During the passage of the heavily trafficked Fangxing Avenue intersection,the shield tunneling in the Yunxing section of the southern extension of Hefei Metro Line 3 suddenly encountered a deep buried large-diameter waste gas pipeline,and the combination of excavation and drilling coring was adopted to find out that the abandoned pipeline was in conflict with the left and right line tunnels in the Yunxing section,which affected the shield tunneling.From the aspects of construction period,cost and construction risk,the scheme compar-ison and expert demonstration were carried out,and the scheme of pulling out the waste steel pipe with"shaft+horizontal channel+jack"was determined in the limited space,supplemented by the construction technology of drag reduction around the pipeline,the waste large-diameter steel pipe was successfully and quickly pulled out,so as to ensure the smooth excavation of the shield construction,and pro-vide reference for the uprooting of large-diameter steel pipes under similar conditions in the future.
维普
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