摘要
依托粤北山区新建青云山隧道工程施工难点,运用数字模型模拟分析了隧道开挖对边坡、隧道进洞稳定性影响。结果表明:原始边坡水平方向的位移自上而下呈线性增大的趋势,坡脚部位的水平位移最大;隧道拱顶上方的边坡锚杆拉力最大,在此处加大锚杆支护力;在下台阶开挖完成后,开挖是边坡稳定性的最大影响因素,出现塑性区明显增大,初支的及时施作能很好地控制隧道及边坡的安全稳定性;在进行隧道下台阶的开挖支护时,在拱脚位置产生了应力集中,容易对围岩稳定性造成不利影响;拱脚部位的初期支护容易发生拉裂破坏,设计施工时应加大拱脚初期支护的刚度,施工期间加快二衬台车安装,尽早施工明洞衬砌;锁脚锚杆对隧道的洞周收敛效果明显,可有效控制围岩向内侧挤压;锚杆轴力最大处位于拱脚,该处为结构的薄弱处,施工时应加强该处锁脚锚杆的质量,开挖后尽早施工初期支护。
Relying on the construction difficulties of the new Qingyunshan Tunnel in the mountainous area of northern Guangdong Province,we simulated and analyzed the influence of tunnel excavation on the stability of slope and tunnel entrance by using digital model.The result shows that(1)the horizontal displacement of the original slope increases linearly from top to bottom,and the horizontal displacement at the slope foot is the largest;(2)the anchor tension of the slope above the vault of the tunnel is the largest,and the anchor support force is increased here;(3)after the excavation of the lower step is completed,the excavation is the biggest factor affecting the slope stability,the plastic zone is obviously enlarged,and the timely construction of the initial support can well control the safety and stability of the tunnel and the slope;(4)during the excavation and support of the lower steps of the tunnel,stress concentration occurs at the arch foot,which is easy to cause adverse impact on the stability of surrounding rock;(5)the initial support at the arch foot is prone to crack damage,so the stiffness of the initial support at the arch foot should be increased in the design and construction,the installation of the second lining trolley should be accelerated during the construction,and the open cut tunnel lining should be constructed as soon as possible;(6)the lock-foot anchor has an obvious effect on the convergence of the tunnel circumference,which can effectively control the surrounding rock from squeezing to the inside;(7)the maximum axial force of the anchor is located at the arch foot,which is the weak part of the structure,the quality of the foot locking anchor should be strengthened during construction,and the initial support should be constructed as soon as possible after the excavation.
作者
刘明
谭勇
刘志强
LIU Ming;TAN Yong;LIU Zhi-qiang(Wushen Contact Line Management Office of Guangdong Nanyue Transport Investment and Construction Co.,Ltd.,Shaoguan Guangdong 512600,China;Renxin Management Office of Guangdong Nanyue Transport Renbo Expressway Management Center,Shaoguan Guangdong 512600,China;Research Institute of Highway,Ministry of Transport,Beijing 100088,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2020年第S02期154-158,共5页
Journal of Highway and Transportation Research and Development
关键词
隧道工程
数值模拟
水平位移
锚杆支护力
塑性
稳定性
锚杆轴力
tunnel engineering
numerical simulation
horizontal displacement
anchor supporting force
plasticity
stability
axial force of anchor
