JPH09303091A - Segment joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform plastic deformation of a male joint by the press into a female joint to mutually connect them in the assembling of a segment, and provide a sufficient pullout proof stress when an external pullout force is added. SOLUTION: A cylindrical male joint 27 has no axial slit as in the conventional way. The male joint is pressed into the ring clearance 31 of a female joint 29, and flared by being extended by a substantially conical projection 33. After the male joint is flared, even when an external pulling force is added, the male joint can be pulled out only when the thick part of the male joint is contracted and returned to the original cylindrical form by compression, or a plurality of wrinkles are axially formed to cause a surface bucking. Such a compression or buckling requires a rather large force, compared with the bending back of an extending element formed by a slit as in the conventional way, and this joint thus has a larger pullout proof stress.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a segment joint used when assembling a segment used in a tunnel shield construction method or the like.

[0002]

2. Description of the Related Art As is well known, a structure called a segment used in a shield construction method is composed of a segment piece obtained by dividing a ring body, which is shortly divided in the tunnel axis direction, into a plurality of pieces in the circumferential direction.

The segment pieces are fastened to each other by using segment joints provided in advance in the respective segment pieces, and a hydraulic cylinder provided in a shield excavator for carrying out the shield construction method presses the segment pieces in the fastening direction. It is proposed to be done.

This conventional segment joint (Japanese Patent Laid-Open No. 7-
No. 247796) is shown in FIG. That is, when a hydraulic cylinder (not shown) presses the segment piece in the fastening direction, the male joint 3 provided on one segment piece 1 side is press-fitted into the female joint 7 provided on the other segment piece 5 to provide plasticity. It is transformed and fastening is performed.

The male joint 3 is composed of a plurality of expansion sleeves 9 each having an open front end, which are divided into a plurality of expansion pieces 11 on the front end side by slits formed in the circumferential direction and running in the axial direction.
The female joint 7 has a gap 13 having a ring-shaped cross section for receiving the male joint 3, and the center of the ring-shaped gap 13 is press-fitted into the center of the male joint 3 to expand the male joint 3, and An extension 15 to be deformed is provided.

[0006]

However, in the above-mentioned prior art (Japanese Patent Laid-Open No. 7-247796), it was difficult to obtain sufficient pull-out strength (drag resistance against pulling, the same hereinafter). That is, the plurality of expansion pieces 11 are plastically deformed by the bending force at the time of fastening.

Further, when a pulling force is applied from the outside, if plastic deformation occurs due to a bending force in the opposite direction, there is a defect that the pulling force is pulled out. The bending force at the time of fastening is given by the pressing force of the hydraulic cylinder provided in the shield excavator. The bending force necessary for pulling out is that the tip of the male joint 3 has already undergone plastic deformation,
The bending force required to deform it in the opposite direction is smaller than the bending force required to deform when pushed.

Therefore, when a pulling force larger than the force corresponding to the pressing force of the hydraulic cylinder is applied, sufficient pulling resistance cannot be obtained. Therefore,
The present invention has been made in order to solve the above problems, and an object of the present invention is to provide a joint for a segment that can obtain a more sufficient drawing resistance.

[0009]

The invention for achieving the above object is as follows. A first aspect of the present invention is a segment joint in which a male joint is press-fitted into a female joint during plastic assembly to be fastened by plastic deformation, and the male joint has a cylindrical shape of a continuous surface body having no slit portion with an open tip. The female joint has a ring-shaped gap for receiving the cylindrical male joint, and the male joint is press-fitted into the center of the cylindrical male joint at the center of the ring-shaped gap. Is a joint for a segment, which is provided with a substantially conical projection that expands.

In a second aspect of the invention, the substantially conical projection of the female joint projects toward the male joint from the female joint surface, and the diameter of the tip of the projection is larger than the cylindrical inner diameter of the male joint. A segment joint characterized by being sufficiently small.

According to a third aspect of the present invention, the substantially conical projection of the female joint projects from the female joint surface toward the male joint, and the diameter of the projection tip is the cylindrical inner diameter of the male joint. The segment joint is characterized by being sufficiently smaller.

A fourth aspect of the present invention is characterized in that the radius of the circular cross section of the substantially conical projection perpendicular to the axis is increased toward the inner side at a larger rate than when it is linear. It is a joint for a segment.

According to a fifth aspect of the present invention, the projection having the substantially conical shape is reduced in diameter at a base end portion, and a corner portion is formed by the reduction in diameter, and the corner portion is formed with the male joint in a state where the fastening is completed. A segment joint characterized in that the tips are in contact.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, one embodiment of the present invention will be described.
This will be described with reference to FIGS. As is well known, in the shield construction method, the inside of the tunnel excavated by the shield excavator is supported by a tubular structure 21 (FIG. 2) called a segment. The structure 21 is formed by connecting ring bodies 23, which are shortly divided in the tunnel axis direction, in the tunnel axis direction.

That is, the shield excavator (not shown) excavates by making the hydraulic cylinder work while applying the reaction force of the hydraulic cylinder to the already constructed structure 21. Then, when the excavation is performed by the width of the one ring body 23 in the tunnel axial direction, the hydraulic cylinder is contracted, and a new ring body 23 is arranged between the rear of the excavator and the already constructed structure 21. Then, it is fastened to the structure 21 already constructed by the segment joints 27 and 29.

The new ring body 23 is composed of a plurality of segment pieces 25 which are divided in the circumferential direction, and are fastened to each other by bolts and nuts or the like. An enlarged perspective view of the segment joints 27 and 29 used in FIG. 2 is shown in FIG.

That is, the male joint 27 has a perfect cylindrical shape with an open end. That is, the conventional slit is not provided. The female joint 29 has a ring-shaped gap 31. The size of the ring-shaped gap 31 is such that the thickness of the ring-shaped end face at the tip of the male joint 27 can be received almost barely.

At the center of the ring-shaped gap 31, a substantially conical projection 33 is formed concentrically with the gap 31.
Is provided. This protrusion 33 is the same as the male joint 27.
It has a function of expanding the male joint 27 by being pressed into the center of the.

Next, the segment joint 2 of this embodiment
A comparative experiment with the conventional example was conducted using Nos. 7 and 29. FIG.
In, the dimensions of the respective portions of the segment joints 27 and 29 of this embodiment used in the experiment will be described. Male joint 27
Has a cylindrical steel pipe embedded in the pedestal hardware 35 and fixed by welding. The outer diameter D1 of this steel pipe is 50
mm, and the wall thickness t is 5 mm. Also, pedestal hardware 3
The length L protruding from 5 is 50 mm.

A notch 37 having a triangular cross section is formed on the circumference of the pedestal metal member 35 at a portion in contact with the steel pipe. The notch 37 is for facilitating the deformation of the steel pipe. The steel pipe is fixed to the pedestal metal member 35 by welding. The depth (upward direction in FIG. 5) of the steel pipe is sufficiently deep, and when the steel pipe is fastened to the female joint 29, the escape space 38 (FIG. (B)) is formed.

In the female joint 29, a round hole is formed in an upper steel plate 39. The diameter D2 of this round hole is 63.5 mm, and the thickness of the upper steel plate is 15 mm. This upper steel plate 39
The lower steel plate 43 is welded in parallel to the inside of the through a connecting member 41 made of steel.

A truncated cone-shaped protrusion 33 is welded to the lower steel plate 43. The axis of the protrusion coincides with the axis of the hole in the upper steel plate 39. Diameter d of the tip of the truncated cone-shaped protrusion 33
Is 16.9 mm and the diameter D3 of the base is 95 mm. As for the height of the truncated cone-shaped protrusion 33, the height H to the surface of the upper steel plate 39 is 50 mm, and the height h protruding further outward from the surface of the upper steel plate 39 is 15 mm.
It is 5 mm. Therefore, the angle θ of the truncated cone-shaped slope is 30
Degrees.

It should be noted that, in the state where the fastening is completed by design, the pedestal metal piece 35 of the male joint 27 and the upper steel plate 39 of the female joint 29 are provided.
A small gap g is left between and. By providing such a gap g, sufficient fastening can be performed even when an error occurs in the axial direction of the segment, that is, the press-fitting direction. However, it is also possible to design without the gap g.

On the other hand, the conventional joint to be compared is shown in FIG. 6, and the dimensions are the same as those in FIG.
The difference is that a plurality of slits 45 are provided in the steel pipe in the axial direction. That is, 30 in the circumferential direction of the steel pipe.
15 slits 45 at 15 degree intervals in the axial direction
Provided in the length of.

The results of this experiment are shown in FIG. In the figure, (A) is the result of this embodiment, and (B) is the result of the conventional joint. As can be seen from these figures, the withdrawal force was 18 tonf for (A) and 5.0 tonf for (B). Since the strength at which fracture occurs when a steel pipe not provided with the slit 45 is fixed and a tensile force is applied is about 29 tonf in calculation, the ratio of the pulling force to this strength is (A) 62%, (B) is 1
The result was 7%.

The force required to press-fit the male joint 27 into the female joint 29 is larger in this embodiment (FIG. 3) than in the conventional type (FIG. 4), but both are shielded. It is within the range of the pressing force of the hydraulic cylinder equipped in the excavator.

The reason why a much larger pulling force can be obtained in this embodiment as compared with the conventional type is considered as follows. That is, in the case of the conventional type, the male joint 27 has 12 expansion pieces 11 due to the slits 45, and the plastic deformation due to the press-fitting occurs when these expansion pieces 11 are bent. The pull-out force is a force that causes the expansion pieces 11 to be plastically deformed again by bending in the opposite direction.

On the other hand, the pull-out force in this embodiment of the present invention is that the male joint 27 (FIG. 3B) plastically deformed by the trumpet shape by press-fitting is contracted again by the compressive force in the circumferential direction, The force required to return to the original cylindrical shape by wrinkling in the axial direction due to surface buckling or the original cylindrical shape.

Comparing these pulling forces, a very large force is not required to cause plastic deformation due to bending,
In comparison with this, an extremely large force is required to restore the original cylindrical shape by the compressive force, and a considerably large force is also required to cause buckling. From these facts, it is considered that this embodiment can obtain a much larger pulling force than the conventional type.

Further, according to this embodiment, the female joint 2
The projection 33 of 9 projects from the surface of the upper steel plate 39 of the female joint 29 to the male joint 27 side, and the diameter d of the tip of the projection 33 is sufficiently larger than the cylindrical inner diameter D1 of the male joint 27. Since it is small (FIG. 3), even if the eccentricity e (FIG. 6) is generated between the axes of the male joint 27 and the female joint 29, the guide due to the protrusion of the protrusion 33 is sufficient at the time of fastening. Therefore, the tip of the protrusion 33 easily enters the cylindrical male joint 27, the male joint 27 is guided by the protrusion 33, the eccentricity error can be absorbed, and the fastening can be performed. In the experiment of the joint having the dimensions described with reference to FIG. 3, the fastening could be performed without any problem up to the eccentricity e = 5 mm.

(Other Embodiments) In the above embodiments, the protrusion 33 of the female joint 29 has a perfect truncated cone shape.
That is, the radius of the cross section perpendicular to the axis of the protrusion 33, that is, the radius of the circular cross section, increases linearly in the inward direction, that is, in the direction opposite to the press-fitting direction.

However, as shown in FIG. 7, the shape may be further increased in a curved line instead of a straight line. In this case, the tip end of the male joint 27 expanded like a trumpet has a wider diameter, and a larger pull-out resistance can be obtained.

Further, as shown in FIG. 8, the curve of the increasing rate in which the radius increases may have a curvature changing on the way. Further, in another embodiment, as shown in FIG. 9 or 10, the base end portion of the protrusion 33 may have a reduced diameter.

A corner portion 47 is formed by this reduced diameter, and the position of the corner portion 47 can be a position where the tip of the male joint 27 can come into contact with the joint when fastening is completed. . The expanded male joint 27 tries to spring back at the reduced diameter portion and strongly contacts this corner portion 47, so that it is in a state of being hooked by the corner portion. Therefore, the pull-out resistance can be further increased. further,
The surface of the protrusion 33 may be provided with a convex circle, a band-shaped emboss, or the like. The frictional force for embossing is increased, and the pull-out resistance can be increased.

In the above embodiment, the male joint 27 is used.
Although the female joint 29 is made of steel, it may be made of plastic or the like in other embodiments. Especially at this time, the male joint 27
The length L (see FIG. 3) must be dimensioned so that cracks do not occur at the tip when fastening is completed in relation to the wall thickness t. In addition, in the female joint 29, for example, the protrusion 3
3, parts corresponding to the connecting member 41 and the lower steel plate 43 may be made of cast steel, and then welded or bolted to the upper steel plate 39.

It should be noted that the actual dimensions in each of the figures described above with reference to FIG. 3 are for experimental purposes, and of course other dimensions may be adopted in other embodiments. At that time, it is desirable to determine the main dimensions of each part as follows (unit: mm). D2 ≧ D1 + 2e a = t · sec θ + 1.0 h = (1/2 (D3-D1) + e + t) cot θ−H + 10

Here, the symbols are as follows. D2: hole diameter of upper steel plate, D1: outer diameter of steel pipe, e: eccentricity between shafts of male joint and female joint during segment assembly, a: (D2-D1) / 2, t: wall thickness of steel pipe, θ: Inclined angle of frustum protrusion, h: Height of truncated cone protrusion from upper steel plate, D3: Diameter of base, H: Height of truncated cone to upper steel plate

[0038]

As described above, according to the present invention, since the male joint is not formed with the conventional slit, the male joint which is plastically deformed into a trumpet shape by fastening is
At the time of pulling out, an extremely large force is required to restore the original cylindrical shape due to the compression force associated with the pulling out, and a considerably large force is also required to cause surface buckling. Therefore, the pulling-out proof strength larger than the conventional one can be obtained (claim 1).

Furthermore, by making the substantially conical projection of the female joint project from the female joint surface and / or making the diameter of the tip sufficiently smaller than the cylindrical inner diameter of the male joint, Fastening can be performed even when eccentricity e is generated between the shafts of the joint and the female joint (claims 2 and 3).

By increasing the rate of increase in the radius of the circular cross section of the protrusion, the tip of the male joint expanded in a trumpet shape has a wider diameter, and a larger pulling strength can be obtained. Item 4). When the tip of the male joint comes into contact with the corner formed by reducing the diameter of the base end of the protrusion, the expanded male joint becomes, so to speak, hooked by the corner, further increasing pull-out resistance. (Claim 5).

[Brief description of drawings]

FIG. 1 is a perspective view of a joint according to an embodiment of the present invention.

FIG. 2 is a schematic overall perspective view showing a state where segments are assembled by the segment piece having the joint shown in FIG.

3A and 3B are vertical cross-sectional views of the joint of FIG. 1, where FIG. 3A is a cross-sectional view before fastening and FIG. 3B is a cross-sectional view after fastening.

FIG. 4 shows a joint to be compared in an experiment,
(A) is a perspective view before fastening, (B) is a front end view of the male joint of (A).

5A and 5B are diagrams showing an experimental result of a comparative experiment, FIG. 5A is a diagram showing a result of this embodiment, and FIG. 5B is a diagram showing a result of a comparison target.

FIG. 6 is a diagram showing another operation and effect of this embodiment,
(A) is a sectional view before fastening and (B) is a sectional view after fastening.

FIG. 7 is a sectional view of a joint according to another embodiment of the present invention after fastening.

FIG. 8 is a sectional view of a joint according to another embodiment of the present invention after fastening.

FIG. 9 is a sectional view of a joint according to another embodiment of the present invention after fastening.

FIG. 10 is a cross-sectional view after fastening of a joint according to another embodiment of the present invention.

FIG. 11 is a sectional view showing a joint of a conventional example.

[Explanation of symbols]

 21 segment 25 segment piece 27 male joint 29 female joint 31 ring-shaped gap 33 protrusion 47 corner

Claims (5)

[Claims] 1. A segment joint in which a male joint is press-fitted into a female joint to be plastically deformed and fastened at the time of assembling a segment, wherein the male joint has a cylindrical shape of a continuous surface body with an open end. The mold joint has a ring-shaped gap that receives the cylindrical male joint, and the center of the ring-shaped gap expands the male joint press-fitted into the center of the cylindrical male joint. A segment joint characterized in that it is provided with a projection having a shape. 2. The segment joint according to claim 1, wherein the diameter of the substantially conical projection of the female joint is sufficiently smaller than the cylindrical inner diameter of the male joint. 3. The substantially conical projection of the female joint projects toward the male joint from the female joint surface, and the diameter of the projection tip is sufficiently smaller than the cylindrical inner diameter of the male joint. The segment joint according to claim 1, wherein: 4. The increasing rate at which the radius of the circular cross section perpendicular to the axis of the substantially conical projection increases toward the inside is larger than that in the case of being linear. 3. The segment joint described in any one of 3. 5. The projection of the substantially conical shape is reduced in diameter at the base end, and a corner is formed by this reduction, and the tip of the male joint contacts the corner when the fastening is completed. The joint for a segment according to any one of claims 1 to 4, wherein