强震区软弱破碎千枚岩隧道系统锚杆支护作用效果分析  

Analysis of supporting effect of systematic bolts applied to weak and broken phyllite tunnels in meizoseismal area

作　　者：邹育麟[1] 何川[1] 周艺[1] 汪波[1] 许金华[1,2] 

机构地区：[1]西南交通大学交通隧道工程教育部重点实验室土木工程学院,成都610031 [2]四川高速公路建设开发总公司,成都610041

出　　处：《岩土力学》2013年第7期2000-2008,共9页Rock and Soil Mechanics

基　　金：国家科技支撑计划课题(No.2012BAG05B03);国家973计划(No.2010CB732105);国家杰出青年科学基金项目(No.50925830);中央高校基本科研业务费专项资金资助(No.SWJTU11ZT33;No.SWJTU12CX66);四川省交通科学技术项目(No.2008.1-1-1)

摘　　要：以在建的穿越5.12强震区发震断裂带的广甘高速公路杜家山隧道为工程依托,选取20 m典型围岩区段为试验段,对有、无系统锚杆时的洞周位移、锚杆轴力、钢拱架内力、围岩与初支接触压力、及其二衬内力进行实测对比分析,探讨锚杆支护作用效果不明显的成因,提出了在强震区软弱破碎千枚岩隧道围岩中采用"钢喷"初期支护的支护方案。研究结果表明:设置锚杆的断面,其锚杆轴力值较小,最终洞周变形值及围岩与初支的接触压力值相对偏大,钢拱架和二衬的安全储备相对不足;锚杆的施工不仅在某种程度上加剧了对深部围岩的扰动,而且还延误了喷射混凝土和钢支撑支护对暴露围岩及时封闭的最佳时机;震后深部围岩的震裂损伤和震裂岩体地下水的渗透性增强,致使围岩松弛区域超过了锚杆设置范围,且锚杆与围岩间的黏结力被削弱。Choosing 20 meters long tunnel with typical wall rock condition as the subject of study,which is a part of the Dujiashan tunnel belongs to the Guang-Gan Expressway and located in the earthquake fault zone of the 5.12 meizoseismal area,and comparing the follow items when there exists systematic bolts or not,including displacement of tunnel inner perimeter,axial force of the bolts,internal force of the steel arch truss,pressure between wall rock and preliminary support,and the internal force of second lining are analyzed.The essay also discusses why the bolts support effect is not evident and proposes to adopt the preliminary support method which is jet steel in broken phyllite tunnel in meizoseismal area.The research shows： for tunnels with bolts,axial force of the bolt is smaller;the final displacement of tunnel inner perimeter and the pressure between the wall rock and preliminary support are large relatively;the safety stock of the steal and second lining is not enough.The process of applying bolts will disturb the deep wall rock to some degree and miss the best time to apply the shotcrete and steel arch truss to support the weak and broken phyllite tunnel.What’s more,the damage to the deeper wall rock and the penetrability of the broken rock mass increase,which result in that wall rock relaxation region exceeds bolt setting range and the cohesive force between bolts and wall rock decreases.

关 键 词：隧道工程 软弱破碎围岩 现场试验 系统锚杆 强震区 支护作用效果 

分 类 号：U455[建筑科学—桥梁与隧道工程]