考虑隧道开挖时间影响的一种支护结构计算方法

基于硬化土模型，针对公路山岭隧道的初期支护结构，建立地层结构法数值模型，分析初期支护结构在施工过程中的安全性。由于隧道开挖的时空效应影响显著，采用二维平面应变模型的关键因素是如何确定围岩的应力释放系数，通过结合土体反力曲线（ＧＲＣ）及纵面变形曲线（ＬＤＰ），推导出支护结构不同施工阶段的应力释放系数，并采用内力包络图来分析每一施工步支护结构是否安全。所述方法在满足隧道精细化设计的同时，便捷有效，对隧道设计和施工有重要的指导意义。

A Support Structure Calculation Method Considering the Influence of Tunnel Excavation Durataion

An embedded frame analysis with hardening soil constitutive model was established to analyze the safety of highway tunnel’s initial support during construction. Due to the significant effect of the spatial and temporal effects during tunnel excavation, the key factor is how to determine the stress reduction coefficient if two-dimensional plane strain model was adopted. In this paper, stress reduction coefficient of each construction phase was deduced based on ground reaction curve and longitudinal deformation profile, and envelope diagrams of internal forces were adopted to verified structure safety in each construction phase. The results show that this method is convenient and effective to satisfy the detailed design of tunnels, and it is significant for tunnel design and construction.