东山公路隧道开挖支护过程数值分析研究

Numerical Analysis of Excavating and Supporting Dongshan Highway Tunnel

应用有限元分析软件MIDAS/GTS,采用地层结构法分析了东山公路隧道开挖支护过程中的稳定性问题。分析结果表明,开挖不同断面过程中,围岩内最大主应力集中在钢架脚部,钢架架设时应及时施工锁脚锚杆,必要时可采用小导管注浆等方法对拱架脚部围岩进行加固;从衬砌变形角度分析,变形量最大处为拱顶下沉及底脚位置,施工中应注意对拱顶沉降的监测,逐步开挖核心土,保证施工及结构安全,同时应及时施作基础工程,以控制洞室变形;围岩最不利位置出现在拱顶及仰拱两侧,应是重点加强部位。

The stability during excavating and supporting Dongshan Highway Tunnel is analyzed using layer structure method and finite element software MIDAS/GTS.The result shows： during excavating various section,the maximum principal stress concentrates in the feet of steel frame,the locking-feet anchor should be constructed in time when steel frame is erected,the wall rock at the feet of arch could be reinforced through slip casting by ductules when necessary;the maximum distortion of lining is at the sinkage of vault and bottom,the settlement of vault should be monitored in construction and the core soil should be excavated step by step to ensure the safety of construction and structure,meanwhile the foundation work should be constructed in time in order to control the distortion of cavern;the most disadvantageous location of wall rock is vault and both sides of inverted arch,which is the key position deserving reinforcement.