泥质软岩隧道穿越富水断层带初期支护变形侵限机理及处治对策

Support Deformation Induced Clearance Invasion and Treatment for a Pelitic Soft-Rock Tunnel Passing through a Water-Rich Fault Zone

南广高铁泥质软岩北岭山隧道出口端穿越F_(10)富水断层带,发生严重初期支护变形侵限,现场采取一系列处治措施但未有成效。针对此情况,文章首先分析了初期支护变形侵限演化全过程及隧道宏观表征,随后从不良地质、地下水与泥岩耦合循环作用、隧道结构、原设计与施工方案四个方面对初期支护侵限原因展开分析,并结合灾变期监控量测实测数据,对穿越富水断层隧道初期支护侵限机理展开进一步挖掘,最后在掌握初期支护侵限机理的基础上,提出切实可行的北岭山隧道穿越富水断层初期支护侵限"洞内+洞外"综合处治方案,并基于数值模拟对处治方案的关键——换拱环节进行计算,获取最优换拱参数。采用此处治方案后,隧道出口端成功穿越富水断层带,该研究思路及处治对策能够为隧道穿越富水断层带初期支护变形侵限提供理论及现场实际借鉴。

Serious initial support deformation occurred when the exit of the Beilingshan tunnel on the Nanning- Guangzhou railway passed through a water-rich fault zone in pelitic soft rock, and a series of countermeasures were adopted at the site, but they failed. Regarding this situation, the whole evolution of the initial support induced clearance invasion and the macroscopic characteristics of tunnel were analyzed, then further analysis and research was carried out regarding the reasons and mechanism of clearance invasion for tunnels passing through water-rich fault zones in terms of unfavorable geology, the coupling cycle of underground water and mudstone, tunnel structure, original design and construction scheme based on the actual measured data. Comprehensive schemes for the inside tun- nel and outside tunnel were proposed. By way of numerical simulation, a calculation regarding arch replacement was carried out and the relative optimum parameters were obtained. With this treatment scheme, the exit end of the tunnel successfully passed through the water-rich fault zone, which provides a theoretical and practical references for similar tunnels regarding initial support deformation induced clearance invasion.