超高水压越江海长大盾构隧道工程安全

随着中国交通建设和城市建设的迅猛发展,越江跨海盾构隧道工程大量增加,而且工程规模(隧道的直径和长度等)和水压条件也在增加。现阶段,仍未明确定义高水压,但一般以0.5 MPa作为高水压的分界线。近期,中国在长江、黄河以及珠江等所建设的高铁、公路以及地铁等盾构隧道工程水压均超过了0.5 MPa,正在筹划建设的琼州海峡隧道等水压更大,将高达2.0 MPa,面临巨大挑战。为此,国家决定针对超高水压(2.0 MPa)越江海长大盾构隧道工程安全问题展开“九七三”计划基础研究。研究采用理论分析、物理试验(室内、室外试验和模型试验)、数值模拟分析和监控测量等多种手段,针对其中涉及的多元、多相和多场耦合物理本质,对高水压水土与结构静动相互作用机理、盾构掘进中的动静力学机理、隧道结构特性及防水特性动态演化机理等核心问题进行深入系统的基础研究,提出了高水压下考虑渗流条件下的水土荷载计算理论和深水盾构隧道地震分析方法,建立了“机-土”动态作用力学模型,提出了盾构姿态、刀具磨损、开挖面稳定和高压成膜及闭气控制方法,提出了高水压大直径盾构隧道衬砌结构设计理论和高水压盾构隧道接缝长期防水安全与监控技术,最终形成超高水压越江海长大盾构隧道工程安全控制理论体系。为确保超高水压越江海长大盾构隧道工程安全提供设计理论依据,为实现大直径泥水盾构在超高水压等复杂条件下安全长距离施工提供理论支持。

Engineering Safety of Cross-River or Cross-sea Long-distance Large-diameter Shield Tunneling Under Superhigh Water Pressure

With the rapid development of transportation and urban construction in China, cross-river or cross-sea shield tunnel projects have increased significantly with increasing tunnel diameter, length, and water pressure. At present, high water pressure has not been clearly defined. Generally, 0.5 MPa is used as the boundary of high water pressure. Recently, the water pressures of high-speed railways, highways, and subway shield tunnels of the Yangtze River, Yellow River, and Pearl River have all exceeded 0.5 MPa, and it is highly challenging and unprecedented that the Qiongzhou Strait Tunnel that is being planned is under a pressure as high as 2.0 MPa. Therefore, the state decided to conduct basic research on the “973” plan for the engineering safety of cross-river or cross-sea long-distance large-diameter shield tunneling under superhigh water pressure. In this article, the research results of the project are briefly discussed. Theoretical analysis, physical testing (indoor, outdoor, and model testing), numerical simulation analysis, and monitoring measurement were conducted, aiming at the essential multielement, multiphase, and multifield coupling physics. Deep and systematic basic research was performed for the static and dynamic interaction mechanism of water-soil-structure under high water pressure, the dynamic and static mechanics mechanism in shield tunneling, tunnel structure characteristics, and dynamic evolution mechanism of waterproofing. Theoretical analysis, physical tests (indoor, outdoor, and model tests), numerical simulation analysis, monitoring and measurement, etc. were employed in response to the multielement, multiphase, and multifield coupling physical characteristics. Such core issues as static and dynamic interaction mechanisms, dynamic and static mechanics mechanisms during shield tunneling, tunnel structure characteristics, and the dynamic evolution mechanism of waterproofing characteristics were studied in depth and systematically. The deep-water shield tunnel seismic analysis method established the machine-soil dynamic interaction mechanical model. The shield posture, tool wear, excavation surface stability, high-pressure film formation, and closed-air control methods were determined. A high-water-pressure large-diameter shield is proposed herein. The design theory of tunnel lining structure, using the long-term joint waterproof safety and monitoring technology of high-pressure shield tunnels, has finally been used to form a theoretical system of safety control for superhigh-pressure shield tunnel engineering. The research results provide a theoretical basis for ensuring the safety of cross-river or cross-sea long-distance large-diameter shield tunneling under superhigh water pressure. They provide theoretical support and safety for the long-distance construction of large-diameter slurry shield tunneling under superhigh water pressure and other complex conditions.