地表超载作用下既有盾构隧道附加土压力计算方法研究

Deformation and service state of shield tunnel in the operation stage in soft soil area were investigated, and it had shown that the current calculation theory of the earth pressure acting on shield tunnel caused by surcharge is not in conformity with engineering practice. According to the character of tunnel deformation and ground movement, mechanism of the interaction between tunnel and ground is analyzed, and computational method for relative squeezing on surrounding earth caused by tunnel is proposed. According to the relationship between the additional earth pressure and the relative squeezing on surrounding earth caused by tunnel, the change laws of the earth pressure on the tunnel and influencing factors are explored. Besides, influencing mechanisms of factors are clarified. Under the surcharge, computational model of the deformation for tunnel and compressive deformation of soil are established. Solving equation set, which was established basing on relationships of co-deformation and interaction between tunnel and its surrounding earth, analytic computation methods for tunnel deformation and additional earth pressure on tunnel induced by the surcharge are obtained. At last, referred to results of model test and site investigation, analytic computation methods are verified. Correcting the analytic computation method, corresponding practical calculation software is obtained. Achievements obtained in this research provide theoretical references for the design of shield tunnel and the maintenance of the operation tunnel.

软土地区运营期地铁盾构隧道变形与服役状态的调研与分析表明，对于地表超载对既有盾构隧道的影响，现有的分析计算理论与工程实际不符。本研究根据地表超载作用下盾构隧道变形特性与地层位移特性，对隧道与地层的相互作用机理展开分析，并提出隧道对周围土体相对挤压的计算方法。根据隧道周围附加土压力与隧道对周围土体的相对挤压量之间的关系，探明地表超载过程中隧道周围附加土压力的变化规律与影响因素，并阐明各影响因素的影响方式。建立地表超载作用下隧道变形的结构力学计算模型与隧道周围土体的压缩变形计算模型，根据隧道与地层的共同变形关系与相互作用关系构建方程组，通过求解方程组从而获得地表超载导致的隧道变形与隧道周围附加土压力的解析计算方法。最后通过模型试验与现场调研结果，对解析计算方法进行验证，修正后再形成相应的工程实用计算软件。研究成果为盾构隧道的设计、运营期周边环境的管控提供理论依据。

软土地区运营期地铁盾构隧道变形与服役状态的调研与分析表明，对于地表超载对既有盾构隧道的影响，现有的分析计算理论与工程实际不符。课题根据地表超载作用下盾构隧道变形特性与地层位移特性，对隧道与地层的相互作用机理展开了分析，并提出了隧道对周围土体相对挤压的计算方法。根据隧道周围附加土压力与隧道对周围土体的相对挤压量之间的关系，探明了地表超载过程中隧道周围附加土压力的变化规律与影响因素，并阐明各影响因素的影响方式。建立了地表超载作用下隧道变形的结构力学计算模型与隧道周围土体的压缩变形计算模型，根据隧道与地层的共同变形关系与相互作用关系构建方程组，通过求解方程组从而获得了地表超载导致的隧道变形与隧道周围附加土压力的解析计算方法。最后通过模型试验与现场调研结果，对解析计算方法进行验证，并形成了相应的工程实用计算软件。研究成果为盾构隧道的设计、运营期周边环境的管控提供理论依据。