论文部分内容阅读
狭小场地施工大跨暗挖隧道是城市地铁建设中的常见问题,而小竖井施工浅埋暗挖大跨隧道的安全控制是狭小场地修建城市地铁的关键技术,在施工时容易发生横通道坍塌或引起地表过大沉降及周围建筑的破坏。本文以广州市轨道交通五、六号线换乘站区庄站南端浅埋暗挖大跨隧道施工为背景,介绍竖井横通道内利用桩梁体系转向施工及狭小场地施工地铁浅埋暗挖大跨隧道的关键技术。利用大型有限元分析软件ABAQUS对超前小导管、超前管棚等预加固措施进行论证,并对小竖井施工大跨隧道过程进行三维数值分析。计算结果表明:开挖到横通道顶标高后在竖井四个角增设一榀竖向格栅,加固横通道马头门、采用超前小导管对通道进行预支护,有效地保证了支护结构安全和隧道围岩稳定;在竖井转入横通道后采用桩梁体系成功地解决了因上部荷载过大引起的横通道稳定问题,并有效地控制了地表沉降。
Small-site construction of large-span tunneling is a common problem in the construction of urban subway, while the construction of small vertical shaft shallow excavation of long-span tunnel safety control is a small venue for the construction of the city subway key technology prone to cross-channel collapse during construction or Causing excessive surface subsidence and the destruction of the surrounding buildings. In this paper, the construction of Shallow-buried and undercut long-distance tunnel at the south end of Zhuangzhuang station of Guangzhou Metro Line 5 and 6 is taken as the background. Cross-tunneling key technologies. The large-scale finite element analysis software ABAQUS is used to demonstrate the pre-reinforcement measures such as advanced small pipe and advanced pipe shed, and the three-dimensional numerical analysis of long-span tunnel construction in small vertical shaft is carried out. The calculation results show that: after digging to the top elevation of horizontal channel, a vertical grid is added to the four corners of the vertical shaft to reinforce the transverse channel Ma Taumen, and pre-support the channel by using small lead pipelines, effectively ensuring the safety of the support structure And the surrounding rock of the tunnel are stable. The adoption of pile-beam system after the shaft transits into the horizontal channel successfully solves the problem of cross-channel stability caused by the excessive load on the upper part and effectively controls the settlement of the ground surface.