摘要
为确定分离式隧道后行洞爆破施工对先行洞以及后行洞结构稳定性的影响,以某公路隧道为研究对象,采用理论计算、数值分析和现场监测相结合的手段,研究后行洞爆破过程中先行洞及后行洞初次支护位移及振动速度的变化规律,确定爆破振动影响范围。结果表明:后行洞爆破施工对先行洞初支迎爆侧的影响大于背爆侧,且对迎爆侧拱腰的影响最大;监测断面前后10 m范围内初支变形量波动较明显,当控制标准为10 cm/s时,后行洞爆破施工对先行洞初支稳定性的影响较小。爆破施工过程中后行洞拱顶竖向位移最大,而拱腰水平位移最大,第10开挖步后竖向位移和水平位移均基本收敛;在此过程中,上台阶爆破对初支位移的影响大于下台阶。当以10 mm/d为控制标准时,爆破振动对后行洞初支的影响范围为20 m,与萨氏理论所确定的19.7 m的安全距离基本吻合。此外,数值模拟与现场监测所得后行洞拱腰收敛和拱顶下沉的变化规律基本一致,但其值前者略小于后者,分别减小了1.2%和2.3%。
The separated highway tunnel was taken as an example to study the stability influenced by the blasting construction of the second tunnel on the first one.In the process of blasting construction of the second tunnel,the variation of displacement and vibration velocity of the initial support of the first and second tunnels were studied through theoretical calculation,numerical analysis,and in-site monitoring,and the influence range of blasting vibration was also determined.Results indicated that the blasting construction of the second tunnel has a considerable impact on the blasting side of the initial support of the first tunnel than on the back-blasting side,and the impact on the arch waist at the blasting side is the largest.The deformation of the initial support fluctuates within 10 m before and after the monitoring section.The blasting construction of the second tunnel has minimal impact on the stability of the initial support of the first tunnel when the control standard is 10 cm/s.During the blasting construction,the maximum vertical and horizontal displacements occur at the vault and arch waist of the second tunnel,respectively,and the vertical and horizontal displacements are convergent after the 10th excavation step.In this process,the blasting influence of the upper bench on the displacement of the initial support is greater than that of the lower bench.When the control standard is 10 mm/d,the influence range of blasting vibration on the initial support of the second tunnel is 20 m,which is consistent with the safe distance of 19.7 m determined by Saskatchewan theory.In addition,the variation rules of arch waist convergence and vault settlement of the second tunnel obtained from numerical simulation are consistent with the in-site monitoring results,but the former is slightly smaller than the latter,reducing by 1.2%and 2.3%,respectively.
作者
贾剑青
王鑫
席博琪
张帮鑫
刘中帅
JIA Jianqing;WANG Xin;XI Boqi;ZHANG Bangxin;LIU Zhongshuai(School of Traffic and Transportation,Lanzhou Jiaotong University,Lanzhou 730070,Gansu,China;Inner Mongolia Dongwu Railway Co.,Ltd.,Ordos 017000,Inner Mongolia,China;China Merchants Chongqing Communications Technology Research&Design Institute Co.,Ltd.,Chongqing 400067,China)
出处
《地震工程学报》
CSCD
北大核心
2024年第5期1074-1083,共10页
China Earthquake Engineering Journal
基金
国家自然科学基金项目(42261029)
甘肃省科技计划资助(20YF8FA042)。
关键词
分离式隧道
爆破
后行洞
先行洞
separated tunnel
blast
second tunnel
first tunnel
