拱腰溶洞大小对隧道围岩和初期支护的影响研究

Study on the Influence of the Size of the Karst Caves at the Arch Waist on the Tunnel Surrounding Rock and Initial Support

隧道建设中通常会遇到岩溶、地下水等地质环境,岩溶水环境会对隧道的施工和运营安全造成严重威胁。隧道开挖方法、岩溶处置方式不当和施工质量不达标将导致隧道局部偏压、坍塌等安全事故的发生。以云南省威信县下坝隧道为研究背景,采用有限元分析软件Midas GTS NX对隧道右拱腰处存在的不同洞径溶洞进行数值模拟,探讨隧道围岩中渗流场、应力场和位移场的相互作用与相互影响。基于围岩应力、位移、支护结构内力分析发现,应加强对隧道墙脚和拱腰处的开挖控制,以提高隧道初期支护不利断面上的安全性,确保隧道衬砌结构的安全。

During tunnel construction,geological environments such as karst and groundwater are often encountered,which pose a serious threat to the construction and operation safety of tunnels.Inappropriate tunnel excavation methods,as well as karst disposal methods,and substandard construction quality will lead to safety accidents such as local partially pressure and collapse in the tunnel.Taking the Xiaba Tunnel in Weixin County,Yunnan Province as the research background,the finite element analysis software Midas GTS NX was used to numerically simulate the existence of karst caves with different diameters at the right arch waist of the tunnel,exploring the interaction and influence of seepage field,stress field,and displacement field in the surrounding rock of the tunnel.Based on the analysis of surrounding rock stress,displacement,and internal forces of the support structure,it is found that excavation at the foot of the tunnel wall and arch waist should be controlled to improve the safety of unfavorable sections in the initial support of the tunnel and ensure the safety of the tunnel lining structure.