摘要
以兰张三四线新乌鞘岭隧道千枚岩地段挑顶为例,介绍千枚岩地段斜井转正洞垂直挑顶的施工技术。斜井转正洞段往往因其结构形状特殊、受力状态复杂而出现应力集中现象,施工不当极易引起塌方,传统施工方法存在工期长、安全风险控制难度大等缺点。新乌鞘岭隧道部分段落为大变形的千枚岩Ⅶ级风险段落,采用垂直挑顶施工技术,通过设置临时门架进入正洞开挖,在临时门架保护下进行正洞上台阶支护施工,无需反向扩挖,减少对围岩的扰动,有效控制围岩变形,确保千枚岩地段斜井转正洞的施工安全。
This paper introduces the construction technology of vertical top picking for transition from inclined shaft to main tunnel in phyllite section by taking the top picking in phyllite section of New Wushaoling Tunnel of Lanzhou-Zhangjiakou Third and Fourth Line Railway as an example.Stress concentration often occurs at the transition from inclined shaft to main tunnel due to the special structural shape and complex load status.Improper construction is easy to cause collapse.Traditional construction methods have disadvantages such as long construction period and great difficulties in safety risk control.Some sections of the new Wushaoling Tunnel are large-deformation phyllite Class VII risk sections.The vertical top picking construction technology is adopted.A temporary portal frame was set up to allow excavation in the main tunnel,and upper bench support construction was carried out in the main tunnel under the protection of the temporary portal frame.This required no reverse expansion excavation.As a result,disturbance to the surrounding rock was mitigated,deformation of the surrounding rock was effectively controlled,ensuring the construction safety at the transition from inclined shaft to main tunnel in the phyllite section.
作者
王新胜
WANG Xinsheng(Gansu Xinda Railway Engineering Supervision&Consultation Co.,Ltd.,Lanzhou Gansu 730000,China)
出处
《铁路技术创新》
2022年第5期29-34,共6页
Railway Technical Innovation
关键词
兰张三四线
隧道
千枚岩
临时门架
垂直挑顶
Lanzhou-Zhangye Third and Fourth Line
tunnel
phyllite
temporary portal frame
vertical top picking
