【摘要】 中老铁路友谊隧道穿越盐岩地层，石盐含量高达80%，国内外罕见。隧道穿越盐岩地层时发生了较为严重的开裂、底鼓和变形等病害。结合现场补勘及监控量测，对衬砌开裂和变形机理进行了深入研究。研究结果表明：（1）盐岩段衬砌开裂和变形主要是由盐岩重结晶作用产生的膨胀力引起；（2）重结晶易发生在初支与二衬间空隙、初支与围岩间的空隙、离开挖轮廓距离较近的围岩裂隙内；（3）重结晶作用的发生程度与盐岩含量和地下水发育程度紧密相关；（4）对仅施作矮边墙及仰拱段落，随着膨胀力的增大表现出不同的受力状态；对于全环衬砌地段，当膨胀力大于126 kPa时，衬砌将出现开裂破坏；（5）对于盐岩段衬砌，应重点控制地下水流动，防止盐岩重结晶发生，同时采用圆形以结构加强，以防止隧道开裂变形。更多还原

【Abstract】 Youyi Tunnel of China-Laos Railway traverses the halite formations with an exceptionally high halite content of up to 80%,which is rare both in and out of China. In the halite formations,significant issues such as cracking,bottom heave,and deformation occurred in the tunnel. Through on-site surveys and monitoring measurements,a comprehensive study was conducted on the mechanism of lining cracking and deformation. The findings are as follows:(1)Lining cracking and deformation in the halite section are primarily caused by the expansive force generated by halite recrystallization.(2)Recrystallization tends to occur in the gaps between the initial support and the second lining,gaps between the initial support and the surrounding rock,and cracks in the surrounding rock located close to the excavation contour.(3)The degree of recrystallization is closely related to the halite content and the extent of groundwater development.(4)In sections with only low sidewalls and arch invert,different stress states are observed as the expansive force increases. In fully lined sections,when the expansive force exceeds 126 k Pa,lining cracking and failure will occur.(5)Measures for the halite section should focus on controlling groundwater flow to prevent halite recrystallization.Additionally,a circular reinforcement structure should be employed to strengthen the tunnel and prevent cracking and deformation.更多还原