Study on Design and Construction Method of Closely Adjacent Middle Wall Multi-arch Tunnel
This article aims to propose a new type of closely bonded mid-wall multi-arch tunnel structure to address the high cost,long construction period,multiple diseases,and difficult management issues encountered in the construction of traditional multi-arch tunnels.The structural feature of closely bonded mid-wall multi-arch tunnel is that the middle wall is closely adjacent to the straight wall of the middle guide tunnel.During construction,after the excavation and support of the middle guide tunnel are completed,only one-sided formwork is required to finish the concrete pouring of the middle wall,and the main tunnel can be excavated without backfilling.In addition,the construction effect and efficiency of these two methods are compared by construction schedule diagram.Results show that:1)The working site is spacious,procedures are simple,and the work is easy to mechanize.2)The construction efficiency of the closely adjacent middle wall multi-arch tunnel has increased by at least 23%.3)Under the same construction conditions,the closely adjacent middle wall multi-arch tunnel has more advantages in controlling the surrounding rock changes,and it is more effective in controlling surface settlement,crown settlement,and horizontal displacement of the middle wall top.The closely adjacent middle wall multi-arch tunnel structure has significant construction advantages and better rock control effects with a broad application prospect.This study provides new ideas and methods for the design and construction of multi-arch tunnels.
closely bonded middle wallmulti-arch tunnelconstruction efficiencydeformation of surrounding rock
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