JP2017053489A - Protection structure and protection method of underground pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protection structure and projection method of an underground pipe, capable of properly and surely preventing breakage or damage of the underground pipe from an excavator.SOLUTION: There is provided a protection structure of an underground pipe characterized in that an upper surface and both side surfaces of the underground pipe are covered with a protection material extending along the pipe axial direction of the underground pipe with an interval between itself and the underground pipe. There is also provided a protection method of the underground pipe, including a step of laying the protection material extending along the pipe axial direction of the underground pipe around the underground pipe so as to cover the upper surface and both side surfaces of the underground pipe with the interval between the protection material and the underground pipe.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a protection structure and a protection method for underground underground pipes, and more particularly to a protective structure and a protection method for underground underground pipes capable of preventing damage and damage of underground underground pipes due to excavation equipment. .

  Under the grounds of public sites such as roads, water pipes, gas pipes, sewage pipes, pipes for storing power lines and communication lines, etc. are buried, and infrastructure pipe networks important for the formation of cities are maintained. Has been. In recent years, from the viewpoints of workability and durability, the material of underground pipes that constitute such infrastructure pipes has been changed to plastic. However, plastic pipes are more susceptible to breakage and damage due to collision during excavation by excavating equipment such as backhoes, scoops and pickaxes, compared to conventional concrete and cast iron pipes.

  In general, water pipes, gas pipes, sewage pipes and the like are buried close to each other for the convenience of road management, so that other laying pipes may be damaged or damaged during pipe laying work. Especially for water pipes and gas pipes that are under constant pressure, the contents leak due to damage and temporarily stop the distribution of nearby infrastructure, adversely affecting the environment and the lifeline of the surrounding residents. Will be affected.

  In order to prevent the underground pipe from being damaged during such excavation work, a burial display is provided on the road as a means of notifying that the pipe is buried, or a non-woven fabric is wrapped around the pipe itself to prevent the excavation impact. To mitigate and prevent fatal damage to the tube. However, even if it is displayed, it may cause damage to the underground pipe during construction, or may break through the nonwoven fabric and cause fatal damage.

  For example, in Patent Document 1, a protective iron plate and a high-hardness ceramic plate are arranged on the underground pipe so that the underground pipe is not damaged by the underground boring machine or excavating equipment. An anti-damage device that is embedded together is disclosed. However, in this device, the side of the underground pipe is not protected, so it cannot withstand excavation from the side, and an iron plate is embedded for protection, so there is a concern that the damage prevention device itself may corrode and deteriorate. In addition, there is a problem that the base is an iron plate and is heavy and not easy to handle.

  Also, in Patent Document 2, three woven fabrics are laminated, and these woven fabrics are bonded to each other in a thin line shape in the longitudinal direction by an adhesive means at the center thereof, and used as a protective material on the upper part of the pipe. A method is disclosed. However, in this method, since the protective material is a knitted fabric, it is difficult to resist a sharp pickle or excavation impact by a large excavating machine, and there is a concern about damage to underground pipes.

  Furthermore, Patent Document 3 discloses a structure in which a protective plate composed of a metal plate and a resin layer is buried in the ground above an existing buried pipeline. However, this structure has problems that it cannot withstand excavation from the side of underground pipes and that the base is heavy because it is an iron plate and is not easy to handle.

JP-A-10-152828 JP-A-6-337090 JP 2011-114940 A

  Therefore, the object of the present invention is to focus on the problems in the prior art as described above, and more appropriately and reliably prevent breakage and damage of underground pipes by excavating equipment such as backhoes, scoops and pickaxes during excavation work. In addition, it is possible to inform the installer that underground pipes exist, and it is possible to improve the handleability by reducing the weight of the laying protective material, and also preventing the corrosion deterioration of the protective material itself An object of the present invention is to provide a protective structure and a protective method for underground pipes.

  In order to solve the above problems, the underground buried pipe protection structure according to the present invention is such that the upper surface and both side surfaces of the underground buried pipe are spaced apart from the underground buried pipe in the axial direction of the underground buried pipe. It consists of the structure characterized by being covered with the protective material extended along. The underground buried pipe in the present invention includes a pipe having a circular cross section and a substantially circular or box shaped pipe having a cross section of an ellipse or the like. Typically, the pipe is a water pipe or a gas pipe. A pipe used as an infrastructure pipe such as a sewer pipe, a pipe for storing a power line or a communication line.

  In such a buried underground pipe protection structure according to the present invention, the upper surface and both side surfaces of the underground buried pipe are covered with a protective material extending along the pipe axis direction of the underground buried pipe at intervals. In addition to the excavation impact from above the underground pipe, the underground pipe can withstand the excavation impact from the side of the underground pipe due to the protective material laid. Since the excavation impact is basically not applied from below the underground pipe, the underground pipe is substantially protected from the excavation impact from all directions. As a result, it is possible to more appropriately and reliably prevent breakage and damage to underground pipes caused by excavating equipment such as backhoes, scoops, and pickaxes during excavation work, compared to conventional structures.

  In the underground buried pipe protection structure according to the present invention, the distance between the protective material inner surface and the underground buried pipe outer surface is preferably in the range of 1 cm to 30 cm. By setting the distance within this range, it is possible to appropriately prevent the excavation impact from the outside of the protective material from being directly transmitted to the underground pipe through the protective material, and this suitable protective structure is It is easily completed without requiring much space around the buried pipe.

  Moreover, it is preferable that an appropriate buffer material is interposed between the protective material and the underground pipe. Since the protective material and the underground pipe support each other due to the buffer material, the desired shape and posture of both can be easily maintained, and excavation impacts from outside the protective material can pass through the protective material. When it is going to be transmitted to the underground buried pipe, it becomes possible to absorb the impact energy to be transmitted more or less with the buffer material interposed, and the impact applied to the underground buried pipe itself. Energy is reduced, and breakage and damage of underground pipes are more appropriately and reliably prevented.

  As the buffer material, for example, soil (including backfill soil, construction generated soil, mountain sand), EPS (styrofoam), and the like can be used, and soil is preferable in consideration of economy and environment. That is, as the cushioning material, it is possible to use a member other than the protective material having energy absorption performance, but the cushioning material is soil, especially backfill soil (generally, mountain sand and improved soil). In this case, an appropriate cushioning material can be easily interposed without preparing a special member. That is, it is a protective structure in which the backfill soil functions as the foundation of the underground buried pipe and the cushioning material.

  In the protection structure for underground buried pipes according to the present invention, as the cross-sectional shape of the protective material, a gate type or a horseshoe type opened downward is basically adopted. Other cross-sectional shapes can be used as long as the protective structure defined in (1) can be satisfied. As a gate type, it may be comprised by the integral type and may be comprised from three flat plates.

  Moreover, it is preferable that the outer wall which makes the said protective material has the impact resistance performance of 35J or more so that it can endure the impact of excavation construction machines, such as a backhoe.

  Moreover, it is preferable that at least a part (preferably the whole) of the protective material is made of a fiber reinforced plastic. It is made of fiber reinforced plastic, so the weight of the protective material can be reduced to improve handling, the strength and rigidity of the protective material itself can be increased, and the risk of corrosion deterioration of the protective material itself is eliminated. it can.

  As said fiber reinforced plastic, what is comprised using the sheet | seat formed with the reinforced fiber at least is preferable. By using the reinforcing fiber sheet, even a protective material having a relatively small thickness can exhibit high strength and rigidity while achieving weight reduction.

  The form of the sheet formed of the reinforcing fibers is not particularly limited, and for example, a sheet formed from a woven fabric, felt, or mat, or any combination thereof can be used.

  In addition, the fiber reinforced plastic is not particularly limited, but from the viewpoint of providing high strength and rigidity against excavation impact from the outside of the protective material, the fiber reinforced plastic constituting the fiber has high impact resistance. In order to satisfy this, at least one of aramid fiber, ultrahigh molecular weight polyethylene fiber or glass fiber is preferably used as the reinforcing fiber. Especially, since the fiber reinforced plastic using an aramid fiber can express the outstanding impact resistance, it is especially preferable to use an aramid fiber as a reinforcing fiber. The matrix resin of the fiber reinforced plastic is not particularly limited. For example, an epoxy resin, a vinyl ester resin, an unsaturated polyester resin, or a phenol resin can be used for a thermosetting resin, and a nylon resin for a thermoplastic resin. Polyester resins and polyimide resins can be used.

  As a method of molding such a protective material, when a thermosetting resin is used, hand lay-up molding, pultrusion molding, RTM (Resin Transfer Molding) molding, press molding, autoclave molding, etc. are used, and a thermoplastic resin is used. In this case, extrusion molding, injection molding or press molding can be used.

  In the underground buried pipe protection structure according to the present invention, since the underground buried pipe is usually laid so as to extend long, a plurality of protective materials are connected along the tube axis direction of the underground buried pipe. It is preferable to adopt the structure. As the joint portion between the protective members of the articulated structure, any of a structure in which the end portions are somewhat overlapped, a structure in which the end surfaces are butted together, or a structure in which a minute gap exists between the end portions can be employed. The length of one protective material in the case where a plurality of protective materials are connected is not particularly limited, and may be set as appropriate in consideration of handleability and ease of installation.

  In the underground buried pipe protecting method according to the present invention, the protective material extending along the pipe axis direction of the underground buried pipe covers the upper surface and both side surfaces of the underground buried pipe with a space between the underground buried pipe. As described above, the method includes a step of laying around the underground pipe. In other words, the method according to the present invention can be applied to an existing underground pipe without being renewed.

When excavating a ditch and laying a new pipe or renewing an existing underground pipe, for example, the method for protecting an underground pipe according to the present invention is as follows.
After laying the underground pipe in the excavation groove, backfilling the soil that also serves as the foundation of the underground pipe around the underground pipe, and compacting the backfilled soil;
Laying the protective material around the underground pipe;
After laying the protective material, the method can include a step of backfilling the entire excavation groove with soil and compacting the backfilled soil.

  In such a method of protecting the underground pipe, in the step of laying the protective material, the portion of the protective material that covers both sides of the underground pipe is penetrated into the soil that also serves as the foundation of the underground pipe. The method can be adopted. That is, the cross-sectional shape described above is a method of penetrating both leg portions of the gate-shaped or horseshoe-shaped protective material into the soil that also serves as the foundation of the underground pipe.

  In the process of laying such a protective material, after forming a guide groove into the soil that also serves as the foundation of the underground pipe, a portion that covers both sides of the underground pipe of the protective material can be inserted. The site | part which covers the both sides | surfaces of an underground pipe | tube can also be penetrated into the soil which serves as the foundation of the said underground pipe | tube. If the guide groove is formed before laying the protective material in this way, the parts (both leg parts of the protective material) that cover both sides of the underground pipe of the protective material are more easily buried with a small resistance. It can penetrate into the soil that also serves as the foundation of the pipe, facilitating construction.

  Further, in the method for protecting underground underground pipes according to the present invention, when laying the protective material, a method is adopted in which a pushing jig is placed on the upper surface of the protective material and the protective material is laid through the jig. You can also In this way, when penetrating the soil covering both sides of the underground buried pipe of the protective material into the soil that also serves as the foundation of the underground buried pipe, the protective material is removed via the pushing jig using a backhoe or the like. It can be pushed in, and the protective material laying work can be facilitated. After laying the protective material at the target position, the pushing jig can be removed from the protective material, and the jig can be used for the protective material to be laid next.

  Also in the underground pipe protecting method according to the present invention, the length of one protective material is appropriately set in consideration of handling and laying ease, and a plurality of protective materials are installed in the underground pipe. It is preferable to connect along the tube axis direction.

  According to the protection structure and protection method for underground pipes according to the present invention, by providing a specific protective material around the underground pipe, high impact resistance against external forces from virtually all directions is achieved. It is possible to achieve a protective structure for the buried underground pipe, and to prevent the underground buried pipe from being damaged and damaged by excavating equipment such as backhoe, scoop and pickaxe during excavation work.

  In addition, by interposing a protective material, it is possible to make the construction worker aware that underground pipes exist during excavation work, and the breakage and damage of underground pipes can be prevented more reliably. it can.

  Furthermore, by configuring the protective material with fiber reinforced plastic, the protective material can be reduced in weight to improve handling and workability, and the protective material itself can have high strength, rigidity, and durability. Maintenance-free can be achieved by removing the risk of corrosion deterioration of the protective material itself. In particular, by using a specific reinforcing fiber such as an aramid fiber for the fiber reinforced plastic, the protective material itself can be provided with excellent impact resistance, and the underground pipe can be protected more appropriately. .

It is a perspective view which shows the example of the protective material in this invention. It is a construction process figure which shows the protection method of the underground buried pipe which concerns on one embodiment of this invention. It is a perspective view which shows an example in the case of forming the guide groove for protective materials in this invention.

Hereinafter, embodiments of a protection structure and a protection method for underground underground pipes according to the present invention will be described with reference to the drawings.
The underground buried pipe protection structure according to the present invention is covered with a protective material in which the upper surface and both side faces of the underground buried pipe extend along the tube axis direction of the underground buried pipe with a space between the underground buried pipe. The underground buried pipe protecting method according to the present invention is characterized in that a protective material extending along the pipe axis direction of the underground buried pipe is spaced from the underground buried pipe. And laying around the underground pipe so as to cover the upper surface and both side surfaces of the underground pipe.

  The protective material in this protective structure and protective method is configured, for example, as shown in FIG. The protective material 1 illustrated in FIG. 1A has a gate-shaped cross-sectional shape having a flat plate-like top portion 1a and flat plate-shaped leg portions 1b, and the protective material 2 illustrated in FIG. It has a horseshoe-shaped cross-section having a curved plate-like top 2a and flat plate-like legs 2b. In such protective materials 1 and 2, the upper surfaces of the underground buried pipes are the top portions 1 a and 2 a of the protective materials 1 and 2, and both side surfaces of the underground buried pipes are the both leg portions 1 b and 2 b of the protective materials 1 and 2, respectively. It is laid around the underground pipe so that it is covered with a gap between it and the underground pipe.

  It is preferable that at least a part (preferably the whole) of the protective materials 1 and 2 as described above is made of a fiber reinforced plastic. As the reinforcing fiber of the fiber reinforced plastic, for example, at least one of aramid fiber, ultrahigh molecular weight polyethylene fiber or glass fiber is preferably used, and among them, it is preferable to use an aramid fiber. Examples of matrix resins for fiber reinforced plastics include thermosetting resins such as epoxy resins, vinyl ester resins, unsaturated polyester resins or phenol resins, and nylon resins, polyester resins, and the like. Thermoplastic resins such as polyimide resins can be used.

For example, as shown in FIG. 2, the protective materials 1 and 2 are laid around the underground pipe.
FIG. 2 shows the underground buried pipe 3 and its peripheral part, and 4 shows the excavation groove part excavated for embedding the pipe 3. In the example shown in FIG. 2, first, as shown in FIG. 2A, after the underground pipe 3 is laid in the excavation groove 4, the foundation of the underground pipe 3 is placed around the underground pipe 3. The double soil is backfilled (backfill soil 5), the backfill soil 5 is compacted, and the protective material 1 is prepared in this state (protective material installation preparation step). The protective material 1 is positioned at a target position and prepared in a predetermined posture. In the illustrated example, a pushing jig 6 is placed on the upper surface of the protective material 1. Although the material of the jig 6 is not particularly limited, for example, a wooden material can be used in consideration of handling properties.

  Next, as shown in FIG. 2 (B), the protective material 1 is laid around the underground pipe 3 (protective material laying step). In the illustrated example, the backhoe 7 is used and pressure is applied downward to the jig 6, and the parts covering both side surfaces of the underground pipe 3 of the protective material 1 (that is, the protective material) via the jig 6. The protective material 1 is laid so that both legs 1b) of 1 are inserted into the backfill soil 5.

  Then, as shown in FIG. 2 (C), the jig 6 is removed after the protective material 1 is laid, the soil is backfilled in the entire excavation groove 4, and in particular, the surface after the jig 6 is removed. The soil is backfilled in the upper part of the top portion 1a of the protective material 1 (finishing backfill soil 8), and the backfill soil 8 is compacted by the vibration tool 9 or the like.

  In laying the protective material 1 as described above, as work before the protective material 1 is installed, for example, as shown in FIG. 3, the backfill soil 5 covers both side surfaces of the underground pipe 3 of the protective material 1. A guide groove 10 into which a portion (that is, both legs 1b of the protective material 1) can be inserted can also be formed. In the illustrated example, the guide groove 10 is formed by penetrating a guide groove forming tool 11 constituted by an iron plate or the like into the backfill soil 5 and extracting it after the penetration. By forming the guide groove 10 in advance, both the leg portions 1b of the protective material 1 are easily penetrated into the backfill soil 5.

  The protective material 1 laid as described above is connected in a necessary number along the pipe axis direction of the underground buried pipe 3.

Hereinafter, the present invention will be described more specifically based on examples.
<Example 1>
1. Specification of protective material (fiber reinforced plastic: FRP) (1) Reinforced fiber sheet / fiber: Aramid fiber “Kevlar” (registered trademark) 3300dtex
・ Weaving structure: Plain weave ・ Weight: 461 (g / m ² )

(2) Matrix resin and resin used: Epoxy resin (shown as “EP” in Table 1 below)
・ Application amount: 1.1 (kg / m ² ) (for 1 layer of “Kevlar” (registered trademark) fabric)

(3) Shape and dimensions of protective material ・ Shape: Gate type ・ Dimensions: 300mm × 300mm × 300mm × 1500mm

2. "Kevlar" (registered trademark) FRP production method (1) Use of dedicated mold (gate type) (2) Undercoat->"Kevlar" (registered trademark) fabric lamination-> impregnation work-> top coat-> 5 layers by repeated impregnation work (3) Fiber content: 20-30%

3. Underground pipe as an object to be protected Polyethylene gas pipe with an outer diameter of 200mm (200A) * In the case of 200A pipe, the above 1. The dimensions of (3) apply.

4). Construction method (1) After installing a gas pipe in the soil and backfilling the soil, a protective material of “Kevlar” (registered trademark) FRP was penetrated from above with a backhoe.
(2) Between the gas pipe and the protective material, the earth and sand that was pushed in was laid so that there was an interval of about 10 cm on the upper surface and 5 cm on both sides.
(3) After laying the protective material, the soil was backfilled and compacted.

5). Backhoe impact test (1) Test method
Using a 0.45m ³ backhoe, an impact was applied from the top and side of the protective material with an impact load of approximately 70kN, and the damage of the gas pipe was confirmed.
(2) Evaluation criteria Table 1 shows the evaluation criteria.

6). Impact resistance performance In accordance with JIS K 7211, the impact resistance value when an impact fracture occurred in a test piece having a specified size was measured in units (J). It is said that 35J or more is necessary as an impact resistance value that can withstand the impact of excavation construction machines such as backhoes.

  The results are shown in Table 2.

<Examples 2 to 7, Comparative Examples 1 and 2>
Various conditions were changed and tested. In Example 2, the matrix resin was changed to unsaturated polyester (indicated as “UP” in Table 2 below), and in Example 3, the matrix resin was changed to vinyl ester (indicated as “VE” in Table 2 below). All other changes were the same as in Example 1. In Example 4, the reinforcing fiber has a hybrid configuration of “Kevlar” (registered trademark) (indicated as “KV” in Table 2 to be described later) and a glass fiber mat (indicated as “GF” in Table 2 to be described later). In Example 5, the number of laminations of the KV layer / GF layer is increased, in Example 6, the number of laminations of the KV layer / GF layer is decreased, and in Example 7, the glass fiber mat in the hybrid configuration is replaced with an extra layer. The test was conducted using high molecular weight polyethylene (indicated as “PE” in Table 2 below). Moreover, in the comparative example 1, unlike the type which encloses (covers) the gas pipe | tube in Examples 1-7, it tested as a type which winds a protective material around a gas pipe | tube. In Comparative Example 2, a protective plate that protects only the upper surface was prepared in the same manner as in Example 1, a gas pipe was installed in the soil, about half of the soil was backfilled, and then a protective plate was installed. The soil was covered with about 10cm, and it was compacted and tested. The results of these Examples and Comparative Examples are shown together in Table 2.

In addition, the specification of the winding type in the comparative example 1 is as follows.
(1) Reinforcing fiber: PP (polypropylene)
(2) Nonwoven fabric: PET (polyethylene terephthalate)
(3) Lamination structure: Two-layer combination of reinforcing fiber and non-woven fabric (4) Shape and dimensions-Shape: Winding-Dimensions: Width 800mm
About the construction method, the protective material was wound around the gas pipe twice in advance, then the groove was excavated, the gas pipe was installed, the soil was backfilled, and compacted.

  As shown in Table 2, in Examples 1-7, impact resistance performance of 35 J or more was obtained, and in the backhoe impact test, superior results were obtained as compared with Comparative Examples 1 and 2.

<Examples 8 to 10>
Next, a test was performed in which the interval between the protective material and the gas pipe, the type of the buffer material, and the cross-sectional shape of the protective material were changed. Regarding the change of the distance between the protective material and the gas pipe, the above-mentioned Example 2 is used as a comparison target, the distance from the upper surface of the gas pipe is changed to 20 mm in Example 8, and the change of the type of the buffer material is described above. In Example 9, the shock-absorbing material was changed to EPS (Styrofoam), and the change in the cross-sectional shape of the protective material was changed to the above-mentioned Example 4 and the horseshoe-shaped in Example 10 as a comparative object. The cross-sectional shape was changed and tested. These test results are shown in Table 4. In addition, in these tests, in relation to Examples 11 and 12 described later, in order to evaluate the workability, the indentation time required to inject the protective material was evaluated. Table 3 shows the evaluation criteria for the indentation time for this workability evaluation.

  As shown in Table 4, in Example 8, as compared with Example 2, there were no scratches generated in the gas pipe due to the wide spacing of the buffer material installing portions. Moreover, in Example 9, compared with Example 4, by using EPS as a cushioning material, installation of a protective material became easier and the pushing time decreased. Moreover, in Example 10, compared with Example 4, as a result of changing the cross-sectional shape of the protective material to a horseshoe shape, the pushing time increased. Therefore, it was found that the portal shape is preferable as the cross-sectional shape from the viewpoint of the indentation time.

<Examples 11 and 12>
Next, using the construction tool in Examples 11 and 12 with the above-mentioned Example 4 as a comparison object, the pushing time for workability evaluation was evaluated (evaluation criteria are Table 3). In Example 11, as a result of using the jig for forming the guide groove, it is easy to install the protective material. However, since it takes time to form the guide groove at the penetration portion on both sides of the protective material, the pushing time for evaluating the workability is required. However, it was only improved from the B rank of Example 4 to the A rank. In Example 12, as a result of using the pushing jig, pushing of the protective material became easier, and the construction time (pushing time for workability evaluation) was significantly reduced. In the examination of these construction jigs, the indentation time in this Example 12 was the shortest from the result of the construction test. These results are shown in Table 5.

  The underground buried pipe protection structure and the protection method according to the present invention can be applied to any case where it is required to appropriately and reliably prevent the underground buried pipe from being broken or damaged by the excavating equipment.

DESCRIPTION OF SYMBOLS 1, 2 Protective material 1a, 2a Protective material top part 1b, 2b Protective material leg part 3 Underground pipe 4 Excavation groove part 5 Backfill soil 6 Pushing jig 7 Backhoe 8 Finishing back soil 9 Vibration tool 10 Guide groove 11 Guide groove forming tool

Claims (18)

  The underground pipe is characterized in that the upper surface and both side surfaces of the underground pipe are covered with a protective material extending along the pipe axis direction of the underground pipe with a space between the underground pipe and the underground pipe. Protective structure.   The protective structure for underground pipes according to claim 1, wherein the distance between the inner surface of the protective material and the outer surface of the underground pipe is in the range of 1 cm to 30 cm.   The protective structure for underground buried pipes according to claim 1 or 2, wherein a buffer material is interposed between the protective material and the underground buried pipe.   The protection structure for underground buried pipes according to claim 3, wherein the cushioning material is soil.   The protective structure for underground buried pipes according to any one of claims 1 to 4, wherein a cross-sectional shape of the protective material is a gate type or a horseshoe type.   The underground buried pipe protection structure according to claim 5, wherein the gate type is an integral type or is constituted by three flat plates.   The underground buried pipe protective structure according to any one of claims 1 to 6, wherein an outer wall constituting the protective material has an impact resistance of 35 J or more.   The underground buried pipe protective structure according to any one of claims 1 to 7, wherein at least a part of the protective material is made of fiber reinforced plastic.   The protective structure for underground buried pipes according to claim 8, wherein the fiber reinforced plastic is constituted by using a sheet formed of at least reinforcing fibers.   The protective structure for underground pipes according to claim 9, wherein the sheet formed of reinforcing fibers is formed of woven fabric, felt, mat, or any combination thereof.   The underground buried pipe protective structure according to any one of claims 8 to 10, wherein at least one of aramid fiber, ultrahigh molecular weight polyethylene fiber, or glass fiber is used as the reinforcing fiber of the fiber reinforced plastic.   The protective structure for underground pipes according to any one of claims 1 to 11, wherein a plurality of protective materials are connected along the pipe axis direction of the underground pipes.   Laying a protective material extending along the pipe axis direction of the underground pipe around the underground pipe so as to cover the upper surface and both side surfaces of the underground pipe with a space between the protective material and the underground pipe A method for protecting underground underground pipes. After laying the underground pipe in the excavation groove, backfilling the soil that also serves as the foundation of the underground pipe around the underground pipe, and compacting the backfilled soil;
Laying the protective material;
The method for protecting a buried underground pipe according to claim 13, further comprising a step of refilling the entire excavation groove with soil after the protective material is laid and compacting the backfilled soil.   The method for protecting a buried underground pipe according to claim 14, wherein, in the step of laying the protective material, a portion of the protective material that covers both sides of the underground buried pipe is penetrated into the soil that also serves as a foundation of the underground buried pipe. .   In the process of laying the protective material, after forming a guide groove into the soil that also serves as the foundation of the underground pipe, the part that covers both sides of the underground pipe of the protective material is formed, and then the protective material is buried underground The underground buried pipe protecting method according to claim 15, wherein portions covering both side surfaces of the pipe are penetrated into soil serving also as a foundation of the underground buried pipe.   The method for protecting an underground pipe according to any one of claims 13 to 16, wherein a pushing jig is placed on the upper surface of the protective material, and the protective material is laid through the jig.   The method for protecting a buried underground pipe according to any one of claims 13 to 17, wherein a plurality of protective materials are connected along the pipe axis direction of the buried underground pipe.

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