中文摘要：

以连云港北固山隧道为工程背景,利用有限元分析软件,分析了隧道开挖后在不同荷载释放系数下施加支护的作用效果;同时,结合超前注浆加固机理,对施作超前支护与不施作超前支护两种工况在不同支护时机下施作初期支护的围岩及支护结构的力学特征进行了对比分析,并根据两种工况下支护时机对隧道开挖后围岩及支护结构力学特征的影响,初步确定了较理想的初期支护时机。

英文摘要：

Based on the Beigushan Tunnel,this paper analyzes the support effects on a tunnel under different load release factors.Combined with the mechanism of advanced grout reinforcement,the stability of rock mass and mechanical features of the support structure were comparatively analyzed considering the different support times in the case of advanced grouting or without advanced grouting.The best time for primary support is proposed.