Steel bar construction for secondary lining of tunnel

Abstract

The invention discloses a steel bar construction for secondary lining of a tunnel. The steel bar construction for the secondary lining of the tunnel comprises outer layer bar-mat reinforcement and inner layer bar-mat reinforcement, the outer layer bar-mat reinforcement comprises multiple outer layer annular main reinforcing bars which are laid in the longitudinal extending direction of the constructed tunnel and outer layer longitudinal connecting ribs which are bound to the outer layer annular main reinforcing bars, and the inner layer bar-mat reinforcement comprises multiple inner layer annular main reinforcing bars which are laid in the longitudinal extending direction of the constructed tunnel and inner layer longitudinal connecting ribs which are bound to the inner layer annular main reinforcing bars. The steel bar construction for the secondary lining of the tunnel further comprises interlayer connecting ribs connecting the outer layer bar-mat reinforcement with the inner layer bar-mat reinforcement, and each interlayer connecting rib is fixed between the corresponding outer layer annular main reinforcing bar and the corresponding inner layer annular main reinforcing bar of the same layer in a welding mode. Sinking of the outer layer bar-mat reinforcement and the inner layer bar-mat reinforcement can be effectively controlled by adding the interlayer connecting ribs which are fixed between the outer layer annular main reinforcing bars and the inner layer annular main reinforcing bars in the welding mode, the stability of the interval between an inner reinforcing steel bar layer and an outer reinforcing steel bar layer of a reinforcement cage is maintained, the thickness of a protection layer is guaranteed, safety and attractiveness of the tunnel structure are guaranteed, and working efficiency is improved.

Description

technical field [0001] The invention relates to a steel bar skeleton structure, in particular to a tunnel secondary lining steel bar structure. Background technique [0002] Tunnel engineering has been used so far, mainly for railways, highways, mines, water conservancy, municipal engineering, etc. Most tunnels are composed of primary support and secondary lining. The secondary lining reinforcement structure is basically arranged according to double-layer reinforcement. The reinforced skeleton structure is mainly composed of an outer layer of steel mesh (close to the surrounding rock side) and an inner layer of steel mesh (close to the inner side of the tunnel). The outer layer of steel mesh includes a number of outer circumferential main reinforcements arranged along the longitudinal extension of the tunnel being constructed. and the outer longitudinal connecting bars bound on the outer ring main reinforcement, the inner reinforcement mesh includes a plurality of inner rin...

AI Technical Summary

Problems solved by technology

The reinforced skeleton structure is mainly composed of an outer layer of steel mesh (close to the surrounding rock side) and an inner layer of steel mesh (close to the inner side of the tunnel). The outer layer of steel mesh includes a number of outer circumferential main reinforcements arranged along the longitudinal extension of the tunnel being constructed. and the outer longitudinal connecting bars bound on the outer ring main reinforcement, the inner reinforcement mesh includes a plurality of inner ring main bars arranged along the longitudinal extension direction of the tunnel to be constructed and the inner ring bars bound on the inner ring main bars Layer longitudinal connecting bars; the installation of the second lining steel bars mainly includes three control indicators: the layer spacing of the inner and outer layer steel bars, the thickness of the main bar protective layer, and the design contour line. The stability of the skeleton is usually connected by binding "S"-shaped hook bars between the outer layer of steel mesh and the inner layer of steel mesh; However, steel bars have certain stiffness and weight. After fine-tuning, although the spacing between the main hoop bars may meet the design requirements, they cannot be accurately positioned on the same cross-section due to the artificially bent hoop main bars. The deformation is pressed on the waterproof layer, so that the thickness of the protective layer is insufficient when the concrete is poured; while the inner circumferential main reinforcement is often seriously deformed towards the surrounding rock side at the spandrel, arch waist, etc. (the larger the tunnel span, the more obvious the deformation), affecting The bearing capacity of this section can easily lead to the deformation and displacement of steel bars during pouring of concrete, and the thickness of the protective layer is insufficient. What's more, after the formwork is removed, the concrete surface shows grid-like traces of steel bars, which affects the safety and beauty of the tunnel structure; in addition, The binding operation of hook bars takes a lot of time, which increases the labor intensity of workers in the harsh environment in the tunnel, prolongs the construction period, and is not conducive to the improvement of work efficiency

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