富水软岩隧道跨越断层段塌方机制分析及处治措施

 针对沪昆客运专线长昆湖南段油坊坪隧道跨越断层段遭受的塌方问题，总结隧道宏观变形演化历史，分析跨越断层富水软岩隧道塌方的影响因素及围岩失稳破坏模式，据此提出针对性的处治措施。分析结果表明：地质构造和地下水的协同作用对本次隧道塌方的影响最为显著，大气降水在一定程度上促进了隧道塌方的形成，施工工法和支护措施对本次隧道塌方的影响体现为人为认识的不足，多因素的共同作用促成了本次塌方的发生；跨越断层区富水软岩隧道围岩的失稳模式可归结为弯曲内鼓和顺层滑移相结合的协同破坏模式；在分析隧道塌方机制的基础上提出“洞内+洞外”的综合处治措施，具有较强的实效性和针对性，从根本上防止塌方的发生。该研究成果可为富水软岩隧道跨越断层的设计和施工提供工程类比的素材，具有重要的工程意义。

Collapse mechanism and treatment measures for tunnel in water-rich soft rock crossing fault

With respect to the collapse of Youfangping tunnel crossing fault at Changsha to Kunming Section in Shanghai to Kunming High-speed railway of China，the macroscopical history of the tunnel deformation was summarized，and the influencing factors of the collapse in water-rich soft rock tunnel crossing fault and the surrounding rock failure mode were analyzed. The treatment measures were proposed. The results showed that the synergistic effect of geological structure and groundwater had the most significant influence on the tunnel collapse，and to some extent，the atmospheric precipitation promoted the tunnel collapse. The impact of construction methods and supporting measures on the tunnel collapse reflected the insufficiency of knowledge. It was a combination of multiple factors that contributed to the tunnel collapse. The surrounding rock failure mode of water-rich soft rock tunnel crossing fault was concluded as the synergistic failure mode of flexural deformation and bedding slippage. Based on the analysis of tunnel collapse mechanism，the comprehensive treatment measures inside and outside tunnel were proposed to prevent the occurrence of collapse effectively.