城市深隧排水系统盾构隧道结构力学特性研究

At present the majority of urban drainage pipe network in China has been unable to meet the development needs of the urban. Renovating, expanding and new building drainage systems have become very urgent tasks. Guangzhou, Wuhan and other cities have proposed the construction of deep drainage tunnel project. However, similar projects and relevant research at domestic and overseas are rare. Based on the characteristics of shield tunnel for urban deep tunnel drainage system, that deep burial and high internal and external water pressure, in this project the interaction mechanism between the structure and surrounding rock for deep buried tunnels have been explored, and the load model of the shield tunnel under the combined effects of the external water soil load and the internal water pressure has been established. The effects of the lining type, block mode, assembling mode, lining thickness and width on the mechanical behavior have been studied, then the structure type of the shield tunnel suitable for urban deep tunnel drainage system has been put forward. The internal forces, deformation and destruction law of the segment joint have been investigated, then the joint form of the shield tunnel adapted to the high water pressure has been proposed. The structure mechanical behavior of the shield tunnel under the three typical working conditions, including the construction period, normal operating period, and deterioration corrosion period have been studied, then the carrying capacity and long-term safety have been revealed. The research results will offer theoretical bases and practical approaches to the structural optimization design of shield tunnel for urban deep tunnel drainage system.

目前我国大多数城市的排水管网已经不能满足城市发展需要，改建、扩建和新建排水系统迫在眉睫，广州、武汉等城市相继提出了建设深隧排水系统工程，但国内外类似工程和相关研究鲜少。本项目针对城市深隧排水系统盾构隧道的深埋、内外高水压特点，探明深埋隧道结构与围岩间的相互作用机理，建立外水土压力和内部水压联合作用下的盾构隧道荷载模式；探明衬砌型式、管片分块方式、拼装方式、衬砌厚度及幅宽等对结构力学性能的影响，提出适合于城市深隧排水系统盾构隧道的结构型式；探明管片接头的受力、变形和破坏规律，提出适应于内外高水压条件的盾构隧道接头形式；探明施工期、正常运营期以及腐蚀劣化期3种典型工作状态的盾构隧道结构力学性态，揭示其承载能力和长期安全性。研究成果将为城市深隧排水系统盾构隧道的结构优化设计提供理论依据和实用方法。

近年来，我国北京、上海、成都、广州、武汉等城市相继提出了建设深隧排水系统工程，广州试建成了东濠涌排水深隧，武汉已经建成运营大东湖污水深隧，但国内外类似工程尚少。国内外盾构隧道的相关理论研究主要针对交通隧道，而对城市深隧排水盾构隧道的研究也鲜少。本项目以内径为3m的城市深埋排水盾构隧道为工程研究对象，围绕其结构力学特性展开研究。采用理论分析的方法，研究了施工期、运营期不同阶段的隧道外水土荷载和内部水压的荷载组合工况，以及管片和二衬的荷载分担情况，探明了深埋隧道结构与围岩间的相互作用机理，建立了深埋排水盾构隧道的结构荷载模式。采用模型试验和数值模拟两种方法，研究了衬砌型式、管片分块方式、拼装方式、衬砌厚度和幅宽对结构力学性能的影响，提出了适合于深埋、内外高水压条件下盾构隧道的管片结构型式，明确了结构关键设计参数。对管片接头进行了原型加载试验，并与数值模拟的结果进行了对比研究，探明了施工期、运营期不同工作阶段的盾构隧道管片接头受力、变形和破坏规律，获得了各工作阶段的接头抗弯刚度，接头张开量等参数，提出了适应于内外复杂环境联合作用下深埋盾构隧道的管片接头形式。分析了隧道施工期、正常运营期工作状态的管片和二衬的受力、变形，开裂以及接缝的张开等，探明了内水压对管片和二衬弯矩、轴力的影响，揭示了其结构承载能力。本项目的研究成果可为我国城市深隧排水系统盾构隧道的结构优化设计提供理论依据和实用方法，并已在武汉污水深隧盾构隧道的施工和设计中得以应用。