大埋深盾构隧道围岩压力作用机理与新型管片结构体系研究

Deep buried shield tunnel is an important direction for the future development of tunnel engineering, which will be subsequently and vastly applied in certain construction fields such as deep drainage tunnels, intercity railway tunnels, coal-mine roadways, and long-distance water conveyance projects. In view of this, this research will focus on the challenges such as the calculation of surrounding rock pressure, supporting measures and the lining structure selection and parameter optimized design. Besides, method is adopted in the research combined with theoretical analysis, numerical simulation, laboratory tests, model tests and full-scale tests in order to verify the interactive relationship between lining structure and surrounding rock of shield tunnels with large cover depth, and propose the calculation method for deformation pressure of surrounding rocks. Then the support characteristics of the support measures in large cover depth shield tunnel can be acknowledged, and the measures for controlling the deformation pressure of surrounding rock can be recommended. Moreover, the mechanical behaviors of the combined support structure system of segmental lining and different support measures for deep buried shield tunnels can be investigated, and the safety control criterion of segmental lining structure is expected to be put forward under different support measures. In addition, the new-type segmental lining structure with high toughness can be developed against the soft rock or highly weathered rock. Furthermore, the evaluation methodology and target for support structure efficiency is raised in overall consideration of releasing rate for rock deformation energy and controllable deform-ability for support structure, and finally segment lining structure system and analytical method is established and completed in deep buried shield tunnels. Consequently, the calculation of deformation pressure can be summarized and then the corresponding control countermeasures will be recommended in order to provide theoretical foundation and technical support for lining structure design and safety evaluation of deep buried shield tunnels.

大埋深盾构隧道是我国未来隧道工程发展的重要方向，将在我国城市深排水隧道、城际铁路隧道、煤矿井巷、长距离调水工程等领域大量出现。有鉴于此，本项申请针对大埋深盾构隧道穿越复杂岩层所面临的围岩压力计算及支护措施与衬砌结构选择等难题，采用资料调研、理论分析、数值仿真、室内试验、模型试验、足尺试验、现场试验相结合的方法，探明大埋深盾构隧道管片衬砌结构-围岩的相互作用关系，提出形变压力的计算方法；探明大埋深盾构隧道各支护措施的支护特性，形成围岩形变压力的控制对策；探明大埋深盾构隧道联合支护结构体系的受力性能，提出不同支护措施下管片结构的安全性控制标准；研发可用于大埋深软弱破碎岩层的高韧性管片衬砌结构；提出综合考虑围岩变形能释放率、支护结构可控变形能力的支护结构效能评价方法与指标，并最终建立与完善大埋深盾构隧道的管片衬砌结构体系与分析方法，为大埋深盾构隧道的结构设计与安全性评价提供理论依据和技术支撑。

本项研究结合大埋深条件下盾构隧道特点，针对大埋深盾构隧道的围岩压力作用机理、支护措施、衬砌结构受力性能、新型管片结构开发、支护结构效能评价方法等多方面开展研究。首先，基于理论分析手段，构建了盾构隧道松动土压力的解析方程和考虑注浆层影响的盾构隧道径向地基模量解析解。开展了壁后填充层压缩剪切试验和围岩蠕变试验，探明了不同填充层的压缩剪切性能及其对管片受荷的影响规律和围岩蠕变特性。在此基础上，结合盾构隧道施工特点拓展了“两阶段分析方法”，建立了盾构隧道施工第一阶段分析模型和第二阶段分析模型，探明了支护措施对于管片衬砌结构-围岩的相互作用关系的影响，形成大埋深盾构隧道的支护措施体系，并开展了管片衬砌与可压缩层联合支护的模型试验和现场实测，揭示了围岩形变压力作用下联合支护结构体系的受力特征与形变规律。其次，从管片自身的支护特性、承载力及变形性能等角度研发可用于软弱破碎岩层，并具有可控变形能力的新型管片衬砌结构，采用数值模拟手段探明了盾构隧道管片纵缝“DDCI+斜螺栓”新型连接构造的力学行为以及钢包咬合式接头的性能，并开展了管片接缝弯、剪试验，研究了管片接头部位的力学特征和破环特征。最后，开展盾构隧道管片结构原型破坏试验，对比分析了盾构隧道通缝拼装与错缝拼装管片衬砌的破坏形态，从整体评价和局部评价两方面分别建立结构承载性能评价指标，并结合试验数据对其承载性能进行了评价。研究成果直接应用于广佛环线东环隧道大源~太和区间大埋深盾构隧道、滇中引水工程龙泉倒虹吸隧洞大埋深盾构隧道、新疆EH输水隧洞大埋深盾构隧道结构分析与管片设计中，并可为类似大埋深盾构隧道的支护结构设计与安全评价提供重要参考。