基于修正纵向等效连续化模型的隧道变形受力研究

及时掌握隧道结构变形受力情况对于保证地铁运营安全意义重大。通过增加考虑横向刚度、环缝作用范围和螺栓预应力的影响,建立了新型的盾构隧道修正纵向等效连续化模型,据此提出了弹、塑性状态下隧道纵向等效抗弯刚度、极限弯矩以及最大环缝张开量的计算方程；以上海地铁二号线为工程背景,分析了横向刚度和环缝作用范围对隧道等效抗弯刚度的影响规律；之后建立了5类隧道结构临界状态下隧道纵向曲率半径、接缝张开值、管片应力、螺栓拉力的求解公式,并求得了对应的界限指标,所得指标值可作为隧道健康状态诊断的依据。

Deformation and stress of tunnel structures based on modified longitudinal equivalent continuous model

It is of great importance for guaranteeing the metro operation safety to promptly grasp the condition of deformation and stress of tunnel structures. A new modified longitudinal equivalent continuous model for shield tunnels is established based on the conventional one by taking into consideration the lateral rigidity, influence scope of annular gap and bolt pre-stress. Subsequently the equations for solving the equivalent longitudinal bending stiffness, the ultimate moment of tunnel and the maximal amount of joint opening under elastic and plastic states are derived respectively using to the modified model. Based on the engineering practice of Shanghai metro line 2, the influence laws of lateral rigidity and influence scope of annular gap on the equivalent longitudinal bending stiffness are analyzed. Finally, the formulae for longitudinal curvature radius, joint opening, segment stress and bolt tension are proposed according to five critical conditions of tunnel structures, and the corresponding critical indexes which can be used to diagnose the tunnel health are obtained.