红粘土隧道初期支护结构沉陷开裂机理分析与处治对策

摘要

渝黔铁路青冈山隧道穿越红粘土地层，施工中出现初期支护结构大变形及大面积开裂的问题。文章对青冈山隧道的地层条件以及初期支护结构变形过程进行了系统分析，探讨了初期支护结构沉陷开裂的原因与机理，并在此基础上提出了径向管棚注浆、初期支护加强、挑顶换拱相结合的综合处治对策。实践表明，该处治对策是合理有效的，对类似地质区隧道沉陷开裂处治具有参考价值。%Large deformation and large-area cracking of the primary support structure occurred during construc⁃tion of the Qinggangshan tunnel on the Chongqing-Guizhou Railway passing through a red clay stratum. In order to solve these problems, a systematic analysis is conducted on the terrain conditions and the deformation process of the primary support structure of the Qingganshan tunnel, the cause and mechanism of its settlement and cracking are ex⁃plored, and a comprehensive treatment is proposed that combines radial pipe-roof grouting, primary support strengthening, roof ripping and arch replacement. Practices prove that the treatment is reasonable and effective.