当金山特长隧道设计方案研究

在高原、高寒地区修建单线单洞特长隧道,面临隧道勘察选线、施工方法选择、长距离通风、深竖井施工、生态脆弱区环境保护以及低氧环境下施工等一系列世界性技术难题。结合敦煌至格尔木铁路当金山特长隧道的设计全过程,对特长隧道的勘察设计进行全方位介绍。针对当金山特长隧道"三高(高海拔、高地应力、高地震烈度)"、"两低(气温低、气压低)"的地域特点,以及"三长(单面坡长、独头通风距离长、反坡排水距离长)"、"两多(断层破碎带多、不良地质多)"、"两大(埋深大、水量大)"等工程特点,对"钻爆法、TBM法、钻爆法+TBM法"3种施工方案进行系统的经济技术比选,最终确定大型机械配套的钻爆法施工方案。最后对单线铁路特长隧道的设计与施工提出了一些建议:1)特长隧道选线时重视物探技术;2)处理好勘察与设计的关系;3)高海拔特长隧道应加大机械化施工;4)特长隧道应充分发挥平行导坑的作用;5)重视环境设计。

Case Study on Design of Dangjinshan Super-long Tunnel on Dunhuang-Golmud Railway

For super-long single-tube single-track railway tunnels in extremely-cold high-plateau area,world-level technological challenges in surveying and alignment selection,construction method selection,long-distance dead-end ventilation,deep vertical shaft sinking,ecologically-fragile environment protection and tunneling in low-oxygen environment are faced. In the paper,the design of super-long Dangjinshan tunnel on Dunhuang-Golmud railway is presented. Dangjinshan tunnel has the following characteristics： 1） high altitude,high ground stress and high seismic intensity; 2） low temperature and low atmospheric pressure; 3） long single-direction slope,long-distance dead-end ventilation and longdistance anti-slope water releasing; 4） lots of fractured zones and lots of adverse geological units; 5） deep cover and serious water inflow. Comparison and contrast is made among three construction methods considered for the tunnel,i. e., drill and blast method,TBM method and ＂drill and blast ＋ TBM＂method,in terms of economy and technology,and drill and blast method assisted by heavy-duty construction equipment and machinery is proposed for the tunnel. Finally, the following advice is made on the design and construction of super-long single-track railway tunnels： 1） More attention should be paid to the geophysical prospecting technology in the selection of the alignment of super-long tunnels; 2） The relationship between the survey and the design should be well dealt with; 3） Mechanized construction should be adopted for super-long tunnels in high-plateau area; 4） The function of the parallel service gallery should be fully used; 5） More attention should be paid to the design of the environment protection measures.