摘要
软弱围岩隧道采用传统台阶法施工时,仰拱的开挖及其初期支护均作为独立工序存在,可能引起由于初支封闭不及时而产生的初支过大变形、掉拱、关门塌方等安全事故,与掌子面开挖施工不可避免会产生相互干扰。依托蒙华铁路段家坪隧道,采用FLAC3D数值模拟方法,建立不同台阶高度和长度的数值模拟计算模型,从拱顶沉降、周边收敛、初期支护的最大主应力、掌子面稳定性、施工工效和施工便利性方面,对软弱围岩隧道台阶法(含仰拱)一次开挖台阶高度与长度进行研究,研究结果表明,中台阶高度宜控制在3m左右,下台阶高度控制在隧道高度的30%~45%之间且不宜小于中台阶的高度,上台阶高度控制在隧道高度的25%~40%之间,中上台阶长度易控制在4~6m以内,为工程施工提供参考。
When the weak rock tunnel is constructed by the traditional bench method,the excavation of the inverting arch and its initial support all exist as independent processes,which may causeexcessive primary deformation,falling arches,and door-to-door collapse due to untimely closure of theprimary branch. Safety accidents will inevitably interfere with the excavation of the face. Relying onmenghua railway duanjiaping tunnel,numerical simulation model is established for the different benchheight and length by FLAC3D numerical simulation method. It is studied that bench height and lengthof first step excavation of bench method （containing invert arch）in weak rock tunnel,through vaultsettlement,peripheral convergence,initiall support of the maximum principal stress,tunnel face stability,construction efficiency and construction convenience. The results of the study shows that theheight of the middle step should be controlled around 3m,the height of the lower step is controlled between 30% and 45% of the height of the tunnel and should not be less than the height of the middlestep,The height of the upper stage should be controlled between 25% and 40% of the tunnel height,the length of the middle and upper steps is easily controlled within 4-6m. The study results provide reference for the construction of the project.
作者
白银
种玉配
何伟
BAI Yin;CHONG Yupei;HE Wei(Hangzhou Branch of China Railway Tunnel Group Co.,Ltd.,Hangzhou 310000,Zhejiang,China;Design and Research Institute of China Railway Tunnel Group Co.,Ltd.,Guangzhou 510000,China)
出处
《低温建筑技术》
2018年第5期131-135,139,共6页
Low Temperature Architecture Technology
关键词
软弱围岩
台阶法
台阶高度
台阶长度
数值模拟
weak surrounding rock
bench method
bench height
bench length
numerical simulation
