JP2023158429A - Buried structure of buried pipe and method for burying buried pipe - Google Patents

Abstract

To provide a burying technology for a buried pipe that effectively utilizes a weight of a burying material as a counterweight for a buried pipe.SOLUTION: A buried structure of a buried pipe is configured to: mount an earth clod weight structure 20 made of an earth clod structure, which is constructed by filling a plurality of cell structures 30 with a filler material 33 while stacking them on site, over a buried pipe 10; and make a total weight of the earth clod weight structure 20 and a total weight of a backfilling material 43 function as a counterweight for the buried pipe 10.SELECTED DRAWING: Figure 1

Description

The present invention relates to a buried pipe burying structure and a buried pipe burying method that use a cell structure to prevent a large diameter buried pipe from floating.

Generally, when laying various large-diameter underground pipes such as pipelines underground, it is necessary to excavate a large area of ground and bury them deep underground.
In particular, in sites where the ground water level is high or where backfill soil is expected to liquefy, it is necessary to increase the depth of buried pipes to increase the overburden load.

A conventional burying method will be described with reference to FIG. 8. Retaining plates 61 are driven into the ground G so as to face each other, and a trench 62 is excavated between the retaining plates 61.
After constructing a layered support foundation 63 at the bottom of the installation trench 62, the buried pipe 60 is laid on the support foundation 63.
Backfilling material 64 is put into the entire area within the laying trench 62 and compacted, and finally the retaining board 61 is removed.

The excavation width of the laying groove 62 is larger than the diameter of the buried pipe 60, and the depth of the laying groove 62 needs to be the diameter of the buried pipe 60 plus a predetermined earth cover.
The excavated cross-sectional dimension of the laying groove 62 increases according to the diameter of the buried pipe 60.
When the buried pipe 60 has a large diameter such as a pipeline, the depth and width of the trench 62 become very large.

Japanese Patent Application Publication No. 11-101369 Japanese Patent Application Publication No. 2007-120721 Japanese Patent Application Publication No. 2007-170678 JP2008-267567A

The conventional technique for burying the buried pipe 60 described above includes the following problems.
<1> As shown in FIG. 8(A), among all the backfilling materials 64, the one that acts as a weight to prevent floating of the buried pipe 60 is the central vertical part of the backfilling material 64 located directly above the buried pipe 60. Only the weight _w5 , and the lateral vertical weight _w6 of the backfilling material 64 located on both the left and right sides of the buried pipe 60, cannot be fully utilized as the weight to prevent the buried pipe 60 from floating.
<2> As described above, the weight of the backfilling material 64 that functions to prevent the buried pipe 60 from floating is only the center vertical weight _w5 .
Therefore, when the buried pipe 60 is a large-diameter pipe or in ground with a high groundwater level, in order to increase the central vertical weight _w5 of the backfill material 64, the trench 62 is excavated deeper than the normal excavation depth. , it is necessary to use a large amount of backfill material 64.
Therefore, in such a site, the construction work for laying the buried pipe 60 becomes large-scale, and the burden of construction cost and construction period increases.
<3> As shown in FIG. 8(B), when the retaining board 61 is removed after being covered with the backfilling material 64, the nearby backfilling material 64 expands into the gap of the retaining board 61 and loosens.
If the backfilling material 64 loosens, the buried pipe 60 will deform into a horizontally long shape, and if the amount of deformation exceeds the allowable strain, not only will there be a problem that the buried pipe 60 will be damaged, but the loosening of the backfilling material 64 will cause the buried pipe 60 to deform. On the other hand, the original load of the backfilling material 64 is not transmitted, causing a problem that the floating restraint force of the buried pipe 60 is reduced.

On the other hand, as shown in FIG. 9, Patent Documents 1 to 4 disclose that the lateral backfilling materials 64a, 64a are wrapped with geotextile 65 on both the left and right sides of the buried pipe 60, and the weight of the lateral backfilling materials 64a, 64a is buried. It has been proposed to utilize it as a source of reaction force to prevent the tube 60 from floating.
This technology for preventing floating of the buried pipe 60 includes the following problems.
<1> Theoretically, this will work if the lateral backfilling materials 64a, 64a can be wrapped and firmly compacted while the geotextile 65 is under tension.
In actual construction, it is technically difficult to wrap the lateral backfilling materials 64a, 64a while applying tension to the geotextile 65, or to firmly compact the lateral backfilling materials 64a, 64a.
If the geotextile 65 is loose or the lateral backfilling materials 64a, 64a are insufficiently compacted, the floating prevention force of the backfilling materials 64a, 64a against the buried pipe 60 will be reduced, and the lateral The original weight of the backfill materials 64a, 64a is not fully utilized.
<2> It is technically difficult to firmly compact the side backfill materials 64a, 64a over the entire length of the buried pipe 60.
If variations occur in the compaction of the lateral backfilling materials 64a, 64a, the effectiveness of utilizing the weight of the lateral backfilling materials 64a, 64a will be significantly reduced.
<3> Since the weight of the side backfilling materials 64a, 64a cannot be fully utilized, in order to prevent the buried pipe 60 from floating up, the burial depth of the buried pipe 60 is deepened and a large amount of it is buried upward. It is necessary to backfill with backing material 64b.

The present invention has been made in view of the above points, and its purpose is to provide a buried pipe burying structure and a buried pipe burying method that can solve the above problems.

The present invention relates to a buried pipe buried structure in which a buried pipe is buried underground, and the cross-sectional shape is gate-shaped or hook-shaped. It was placed across the buried pipe so that the total weight of the earth clod weight structure functioned as a counterweight for the buried pipe.
Furthermore, the present invention includes a first step of excavating a laying trench between the ground where the retaining material has been placed, a second step of laying a buried pipe in the laying trench, and a third step of backfilling the laying trench. A buried pipe burying method for burying a buried pipe in the ground, wherein the third step includes attaching an earth clot weight structure made of a highly rigid earth clod structure having a gate-shaped or hook-shaped cross-sectional shape to the buried pipe. By placing it astride, the laying trench was backfilled, and the total weight of the soil clod weight structure was made to function as a counterweight for the buried pipe.
In another embodiment of the present invention, the upper surface of the earth clod weight structure may be covered with backfilling material, and the total weight of the backfilling material may be supported by the earth clod weight structure.
In another embodiment of the present invention, the block weight structure may be placed continuously or intermittently over the entire length of the buried pipe.
In another form of the present invention, the buried pipe may have a bent portion, and the lump weight structure may be placed astride the bent portion of the buried pipe.
In another embodiment of the present invention, the mass structure may be symmetrical with respect to the buried pipe, or may be asymmetrical with respect to the buried pipe.
In another embodiment of the present invention, the earth clod weight structure has a saddle portion that can cover the upper part of the buried pipe horizontally, and a saddle portion that hangs down integrally with an end of the saddle portion so that the clod weight structure can cover the side portion of the buried pipe. and a plurality of cell structures in which the saddle parts and the side legs are stacked on site, and a filling material filled and compacted into the cell spaces of the cell structures on site. do.
In another aspect of the present invention, the saddle portion and the side leg portions are integrally connected to each other so as to transmit a load via a connecting body extending vertically or horizontally between the saddle portion and the side leg portions. Good too.

The present invention provides at least one of the following effects.
<1> By placing the earth clod weight structure across the buried pipe, not only the central vertical weight of the earth clod weight structure located directly above the buried pipe but also the earth clod weight structure located on the side of the buried pipe can be reduced. The lateral vertical weight of the body can be used as a counterweight for buried pipes.
<2> When the top surface of the earth clod weight structure is covered with backfilling material, the total weight of the backfilling material located directly above the earth clod weight structure can also be utilized as a counterweight for the buried pipe.
<3> Since the total weight of the earth clod structures constituting the earth clot weight structure and the total weight of the soil covered by backfilling material can be used as a counterweight, the buried depth of the buried pipe can be made shallower than in the past.
Therefore, not only can the amount of excavation of laying trenches be reduced, but also the amount of backfilling of earth and sand can be significantly reduced, improving construction costs and construction periods, and the operating time of construction machinery can be significantly shortened, making it possible to It can be said to be an important technology in line with the SDGs (Sustainable Development Goals).
<4> Even if the retaining board used to retain the earth in the trench was removed, the clod weight structure placed across the buried pipe did not lose its shape, and the protective function of the clod weight structure for the buried pipe was maintained. maintained.
Therefore, compressive deformation of the buried pipe and damage to the buried pipe can be reliably prevented.
<5> Consisting of a plurality of cell structures in which the saddles and side legs constituting the earth clod weight structure are stacked on site, and filling material filled and compacted into the cell spaces of the cell structures on site. By doing so, there is no variation in the compaction of the filling material, and the filling material can be compacted strongly and uniformly.
<6> When the earth clod weight structure is placed on the bent portion of the buried pipe, the thrust force acting on the bent portion of the buried pipe can be counteracted by the vertical weight of the earth clod weight structure.
<7> Since the block weight structure can be formed asymmetrically with respect to the buried pipe, it is possible to apply a vertical load to each part of the block weight structure according to the burial environment at the site. In addition to increasing the degree of freedom in design, it becomes possible to design an economical counterweight.

A partially broken perspective view of the buried structure of the buried pipe according to the first embodiment of the present invention These are explanatory diagrams of a cell structure constituting an earth clod weight structure, in which (A) is an explanatory diagram of a cell structure having a rectangular cell space, and (B) is an explanatory diagram of a cell structure having a honeycomb-shaped cell space. These are explanatory diagrams of an example of joining the saddle part and side leg parts constituting the earth clod weight structure. (A) is an explanatory diagram of a form in which the side leg parts are joined to the lower surface of both ends of the saddle part, and (B) is an explanatory diagram of a form in which the side leg parts are joined to the lower surface of both ends of the saddle part. Explanatory diagram of the form in which the legs are joined An explanatory diagram of the method of burying a buried pipe, (A) is an explanatory diagram from the process of excavating a laying trench to the process of laying a buried pipe, and (B) is an explanatory diagram of the process of constructing the saddle of the earth clod weight structure. An explanatory diagram of the method of burying a buried pipe, (C) is an explanatory diagram of the construction process of the saddle part of the earth clod weight structure, and (D) is an explanatory diagram of the backfilling process of the earth clod weight structure. An explanatory diagram of the buoyancy prevention effect of a buried pipe using a clod weight structure FIG. 2 is an explanatory diagram of Example 2 regarding a left-right asymmetrical earth clod weight structure, in which (A) is an explanatory view of a portal-shaped earth clod weight structure, and (B) is an explanatory view of a hook-shaped earth clod weight structure. These are explanatory diagrams of Example 3 in which a clod weight structure is applied to the bent part of a buried pipe, in which (A) is a longitudinal cross-sectional view of the bent part of the buried pipe, (B) is a plan view of the bent part of the buried pipe, and (C) ) is a plan view of the bent part of the buried pipe covered with the earth clod weight structure. These are explanatory diagrams of the conventional buried structure for buried pipes, in which (A) is a cross-sectional view of the trench in which the pipe is buried, and (B) is a cross-sectional view of the trench in which the pipe is buried after the retaining board has been removed. An explanatory diagram of a conventional buried structure in which a buried pipe is buried using geotextile.

[Example 1]
<1> Buried pipe The buried structure of the buried pipe 10 will be explained with reference to FIG. 1. The buried pipe 10 is a conduit that can transport various liquids or gases, and its cross-sectional shape includes a rectangular shape as well as a circular shape. .
The buried pipe 10 includes a large-diameter pipe body such as a pipeline, and its cross-sectional diameter can be selected as appropriate.

<2> Earth clod weight structure (means for preventing floating of buried pipes)
In the present invention, as a means for preventing floating of the buried pipe 10, an earth clot weight structure 20 having a gate-shaped or hook-shaped cross-sectional shape and capable of being placed across the buried pipe 10 is used.
The earth clod weight structure 20 is a highly rigid earth clod structure for functioning as a counterweight (balance weight) for the buried pipe 10, and the total weight of the earth clod weight structure 20 is utilized as the counterweight for the buried pipe 10.

The clod weight structure 20 includes a saddle part 21 that can cover the upper part of the buried pipe 10 horizontally, and a side leg that hangs down integrally with the end of the saddle part 21 and can cover the side part of the buried pipe 10. 22.
The earth clod weight structures 20 are formed continuously along the longitudinal direction of the buried pipe 10, or are formed intermittently (discontinuously) along the longitudinal direction of the buried pipe 10.
In this example, a form will be described in which the earth clod weight structure 20 is formed in a bilaterally symmetrical shape with the center of the earth clod weight structure 20 interposed therebetween.

The saddle portion 21 and the side leg portions 22 that constitute the earth clod weight structure 20 are constituted by a plurality of cell structures 30 stacked on-site and a filling material 33 filled in the cell structures 30 on-site.
The reason why a plurality of cell structures 30 are used in the earth clod weight structure 20 is to enhance the compaction effect of the filling material 33 and to make the compaction of the filling material 33 uniform.

<2.1> Cell structure The cell structure 30 is a three-dimensional structure in which a plurality of strips 31 are arranged vertically in a row, and a plurality of cell spaces 32 with open top and bottom are defined between the plurality of strips 31. It is the body.
The band plate 31 is a flexible plate made of a resin material or a metal material with excellent weather resistance and durability, and may have either a perforated structure or a non-perforated structure.
The height of the strip plate 31 is, for example, 75 to 300 mm, and the length (inner dimension) of one side defining the cell space 32 is, for example, 200 to 500 mm.
The cell structure 30 has a weight that can be transported by hand, and is transported to the site in a folded state and then unfolded for use.

The reason why the clod weight structure 20 is composed of an aggregate of cell structures 30 is to enable the width and height of the saddle portion 21 and the side leg portions 22 to be freely set, and to improve the compaction of the filling material 33. This is to make it easier to compact the material and to compact it firmly, and to minimize leakage of the filling material 33 if a part of the cell structure 30 is damaged.

<2.1.1> Example of cell structure To explain the cell structure 30 illustrated in FIG. 2, FIG. FIG. 2B shows a cell structure 30 in which a cell structure 32 is defined, and FIG. 2B shows a cell structure 30 in which a part of a band plate 31 formed in a wave shape is joined by heat fusion or the like to define a honeycomb-shaped cell space 32. The cell structure 30 is shown in the form shown in FIG.
The planar shape of the cell space 32 is not particularly limited, and may be a polygonal planar shape other than that illustrated in FIG. 2 .

<2.2> Filling material The filling material 33 is not particularly limited, but for example, hard particles such as earth and sand, crushed stone, gravel, and slag can be used.
Further, as the filling material 33, it is also possible to use a fluidized solidified material such as fluidized soil.
The filling work of the filling material 33 is performed in units of single layers of the cell structures 30 stacked in multiple stages, thereby realizing strong compaction.

<2.3> Form of integration of saddle portion and side leg portions The saddle portion 21 and side leg portions 22 that constitute the clod weight structure 20 are constituted by the plurality of cell structures 30 and the filling material 33 described above.

Referring to FIG. 3, a description will be given of a form in which the saddle portion 21 and the side leg portions 22 constituting the earth clod weight structure 20 are joined together.

<2.3.1> Connection form of saddle and side legs (1)
FIG. 3(A) shows a clod weight structure 20 in which the upper surface 22a of the side leg portion 22 is joined to the lower surface 21b of both ends of the saddle portion 21 and integrated.

In this embodiment, in order to integrate the saddle part 21 and the side leg parts 22, a plate-shaped or sheet-shaped support material 23 is arranged on the upper surface 21a of the saddle part 21 and the lower surface 22b of the side leg parts 22, and the saddle part 21 and the side leg parts 22 are integrated. One or more connecting bodies 24 are vertically inserted between the side legs 22 and the connecting bodies 24, and both ends of the connecting bodies 24 penetrated through the bearing pressure member 23 are fixed with fixtures 25.
The connecting body 24 has a full length that can be penetrated over the saddle portion 21 and the side leg portions 22, and has a structure to which a fixture 25 can be attached to both ends thereof.
The weight of the side legs 22 can be transmitted to the saddle 21 via the coupling body 24 .
Although not shown, one or more connecting bodies 24 are additionally installed vertically between the top and bottom of the saddle section 21 located directly above the buried pipe 10 to rigidly connect the center section of the saddle section 21. It's okay.

Note that in order to make the present invention easier to understand, the side legs 22 are shown with the same width dimension in the drawings for convenience, but in actual construction, the cell structure 30 has flexibility. Therefore, it is possible to construct the side leg portion 22 by bringing the inner surface of each cell structure 30 into contact with the outer circumferential surface of the buried pipe 10, and the inner surface of the side leg portion 22 and the outer circumference of the buried pipe 10 can be constructed. There are no large gaps between them.

<2.3.2> Connection form of saddle and side legs (2)
FIG. 3(B) shows a clod weight structure 20 in which the side surface 21c of the saddle portion 21 and the side surface 22c of the side leg portion 22 are joined and integrated.

In this embodiment, in order to integrate the saddle portion 21 and the side leg portions 22, one or more connecting bodies 24 are disposed to pass through the saddle portion 21 and the side leg portions 22 laterally. Both ends are fixed with fixtures 25.
The weight of the side legs 22 can be transmitted to the saddle 21 via the plurality of connectors 24 .

In addition, in the connection structure shown in FIG. 3(B), the vertical connection body 24 shown in FIG. 3(A) may be additionally installed on the side leg portion 22.

<2.3.3> Connection means between the saddle section and the side leg sections In this example, the connection means between the saddle section 21 and the side leg sections 22 include a connection body 24 having a belt shape, a rod shape, or a string shape, for example; It is possible to use a combination of a fixing device 25 that can be attached to the end of 24 and fixed.
As the means for connecting the saddle portion 21 and the side leg portions 22, any of various known connection means may be used as long as the load can be transmitted between the saddle portion 21 and the side leg portions 22.

[How to bury the buried pipe]
A method for burying the buried pipe 10 will be described with reference to FIGS. 4A and 4B.

1. Excavation process of laying trench (Figure 4A(A))
An earth retaining plate 41 such as a sheet pile is driven opposite to the ground G, and a trench 40 having a size that allows the buried pipe 10 to be laid is excavated with the earth retaining plate 41 preventing earth and sand from collapsing.
A supporting foundation 42 is constructed by spreading sand, high-quality soil, etc. in layers over the entire bottom of the laying trench 40.

2. Buried pipe installation process (Figure 4A(A))
After the buried pipe 10 is suspended horizontally inside the laying groove 40, the buried pipe 10 is laid on the upper surface of the support foundation 42.

3. Backfilling process of laying trench (Fig. 4A(B) to Fig. 4B(D))
The buried pipe 10 laid inside the laying trench 40 is buried in the following manner.

<1> Construction of earth clod weight structure After first constructing the side leg parts 22, the saddle part 21 is constructed, and the earth clod weight structure 20 having a portal shape is constructed so as to straddle the buried pipe 10.

<1.1> Construction of side legs (Figure 4A(B))
A step of laying the cell structure 30 described above on the upper surface of the supporting foundation 42 exposed on both sides of the buried pipe 10, a step of filling the cell space 32 of the cell structure 30 with the filling material 33, and a step of filling the filling material 33. The steps of rolling and compacting the cell structure 33 are repeated until a predetermined height is reached, thereby forming the side legs 22, 22 on both sides of the cell structure 30.
The compaction work of the filling material 33 can be efficiently performed using a known rolling machine such as a roller type, vibration type, compaction type, etc.

When constructing the side legs 22, the filling material 33 is restrained in each cell space 32, and the cell structure 30 is compacted individually, so that the side legs 22 are completely filled with filling materials. There is no variation in the compaction of the material 33, and the filling material 33 can be compacted homogeneously and firmly over the entire length of the earth clod weight structure 20 (laying groove 40).

<1.2> Construction of saddle (Figure 4B(C))
A saddle portion 21 is constructed spanning both side leg portions 22, 22 provided on both sides of the cell structure 30.
The method for constructing the saddle portion 21, like the side leg portions 22, includes a step of laying the cell structure 30, a step of filling the cell space 32 of the cell structure 30 with the filling material 33, and a step of filling the cell structure 30 with the filling material 33. It is constructed by repeating the rolling and compaction process until a predetermined height is reached.

In constructing the saddle portion 21, the filling material 33 is compacted for each cell structure 30, and the filling material 33 is compacted in a restrained state in each cell space 32 of the cell structure 30. Accordingly, there is no variation in the compaction of the filling material 33 over the entire saddle portion 21, and it is possible to compact the filling material 33 firmly and uniformly over the entire length of the clod weight structure 20 (laying groove 40). can.

<1.3> Connection between the side legs and the saddle The side legs 22 and the saddle 21 are integrally connected using the connecting member 24 shown in FIG. .
The installation form of the side legs 22 and the saddle 21 and the connection form between the side legs 22 and the saddle 21 are appropriately selected from either of the forms shown in FIG. 3(A) or (B).

The clod weight structure 20 constructed in such a manner as to straddle the buried pipe 10 at the site has its side legs 22 , 22 located adjacent to both left and right sides of the buried pipe 10 , and the saddle portion 21 is located on both sides of the buried pipe 10 . Located adjacent to the top.

4. Soil covering process using backfill material (Figure 4B(D))
The upper surface of the earth clod weight structure 20 is covered with backfilling material 43 such as earth and sand by repeating spreading and rolling.
The backfilling material 43 not only functions as a mere soil covering material, but also functions as a counterweight for the buried pipe 10 by supporting the total weight of the backfilling material 43 on the clod weight structure 20.

Note that covering with the backfilling material 43 is not essential, and the structure may be such that the clod weight structure 20 itself serves as the covering without using the backfilling material 43.

5. Removal process of earth retaining board (Figure 4B(D))
After covering the backfilling material 43 to the height of the ground G, the retaining board 41 is removed.
The upper surface of the earth clod weight structure 20 is covered with backfilling material 43 such as earth and sand by repeating spreading and rolling.
Covering with the backfilling material 43 is not essential, and the clod weight structure 20 may also serve as the covering without using the backfilling material 43.

The side legs 22, 22 of the clod weight structure 20 are located on both the left and right sides of the buried pipe 10 close to the outer peripheral surface of the buried pipe 10, so even if the retaining plate 41 is removed, the side legs 22, 22 will not be removed. No displacement in the width expansion direction.
More specifically, even if the retaining plate 41 is removed, the clod weight structure 20 does not lose its shape.
Since the filling material 33 is restrained by the cell structure 30 constituting the side leg part 22, the filling material 33 does not loosen or fall off and maintains a strong compacted state.
Since the protection function of the buried pipe 10 by the earth clod weight structure 20 is maintained, even if the earth retaining plate 41 is removed, compressive deformation and damage in the horizontal direction of the buried pipe 10 can be reliably prevented.

Note that the space where the retaining board 41 has been removed is preferably filled with a portion of the backfilling material 43.

[Effect to prevent floating pipes from floating]
Referring to FIG. 5, the effect of preventing the buried pipe 10 from rising during an earthquake will be described.

<1> Relationship between the vertical weight acting on the clod weight structure and the backfilling material Figure 5 shows the relationship between the buoyant force U acting on the buried pipe 10 and the downward vertical weight acting on the clod weight structure 20 and the backfilling material 43. ing.

Regarding the vertical weight of the earth clod weight structure 20, the central vertical weight of the part located directly above the buried pipe 10 (saddle part 21) is _w1 , and the part located directly above the side of the buried pipe 10 (side leg part 22) ) is the lateral vertical weight _w2 .
Similarly, regarding the vertical weight of the backfilling material 43, the central vertical weight of the part located directly above the buried pipe 10 is _w3 , and the lateral vertical weight of the part located directly above the side of the buried pipe 10 is _w4. shall be.

<2> Vertical weight of the earth clod weight structure In the present invention, the saddle portion 21 and the side leg portions 22 that constitute the earth clod weight structure 20 are integrated so as to be able to transmit a load, so that they can resist the buoyancy U of the buried pipe 10. The obtained vertical weight is not only the central vertical weight w ₁ but also the left and right lateral vertical weights w ₂ and w ₂ which function as weights that oppose the buoyancy U of the buried pipe 10.
That is, since the earth clod weight structure 20 is a highly rigid earth clod structure, the entire weight (w ₁ +w ₂ +w ₂ ) functions as a counterweight for the buried pipe 10.

<3> Vertical weight of backfilling material Furthermore, the weight of the backfilling material 64 located above the earth clod weight structure 20 is the sum of the center vertical weight w ₃ and the lateral vertical weights w ₄ and w ₄ of the buried pipe 10. counteracts the buoyant force U of
That is, the weight (w ₃ +w ₄ +w ₄ ) of all the backfill materials 64 functions as a counterweight via the highly rigid earth mass structure.

<4> Overall vertical weight When these are put together, the total weight of the earth clod weight structure 20 and the total weight of the backfilling material 43 (w ₃ +w ₄ +w ₄ ) function as a counterweight to the floating of the buried pipe 10.
Therefore, even when the buried pipe 10 is a large diameter pipe or in the ground where the underground water level is high, the buried depth H of the buried pipe 10 can be made shallow.
By reducing the burial depth H of the buried pipe 10, the amount of excavation of the laying trench and the amount of backfilling material 43 used can be reduced, and the burden on construction cost and construction period can be significantly reduced.

[Example 2]
Other embodiments will be described below, but in the description, the same parts as in the above-mentioned embodiments will be given the same reference numerals, and detailed explanation thereof will be omitted.

<1> Other earth clod weight structures The earth clod weight structures 20 are not limited to the laterally symmetrical form shown in the first embodiment.
The asymmetrical earth clod weight structure 20 will be described with reference to FIG. 6.

FIG. 6(A) shows another clod weight structure 20 in which the widths L ₁ and L ₂ of the left and right side leg portions 22 and 22 provided on both sides of the saddle portion 21 are different.
Furthermore, the height and width H ₁ , H ₂ of the left and right side leg portions 22 , 22 may be made different.

FIG. 6(B) shows a configuration in which a side leg portion 22 is provided only on either the left or right side of the saddle portion 21, and the clod weight structure 20 is formed into a hook shape.
The total weight of the saddle portion 21 is adjusted in consideration of the buried environment of the buried pipe 10, the direction of buoyancy generated in the buried pipe 10, and the like.

<2> Effects of this example In addition to being able to obtain the same effects as in Example 1, this example can also adjust the vertical load according to each part of the clod weight structure 20 according to the burial environment at the site. Since it is possible to provide a counterweight, the degree of freedom in design is expanded, and it is also possible to design an economical counterweight.
Furthermore, even at sites where there are existing underground obstacles, rocks, hard ground, etc. that are close to the buried pipe 10 and cannot be excavated on the side of the buried pipe 10, a horizontally asymmetrical The earth clod weight structure 20 can function as a counterweight for the buried pipe 10.

[Example 3]
The earth clod weight structure 20 applied to the bent buried pipe 10 will be described with reference to FIG. 7.
The buried pipe 10 is, for example, a pipe body such as an agricultural pipeline or a drainage pipe of a hydroelectric power plant, and may be buried bent in a dogleg shape.

<1> Thrust force acting on bent portion of buried pipe To explain with reference to FIG. 7(B), if a buried pipe 10 having a bent portion is buried in the ground such as embankment without taking any measures, the buried pipe It is known that when water flows inside the buried pipe 10, an outward centrifugal force is generated at the bent portion of the buried pipe 10, and a thrust force F that moves the buried pipe 10 obliquely upward is generated.
If the thrust force F of the buried pipe 10 is left unaddressed, there is a risk that the road 44 located above will be deformed, such as upheaval or fracture, or that a part of the buried pipe 10 will be destroyed.

Countermeasures for this include, for example, driving an anchor underground and using the anchor as a source of reaction force to fix the buried pipe 10 toward the inside of the curve, or burying the buried pipe 10 in hard ground such as a mountain. Methods such as doing this have been proposed, but these countermeasures are costly and time consuming, and there is room for improvement.

<2> Earth clod weight structure capable of resisting thrust force To explain with reference to FIG. establish.
By simply installing the above-mentioned clod weight structure 20 across the bent portion of the buried pipe 10, the thrust force F acting on the bent portion of the buried pipe 10 can be reduced by the vertical weight of the clod weight structure 20. can be countered.
In this example, it is desirable to employ a left-right asymmetrical clod weight structure 20 as shown in FIG.

<3> Effects of this Example In addition to being able to obtain the same effects as in Example 1, this example also provides thrust force by simply applying the clod weight structure 20 to the buried pipe 10 having a bent portion. It has the advantage of being able to resist against
Furthermore, the clod weight structure 20 suppresses the behavior of the embankment in which the buried pipe 10 is buried and serves as a seismic reinforcement member for the embankment, and the load dispersion effect of the clod weight structure 20 reduces the wheel load acting on the buried pipe 10. can do.
In addition, even if the embankment slope is eroded by rainwater, tsunami, etc., the buried pipe 10 can be protected by the protective action of the earth clod weight structure 20.

10... Buried pipe 20... Earth clod weight structure 21... Saddle part 22... Side leg part 23... Bearing material 24... Connecting body 25... Fixing tool 30... Cell structure 31... Strip plate 32... Cell space 33... Filling material 40... Laying groove 41... Earth retaining board 42...・Support foundation 43...Backfilling material 44...Road

Claims (14)

A buried structure for a buried pipe that is buried underground,
An earth clod weight structure having a gate-shaped or hook-shaped cross-sectional shape and made of a highly rigid earth clod structure manufactured on site is placed astride the buried pipe,
characterized in that the total weight of the earth clod weight structure functions as a counterweight for the buried pipe,
Buried structure of buried pipe. The buried structure for a buried pipe according to claim 1, wherein the upper surface of the earth clod weight structure is covered with backfilling material, and the total weight of the backfilling material is supported by the earth clod weight structure.
buried structure. 3. The buried structure for a buried pipe according to claim 1, wherein a block weight structure is placed continuously or intermittently over the entire length of the buried pipe. 3. The buried structure for a buried pipe according to claim 1, wherein the buried pipe has a bent part, and the lump weight structure is placed astride the bent part of the buried pipe. 3. The buried structure for a buried pipe according to claim 1, wherein the block weight structure is asymmetrical with respect to the buried pipe. The earth clod weight structure includes a saddle part that can cover the upper part of the buried pipe horizontally, and a side leg part that hangs down integrally with an end of the saddle part and can cover the side part of the buried pipe. , wherein the saddle portion and the side leg portions are constituted by a plurality of cell structures stacked in layers on site, and a filling material filled and compacted into the cell spaces of the cell structures on site. The buried structure of the buried pipe according to item 1 or 2. Claim 6, characterized in that the saddle portion and the side leg portions are integrally connected to each other so that a load can be transmitted through a connecting body that extends vertically or horizontally between the saddle portion and the side leg portions. The buried structure of the buried pipe described in . The first step is to excavate a trench between the ground where the retaining material has been placed, the second step is to lay the pipe in the trench, and the third step is to backfill the trench. A method of burying a buried pipe buried in
The third step is to backfill the laying trench by placing an earth clod weight structure having a gate-shaped or hook-shaped cross-sectional shape and made of a highly rigid earth clod structure manufactured on site over the buried pipe. , characterized in that the total weight of the earth clod weight structure functions as a counterweight for the buried pipe,
Burying method for underground pipes. 9. The method according to claim 8, further comprising a fourth step of covering the upper surface of the earth clod weight structure with backfilling material, and the total weight of the backfilling material is supported by the earth clod weight structure. Burying method for underground pipes. 10. The method for burying a buried pipe according to claim 8, wherein a block weight structure is placed continuously or intermittently over the entire length of the buried pipe. 10. The buried pipe burying method according to claim 8, wherein the buried pipe has a bent part, and the block weight structure is placed astride the bent part of the buried pipe. 10. The method for burying a buried pipe according to claim 8, wherein the block weight structure is asymmetrical with respect to the buried pipe. The earth clod weight structure includes a saddle part that can cover the upper part of the buried pipe horizontally, and a side leg part that hangs down integrally with an end of the saddle part and can cover the side part of the buried pipe. , wherein the saddle portion and the side leg portions are constituted by a plurality of cell structures stacked in layers on site, and a filling material filled and compacted into the cell spaces of the cell structures on site. The method for burying a buried pipe according to item 8 or 9. Claim 8 or 9, characterized in that the saddle portion and the side leg portions are integrally connected to each other so that a load can be transmitted through a connecting body that passes through the saddle portion and the side leg portions in a vertical or horizontal direction. Burying method for buried pipes described in .

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