摘要
无中墙连拱隧道相较传统连拱隧道取消了中墙结构,其先行洞与后行洞初支拱架相互搭接构成整体隧道结构,因此在后行洞爆破开挖时,先行洞及连拱处的爆破振动安全控制极为关键。依托榨坊隧道工程,开展后行洞爆破振动跟踪监测,并对先行洞二衬的爆破振动衰减规律及频谱特性进行了分析;通过LS-DYNA三维有限元数值模拟,研究了先行洞横断面及轴向的爆破振动响应特性,比较分析了注浆加固及布设减震层对连拱处三角区围岩与先行洞衬砌结构的安全控制效果,并通过现场监测,对其应用于实际工程的控制效果进行了评价。实测数据显示:无中墙连拱隧道后行洞开挖时,先行洞边墙二衬的水平径向振动强度最大,且以掏槽孔爆破振动为主,主频集中在40~65 Hz。数值分析显示:先行洞爆破振动速度沿其横断面和轴向的分布均不对称,迎爆侧振动速度显著大于背爆侧,且迎爆侧拱腰至拱肩部位的振速最大;受波传播路径的影响,先行洞未开挖方向的振速相对较高,爆破振动速度沿隧道已开挖方向衰减更快;围岩超前注浆加固可保证连拱处上方三角区围岩的稳定与安全,可分别降低振速和最大主应力69.2%和57.9%;布设减震层可有效控制先行洞衬砌结构的振动安全,可分别降低拱腰和拱肩振速65.2%和57.3%。现场实践也表明:围岩注浆加固和布设减震层2种控制措施各有侧重,二者结合可有效控制爆破振动安全,总体可降低先行洞二衬质点峰值振速35%~50%,且均未超过安全控制标准。
In contrast to traditional multi-arch tunnels,the middle wall is removed and replaced by overlapping initial arch frames,forming a new multi-arch tunnel without a middle wall.However,the safety control of the blast vibration of the overlapping zone and the excavated tunnel is important during the excavation of a multi-arch tunnel without a middle wall.For the Zhafang tunnel,the attenuation law and spectrum characteristics of the blast vibration at the sidewall of the first excavated tunnel during the excavation of the following tunnel were analyzed using blast vibration monitoring data.Using a 3D dynamic finite-element numerical simulation software(LS-DYNA),the blast vibration characteristics in the axial direction and cross-section of the first excavated tunnel were studied.In addition,the safety control effects of the grouting reinforcement and buffer layer on the triangular zone surrounding rock and second lining of the first excavated tunnel were compared and analyzed.Finally,the two combined safety measures were applied,and their control effects were evaluated.The measured data showed that during the blasting excavation of the following tunnel,the horizontal radial vibration of the sidewall of the second lining of the first excavated tunnel was the highest.The peak vibration was mainly caused by the cutting blastholes.In addition,the dominant vibration frequency was in the range of 40-65 Hz.The numerical results indicated that the distributions of the blast vibration velocities at the cross-section and axial direction of the first excavated tunnel were symmetrical.The vibration velocity near the blasting side was significantly higher than that at the back side,and the vibration velocities near the arch waist and arch shoulder of the blasting side were the largest.In contrast,the vibration velocity near the working face was higher than that in the other monitoring sections.Owing to the effect of the traveling path of the blasting seismic wave,the vibration velocity in the unexcavated direction was higher than
作者
王亚琼
杨御博
高启栋
江伟
周海孝
杨瑞鹏
WANG Ya-qiong;YANG Yu-bo;GAO Qi-dong;JIANG Wei;ZHOU Hai-xiao;YANG Rui-peng(School of Highway,Chang'an University,Xi'an 710064,Shaanxi,China;Key Laboratory for Bridge and Tunnel of Shaanxi Province,Chang'an University,Xi'an 710064,Shaanxi,China)
出处
《中国公路学报》
EI
CAS
CSCD
北大核心
2023年第11期266-277,共12页
China Journal of Highway and Transport
基金
国家自然科学基金项目(52009003)
陕西省自然科学基础研究计划项目(2021JQ-258)
中央高校基本科研业务费专项资金项目(300102212205)。
关键词
隧道工程
无中墙连拱隧道
爆破振动
响应特性
安全控制
tunnel engineering
multi-arch tunnel without middle wall
blast vibration
vibration characteristics
safety control
