失稳等工程灾害。目前隧道施工时空效应已滞后于工程实践需要，在一定程度上制约了我国隧道工程的健康发展。为了从理论上解决好我国隧道工程建设发展中面临的这一重大需求，首先，建立Ⅳ、Ⅴ、Ⅵ级软弱围岩隧道统一的时空效应分析方法、揭示软弱围岩隧道施工失稳的时空演化规律。第二，基于蠕变损伤耦合理论的时空效应分析，从而更符合工程实际地反映软弱围岩隧道变形和受力的时空演化特性。第三，建立了集变形判据和安全系数判据于一体的综合控制指标以及反映变形控制标准与安全系数标准一致性的量化分析方法；建立集综合控制指标、量化控制标准、分阶段控制方法和时空量化控制参数于一体的时空效应量化控制理论。开展软弱围岩隧道施工过程中的失稳时空演化机理和时空控制理论研究，为我国软弱围岩隧道施工实现安全施工提供科学依据，为我国考虑时空效应的隧道设计、施工与安全控制提供基础理论，满足我国当前软弱围岩隧道建设中的重大理论需求，研究成果对形成我国软弱围岩隧道工程的时空效应理论具有重大意义。