雁门关隧道挤压性围岩变形控制技术
|
摘要
北同蒲取直线雁门关隧道软弱围岩段埋深大,构造应力水平高,给隧道施工变形控制造成了极大困难。文章根据雁门关隧道挤压性围岩的工程特性,对洞室变形控制措施进行了研究。首先通过有限差分法(FLAC3D)数值计算确定了弧形导坑预留核心土三台阶七步开挖法的核心土合理长度;其次根据隧道塑性区范围与形状优化了系统锚杆的长度;而后通过对双层支护力学效应及内层支护施作时机的研究,得出理论上雁门关隧道的内层支护最佳时机为内层支护与外层仰拱同时施作;最后通过数值计算和现场工程实践,形成了"3~4 m核心土长度+超前支护+优化设计的系统锚杆及锁脚锚管+双层支护(H175+I22a)"的雁门关隧道挤压性围岩变形综合控制技术。该技术对在构造应力发育的软岩地区修筑隧道具有一定的借鉴意义。
The section of soft surrounding rock around the Yanmenguan tunnel,which exhibits a straight alignment,has large overburdens and tectonic stresses,which is extremely challenging for deformation control during tunnel construction.Considering the characteristics of the squeezing surrounding rock around the Yanmenguan tunnel,a study was conducted with respect to measures for excavation deformation control.The Finite Differential Method(FLAC3D)was used to determine the rational length of the reserved core soil of the arced pilot tunnel during threebench seven-step construction,and the length of the system anchor bolt was optimized based on the scope and shape of the plastic zone of the tunnel surrounding rock.Furthermore,a study on the mechanical effect of the double-layer support and the construction time of the inner support was carried out:it concludes that it is best for construction of the inner support to take place at the same time as that of the inverted arch of the outer support.Comprehensive deformation control techniques,which include a 3~4 m long core soil,advanced support,an optimized system anchor bolt,a feet-locked anchor bolt and double-layer support(H175+I22a),are proposed based on numerical simulation and engineering practice that consider the squeezing surrounding rock around the Yanmenguan tunnel.
The section of soft surrounding rock around the Yanmenguan tunnel,which exhibits a straight alignment,has large overburdens and tectonic stresses,which is extremely challenging for deformation control during tunnel construction.Considering the characteristics of the squeezing surrounding rock around the Yanmenguan tunnel,a study was conducted with respect to measures for excavation deformation control.The Finite Differential Method(FLAC3D)was used to determine the rational length of the reserved core soil of the arced pilot tunnel during threebench seven-step construction,and the length of the system anchor bolt was optimized based on the scope and shape of the plastic zone of the tunnel surrounding rock.Furthermore,a study on the mechanical effect of the double-layer support and the construction time of the inner support was carried out:it concludes that it is best for construction of the inner support to take place at the same time as that of the inverted arch of the outer support.Comprehensive deformation control techniques,which include a 3~4 m long core soil,advanced support,an optimized system anchor bolt,a feet-locked anchor bolt and double-layer support(H175+I22a),are proposed based on numerical simulation and engineering practice that consider the squeezing surrounding rock around the Yanmenguan tunnel.
引文
[1]刘高,张帆宇,李新召,等.木寨岭隧道大变形特征及机理分析[J].岩石力学与工程学报,2005,24(增2):5521-5526.LIU Gao,ZHANG Fanyu,LI Xinzhao,et al.Research on Large Deformation and Its Mechanism of Muzhailing Tunnel[J].Chinese Journal of Rock Mechanics and Engineering,2005,24,(S2):5521-5526.
[2]韩现民,孙明磊,李文江,等.复杂条件下隧道断面形状和支护参数优化[J].岩土力学,2011,32(增1):725-731.HAN Xianmin,SUN Minglei,LI Wenjiang,et al.Optimization of Section Shape and Support Parameters of Tunnel under Complicated Conditions[J].Rock and Soil Mechanics,2011,32(S1):725-731.
[3]刘志春,李文江,孙明磊,等.乌鞘岭隧道F4断层区段监控量测综合分析[J].岩石力学与工程学报,2006,25(7):1502-1511.LIU Zhichun,LI Wenjiang,SUN Minglei,et al.Monitoring and Comprehensive Analysis in F4 Section of Wushaoling Tunnel[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(7):1502-1511.
[4]张祉道.关于挤压性围岩隧道大变形的探讨和研究[J].现代隧道技术,2003,40(2):5-12.ZHANG Zhidao.Discussion and Study on Large Deformation of Tunnel in Squeezing Ground[J].Modern Tunnelling Technology,2003,40(2):5-12.
[5]李国良,刘志春,朱永全.兰渝铁路高地应力软岩隧道挤压大变形规律及分级标准研究[J].现代隧道技术,2015,52(1):62-68.LI Guoliang,LIU Zhichun,ZHU Yongquan.On the Large Squeezing Deformation Law and Classification Criteria for the LanzhouChongqing Railway Tunnels in Soft and High Geostress Rocks[J].Modern Tunnelling Technology,2015,52(1):62-68.
[6]刘阳,伍晓军,刘志强,等.关于碳质板岩隧道大变形机理及应对措施的探讨[J].现代隧道技术,2014,51(6):19-24.LIU Yang,WU Xiaojun,LIU Zhiqiang,et al.Discussion of and Solutions for the Large Deformation Mechanism of a Tunnel in Carbonaceous Slate[J].Modern Tunnelling Technology,2014,51(6):19-24.
[7]喻渝.挤压性围岩支护大变形的机理及判定方法[J].世界隧道(现代隧道技术),1998,(1):46-51.YU Yu.Serious Deformation of Surrounding Rock in Squeezing Ground[J].World Tunnelling(Modern Tunnelling Technology),1998,(1):46-51.
[8]中华人民共和国国家标准.工程岩体分级标准:GB50218-1994[S].北京:中国计划出版社,1994.National Standards of the People′s Republic of China.Standard for Engineering Classification of Rock Masses:GB50218-1994[S].Beijing:China Planning Press,1994.
[9]JETHWA J L,SINGH B,SINGH B.Estimation of Ultimate Rock Pressure for Tunnel Linings under Squeezing Rock Conditions-ANew Approach[C]//Design and Performance of Underground Excavations[Sl]:ISRM Symposium,1984:231-238.
[2]韩现民,孙明磊,李文江,等.复杂条件下隧道断面形状和支护参数优化[J].岩土力学,2011,32(增1):725-731.HAN Xianmin,SUN Minglei,LI Wenjiang,et al.Optimization of Section Shape and Support Parameters of Tunnel under Complicated Conditions[J].Rock and Soil Mechanics,2011,32(S1):725-731.
[3]刘志春,李文江,孙明磊,等.乌鞘岭隧道F4断层区段监控量测综合分析[J].岩石力学与工程学报,2006,25(7):1502-1511.LIU Zhichun,LI Wenjiang,SUN Minglei,et al.Monitoring and Comprehensive Analysis in F4 Section of Wushaoling Tunnel[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(7):1502-1511.
[4]张祉道.关于挤压性围岩隧道大变形的探讨和研究[J].现代隧道技术,2003,40(2):5-12.ZHANG Zhidao.Discussion and Study on Large Deformation of Tunnel in Squeezing Ground[J].Modern Tunnelling Technology,2003,40(2):5-12.
[5]李国良,刘志春,朱永全.兰渝铁路高地应力软岩隧道挤压大变形规律及分级标准研究[J].现代隧道技术,2015,52(1):62-68.LI Guoliang,LIU Zhichun,ZHU Yongquan.On the Large Squeezing Deformation Law and Classification Criteria for the LanzhouChongqing Railway Tunnels in Soft and High Geostress Rocks[J].Modern Tunnelling Technology,2015,52(1):62-68.
[6]刘阳,伍晓军,刘志强,等.关于碳质板岩隧道大变形机理及应对措施的探讨[J].现代隧道技术,2014,51(6):19-24.LIU Yang,WU Xiaojun,LIU Zhiqiang,et al.Discussion of and Solutions for the Large Deformation Mechanism of a Tunnel in Carbonaceous Slate[J].Modern Tunnelling Technology,2014,51(6):19-24.
[7]喻渝.挤压性围岩支护大变形的机理及判定方法[J].世界隧道(现代隧道技术),1998,(1):46-51.YU Yu.Serious Deformation of Surrounding Rock in Squeezing Ground[J].World Tunnelling(Modern Tunnelling Technology),1998,(1):46-51.
[8]中华人民共和国国家标准.工程岩体分级标准:GB50218-1994[S].北京:中国计划出版社,1994.National Standards of the People′s Republic of China.Standard for Engineering Classification of Rock Masses:GB50218-1994[S].Beijing:China Planning Press,1994.
[9]JETHWA J L,SINGH B,SINGH B.Estimation of Ultimate Rock Pressure for Tunnel Linings under Squeezing Rock Conditions-ANew Approach[C]//Design and Performance of Underground Excavations[Sl]:ISRM Symposium,1984:231-238.