JP2000193138A - Laying structure and method for pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laying method for a pipe which can arrange an invert member around a small diameter pipe with satisfactory workability without fixing column nor supporting beam, grout such as mortar can be pressurizingly charged between the invert member and the small diameter pipe. SOLUTION: A small diameter pipe 3 is supported and fixed by an upper surface of a pipe pad member 2 arranged in and fixed to a bottom of a large diameter pipe 12 with a spacing. A scaffolding plate 5 is installed on the bottom of the large diameter pipe 12 other than the position where the small diameter pipe 3 is mounted. Cross beam members 6 are arranged and fixed with spacings in an axial direction so as to stride over the small diameter pipe 3. A lengthy FRP invert member 7 having a reinforcing rib continued longitudinally on one side surface is fixed onto the cross beam member 6, over all length of the small diameter pipe 3. Grout 8 is charged into a space S prepared by the invert member 7, an outer surface of the small diameter pipe 3, and an inner surface of the large diameter pipe 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe laying structure in which a small-diameter pipe is laid inside a large-diameter pipe, and a method of laying the pipe.

[0002]

2. Description of the Related Art Conventionally, as a method of laying a small-diameter pipe in an existing or primary-lined large-diameter pipe, for example, Japanese Unexamined Patent Publication No.
JP-A-157271, a method in which a mounting base is installed at the center of the bottom of a large-diameter pipe, a small-diameter pipe is mounted on the base, and the outer periphery of the small-diameter pipe is fixed with a U-shaped steel band. Is described.

In the pipe laying structure obtained by the above method, a space formed by the inner surface of the large-diameter pipe and the outer surface of the small-diameter pipe is used, for example, as a conduit for sewage or medium water. In consideration of this, upward buoyancy acts on the small-diameter pipe. For this reason, it is necessary to firmly fix to the bottom of the large diameter pipe with more U-shaped steel bands with a fixing force that overcomes this buoyancy. Further, since the steel band is exposed to sewage, it is necessary to use a material having excellent corrosion resistance such as stainless steel.

[0004] For this reason, since the stainless steel band itself is relatively expensive, there arises a problem that the construction cost is relatively high. In addition, since both ends of the steel band are fixed to the bottom of the large-diameter pipe, a local tensile load acts on the bottom of the large-diameter pipe, thereby deteriorating the strength of the large-diameter pipe. Also occurs.

Further, the small diameter pipes are connected to each other by inserting the inlet of the adjacent small diameter pipe into the receptacle of the small diameter pipe, so that the receptacle extends over the entire length of the pipeline, and The inner bottom surface of the large diameter pipe is not flat over the entire length of the pipe. For this reason, there also arises a problem that flow characteristics of sewage and the like are deteriorated.

[0006]

Therefore, the present inventors covered the entire circumference of the small-diameter pipe 3 with a curved inverting member 7 made of FRP resin, and provided the inverting member 7 and the small-diameter pipe 3 to each other. Of the grouting material 8 such as mortar into the space S formed by the outer surface of the large diameter pipe 12 and the inner surface of the large diameter pipe 12 and hardened.

In order to inject the mortar 8 into the space S, a certain injection pressure is required. Therefore, in order to prevent distortion and deformation of the inverting member 7 due to the injection pressure, as shown in FIG.
22 had to be arranged vertically and horizontally. After the mortar 8 has hardened, the fixing support columns 121 and the support beams 122 must be removed. For this reason, there have been problems that many man-hours are required for attaching and detaching the fixing support pillars and the support beams, workability is poor, and construction costs are high.

Further, the inverting member 7 with the mortar 8
In order to improve the adhesion of the mortar 8, it is necessary to perform a post-treatment such as a sanding treatment on one side of the inverting member 7 in contact with the mortar 8. However, there is a limit to the improvement of the adhesiveness in spite of the trouble.

An object of the present invention is to provide a pipe laying structure in which a space formed by an inner surface of a large-diameter pipe and an outer surface of a small-diameter pipe can also be used as a pipe for sewage or the like. It is.

Another object of the present invention is to provide a pipe laying structure in which the grout material injected and hardened between the inverting member and the small-diameter pipe and the adhesion to the inverting member are significantly improved. .

SUMMARY OF THE INVENTION It is an object of the present invention to provide an inverting member which can be disposed around a small-diameter pipe with good workability along a longitudinal direction thereof without using a fixing support column or a supporting beam which needs to be detached. To provide a pipe laying method capable of injecting a grout material such as mortar between a small-diameter pipe and a small-diameter pipe.

[0012]

According to the first aspect of the present invention,
A small-diameter pipe is placed on the upper surface of a pipe pillow material arranged in the longitudinal direction at the bottom of the large-diameter pipe, and the longitudinal direction is placed on the bottom of the large-diameter pipe excluding the portion where the small-diameter pipe is placed. A scaffolding plate is arranged along, and on a girder material that is arranged at intervals in the pipe axis direction across the small-diameter pipe, continuously on one side facing the outer surface of the small-diameter pipe along its longitudinal direction. A long inverting member having a reinforcing rib is arranged over the entire length of the small-diameter pipe, and grout material is injected and hardened into a space formed by the inverting member, the outer surface of the small-diameter pipe, and the inner surface of the large-diameter pipe. This is the pipe laying structure.

According to a second aspect of the present invention, a small-diameter pipe is supported on an upper surface of a pipe pillow material disposed at the bottom of a large-diameter pipe, and a beam member having a predetermined shape is reduced around the small-diameter pipe. Elongate with a spacing in the pipe axis direction with the diameter pipe straddling, and on this girder material, a reinforcing rib continuous along its longitudinal direction on one side facing the outer surface of the small diameter pipe Is arranged over the entire length of the small-diameter pipe, and a grout material is injected into a space formed by the invert member, the outer surface of the small-diameter pipe, and the inner surface of the large-diameter pipe.

The material of the pipe pillow material in the present invention may be made of natural wood or concrete. However, in consideration of workability such as handling, hard material reinforced with long fibers such as glass roving is used. It is desirable to use a synthetic resin made of urethane foam resin. This synthetic resin is lightweight and has excellent mechanical strength and corrosion resistance.

In the present invention, the material of the inverting member is
An FRP material reinforced with a reinforcing fiber such as a glass fiber or a laminated type made of an FRP panel member and a thermoplastic resin panel member can be used. A plurality of reinforcing ribs are integrally provided on the side of the inverting member that comes in contact with the grout material along the radial direction of the small diameter pipe. In addition, as the invert member made of FRP, a long member manufactured by, for example, pultrusion molding is preferable.

In the present invention, the material of the girder material is metal or F
What is necessary is just the thing made from RP. The cross-sectional shape of the girder member is desirably an inverted L-shape, T-shape, or U-shape. The shape of the girder material may be determined in accordance with the position of the small-diameter pipe disposed at the bottom in the large-diameter pipe. For example, when the small-diameter pipe is laid on one side of the bottom of the large-diameter pipe, it may be an inverted L-shaped pipe, and the small-diameter pipe is laid at the center of the bottom of the large-diameter pipe. In this case, a U-shape that opens downward may be used. (Action)

In the pipe laying structure according to the first aspect,
A small-diameter pipe is placed on the upper surface of a pipe pillow material arranged in the longitudinal direction at the bottom of the large-diameter pipe, and the longitudinal direction is placed on the bottom of the large-diameter pipe excluding the portion where the small-diameter pipe is placed. A scaffolding plate is arranged along, and on a girder material that is arranged at intervals in the pipe axis direction across the small-diameter pipe, continuously on one side facing the outer surface of the small-diameter pipe along its longitudinal direction. A long inverting member having a reinforcing rib is arranged over the entire length of the small-diameter pipe, and grout material is injected and hardened into a space formed by the inverting member, the outer surface of the small-diameter pipe, and the inner surface of the large-diameter pipe. The injection pressure does not cause distortion or deformation of the inverting member, and grouting is performed by applying a predetermined injection pressure to the space formed by the inverting member, the outer surface of the small-diameter pipe, and the inner surface of the large-diameter pipe. Material can be injected.

A reinforcing rib continuously extending in the longitudinal direction on one side of the inverting member is buried and locked in the grout material, and the inverting member is formed of a pipe firmly adhered to the grout material. Laying structure.

Since the upper surface of the inverting member is flat in the axial direction of the pipe, the space formed by the inner surface of the large-diameter pipe and the upper surface of the inverting member also has a good flow characteristic for sewage or medium water. Can be used as a conduit.

According to a second aspect of the present invention, there is provided a pipe laying method, wherein a small-diameter pipe is supported on an upper surface of a pipe pillow material arranged at the bottom of a large-diameter pipe, and a girder having a predetermined shape is provided around the small-diameter pipe. The material is arranged at intervals in the pipe axis direction while straddling the small-diameter pipe, and on this girder material, there is a reinforcing rib continuous along the longitudinal direction on one side opposite to the outer surface of the small-diameter pipe. A long invert member is placed over the entire length of the small-diameter pipe,
Since the grout material is injected into the space formed by the invert member, the outer surface of the small-diameter pipe, and the inner surface of the large-diameter pipe, the invert member is temporarily fixed on the girder material, thereby reducing the grout material. The grout material can be injected into the space through a predetermined injection hole without causing distortion or deformation of the invert member due to the injection pressure.

The reinforcing ribs of the invert member arranged over the entire length of the small diameter pipe are buried and locked in the grout material over substantially the entire length, so that the invert member is firmly attached to the grout material. Laying structure can be obtained.

As described above, since the reinforcing rib of the inverting member is buried in the grout material as it is over substantially the entire length, workability and workability are remarkably improved as compared with the method using the fixing support pillar or the support beam. .

[0023]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a first embodiment of a pipe laying structure of the present invention, FIG. 2 is an enlarged sectional view of a main part of FIG. 1, and FIG. 3 is a partially enlarged view showing a state where an invert member is attached to a girder member. FIG. 4 is an explanatory sectional view of the inverting member, and FIG.
FIG. 4 is a sectional view taken along line XX of FIG. 3.

In FIG. 1, reference numeral 1 denotes a tunnel constructed by secondary lining on the ground by a shield method, and a steel form segment ring 11 and a large-diameter FRPM pipe (nominal diameter 1800 mm). The mortar 13 is a backfill material injected and hardened into a gap between the large-diameter tube 12 and the segment ring 11.

Reference numeral 2 denotes a pipe pillow material, which is disposed at a predetermined interval in the longitudinal direction at the bottom of the large-diameter pipe 12 and has bolts 2.
5 and a nut 26. A turnbuckle 42 is screwed into the upper end of the bolt 25. The pipe pillow material 2 is a rectangular column made of hard urethane foam resin reinforced by glass roving, and its lower surface 21 is provided with a large-diameter pipe 12.
Has an arcuate curved surface corresponding to the inner surface of. As shown in FIG. 2, the curved surface portion is provided with grooves 27, 27 having a semicircular cross section and communicating in the tube axis direction.

As shown in FIG. 2, a groove 24 having a substantially trapezoidal cross section is provided on the upper surface on the left side of the pipe pillow material 2 over its entire length in the width direction. The dovetail groove 24 is adapted to be fitted with a part of a beam material described later connecting the pipe pillow materials 2 along the longitudinal direction of the pipe. The depth of the dovetail groove 24 is substantially the same as the thickness of the beam so that the beam can be fitted flush.

3 is a small-diameter cast iron pipe (nominal diameter 700
mm), and is placed on the upper surface on the right side of the pipe pillow material 2 and is fixed by a band-shaped fixing band 4. That is, as shown in FIG. 2, one ends of bolts 41, 41 are welded and fixed to the upper surfaces of both ends of the fixing band 4, and the other ends of the bolts 41 are connected to the turnbuckle 42 on the pipe pillow material 2 side. Bolt 121 having one end fixed to the lower wall of bore tube 12
Are fastened and fixed by being screwed with a turnbuckle 42 screwed to the other end of the buckle. In this case, the center of the small-diameter pipe 3 is laid so as to be displaced to the right side of the bottom of the large-diameter pipe 12 by about 350 mm from the center of the large-diameter pipe 12.

Reference numeral 5 denotes a scaffold plate, which is disposed along the longitudinal direction on the left side of the bottom of the large-diameter pipe 12 excluding the portion where the small-diameter pipe 3 is placed, and is provided on the upper surface of the pipe pillow material 2 and the beam. Lumber 5
1 is fixed to the upper surface with nails or the like. That is, a gap is formed between the lower surface of the scaffold plate 5 and the inner surface of the bottom of the large-diameter pipe 12 except for the portion where the pipe pillow material 2 exists.

Numeral 6 denotes a stainless steel beam, which is formed in a substantially inverted L-shape by bending both ends in the longitudinal direction of an angle material having a T-shaped cross-section. The beam member 6 has an upper horizontal portion 61, an intermediate inclined portion 62, and a lower vertical portion 63. On each of the upper surfaces of the upper horizontal portion 61, the intermediate inclined portion 62, and the lower vertical portion 63, one or two square tubular mounting seats 64 are fixed by welding. The height of the mounting seat 64 is substantially the same as the protruding length of a reinforcing rib of an inverting member described later.

The position where the mounting seat 64 is fixed is as follows.
As shown in FIG. 3, it is located between the reinforcing ribs of the inverting member. A plurality of beam members 6 are arranged over the small diameter pipe 3 at intervals of about 4 m in the pipe axis direction. The end of the girder member 6 is located at the end of the upper horizontal portion 61, for example, on an L-shaped angle member fixed to the inner surface of the wall of the large-diameter tube 12, while the end of the lower vertical portion 63 is located on the tube pillow material 2. Each is fixed to the upper surface of the scaffold plate 5 with screws or the like.

Reference numeral 7 denotes an inverting member made of FRP manufactured by pultrusion molding, which is a long member having a length of about 4 m. As shown in FIG. 4, projecting reinforcing ribs 71 are integrally provided at predetermined intervals on the lower surface side of the inverting member 7 at a predetermined interval. A stop 711 is provided. In the case of this embodiment, three types of inverting members 7 are prepared: an inverting member 7a for the upper horizontal portion 61, an inverting member 7b for the inclined portion 62, and an inverting member 7c for the lower vertical portion 63. I have.

The invert members 7a, 7b, 7c
Are arranged over the entire length of the small-diameter pipe 3 at predetermined intervals around the small-diameter pipe 3, and as shown in FIG. 5, the upper horizontal portion 61, the intermediate inclined portion 62, and the lower vertical portion 63 Each mounting seat 64 fixed to the upper surface by welding is fixed to a half of the upper surface with screws or the like.

The lower end of the inverting member 7c is on the upper surface side of the scaffold plate 5, and the side end of the inverting member 7a is a large-diameter pipe 12
Are fixed in a watertight manner on the wall surface side. As shown in FIG. 5, the ends of the inverting members 7a, 7b, 7c in the longitudinal direction are also fixed in a watertight manner at the ends of the adjacent inverting members and the beam member 6.

Then, the inverting member 7 and the small-diameter pipe 3
The air mortar 8, which is a grout material, is injected from an injection port (not shown) into a space S formed by the outer surface of the inner diameter of the large diameter pipe 12 and the inner surface of the lower half part of the large diameter pipe 12, and is hardened. The small-diameter pipe 3 is laid on the bottom of the pipe 12.

The pipe laying structure shown in FIG. 1 is laid in the following manner. First, a plurality of pipe pillows 2 are arranged at predetermined intervals in the longitudinal direction at the bottom of a large-diameter pipe 12 constituting a tunnel 1 secondary-lined by a shield method, and bolts 25. It is fixed with a nut 26.
A bolt 25 is fixed to the bottom of the large-diameter pipe 12 in which the pipe pillows 2 are arranged. On the other hand, a bolt insertion hole through which the bolt 25 is inserted is formed in advance on the pipe pillow material 2 side.

At the same time when the pipe pillows 2 are arranged and fixed, the pipe pillows 2 are connected to each other by the beams 6 along the longitudinal direction of the pipe using the dovetail grooves 24 of the pipe pillows 2. Then, the scaffold plate 5 is arranged along the longitudinal direction of the large-diameter pipe 12 on the upper surface of the pipe pillow material 2 and the upper surface of the beam material 6 located on the left side of the beam material 6 in the drawing, and It is fixed to the pillow material 2 and the beam material 6.

The small-diameter pipe 3 is conveyed into the large-diameter pipe 12 by using a bogie or the like while using the portion on which the scaffold plate 5 is laid as a work passage. The small-diameter pipes 3 are placed unevenly and laid while connecting adjacent small-diameter pipes 3. After the installation of the small-diameter pipe 3 is completed, the bolts 41, 41 at both ends of the fixing band 4 are screwed with the turnbuckles 42, 42, and the small-diameter pipe 3 is fastened and fixed by the fixing band 4. Note that the scaffold plate 5 may be installed after the arrangement and fixation of the small-diameter pipe 3 is completed.

After the small-diameter tube 3 is securely fastened by a plurality of fixing bands 4 over its entire length, the small-diameter tube 3 is straddled over the small-diameter tube 3 at predetermined intervals in the longitudinal direction of the small-diameter tube 3. A plurality of girders 6 are arranged and fixed. Next, using the beam member 6, the small diameter pipe 3 is surrounded around the entire length of the pipe by inverting members 7a, 7b, 7c. At this time, as shown in FIG.
a, 7b, 7c are placed on the beam members 6, 6, and the upper horizontal portion 61 of the beam member 6 is mounted on the mounting member 64 using screws or the like.
It is fixed on the middle inclined portion 62 and the lower vertical portion 63.

Also, a thickness adjusting material also serving as a sealing material is interposed in the overlapped portion of the inverting member 7a and the inverting member 7b and riveted with a screw or the like. The overlap portion of the invert member 7b and the invert member 7c is similarly riveted. Further, the lower end of the inverting member 7c is fixed to the scaffold plate 5 side, and the side end of the inverting member 7a is fixed to the wall surface side of the large-diameter pipe 12 in a watertight manner.

Next, the inverting member 7 and the small-diameter pipe 3
Of the air mortar 8 through an injection hole (not shown) in the space S formed by the outer surface of the
Is pressurized and cured. In this way, the pipe laying structure shown in FIG. 1 is obtained. In this case, since there is a gap between the lower surface of the scaffold plate 5 and the inner surface of the bottom of the large-diameter pipe 12, the injected air mortar 8 is filled in this gap.

As described above, by providing the plurality of reinforcing ribs 71 on the lower surface side of the inverting member 7, the rigidity of the inverting member 7 is significantly increased, and the effect of preventing the distortion and deformation of the inverting member due to the injection pressure of the air mortar 8 is provided. Is further improved.

Further, since grooves 27 having a semicircular cross-section in the pipe axis direction are provided at two places on the lower surface 21 side of the pipe pillow material 2, the air mortar 8 is adjacent to the space through the grooves 27, 27. S will be filled without gaps.

The injection hole may be closed with a cap after the air mortar 8 is injected. 9 is air mortar 8
The lower end of the hose is fixed to a predetermined portion of the scaffold plate 5 and communicates with the space S.

In the above embodiment, the inverting member 7 is directly fixed on the girder 6, but as shown in FIG. 6, a joint member 6A made of hard rubber is fixed on the girder 6 by bonding. The reinforcing rib 71 of the inverting member 7 may be pushed into the fitting groove 61A of the member 6A and fitted. At this time, it is desirable that the locking portion 711 at the tip of the reinforcing rib 71 be locked to the bottom of the fitting groove 61A. The joint member 6A may be made of synthetic resin or FRP.

As described above, by fixing the joint member 6A having the fitting groove 61A on the beam member 6, the work of mounting the invert member 7 can be performed more easily.

In the above embodiment, the small-diameter tube 3 is placed on the upper surface 22 on one end side of the tube pillow material 2. However, a concave portion for placing a tube having an arc-shaped inner surface is provided in a corresponding portion. Alternatively, the bottom of the small-diameter tube 3 may be supported by the inner surface of the concave portion. When the concave portion for mounting the pipe is provided on the upper surface of the pipe pillow material 2 as described above, the rolling of the small diameter pipe 3 can be prevented, and the small diameter pipe 3
Work can be done safely.

[0047]

According to the pipe laying structure of the first aspect, distortion and deformation of the invert member due to the injection pressure are caused in the space formed by the invert member, the outer surface of the small-diameter tube, and the inner surface of the large-diameter tube. The laying structure is such that the grout material is injected by applying a predetermined injection pressure without occurrence. The reinforcing rib of the inverting member is embedded in the grout material, so that the inverting member has a structure firmly attached to the grout material.

Further, the inverting member is a long one having a reinforcing rib continuous on one side thereof along the longitudinal direction, and is arranged at intervals in the pipe axis direction while straddling a small-diameter pipe. Since the inverting member is fixed on the girder material, the inverting member is not deformed or deformed by the injection pressure, and a predetermined injection is performed into a space formed by the inverting member, the outer surface of the small-diameter tube, and the inner surface of the large-diameter tube. Grout material can be injected under pressure.

The fitting rib, which is continuous on one side of the inverting member in the longitudinal direction, is embedded and locked in the grout material, and the inverting member is a tube firmly attached to the grout material. Laying structure.

Since the upper surface of the inverting member is flat in the axial direction of the pipe, the space formed by the inner surface of the large-diameter pipe and the upper surface of the inverting member also has good flow characteristics for sewage or medium water. Can be used as a conduit.

Further, the portion of the scaffold plate disposed along the longitudinal direction at the bottom of the large-diameter pipe excluding the portion where the small-diameter pipe is placed is used as a passage for inspection, thereby providing a pipe line. Inspection inside can be done safely with good workability.

According to a second aspect of the present invention, there is provided a pipe laying method in which a girder material is arranged and fixed around a small-diameter pipe in the axial direction of the pipe with the small-diameter pipe straddling the small-diameter pipe. After placing a long inverting member having a reinforcing rib continuous on its side along its longitudinal direction over the entire length of the small-diameter pipe, the inverting member is formed by the outer surface of the small-diameter pipe and the inner surface of the large-diameter pipe. Since the grout material is injected into the space, the invert member is temporarily fixed on the girder material,
The grout material can be injected into the space through a predetermined injection hole without causing distortion or deformation of the invert member due to the injection pressure of the grout material.

Also, since the reinforcing ribs of the invert member disposed around the small diameter pipe are buried and locked in the grout material over substantially the entire length, the pipe laying structure in which the invert member is firmly attached to the grout material Can be obtained.

Further, since the girder material is also buried in the grout material, there is no need to remove the girder material, and workability and workability are good.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of a pipe laying structure of the present invention.

FIG. 2 is an enlarged sectional view showing a main part of FIG.

FIG. 3 is an enlarged view of a main part showing a mounting part of an invert member in FIG. 1;

FIG. 4 is a sectional view showing an example of an invert member.

FIG. 5 is a sectional view taken along line XX of FIG. 3;

FIG. 6 is a partial perspective view showing a modified example of a girder member.

FIG. 7 is an explanatory view showing a conventional method of fixing an inverting member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tunnel 12 FRPM pipe (large diameter pipe) 2 Pipe pillow material 22 Top surface 3 Cast iron pipe (small diameter pipe) 4 Belt-shaped fixed band 41 Bolt 5 Scaffold plate 6 Girder material 6A Joint member 61A Fitting groove 61 Upper horizontal part 62 Middle Inclined portion 63 Lower vertical portion 64 Mounting seat 7 Inverting member 71 Reinforcement rib 711 Locking portion 8 Air mortar S Space

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shunji Higashi 75, Nojiri, Ritto-cho, Kurita-gun, Shiga Prefecture Inside Sekisui Chemical Co., Ltd. (72) Inventor Masanori Takahashi 2082 Junwell, Ichihara-shi, Chiba Komatsu

Claims (2)

[Claims] 1. A small-diameter pipe is placed on an upper surface of a pipe pillow material arranged in a longitudinal direction at a bottom portion of the large-diameter pipe, and a small-diameter pipe in a large-diameter pipe excluding a portion where the small-diameter pipe is placed is mounted. A scaffold plate is arranged on the bottom along the longitudinal direction thereof, and on a girder material straddling the small-diameter pipe and arranged at intervals in the pipe axis direction, the scaffold plate is disposed on one side opposite to the outer surface of the small-diameter pipe. A long inverting member having reinforcing ribs continuous along the direction is disposed over the entire length of the small-diameter pipe, and grout is formed in a space formed by the inverting member, the outer surface of the small-diameter pipe, and the inner surface of the large-diameter pipe. A pipe laying structure characterized by the material being injected and cured. 2. A small-diameter pipe is supported on an upper surface of a pipe-pillow material in which a pipe-pillow material is arranged at the bottom of a large-diameter pipe, and a girder member having a predetermined shape is provided around the small-diameter pipe. A long invert having a reinforcing rib continuous along its longitudinal direction on one side opposite to the outer surface of the small-diameter pipe on this girder material, with a spacing in the pipe axis direction while straddling A method of laying a pipe, comprising disposing a member over the entire length of a small-diameter pipe, and injecting a grout material into a space formed by the inverting member, the outer surface of the small-diameter pipe, and the inner surface of the large-diameter pipe.