隧道型钢拱架打孔对其刚度影响分析  

Influence of Perforation in Steel Arch on Structural Stiffness

作　　者：王玥[1] 史继尧[1] WANG Yue;SHI Jiyao(Survey Design and Research Institute of China Railway Tunnel Group Co.,Ltd.,Guangzhou 361006)

机构地区：[1]中铁隧道集团有限公司勘测设计研究院

出　　处：《现代隧道技术》2019年第3期118-124,共7页Modern Tunnelling Technology

摘　　要：在软弱围岩隧道施工中常采用型钢拱架进行支护,但当拱架间距小于1m时,施作超前小导管的外张角难以控制。为减小超前小导管外张角,现场施工中采用了型钢拱架腹板打孔的方法。文章通过建立拱架三维模型,计算了不同打孔范围、不同打孔密度情况下拱架的变形情况,研究了型钢拱架腹板打孔对拱架和支护体系的刚度影响。结合现场对比试验,根据初期支护变形、围岩压力和拱架内力的实测情况,提出打孔间距是影响拱架刚度的主要因素。在本工程条件下拱架腹板打孔的安全间距为40cm及以上,其对拱架刚度的削弱程度小于4%,对整个初期支护体系的刚度几乎没有影响。Steel arch is often used as supporting element in soft rock tunnelling,while it is difficult to control the external angle of advanced condulet when the distance between two rows of steel arch is less than 1 m.In order to reduce the external angle,perforation in web of steel arch was conducted during site construction.A 3 D model was established to calculate the deformation of steel arch under different ranges and densities of perforation,and the influence of perforation on stiffness of steel arch and support system was studied.In light of the results of contrast test,measured deformation of primary support,pressure of surrounding rock and internal force of steel arch,it is found that perforation interval is the main factor affecting stiffness of steel arch;for the studied tunnel project,the recommended safe perforation interval of steel arch is 40 cm or larger than 40 cm,with stiffness decrease of the steel arch being less than 4% and the stiffness of primary support being barely decreased.

关 键 词：隧道 软弱地层支护体系 型钢拱架 拱架打孔 变形分析 刚度影响 

分 类 号：U45[建筑科学—桥梁与隧道工程]