JPS6223915Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a small diameter concrete segment for tunnel lining.

Conventionally, it has been considered economical to manufacture tunnel lining segments using reinforced concrete for large diameter segments and steel for small diameter segments.

Therefore, this idea was developed to economically produce small-diameter segments made of concrete.
Conventional concrete segments have double reinforcing bars. In other words, it has a muscle arrangement structure in which the upper chord muscle and the lower chord muscle are connected by the abdominal muscle. This double reinforcement structure is not suitable for thin, small-diameter products with a thickness of about 100 to 150 mm, and a single reinforcement structure is required. It is desired to prevent the occurrence of cracks due to the force applied and to improve the yield strength. Therefore, we considered reinforcing it with wire mesh. By the way, although it has not been put to practical use, it has been proposed to use wire mesh to reinforce concrete segments.By rationally arranging this wire mesh together with reinforcing bars, the force that tries to bend the segment and the jerking can be reduced. We have succeeded in commercializing thin, small-diameter concrete segments that have improved resistance to eccentric loads and impact forces during handling. The details will be explained below with reference to illustrated embodiments.

This concrete segment has a thickness of 100-150
mm, and reinforcing bars 1 with a diameter of 5.5 to 13 mm are arranged in a lattice shape at the center of the concrete thickness or at the slightly outer curved surface. Further, a wire mesh 2 is arranged along the inner curved surface or near the inner curved surface. Expanded metal, lath, etc. are particularly used as the wire mesh 2, and for example, JIS, G3351 (expanded metal), G3554 (tight shell wire mesh), A5505 (metal lath) are used. Further, the periphery of the wire mesh 2 is bent to the inner corner of the segment to protect the corner of the segment. Note that numeral 4 indicates concrete.

This idea consists of the above-mentioned structure, and enables small-diameter concrete segments with a thickness of about 100 to 150 mm to be economically implemented using a single reinforcing bar arrangement, and also allows concrete segments to be used as the primary lining in tunnels. When assembled, the bending stress is greater on the inner surface than on the outer surface, but this is reinforced by the wire mesh placed on the inner curved surface. Also, if a secondary lining is placed inside this concrete segment, it is expected that the wire mesh and reinforcing bars will have the same function as double reinforcement. Additionally, when wire mesh is placed on an internally curved surface, it improves the adhesion performance of secondary lining concrete or mortar. This wire mesh prevents cracks in the concrete, and by bending the ends in particular, it can prevent damage to the corners.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the main part, and FIG. 2 is a partially cutaway perspective view. 1...Reinforcing bar, 2...Wire mesh, 3...Bending.

Claims (1)

[Scope of utility model registration request] A single lattice reinforcing bar is placed approximately at the center of the concrete thickness cross section, and wire mesh is placed only in the concrete on or near the inner curved surface.
Small diameter concrete segments characterized by being 100-150 mm.