Assembled inverted arch unit, assembled inverted arch structure and construction method

Abstract

The invention relates to an assembled inverted arch unit, an assembled inverted arch structure and a construction method, comprising an inverted arch unit which forms the second lining of an inverted arch after a plurality of blocks are connected, the inverted arch unit is a concrete prefabricated part, and the inverted arch unit The ring direction main reinforcement and the longitudinal main reinforcement are provided along the ring direction and longitudinal direction of the tunnel, and the ring direction main reinforcement protrudes from both sides of the inverted arch unit along the tunnel ring direction as a connection structure; the invention shortens the construction time of the second lining inverted arch and improves Improve tunnel construction efficiency and shorten construction period.

Description

technical field [0001] The invention belongs to the technical field of tunnel inverted arch construction, and in particular relates to an assembled inverted arch unit, an assembled inverted arch structure and a construction method. Background technique [0002] The mountain tunnel is usually constructed by the mining method, and its support system includes primary support and secondary lining, wherein the secondary lining includes the bottom inverted arch structure and the upper arch wall lining structure. The inverted arch is a reversed arch structure set at the bottom of the tunnel to improve the stress conditions of the upper support structure, and is one of the main components of the tunnel lining structure. On the one hand, the inverted arch can effectively transmit the stratum pressure and pavement load at the upper part of the tunnel to the underground through the tunnel side wall structure, and can also effectively resist the reaction force from the lower stratum of ...

AI Technical Summary

Problems solved by technology

The slow construction speed of the inverted arch has the following defects: (1) it will affect the pouring of the upper inverted arch backfill, which will prolong the pouring time of the inverted arch backfill; (2) the second lining of the arch wall needs to wait for the inverted arch backfill to be poured before construction , the slow construction speed will prolong the completion time of the construction, which will affect the time for the tunnel lining to be closed and looped, which is extremely unfavorable to the stability of the tunnel; (3) In the current tunnel construction, trestle bridges will be built in the inverted arch construction site, and the existence of trestle bridges will It makes it difficult for vehicles to pass through the cave, and because the trestle bridge is narrow, the risk factor is high when vehicles pass, and the inverted arch cast-in-place makes the procedure time longer, which is not conducive to the traffic and construction safety in the cave

[0004] The cast-in-place inverted arch will not only affect the construction speed of the inverted arch, but also its construction quality cannot be guaranteed. The specific defects are as follows: (1) Many construction units will choose the inverted arch and the backfill construction of the inverted arch in order to reduce the construction time. One-time pouring of arch and inverted arch backfill, because the grade of concrete used for inverted arch backfill is generally lower than that of the inverted arch, which will cause the inverted arch to fail to reach the design strength; (2) The one-time pouring of inverted arch and inverted arch backfill is not conducive to the stability of the tunnel , can not play the role of the inverted arch, which will make the top of the inverted arch backfill under tension, resulting in cracking of the road surface and uplift at the bottom; Under the action, it will cause the inverted arch to crack and break, so that the tunnel lining cannot be closed into a ring, which is not conducive to the stress and stability of the tunnel

[0005] At present, there are mainly the following types of attempts on the fabricated inverted arch: (1) Full ring prefabrication, that is, the inverted arch is prefabricated as a whole. This kind of structural form has good integrity, but it is heavy and requires high hoisting machinery. The on-site operation space requires a lot, which is not conducive to the use in the tunnel; (2) Bolts are used to connect prefabricated blocks. This connection method has high requirements for concrete. Generally, the C35 and C40 concrete used in the lining of mountain tunnels cannot give full play to the role of bolts. At the same time, because the mountain tunnel is excavated by drilling and blasting method, the flatness of the bottom is poor, and the applicability and safety of the bolts are low; Conducive to template making and later demoulding and other processes

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