关角高风险隧道富水环境下施工降效技术经济分析

Techno-economic Analysis of Construction Efficiency Reduction of Guanjiao Tunnel in Water-rich Strata

在岩溶地区或地下水补给丰富地质区域进行隧道施工时,时常会出现突泥和涌水等地质灾害现象,导致施工进度缓慢和资源投入增加。富水环境(涌水量在5 000 m^3/d以上)下施工引起的人工、机械降效和部分支护材料、喷射混凝土等材料消耗增加,在现行定额标准中没有涵盖,概预算编制过程中由于依据不充分,经常导致投资不准和投资变更较为困难等现象的发生。以西格二线关角隧道1~#—6~#斜井及担负的正洞为研究对象,分别在实际富水环境以及正常环境下施工,在完成相同工作内容和工作量的前提下,跟踪、调查、收集数据并建立数据对比模型,量化人工、部分初期支护材料和机械台班消耗量,得出:1)富水环境较正常环境人工、机械以及初期支护综合降效系数;2)富水环境喷射C20素混凝土、C25纤维混凝土回弹量较现行定额增加幅度,并给出其适用范围,为富水工程项目设计及变更提供参考。

The construction efficiency would be reduced and the cost would be increased due to water burst and mud gushing when the tunnel crosses karst areas or water-rich strata. The construction efficiency reduction of labor and machinery and increasing of construction materials of tunnel construction in water-rich environment are not included in existing norm standards. Investing difficulties will be met due to insufficiency of references during budget estimation compilation. Analysis is made for comparison between data model,material and shift consumption of tunneling in waterrich environment and those of tunneling in normal environment,by taking inclined shaft No. 1 to inclined shaft No. 6and related main tunnels of Xining-Golmud 2nd Line of Guanjiao Tunnel for example. The comprehensive construction efficiency reduction coefficient of labor,machinery and primary support in water-rich environment to that in normal environment is obtained. The rebound amplification of concrete C20 and fiber concrete C25 in water-rich environment to that in normal environment is obtained as well.