无中导洞连拱隧道掌子面纵向间距优化  

Optimization of Longitudinal Spacing of Multi-archTunnel without Middle Guide Tunnel

作　　者：王永东[1] 柏文军 陈媛媛 刘洋[1] 万善通 WANG Yong-dong;BAI Wen-jun;CHEN Yuan-yuan;LIU Yang;WAN Shan-tong(School of Highway,Chang an University,Xi'an 710064,China)

机构地区：[1]长安大学公路学院,西安710064

出　　处：《科学技术与工程》2022年第21期9355-9363,共9页Science Technology and Engineering

摘　　要：作为一种大跨径地下结构形式连拱隧道结构复杂,无中导洞法能在提高施工速度的基础上降低中隔墙渗漏水。为研究连拱隧道无中导洞法施工活动对隧道先后行洞的影响程度,以陈家滩隧道为研究对象,通过数值模拟研究了不同间距下先后行洞的影响范围、先后行洞的影响程度以及中隔墙的倾覆趋势。结果表明:当先行洞开挖至控制截面5 m范围内时,对围岩的影响最大,其围岩位移释放系数增量达到了40%以上;超过控制截面10 m时其围岩释放系数达到了93%以上,影响程度较小;超过20 m时影响程度可以忽略。当先后行洞纵向间距大于35 m时,影响程度接近10%,纵向间距大于40 m时,影响程度小于10%。从中隔墙的倾覆程度来看,当先行洞开挖完成时,中隔墙的倾斜程度达到最大,倾斜度约为3.28×10^(-4);而纵向间距大于30 m时倾斜度差值为0.351×10^(-4),此时中隔墙倾斜程度较大极差较小,有利于中隔墙受力。故先后行洞开挖掌子面纵向间距建议控制在30~40 m。As a kind of long-span underground structure,a multi-arch tunnel has a complex structure.The method without a middle guide tunnel can reduce water leakage of the middle partition wall based on improving construction speed.In order to study the influence degree of the construction activities of a multi-arch tunnels without a central guide tunnel on successive tunnels,taking Chenjiatan tunnel as the research object,the deformation of the surrounding rock,the influence degree of successive tunnels,and the overturning trend of the middle partition wall under different spacing were studied by numerical simulation.The results show that when the first tunnel is excavated to the control section within 5 m,the influence on the surrounding rock is the largest,and the displacement release coefficient of surrounding rock increases by more than 40%.When the control section is more than 10 m,the release coefficient of surrounding rock reaches more than 93%,and the influence degree is small.When the control section is more than 20 m,the influence degree can be ignored.When the longitudinal spacing is greater than 35 m,the influence degree is close to 10%,and when the longitudinal spacing is greater than 40 m,the influence degree is less than 10%.In terms of the overturning degree of the middle partition wall,when the excavation of the guide tunnel is completed,the inclination degree of the middle partition wall reaches the maximum,and the inclination angle is about 3.28×10^(-4).When the longitudinal spacing is greater than 30 m,the difference of inclination angle is 0.351×10^(-4).At this time,the inclination of the middle wall is large and the range is small,which is conducive to the stress of the middle wall.Therefore,it is recommended to control the longitudinal spacing of tunnel excavation face tunnel excavation about 30~40 m.

关 键 词：公路隧道 连拱隧道 无中导洞法 开挖面纵向间距 

分 类 号：U455[建筑科学—桥梁与隧道工程]