JPH08145278A - Protection cover for underground pipe or tube - Google Patents

Abstract

PURPOSE: To provide a protection cover for a pipe burried underground capable of being shortened in the exavation length in the non-open-cut method. CONSTITUTION: A protection cover for an underground tube such as a gas tube is in an almost cylindrical shape and has a cross section perpendicular to the axis is a substantially circular shape one part of which is cut. Both ends facing the cut part of the protection cover 21 forms a cut lug part 24 along the axial direction. On the inner circumferential face of the cover 21 a plurality of ribs 233 are formed in the axial direction. A plurality of slits 22 are formed at an interval in the longitudinal direction extending in the circumferential direction from the axial direction. The slit 22 can absorb the displacement of bending through the enlarged slit width, whereby the flexibility of the cover 21 is improved remarkably. In the non-open-cut method, the excavation length can be reduced widely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective cover for underground pipes such as gas pipes.

[0002]

2. Description of the Related Art Generally, underground pipes such as gas pipes (which may be simply referred to as gas pipes hereinafter) are highly likely to be damaged or damaged by excavation due to construction after burial, and therefore have a protective cover. .

FIG. 7 is a perspective view showing a simplified state of mounting a conventional protective cover for a gas pipe in an excavation method. As a method for burying the gas pipe 1, an excavation method for laying the gas pipe 1 in a groove 2 excavated by an excavator such as a drag shovel called a backhoe is generally used.
In that case, since the gas pipe 1 is laid in the groove 2 in an exposed state, the protective cover 3 can be easily attached to the gas pipe 1. As a protective cover to protect the conventional gas pipe,
For example, the device disclosed in Japanese Utility Model Publication No. 2-28815 is known.

FIG. 8 is a perspective view showing a simplified structure of a conventional gas pipe protective cover, and FIG. 9 is shown in FIG.
FIG. 9 is a cross-sectional view showing a state of mounting the gas pipe protective cover shown in FIG. 9 on the gas pipe, FIG. 9 (1) is a sectional view showing a state of the protective cover before being mounted on the gas pipe, and FIG. It is sectional drawing which shows the state of the protective cover after mounting | wearing a pipe.

The protective cover 3 is a substantially circular cylindrical member whose cross section is partially cut away. The cutout edges of the protective cover 3 form cutout ears 4 along the axial direction, and an opening 6 is formed between the ears. A plurality of ribs 5 are formed on the inner peripheral surface of the protective cover 3 along the axial direction of the protective cover 3. Therefore, the rigidity of the protective cover 3 becomes very high. However, its flexibility is extremely poor. As shown in FIG. 9 (1), the protective cover 3 is attached by enlarging the opening 6 of the protective cover 3 in the direction of the arrow 7 to a virtual line 8 and forcibly in the direction of the arrow 9 toward the gas pipe 1. It is done by pushing. After mounting the protective cover 3, FIG.
As shown in (2), the rib 5 forms a gap between the gas pipe 1 and the protective cover 3. Therefore, when the rib 5 comes into contact with an excavator such as a backhoe, the buffer action of the gap prevents damage or damage to the gas pipe 1. To be prevented.

[0006]

As described above, in burying a gas pipe by the excavation method, the conventional gas pipe protective cover 3 is preferably used. However, in recent years, the non-open cutting method has been increasingly adopted due to the deterioration of the construction environment.

FIG. 10 is an explanatory view showing a state of application of a conventional gas pipe protective cover in a non-open cutting method. In the non-excavation method, the first excavation hole 11 and the second excavation hole 12 are excavated at intervals in the gas pipe laying path. First
A propulsion device 13 is installed in the excavation hole 1, and the propulsion device 13 pushes the head 14 toward the second excavation hole 12 while adding the rod 15 to drill into the ground. After the pressing is completed, one end of the mounting jig 16 is mounted on the tip of the head 14.
The gas pipe 1 with the protective cover 3 attached is attached to the other end of the attachment jig 16. After that, the head 14 is pulled back in the opposite direction, and the gas pipe 1 with the protective cover 3 attached is pulled in the direction of arrow 17 into the hole formed by the propulsion device 13. Since the length of the second drill hole 12 is drilled at least longer than the length of the protective cover 3 in order to mount the protective cover 3 having extremely poor flexibility on the gas pipe 1, in the second drill hole 12 The protective cover 3 can be sequentially attached to the gas pipe 1. Therefore, when the pulling back of the head 14 is completed, the embedding of the gas pipe 1 with the protective cover 3 attached is also completed.

As described above, according to the non-open cutting method, the excavation length is greatly shortened as compared with the open cutting method, but recently, there has been a demand for further reduction of the excavation length in the non-open cutting method. In order to reduce the excavation length in the non-excavation method, at least the length of the protective cover 3 is required.
The challenge is to reduce the length of the drill hole 12. As described above, the length of the second excavation hole 12 is restricted by the protective cover 3 having extremely poor flexibility. Therefore, in order to solve the above-mentioned problems, the development of the protective cover 3 having both strength and flexibility. Is required.

An object of the present invention is to provide a protective cover for an underground pipe which can shorten the excavation length in the non-excavation method.

[0010]

DISCLOSURE OF THE INVENTION According to the present invention, in a substantially circular cover having a partially cutaway cross section for surrounding and protecting a synthetic resin pipe buried in the ground, both ends facing the notched part. A protective cover for an underground pipe, characterized in that a plurality of slits extending in the circumferential direction from the edges are formed at intervals in the longitudinal direction.

[0011]

According to the present invention, the protective cover which surrounds and protects the underground pipe made of synthetic resin has a substantially circular cross section, and has a substantially circular shape in the circumferential direction from both edges facing the notched part. A plurality of slits extending in the longitudinal direction are formed at intervals in the longitudinal direction. Since the flexibility of the protective cover is greatly improved by forming the slit, it is possible to bend the synthetic resin underground pipe with the protective cover bent into the excavation hole shorter than the length of the protective cover in the non-cutting method. It will be possible. For this reason, the excavation length can be significantly reduced as compared with the prior art in which an excavation hole longer than the length of the protective cover is required.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a perspective view showing a simplified structure of a protective cover for an underground pipe, which is an embodiment of the present invention, and FIG. 1 (1) shows a state under no load. Reference numeral 1 (2) shows a state at the time of bending.

The protective cover 21 for the underground buried pipe is a substantially cylindrical member, and its cross section perpendicular to the axis is a substantially circular shape with a part cut away. Both end edges of the protective cover 21 facing the cutouts form cutout ears 24 along the axial direction, and an opening 25 is formed between the two ears. Protective cover 2
A plurality of ribs 23 are formed on the inner peripheral surface of No. 1 along the axial direction of the protective cover 21. The formation of the ribs 23 makes the protection cover 21 extremely rigid. A plurality of slits 22 extending in the circumferential direction from the notched ears 24 of the protective cover 21 are formed at intervals in the longitudinal direction. When a bending force is applied to the protective cover 21 as shown in FIG. 1 (2), the slit 22 can expand the slit width to absorb the bending displacement. Therefore, the protective cover 21 can be curved without being damaged, and the flexibility of the protective cover 21 is significantly improved.

The protective cover 21 is made of impact resistant resin and is manufactured by extruding a raw material resin. The slit 22 is formed by sawing, for example. As the impact resistant resin, for example, a hard vinyl chloride resin blended with a resin such as acrylonitrile butadiene rubber that improves impact resistance is suitable. The length of the protective cover 21 is about 1 m per one, and usually 2
Supplied in the fully connected state.

FIG. 2 is an explanatory view showing the application situation of the protective cover shown in FIG. 1 in the non-cutting method. In the non-excavation method, the first excavation hole 31 and the second excavation hole 32 are excavated in the ground 30 at intervals in the laying route of the underground pipe, for example, the gas pipe 26. In the first drill hole 31, the propulsion device 3
3, the propulsion device 33 pushes the head 34 toward the second excavation hole 32 by hydraulic pressure while adding the head 15 to the rod 15 and pierces the ground. Hydraulic pressure is the hydraulic unit 3
6 is supplied to the propulsion unit 33 via the hydraulic hose 37. After the pushing is completed, the mounting jig 38 is attached to the tip of the head 34.
Is attached to the other end of the attachment jig 38, and the gas pipe 26 to which the protective cover 21 is attached is attached to the other end of the attachment jig 38. The protection cover 21 is attached to the gas pipe 26 by a method as shown in FIG. 9 in which the opening 25 of the protection cover 21 is enlarged.

The gas pipe 26 is made of synthetic resin such as polyethylene and has flexibility. Therefore, the gas pipe 26 is wound in a coil shape on a take-up reel (not shown), carried into a construction site, and supplied while being unwound from the take-up reel. After the attachment of the attachment jig 38 is completed, the head 34 is pulled back in the direction of the arrow 39, and the protective cover 2
The gas pipe 26 equipped with 1 is curved while bending the second drill hole 3
2 and further into the hole made by the propulsion device 33 in the direction of arrow 39. Therefore, the head 34
With the completion of pulling back, the burying of the gas pipe 26 equipped with the protective cover 21 in the ground is completed.

As described above, since the protective cover 21 and the gas pipe 26 are flexible, the length of the second excavation hole 32 of the gas pipe 26 with the protective cover 21 attached is longer than that of the protective cover 21. Even if it is shorter than this, it is drawn into the second drill hole 32 without damage. Therefore, in the non-excavation method, the length of the excavation hole can be significantly reduced as compared with the conventional technique that requires the excavation hole longer than at least the length of the protective cover 21. Further, since the length of each protective cover 21 can be increased to reduce the number of times the protective covers are connected, it is possible to save the labor of the connection and to efficiently bury the gas pipe 26 in the ground. Greatly improved. In addition to the method of simultaneously pulling in the protective cover 21 and the gas pipe 26,
A method may be adopted in which only the protective cover 21 is retracted in advance and the gas pipe 26 is inserted into the retracted protective cover 21.

FIG. 3 is an explanatory view showing a construction example of underground burying work of a gas pipe by a non-open cutting method to which the protective cover shown in FIG. 1 is applied. FIG. 3 shows a construction example of the construction in which the gas pipe 26 is buried in the ground across the road 43 from the gas main pipe 41 to the gas meter 42 of the house. At the time of construction, the first excavation hole 31 is excavated on the side of the wide sidewalk 44, and the second excavation hole 32 is excavated on the side of the narrow sidewalk 45. The gas pipe 26 with the protective cover 21 attached thereto is drawn in from the second excavation hole 32 by the non-excavation method shown in FIG. 2, and reaches the first excavation hole 31 through the drainage groove 46 and the underground of the road 43.
After that, the gas pipe 26 is connected to the gas main pipe 41 and the gas meter 4.
It is connected to No. 2 and the underground burial work is completed. When the width of one of the sidewalks is crossed across the road as described above, the protective cover 21 of the present embodiment can be suitably applied to the underground burying work of the gas pipe 26 by the non-open cutting method. The length for which the non-excavation method can be suitably applied is about 2 m to 7 m.

FIG. 4 is an explanatory view showing a situation in which the gas pipe buried underground with the protective cover shown in FIG. 1 comes into contact with the excavator during construction, and FIG. 4 (1) shows the situation. It is a front view, and FIG. 4 (2) is a side view showing the situation. In the vicinity of the gas pipe 26 buried underground, excavation may be performed by an excavator for various works. For example, a drag shovel called a backhoe 48 is used for excavation at a place lower than the machine position such as excavation of a ditch. If the backhoe 48 accidentally contacts the gas pipe 26 with the protective cover 21 shown in FIG.
As shown in (2), the ribs 23 formed on the inner peripheral surface of the protective cover 21 form a gap 49 between the protective cover 21 and the gas pipe 26, so the shock absorbing action is mitigated by the buffering action of the gap 49. be able to. The protective cover 21 is
As described above, since it is made of a hard vinyl chloride resin having excellent impact resistance, and the rib 23 has a very high rigidity, it is possible to sufficiently compensate for the strength reduction due to the formation of the slit 22. Therefore, the protective cover 21 can prevent the gas pipe 26 from being damaged or broken when it comes into contact with the backhoe 48.

FIG. 5 is an explanatory view showing a specific structure of the protective cover shown in FIG. 1, FIG. 5 (1) is a front view of the protective cover, and FIG. 5 (2) is a side view of the protective cover. . The size of the protective cover 21 is appropriately changed depending on the size of the gas pipe 26. When the outer diameter of the gas pipe 26 is, for example, 42 mm, the protective cover 21 has, for example, a length L of 900 mm, an outer diameter D of 68 mm, and a thickness t of 2 to 3 mm. The slits 22 are formed at equal intervals in the axial direction of the protective cover 21. The pitch of the slits 22 is, for example, 150 mm, and the depth of the slits 22 is preferably about 1/4 of the circumferential length of the protective cover 21. For example, six ribs 23 are provided on the inner peripheral surface of the protective cover 21 at equal intervals. The height of the rib 23 is approximately equal to the thickness of the protective cover 21 and is 2 to 3 mm, and the width is preferably larger than the height. The width L of the opening 25 is preferably narrower than the outer diameter of the gas pipe 26 and wider than 1/2 of the outer diameter thereof. As a result, the protective cover 21 can be easily attached to the gas pipe 26, and the outer periphery of the gas pipe 26 can be sufficiently protected.

FIG. 6 is a schematic view showing the shape of the slit provided in the protective cover shown in FIG. 1, FIG. 6 (1) is a schematic view showing a T-shaped slit, and FIG. 6 (2) is a keyhole. It is a schematic diagram which shows a mold slit. The slit 22 provided in the protective cover 21 is provided with the cutout ear portion 2 of the protective cover 21.
4 extends in the circumferential direction and increases in width at the end. The reason why the width is increased at the end of the slit 22 is to alleviate stress concentration in this portion and prevent damage or breakage of the protective cover 21 starting from the slit 22. Slit 22
The shape may be any of the T-shaped shape 51 and the keyhole shape 52, and the same damage prevention effect can be obtained.

[0022]

As described above, according to the present invention, a plurality of slits extending in the circumferential direction from the cutouts are formed in the longitudinal direction in the protective cover having a substantially circular cross section. Therefore, the flexibility of the protective cover is significantly improved. This allows the underground buried pipe made of synthetic resin with the protective cover to be curved and drawn into the excavation hole shorter than the length of the protective cover in the non-excavation method, so an excavation hole longer than the length of the protective cover is required. The excavation length can be greatly shortened as compared with the conventional technology. Further, since the length of each protective cover can be increased to reduce the number of times the protective cover is connected, it is possible to save the labor of the connection and to greatly improve the efficiency of the burying work of the underground burial pipe. .

[Brief description of drawings]

FIG. 1 is a perspective view showing a simplified structure of a protective cover for an underground pipe, which is an embodiment of the present invention.

FIG. 2 is an explanatory view showing an application situation of the protective cover shown in FIG. 1 in a non-open cutting method.

FIG. 3 is an explanatory diagram showing a construction example of underground burying work of a gas pipe by a non-open cutting method to which the protective cover shown in FIG.

FIG. 4 is an explanatory diagram showing a situation in which the gas pipe buried in the ground with the protective cover shown in FIG. 1 contacting the excavator during construction.

5 is an explanatory diagram showing a specific configuration of the protective cover shown in FIG.

FIG. 6 is a schematic view showing the shape of slits provided in the protective cover shown in FIG.

FIG. 7 is a perspective view showing a simplified state of mounting a protective cover for a gas pipe according to a conventional technique in an excavation method.

FIG. 8 is a perspective view showing a simplified structure of a conventional protective cover for a gas pipe.

FIG. 9 is a cross-sectional view showing how the gas pipe protective cover shown in FIG. 8 is attached to a gas pipe.

FIG. 10 is an explanatory view showing a state of application of a conventional gas pipe protective cover in a non-cutting method.

[Explanation of symbols]

 1,26 Gas pipe 3,21 Protective cover 4,24 Notched ear 5,23 Rib 6,25 Opening 11,31 First drilling hole 12,32 Second drilling hole 13,33 Propulsion machine 14,34 Head 15 , 35 Rod 16, 38 Mounting jig 22 Slit

Claims (1)

[Claims] 1. A substantially circular cover with a partially cut-away cross section that surrounds and protects a synthetic resin pipe buried in the ground, and has a plurality of circumferentially extending end edges facing the notched portion. A protective cover for an underground pipe, characterized in that slits are formed at intervals in the longitudinal direction.