JP4391361B2 - Steel segment manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a steel segment for manufacturing a steel segment used for an underground structure, in particular, a steel segment having a defect portion for installing a vertical beam.

As a construction method for urban underground structures (vertical shafts, manholes, bridge substructures, bridge reinforcement, etc.), it has excellent workability without affecting neighboring structures and surrounding living environments (groundwater, vibration, noise, etc.) (The construction space is narrow, the construction period is short, the members are small and lightweight, etc.) and the applicable range is wide (the shape and size can be selected arbitrarily, and the corresponding ground is wide, etc.). The press-fit method (registered trademark) is frequently used.
Such an urban ring press-fitting method is to produce steel segments in an arc shape or straight line in a plan view in a factory, and connect the steel segments to each other at a construction site to form a ring (round, oval, etc.) An annular body is pressed into the ground. At this time, the other annular body is laminated on one annular body and press-fitted into the ground, or the annular body is laminated on the annular body press-fitted into the ground. To build urban underground structures that reach the depth of
The steel segment is a casing formed by welding a pair of main girders and a pair of connection plates to each other to form a frame, and welding a skin plate to the frame. In order to improve accuracy, a device for assembling a steel segment has been disclosed (for example, see Patent Document 1).

Japanese Utility Model Publication No. 56-34854 (page 2-3, Fig. 1)

However, since the idea disclosed in Patent Document 1 is a jig for assembling a steel segment made of a plate material having a simple shape in which the main girder is substantially arc-shaped or linear, the main girder has a missing portion. In some cases, there is a problem that the accuracy cannot be maintained due to welding deformation.
That is, since the longitudinal beam for reinforcing the underground structure is installed inside the underground structure, in the case of a substantially arc-shaped steel segment, the concave side of the main girder (hereinafter referred to as “inner circumferential side”) In the case of a straight steel segment, the missing part for installing the vertical beam is machined in, and the skin plate is welded to the convex side (hereinafter referred to as the “outer side”). The missing part for installing the vertical beam is processed on one side of the girder (hereinafter referred to as “inner side” for convenience of explanation), and the skin is formed on the opposite side (hereinafter referred to as “outer side” for convenience of explanation). The plates are welded together.
Therefore, when the skin plate is welded, the outer peripheral side of the main girder is thermally shrunk by welding heat input, so that an internal stress (same as the bending moment) is generated in the main girder in the direction of expanding its curvature deformation. At this time, since the defect portion is easily deformed because it has a lower bending rigidity than the other portions, the dimensional accuracy of the main girder deteriorates due to plastic deformation concentrated on the defect portion (plastic deformation that refracts).

  The present invention has been made to solve such problems, and it is possible to produce a steel segment (hereinafter referred to as a “segment”) having a defect portion for installing a vertical beam, An object of the present invention is to provide a method for producing a steel segment capable of minimizing the above.

(1) A steel segment manufacturing method according to the present invention is formed by joining together to form an annular body, the annular body is press-fitted into the ground, and joined to the annular body press-fitted into the ground. A steel segment for use in an underground structure formed by being formed into an annular body and further formed by press-fitting the new annular body into the ground,
A step of machining a longitudinal cut of a predetermined length along the substantially longitudinal direction of each of the main girders made of the pair of plate members;
Forming a casing having an opening on one side by welding and bonding a pair of main girders processed in the longitudinal direction, a pair of joint plates made of a plate material, and a skin plate made of a plate material;
After the housing is formed, for each of the pair of main girders, the step of processing a pair of cutting cuts that connect the longitudinal cut and the opening side end,
A defect portion is formed by the longitudinal cut that has been processed in advance and the pair of cutting cuts that are processed after the casing is formed.

(2) Further, they are joined together to form an annular body, the annular body is press-fitted into the ground, joined to the annular body press-fitted into the ground, and formed into a new annular body, A method for manufacturing a steel segment to be used for an underground structure formed by press-fitting a new annular body into the ground,
Each of the main girders made of the pair of plate members has a U-shape including a longitudinal cut portion having a predetermined length along a substantially longitudinal direction thereof and a width direction cut portion having a predetermined width toward one end thereof. A step of processing the cut-in-cut,
Forming a casing having an opening on one side by welding and joining a pair of main girders processed with the U-shaped cuts, a pair of joint plates made of a plate material, and a skin plate made of a plate material; ,
After the housing is formed, for each of the pair of main girders, a step of processing a pair of cutting cuts that connect the width direction cut portion and the end portion on the opening side, and
A defect portion is formed by the U-shaped cut processed in advance and the pair of cutting cuts processed after forming the casing.

  (3) Further, before the step of processing the pair of cutting cuts, vertical ribs for connecting the pair of main girders to each other are installed.

In the method of manufacturing a steel segment according to the present invention, after “longitudinal cut” or “U-shaped cut (consisting of a longitudinal cut and a width cut)” is previously processed in each of the pair of main girders. Since the housing is formed by welding, and finally, the longitudinal notch or U-shaped notch and the inner girder end of the main girder are connected to form a defect, so the accuracy of the steel segment is maintained. There is an effect that can be done.
That is, the outer peripheral side of the main girder is heat-shrinked by welding heat input when welding the skin plates, and internal stress (same as the bending moment) is generated in the main girder in the direction of expanding its curvature deformation, In the main girder before the portion is formed, the inner peripheral side is continuous over the entire length, so that the internal stress (bending moment) is effectively within a range continuous over the entire inner peripheral side. Has been absorbed. In other words, since there is no defect portion where the bending rigidity becomes smaller than in other portions, concentrated plastic deformation (plastic deformation that refracts) is less likely to occur.

Hereinafter, an embodiment will be described based on a flowchart and a schematic perspective view. The description will be given by taking a substantially arc-shaped steel segment as an example, and an end portion having a large curvature radius of the main girder is referred to as an “outer periphery”, and an end portion having a small curvature radius of the main girder is referred to as an “inner periphery”. The straight steel segment shall be replaced in accordance with this.
1 and 2 are a flow diagram and a schematic perspective view for explaining a method for manufacturing a steel segment according to an embodiment of the present invention.

  First, U-shaped cuts 6a and 6b are processed in each of the main girders 1a and 1b made of a pair of plate materials. The U-shaped cuts 6a and 6b are formed of width direction cut parts 61a and 61b, longitudinal direction cut parts 62a and 62b, and width direction cut parts 63a and 63b (step 1).

  Then, the main girders 1a and 1b, a pair of joint plates 2a and 2b made of a plate material, and a skin plate 4 made of a plate material are welded together to form a housing having an opening on one side. The side on which the skin plate 4 is welded is referred to as “outer peripheral side”, and the opening side is referred to as “inner peripheral side”. In step 2 or 3, the longitudinal ribs 3a, 3b, 3c, 3d, and 3e are installed (see step 2 (a) in FIG. 2).

  Further, cutting cuts 71a and 71b for connecting the width direction cut portions 61a and 61b and the inner peripheral end portion, and a cutting cut 72a for connecting the width direction cut portions 63a and 63b and the inner peripheral end portion. , 72b are processed to form rectangular defects 7a, 7b (step 3, see FIG. 2 (a)).

Accordingly, the casing 10 (hereinafter referred to as “segment 10”) having the defect portions 7a and 7b has no defect portion on the inner peripheral side (the inner peripheral end is smoothly continuous in the longitudinal direction). In this state, the skin plate is welded and joined to the outer peripheral end face, so that the outer peripheral side of the main girders 1a and 1b is thermally contracted by welding heat input, and the main girder has an internal stress (in the direction of expanding its curvature deformation) Although the same bending moment is generated, the internal stress (bending moment) is effectively absorbed, and deterioration of the shape accuracy is prevented.
In other words, since there is no defect (small bending rigidity compared to other parts), plastic deformation concentrated on the defect (plastic deformation that refracts) is less likely to occur. In the drawing, an arcuate main girder is illustrated, but in the case of a linear main girder, “warp deformation” such that the outer peripheral side becomes concave is prevented.

Furthermore, in the main girders 1a and 1b at the material stage, the U-shaped cuts 6a and 6b can be machined with high accuracy and low cost and with a clean cross section by an automatic gas fusing machine or the like. Since the cuts 72a and 72b for cutting in the housing 10 are usually processed by gas fusing by manual operation, the missing portions 7a and 7b having the U-shaped cuts 6a and 6b are highly accurate and inexpensive. Moreover, the range of a clean cross section is wide.
Therefore, when the vertical beam is locked to the defective portions 7a and 7b and welded, the workability and reliability of the welded joint are improved.

FIG. 3 is a schematic diagram for explaining the underground structure having the segments shown in FIG. The same parts as those in FIG. 2 are denoted by the same reference numerals and a part of the description is omitted.
In FIG. 3, in the underground structure 100, the segment 10 and other segments (according to the segment 10 not having the defect portion 7) are mutually joined bolts (inserted into the through holes 21a and 21b, not shown). The annular bodies 101, 102,... Formed by connecting with each other are stacked. In addition, in the segment 10 which comprises the annular body 101, and the segment 10 which comprises the annular body 102, arrangement | positioning of the defect | deletion part 7a, 7b is symmetrical with respect to the center of a longitudinal direction.

That is, the missing portions 7a and 7b of the segment 10 in each of the annular bodies 101, 102... Are arranged in the same phase, and the main girders 1a and 1b abut against each other so 11a and 11b (not shown). At this time, the phases of the joint plates 2a and 2b of the segment 10 of the annular body 101 and the joint plates 2a and 2b of the segment 10 of the annular body 102 are different.
And since the vertical beam 5 (indicated by a double oblique line in the figure) that locks to the missing portions 7a, 7b in the annular bodies 101, 102... Is installed, the underground structure 100 is Reinforced and stiffened. In addition, the height (the number of stacked annular bodies to be locked) and the number of the vertical beams 5 are not limited to those shown in the drawings, and may be any of two or more layers or a plurality of them.

FIG. 4 is a schematic plan view for explaining the cutting of the main girder shown in FIG. Note that the subscripts “a, b” are omitted.
4A, the U-shaped notch 6 includes a width-direction notch 61 ("B" to "C" in the figure) and a longitudinal notch 62 ("C" to "D" in the figure). ), The width direction cut portion 63 ("D" to "E" in the figure). And the defect | deletion part 7 is the U-shaped notch 6, and the cutting notches 71 ("a"-"b" in the figure) and 72 (in the figure "e"-"he") connected with this. Formed from.

In addition, the size of the cuts 71 and 72 for cutting, that is, the cutting distance after welding joining (distances “a” to “b”, distances “e” to “f”) does not reveal the plastic deformation. The cutting work is facilitated by shortening to an extent.
In addition, although the processing method of the U-shaped cut | notch 6 and its width | variety (slit space | interval) have illustrated the thing by an automatic gas fusing machine, it is not limited to this. Further, through holes may be provided in advance at the positions “c” and “2”, and cuts may be provided in a manner of connecting the through holes.

In FIG. 4B, instead of the U-shaped notch 6, a linear notch 8 is provided. That is, a longitudinal cut portion 82 (“C” to “D” in the figure) connecting the through holes 81 and 83 is formed. And the defect | deletion part 9 cut | disconnects the cut | notch 91 ("a"-"b" in a figure), 92 (in the figure) which each connects the linear notch 8, the through-holes 81 and 83, and the edge part of an inner peripheral side. In the figure, it is formed from “e” to “f”).
The processing method, position, length, and width (slit spacing) of the linear notch 8 are not limited, and the through holes 81 and 83 may be omitted.

  As described above, in FIGS. 2 and 4, the rectangular defect portion is described, but the present invention is not limited to this, and the shape of the defect portion is changed according to the cross-sectional shape of the vertical beam. is there. At this time, the shape of the longitudinal cut or the U-shaped cut is also changed.

  INDUSTRIAL APPLICABILITY The present invention can be widely used as a method for manufacturing a steel segment provided for an underground structure, particularly as a method for manufacturing a steel segment having a defect portion for installing a vertical beam.

The flowchart explaining the manufacturing method of the steel segments which concern on embodiment of this invention. The schematic perspective view explaining the manufacturing method of the steel segments which concern on embodiment of this invention. The schematic diagram explaining the underground structure which has the segment shown in FIG. FIG. 3 is a schematic plan view for explaining the cutting of the main girder shown in FIG. 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a Main girder 1b Main girder 2a Joint plate 2b Joint plate 3a Vertical rib 3b Vertical rib 3c Vertical rib 3d Vertical rib 3e Vertical rib 4 Skin plate 5 Vertical beam 6a U-shaped notch 6b U-shaped notch 7a Notch 7b Notch 8 Straight cut 9 Defect 10 segment

Claims (3)

Are joined together and formed into an annular body, the annular body is press-fitted into the ground, joined to the annular body press-fitted into the ground to form a new annular body, and further, the new annular body is A method of manufacturing a steel segment to be used for an underground structure formed by being pressed into the ground,
A step of machining a longitudinal cut of a predetermined length along the substantially longitudinal direction of each of the main girders made of the pair of plate members;
Forming a casing having an opening on one side by welding and bonding a pair of main girders processed in the longitudinal direction, a pair of joint plates made of a plate material, and a skin plate made of a plate material;
After the housing is formed, for each of the pair of main girders, the step of processing a pair of cutting cuts that connect the longitudinal cut and the opening side end,
A method of manufacturing a steel segment, wherein a defect portion is formed by the longitudinal cut processed in advance and the pair of cutting cuts processed after forming the casing. Are joined together and formed into an annular body, the annular body is press-fitted into the ground, joined to the annular body press-fitted into the ground to form a new annular body, and further, the new annular body is A method of manufacturing a steel segment to be used for an underground structure formed by being pressed into the ground,
Each of the main girders made of the pair of plate members has a U-shape including a longitudinal cut portion having a predetermined length along a substantially longitudinal direction thereof and a width direction cut portion having a predetermined width toward one end thereof. A step of processing the cut-in-cut,
Forming a casing having an opening on one side by welding and joining a pair of main girders processed with the U-shaped cuts, a pair of joint plates made of a plate material, and a skin plate made of a plate material; ,
After the housing is formed, for each of the pair of main girders, a step of processing a pair of cutting cuts that connect the width direction cut portion and the end portion on the opening side, and
A method of manufacturing a steel segment, wherein a defect portion is formed by the U-shaped cuts processed in advance and the pair of cutting cuts processed after forming the casing. The method of manufacturing a steel segment according to claim 1 or 2, wherein longitudinal ribs for connecting the pair of main girders are installed before the step of processing the pair of cutting cuts.

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