Backfill construction method of pilot tunnel vault in double-arch tunnel

Abstract

The invention provides a construction method for backfilling the vault roof of a pilot tunnel in a double-arch tunnel, comprising the following steps: excavating and supporting the pilot tunnel; Pilot tunnel and support; after the pilot tunnel is excavated to a certain depth, pour the partition wall; arrange the down-the-hole drilling machine in place and form the drill hole, and the drill hole leads to the top of the partition wall from the left pilot hole or the right pilot hole The vault space of the pilot tunnel; the delivery pipe is installed in the borehole so that the shotcrete enters the vault space of the pilot tunnel on the top of the partition wall; the backfill construction of the vault of the pilot tunnel of the double-arch tunnel is realized through the above steps. The backfilling of the vault of the middle pilot tunnel adopts the method of drilling and backfilling from the upper step of the left pilot tunnel. Solve the technical problem that the vault of the pilot tunnel cannot be backfilled under the pouring conditions of the two-way implementation of the central partition wall, and realize the backfilling of the vault of the central pilot tunnel and the pouring of the central partition wall at the same time. The effective working time is greatly shortened.

Description

technical field [0001] The invention relates to the construction field of double-arch tunnels, in particular to a construction method for backfilling a pilot tunnel vault in a double-arch tunnel. Background technique [0002] Due to the constraints of the design structure of the double-arch tunnel itself and the limitation of the force system, the excavation and support of the upper steps of the main tunnel can only be carried out after the pouring of the central partition wall and the backfilling of the vault are completed. That is, firstly, the excavation and initial support of the intermediate pilot tunnel are carried out from the entrance and exit; secondly, the pouring of the intermediate partition wall is carried out in one direction from the entrance to the exit or from the exit to the entrance after the intermediate pilot tunnel is penetrated; Three, the backfilling of the vault of the central pilot tunnel follows the pouring of the central partition wall from the en...

AI Technical Summary

Problems solved by technology

[0004] When the excavation of the central pilot tunnel and the initial support have not been completed, the pouring of the central partition wall from the middle of the central pilot tunnel to the entrance or exit conflicts with the backfilling construction of the central pilot tunnel vault, that is, the reinforcement of the central partition wall is bound and the trolley is in place. Processes such as moving, concrete pouring and backfilling construction of the pilot tunnel vault interact with each other and cannot be carried out at the same time

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