特大断面隧道长期运营预警值的研究

Study on Long Term Warning Value of Super Large Section Tunnel

以特大断面隧道—广州龙头山隧道为研究对象,致力于研究特大断面隧道运营期预警值的确定问题。首先在探讨大跨度隧道围岩变形规律的基础上确定了以拱顶下沉作为运营预警值的主要参数。然后以荷载-结构法为基础,采用有限元法,利用ADINA软件确定衬砌结构极限状态所对应的结构状态量(包括衬砌混凝土开裂、衬砌钢筋屈服),在考虑一定的安全系数后,为龙头山隧道运营阶段的不同围岩段确定了预警值。利用有限元法虽不能全面反映隧道现阶段的受力状态,但能以最不利的工况计算衬砌结构的极限状态,得到的预警值具有明显的参考价值。

This paper focuses on warning value of super large section tunnel. Long Tou Shan Tunnel was the subject investigated. First, main parameter of warning value was researched based on deformation regularity of adjacent rock of super large section tunnel, and arch crown settlement was decided to be the main parameter of warning value. Then, based on load--structure theory, finite element method was used to analyze the mechanical state values, including lining concrete cracks and yield point of steel bar, in ultimate state. After considering safety factor, warning values of Long Tou Shan Tunnel were decided. The finite element method can not roundly reflect the mechanical state of one tunnel, but it can analyze ultimate state in the worst work condition.