大伙房输水工程特长隧洞TBM选型及施工关键技术研究

Study on TBM Type-selection and Key Technologies in Dahuofang Water Diversion Tunnel

大伙房输水工程隧洞长85.32 km,开挖洞径8.03 m,属于深埋特长隧洞。隧洞施工采用以TBM为主、钻爆法为辅的联合施工方式。隧洞穿越区域水文地质条件复杂,开挖中面临的主要工程地质问题有围岩稳定性、隧洞涌水、石英砂岩的掘进效率及岩爆等三大关键技术难题。文章通过对大量文献资料和工程实例的研究,概述了TBM近一个世纪的发展及其在隧道建设中的应用现状和主要问题。通过对大伙房特长隧洞所穿越区域的地质条件以及主要工程地质问题进行分析,并结合国内外已有的TBM施工经验,以及对特长隧洞TBM选型进行分析,决定选用锚喷支护+模筑混凝土复合衬砌结构支护系统代替管片衬砌结构,采用连续皮带机高速度出碴、TBM掘进独头长距离施工通风以及TBM洞内组装和检修等技术,对大伙房输水工程特长隧洞高速度、高标准、高质量的建成发挥了重要的保证作用,也可为今后类似工程提供参考和借鉴。

Dahuofang water diversion tunnel has an excavation diameter of 8.03m and a length of 85.32km with large overburden.TBMs were employed for the main driving supplemented with drill and blast.The hydro-geological conditions along tunnel alignment were very complicated.Three key problems were met with in tunneling,i.e.stability of mass rock,water gushing,tunneling advance rate and rockburst in quartz sandstone.Based on the study of a large amount of data and project cases of TBM application,a brief summary about the development of TBM and its application and the encountered problems is presented in this paper.Considering regional geological conditions,main engineering geological problems and the experience in TBM driving at home and abroad,comparison and selection between open type and double-shield TBMs for this long tunnel project are described.It was decided to adopt composite lining structure made up of shotcrete and in-situ concrete lining instead of segment lining for entire length of the tunnel.Continuous conveyor mucking system,long distant ventilation,TBM assembly and maintenance in the tunnel and underground chambers were also employed in the project.These key technologies played an important role in Dahuofang tunnel construction.Hopefully the practice would be of reference value for similar tunnel projects in the future.