TBM施工深埋水工长隧洞围岩综合分类研究

目前常用的水工隧洞围岩分类方法主要是在浅埋隧洞和钻爆法施工的基础上建立的,在隧道掘进机(TBM)施工的深埋水工长隧洞应用中存在不足。在对国内外常用的围岩分级和分类方法进行统计的基础上,结合深埋水工长隧洞的特点以及TBM施工中可能遇到的主要地质问题进行分析,选取了围岩稳定性、高地应力风险、地下水风险和TBM施工围岩可掘性等作为评价隧洞围岩性质的主要因素,提出了一种既能描述隧洞围岩稳定性,又能描述地质风险类型及等级的TBM施工深埋水工长隧洞围岩综合分类方案。该方法已在新疆某输水工程中进行实践应用,取得了良好的应用效果。研究成果可为深埋水工隧洞开挖和支护设计提供技术支撑,为TBM选型及施工中可能遭遇的地质风险采取处理针对性措施提供依据。

Comprehensive Classification of Surrounding Rock of Deep BuriedLong Hydraulic Tunnel Constructed with Tunnel Boring Machine

Commonly applied methods of classifying the surrounding rock of hydraulic tunnels are based on the construction of shallow buried tunnels and drilling and blasting. Such classifications show poor adaptability to deep buried long hydraulic tunnels constructed with tunnel boring machine (TBM). On the basis of classification methods in China and abroad, we propose a comprehensive classification method which describes not only the surrounding rock stability, and also the types and levels of geological risks for deep buried long hydraulic tunnels constructed with TBM. According to the characteristics of deep buried long hydraulic tunnels and the main geological risks that may be encountered during TBM construction, we select some major assessment factors inclusive of surrounding rock stability, high geostress risk, groundwater risk, as well as excavability. The proposed method is applied to a water conveyance project in Xinjiang and has achieved good result. The research offers technical support for the excavation and support design of deep buried hydraulic tunnel, and also can be regarded as a basis for targeted treatment of possible geological risks during TBM construction.