盾构隧道衬砌截面的承载能力功能函数

Functions for the Bearing Capacity of Lining Cross-section of Shield Tunnel

研究目的:盾构隧道衬砌管片为偏心受压构件,存在正截面大偏心受压、小偏心受压以及斜截面受剪等失效模式。以往的研究中给出了典型条件下弯矩表达或轴力表达的正截面承载能力功能函数,但并不能全面表征衬砌管片的工作模式。本文从盾构隧道衬砌管片承载能力和内力的解析式出发,提出适用于普遍情况的正截面偏心受压承载能力功能函数和斜截面抗剪承载能力功能函数的多种表达形式,为正确计算截面承载能力可靠度提供条件。并在此基础上评价管片截面承载能力功能函数的敏感性因素。研究结论:通过研究建立了盾构隧道衬砌正截面承载能力和斜截面承载能力的功能函数,提出了大小偏心状态的正截面承载能力解析表达式和斜截面抗剪承载能力的解析表达式,并通过实例对影响承载能力功能函数的随机变量进行了敏感性分析,得出如下结论:对于正截面承载能力,当采用不同表达形式的功能函数时,功能函数对随机变量的敏感性是不同的;PV对拱顶截面的正截面承载能力功能函数影响最大;ft对拱腰截面的斜截面承载能力功能函数影响最大。

Research purposes： The duct piece for shield tunnel lining is an eccentric pressed component with failure modes of the pressures on the big and small eccentric centers of the head - on cross - section and the shearing force on the oblique section. The functions expressed by moment of flexion or axial force for the bearing capacity of head - on cross - section under typical condition were given in the previous study, but they can not fully attribute the working mode of the duct piece. This paper offers many expressions for the functions used for the bearing capacity of the pressures on the eccentric center of the head - on cross - section and the shearing resistance of the oblique section based on the analytic formulas for the beating capacity and inner force of the duct piece for the shield tunnel lining in order to provide the reliability for calculating the bearing capacity of the cross - section, and evaluates the sensitive factors of the functions for the bearing capacity of the cross - section of the duct piece. Research conclusions：With establishing the functions for the bearing capacities of the head - on cross - section and oblique section of the shield tunnel lining, the analytic formulas for the bearing capacity of head - on cross - section with big and small eccentric center and shearing resistance of oblique section are offered. The sensitive analyses of the random variations of the functions for bearing capacity are made with an example. It is concluded for the bearing capacity of the head - on cross - section, the sensitivity of random variations is different when using the functions with different expressions, the Pv has the biggest influences on the functions for the bearing capacity of head - on cross - section on the arch top, and the ft has the biggest influence on the functions for bearing capacity of the oblique section on the arch web.