特大断面公路隧道洞口段抗震缝设置效果  

Effect of Seismic Joints for Large-section Highway Tunnel Portal

作　　者：赵冯兵[1] 罗建强 刘涛[1] 任兆丹[2] ZHAO Fengbing;LUO Jianqiang;LIU Tao;REN Zhaodan(College of Civil Engineering,Chongqing Jiaotong University,Chongqing 400074;China Railway Siyuan Survey and Design Group Co.,Ltd,Wuhan 430063)

机构地区：[1]重庆交通大学土木工程学院,重庆400074 [2]中铁第四勘察设计院集团有限公司,武汉430063

出　　处：《现代隧道技术》2020年第S01期203-210,共8页Modern Tunnelling Technology

摘　　要：隧道洞口段是隧道抗震的薄弱区间,其地形地质条件复杂,围岩多破碎,在抗减震设计中应着重考虑。文章从抗震缝出发,通过FLAC 3D有限差分软件建立模型,探究隧道洞口段设置抗震缝对抗震效果的影响。研究结果表明:不同间距抗震缝的设置在使得洞口横断面主应力最大峰值大幅减小的同时也使得应力峰值较小的测点的应力幅值有所增加,从而使应力峰值在洞口横断面上分布更平滑;从纵向对比来看,抗震缝能大幅减小主应力峰值,尤其能在进洞一定范围内减弱第一主应力峰值的幅度逐步增加。综合分析得出,在文章研究背景条件下采用的最佳抗震缝间距为10 m。Tunnel portal section is a weak area in terms of earthquake resistance of tunnel,and its topographic and geologic conditions are complex,the surrounding rocks are fractured,which should be taken into consideration in aseismic design.FLAC 3D finite difference software is used to establish a model to explore the impact of setting anti-seismic joints on the seismic effect of tunnel entrances from the perspective of seismic joints.The research results show that the setting of anti-seismic joints with different spacings not only makes the maximum peak stress of the cross section of the opening significantly decrease,but also increase the stress amplitude of the measuring point with a smaller peak stress,so the distribution of peak stress values on the cross section of portal is smoother;From the longitudinal comparison,seismic joints can be considerably reduce primary peak stress,especially the amplitude of major main peak stress gradually at certain scope after entering the tunnel.Comprehensive analysis shows that the optimal seismic joint spacing is 10 m under the background of this study.

关 键 词：公路隧道 洞口段 抗震缝 FLAC 3D 

分 类 号：U452.28[建筑科学—桥梁与隧道工程]