JP2000336636A - Blind drain pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blind drain pipe having both excellent productivity and sufficient uncrushable strength even when it receives pressure such as earth pressure in the ground. SOLUTION: A blind drain pipe 60 has three-layer structure comprising a perforated pipe 61, an interstitial material 62 and a water permeable sheet 63. The outer peripheral part of the flexible perforated pipe 61 with a large number of water through-holes 64 formed in a pipe wall is covered with the water-air permeable, resilient interstitial material 62 easily manufacturable and having specified strength, and the interstitial material 62 is covered with the water permeable sheet 63. The interstitial material 62 is formed of a material with a larger section modulus compared to conventional fibrous materials. Sufficient strength and manufacturing facility can thereby be realized. A clearance for aeration and water permeation, and cushioning action are maintained while having strength and durability to earth pressure and the like and also having flexibility of following the deformation of the perforated the 61. This blind drain pipe 60 can be directly buried as it is in a golf course, a ground or the foundation ground of the land developed by banking work.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blind drainage pipe,
The present invention relates to a blind drainage pipe suitable for drainage treatment of a ground or golf course, embankment work, backside of a retaining wall, or the like, or for promoting consolidation settlement and degassing in landfill work.

[0002]

2. Description of the Related Art In general, a perforated drainage pipe, that is, a drainage pipe for grounding a golf course, a ground, or the like, has been formed in these grounds in order to reduce the water content of the embankment material in large-scale embankment work. A drain pipe with a large number of water holes formed in the pipe is buried, and rainwater that has infiltrated into the ground is collected in this perforated drain pipe and drained.
The ground is well drained. In technical terms related to civil engineering, such drainage pipes are called culvert drainage pipes or blind drainage pipes.

In the above-mentioned conventional blind drainage pipe, it is necessary to fill the periphery of the pipe with crushed stone generally called No. 4 crushed stone having a diameter of about 3 to 4 cm and having almost the same size and being hard to compact. However, in recent years, there has been a problem that it is difficult to collect the No. 4 crushed stone, which leads to an increase in construction cost.

The inventor of the present invention has sought to omit a small transport or filling operation of a filler such as No. 4 crushed stone or split stone, and to shorten the construction period and reduce the cost, so that a large number of water holes are formed in the pipe wall. Blind drainage pipe comprising a perforated pipe formed with holes, a water-permeable and elastic gap material filled in the outer peripheral portion of the perforated pipe, and a water-permeable covering material covering the outer peripheral portion of the gap material. In Japanese Patent Application Laid-Open No. 9-13358, a blind drainage pipe using a spiral synthetic fiber or the like as a gap material was devised.

[0005]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Laid-Open No. 9-1
The blind drainage pipe described in Japanese Patent No. 3358 has exhibited excellent water collecting performance and flexibility in a place where the earth pressure is small, but has a large earth pressure, a compaction pressure when leveling, or compaction of the embankment. In such cases, there is a problem that the strength is insufficient.

That is, the gap material formed of a synthetic fiber such as a spiral shape is crushed due to insufficient strength, and the perforated pipe and the coating material adhere to each other, so that the gap material has a role of maintaining air permeability and water permeability. There is a problem that it cannot be fulfilled.

Further, in order to increase the strength of the gap material, the fibers are overlapped or combined,
Or it involved a complicated task of weaving other fibers into them. At this time, most of these tasks were manual and poor productivity.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and has both sufficient strength so as not to be crushed even when subjected to pressure such as earth pressure in the ground, and excellent productivity. To provide a blind drainage pipe.

[0009]

In order to achieve the above object, a blind drainage pipe according to the present invention comprises a perforated pipe having a large number of water holes formed in a pipe wall and an outer peripheral portion of the perforated pipe. A gap drainage having water permeability and elasticity to be mounted, and a covering material having a water permeability that coats an outer peripheral portion of the gap, comprising: a blind drain pipe embedded in the ground to drain permeated water; The gap member is characterized by being formed from a member having a cross-sectional shape having a larger section modulus than the fibrous gap member.

According to the present invention, when burying a blind drainage pipe in the ground, the strength in the direction perpendicular to the pipe axis is large, and the blind drainage pipe can be buried in the ground without filling the surrounding area with crushed stone or the like. . In addition, since the band-shaped member and the plate are formed in a bellows-like shape, the production is much easier than the conventional combination of wires such as fibers.

Also, by devising the above-mentioned gap material,
It is possible to omit a covering material such as a water-permeable sheet.
That is, by providing shielding means for preventing intrusion of soil and the like in the water-passing portion constituting the water-passing hole or the water-passing slit of the gap material, the gap material can be used as the outermost material of the outermost layer. Become. Thereby, the number of members can be reduced, and the ease of manufacture is improved.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. In the blind drainage pipe of the present invention, among the three-layer structure of the perforated pipe, the gap material, and the water-permeable covering sheet, particularly, the gap material is newly developed and created. In other words, we developed a gap material that not only has water permeability and elasticity but also has sufficient strength to withstand the compaction of topsoil and other earth pressure when buried in the ground. It is used.

[0013] The perforated pipe has a large number of water holes formed in the wall of the pipe, and collects rainwater or the like that has penetrated into the ground from the water holes into the pipe, discharges the water outside the area, and reduces the earth pressure. With the strength to withstand, and flexibility to be able to draw a curve,
It is preferable that the material has flexibility that can follow the deformation of the ground and has semi-permanent durability in the ground. Therefore, it is made of a synthetic resin such as polyethylene or vinyl chloride, and has a spiral or bellows shape in which the outer surface of the tube is uneven and the inner surface is smooth or uneven.

The water-permeable sheet has ventilation, water permeability, and corrosion resistance, and also has a filter function for preventing inflow of earth and sand. By wrapping the outermost periphery of the blind drainage pipe, the gap material is formed into a perforated pipe. Hold around and integrate as blind drain. The material may be a non-woven fabric or a woven fabric made of natural fibers or synthetic fibers.

Incidentally, the perforated pipe and the water-permeable sheet are
Although each of them is publicly known, there is no equivalent to the gap material in the present invention, and the blind drainage pipe according to the present invention comprises a perforated pipe, a gap material, and a water-permeable sheet, and is a conventional No. 4 crushed stone. It is intended to achieve the intended purpose simply by burying it in the ground without using it. In the present invention, a sufficient measure is taken for the gap material, so that the water-permeable covering sheet can be omitted depending on conditions, as described later.

In the embodiment of the gap material according to the present invention, the strength is increased by increasing the section modulus by forming the cross section into a pipe, polygon, or H shape instead of a wire such as fiber. is there. By setting the cross section in this way, it is possible to realize an improvement in the strength of the gap member and an improvement in productivity.

That is, when a wire such as a fiber is used, various combinations of fibers and a knitting operation can be performed in one operation.
Although the mechanization of 00% is difficult and must be accompanied by a considerable amount of manual work, according to the embodiment described below, production can be easily performed by mechanical work such as press working. The gap material in the present invention may be a single material or a combination of a plurality of materials. When a plurality of components are combined, the cross-sectional shapes, materials, and the like may be the same or different.

FIG. 1 is a perspective view of a gap member 1 in which a plate-like member having a rectangular cross section is formed in a spiral shape. Such a spiral gap material 1 is further spirally wound such that the plate-shaped cross section 2 stands on the outer peripheral surface of a perforated pipe (not shown), and the outermost periphery is formed of a water-permeable sheet (not shown). (Fig.). Thus, the sectional modulus in the direction A in FIG. 1 is much larger than that of a wire such as a fiber, so that the radial strength of the blind drainage pipe is greatly improved.

Although the method of using the gap material has been described above in connection with the method of winding the material around the perforated pipe, as will be described later, the method of passing the perforated pipe through the opening 3 in the center of the gap material 1 will be described later. There is also. According to this method, not only the one shown in FIG. 1 but also a winding work and a bundling work can be omitted, and a perforated pipe is passed through the inside in the manufactured shape, so that a structurally sound one can be obtained. .

FIG. 2 shows a gap member 6 provided with a shaft 5 at the center of the spiral member 4. By providing such a shaft 5, the expansion and contraction of the spiral member 4 in the axial direction is suppressed, so that the layer of the gap member 6 does not unnecessarily loosen. Further, handling of the gap member 6 is also easy. Note that the shaft 5 does not necessarily need to be at the center.

FIG. 3 is a perspective view of a gap member 7 in which a plate-like member having a rectangular cross section is spirally formed with the plate plane parallel to the axial direction. As in FIG. 2, expansion and contraction in the axial direction is suppressed, and for example, by combining with the one in FIG.
Various cross-sectional shapes such as an I type and an H type can be formed.

FIG. 4 shows a disk-shaped member 8 instead of a spiral one.
Is a so-called bellows-shaped gap material 10 in which the plate faces are skewered with a pipe 9 so that the plate faces are parallel. Each bellows is also called a fin below. Although a disk is used for the fins in the figure, a ring-shaped, annular, or polygonal plate may be used. Even if such a gap material 10 is spirally wound around the perimeter of a perforated pipe, a blind drainage pipe which can sufficiently withstand earth pressure or the like can be obtained because the cross-sectional modulus in the direction perpendicular to the perimeter of the perforated pipe is large.

FIGS. 5 to 7 show the configuration of FIG. 4 in which water permeability and air permeability are further considered. That is, FIG.
Has slits 12 in the fins 11. FIG.
The fin 13 is provided with a hole 14 or a projection. FIG.
In the figure, a number of rods 15 are formed radially in the radial direction of the shaft 5 instead of the fins.

According to these, water permeability and air permeability are improved by slits and holes. Such slits and holes are not limited to those shown in FIG. 4 but can be applied to those shown in FIGS. 1 and 2 and have similar functions and effects.

FIGS. 8 to 10 are perspective views of the gap member for increasing the strength of those shown in FIGS. 2 and 4. FIG. FIG. 8 shows a so-called bent fin 16 fixed to the shaft 5. FIG. 9 shows a fin having a fin-like body 17 waving in a so-called shampoo hat shape. FIG.
Numeral 0 has a fin-like body 18 in which adjacent parts are partially connected to each other.

FIGS. 11 to 14 show the shapes of the fins which stand perpendicular to the shaft 5, and each of them is devised. That is, FIG. 11 is a diagram in which a square plate-like fin 19 is erected on a shaft member having a square cross section.
FIG. 13 shows an example in which a fin-shaped body 20 of a disk or a square plate is erected on three shaft members, that is, a plurality of shaft members.
The fins 21 of various shapes are provided upright.

FIG. 14 shows a fin-shaped body 22 standing upright in parallel with the longitudinal direction of the pipe 9. In any case, when wound around a perforated pipe, the sectional modulus in the radial direction is larger than that of a conventional linear material, and therefore, the strength against earth pressure and the like is also large.

These are all examples of the gap material, and fin-like bodies and shafts having an unlimited number of various shapes are also conceivable. In addition, according to the shape of the perforated pipe serving as a base material of the gap material and the state of the ground to be buried, FIG.
~ By combining the features of Fig. 14,
Thousands or tens of thousands of types of gap materials can be manufactured.

That is, it is possible to provide a gap material that can meet various needs, such as adjustment of strength and porosity, or production of finished products of various shapes, depending on the purpose and ground conditions. Further, the gap material in the present invention sufficiently has the flexibility, the earth pressure strength, the water permeability and the air permeability required by the blind drainage pipe.

Further, how to use the gap material in the present invention will be described. Taking FIGS. 1, 2 and 4 as an example, for example, there is a method of passing a perforated pipe (not shown) through the central opening 3 in FIG. In addition, there is a method in which the shaft 5 in FIG. 2 has a pipe structure like the pipe 9 in FIG. In this case, the aperture and the shaft through which the perforated pipe passes need not necessarily be the center of the gap.

As described above, by adopting the method of passing the perforated pipe through the center of the gap member, the conventional winding work, arrangement work in the same direction, and bonding and bundling work are omitted. Alternatively, labor saving can be achieved.

In such a case, as shown in FIGS. 15 and 16, holes 25 and slits 26 are provided in the fin-like body 24 of the gap member 23, or the gap member itself is formed into a mesh structure so that it can pass through. Water performance and ventilation performance can be maintained. As a matter of course, the improvement of the ventilation performance promotes the flow of water in the pipe.

FIG. 17 is a cross sectional view of FIG.
As shown in FIG. 17, the gap member 10 itself has a bellows structure so as to follow the flexibility of the perforated tube 30 serving as a base. In this case, as shown in FIGS. 18A and 18B, the bellows structure may have a V-shaped or U-shaped comb-shaped cross section.
5 to 14 can also be applied in the same manner as the above-described application examples in FIGS. 1, 2, and 4.

Next, another embodiment of the present invention will be described.
The embodiment of the above-mentioned blind drainage pipe is constituted by three members of a perforated pipe, a gap material, and a covering material. By devising this gap material, the outermost covering material can be omitted.
Such a gap material that also serves as the outermost coating material is hereinafter referred to as an outer peripheral material.

That is, the blind drainage pipe of this embodiment has a perforated pipe having a large number of water holes formed in the pipe wall, and a water-permeable and elastic outer periphery mounted on the outer peripheral portion of the perforated pipe. Material (corresponding to the above-described gap material), and is a blind drainage pipe buried in the ground to drain permeated water, wherein the outer peripheral material is a member having a cross-sectional shape having a larger cross-sectional coefficient than a fibrous member. It is characterized in that it has shielding means for preventing intrusion of earth and sand into the formed water-permeable portion.

FIGS. 19 to 21 show an embodiment of a blind drainage pipe in which the outermost water-permeable sheet can be omitted. For example, by reducing the dimension a shown in FIG. 17 as much as possible, it is possible to omit a water-permeable sheet such as a nonwoven fabric forming the outermost layer of a three-layer structure depending on the soil conditions and the method of use.

FIG. 19 shows an example in which a cover 35 made of a nonwoven fabric is provided in an outer peripheral groove 34 of a bellows-like gap member 33 through which a perforated pipe 30 is passed. FIG. 20 and FIG.
This is an example in which the shape of No. 6 is devised so as to wrap adjacent fins. By narrowing the width of the opening 37 of the outer circumferential groove, it is possible to prevent earth and sand having a predetermined diameter or more from entering the groove.
And a two-layered blind drain pipe.

In this case, the soil that can be buried in the ground by omitting the water-permeable sheet such as a nonwoven fabric and the like is mainly sandy soil, gravel soil, or a highly water-permeable soil containing most of them. Is preferred. It is not suitable for soil with low permeability such as cohesive soil.

The soil water permeability is calculated from the size of the soil particles, the particle size distribution of the size, and the like. Moreover, even if the soil has the same properties, it naturally depends on the distribution number, diameter, width, etc. of the holes and slits provided in the blind drainage pipe.

FIG. 22 shows an example in which the outermost water-permeable sheet is omitted depending on the soil conditions. If the soil is appropriate, even if the soil 41 is clogged in the outer circumferential groove of the gap material 40, the entire gap material serving as the coating layer 42 of the perforated pipe 30 has the same air permeability and water permeability as No. 4 crushed stone. Will be brought.

Therefore, the soil condition is checked in advance, the cross section of the porous material and the perforated pipe, the hole / slit, etc. are examined according to the soil quality, and the structure of the blind drainage pipe is set to provide a fine-grained response. Can be. The pores and slits become finer in a clayey soil having poor water permeability, and as a result, it resembles a nonwoven fabric.

FIG. 23 is a view showing still another embodiment of the present invention. In the example shown in FIG. 23 (a), in order to secure a fixed interval between the outer periphery of the perforated pipe 30 which is a base and the gap member 45, and to improve the strength, the inside of the gap member 45 is provided. A protrusion 46 such as a flange or a protrusion is provided.
FIG. 23B shows an example in which such a gap member 45 is spirally wound.

In FIGS. 23 (a) and 23 (b), the flanges or projections have various cross sections, such as polygonal, circular, elliptical, H-shaped, T-shaped, O-shaped and I-shaped, depending on the required strength. Can be formed in the cross-sectional shape. Further, the example of FIG. 23B is one of examples in which the rectangular cross section of the gap member of FIG. 1 is formed into the cross sectional shape indicated by S in the drawing.

In the example shown in FIG. 23, the gap material 45 is formed in a bellows shape or a spiral shape. Therefore, depending on the soil condition, a hole is formed in the gap material or a mesh is used to form the outermost material. The water-permeable sheet can be omitted. This is because the gap between the gap material and the perforated pipe is ensured by the flange and the projection.

FIG. 24 is a view showing still another embodiment of the present invention. A spiral groove 51 is formed on the outer periphery of the perforated tube 50 serving as a base, and the gap member 52 can be wound around the groove 51 by engaging with the groove 51. According to this example, the manufacturability of the blind drainage pipe is improved and the cost is reduced. As shown in the figure, if the gap member 52 is also formed into a shape that engages with the perforated pipe outer peripheral groove 51, the assembly is further facilitated, which is convenient.

FIG. 25 is a perspective view of a blind drainage pipe manufactured using any of the examples of the gap members described in detail above. The blind drainage pipe 60 according to the present invention has a triple structure of an inner perforated pipe 61, a gap member 62, and an outer permeable sheet 63. Flexible perforated pipe 6 having a large number of water passage holes 64 formed in the pipe wall
1 is covered with a gap member 62 having a predetermined strength and having water permeability, air permeability and elasticity, and is covered with a water permeable sheet 63 from above.

Here, the gap member 62 is formed of a material having a much larger section modulus than a conventional wire such as a fiber. As a result, sufficient strength and easiness in production were realized. In addition, while maintaining the gap and cushioning effect for ventilation and water passage, it has strength and durability against earth pressure and the like, and also has flexibility so that it can follow the deformation of the perforated pipe. The blind drainage pipe 60 can be directly buried directly in a foundation ground such as a golf course, a ground, or a ground formed by large-scale embankment work.

As described above, the gap material in the present invention is:
Compared to a conventional wire such as a fiber, the section modulus is much larger, so that it has sufficient strength, is easy to handle, and has excellent manufacturability. Further, by improving the strength, it is possible to prevent shape deformation such as crushing against earth pressure, compaction of the ground, and the like, so that the drainage action can be maintained for a long time. Depending on the soil conditions, the outer layer of the water-permeable sheet may be omitted, and a blind drainage pipe having a two-layer structure of a perforated pipe and a gap material may be used. In this case, the manufacturing cost can be further reduced.

[0049] Still another embodiment of the present invention will be described.
In the above description, for example, FIGS. 1 and 3 show an example in which one gap member is spirally wound, but the present invention is not limited to this. That is, a plurality of gap members having the same or different cross-sectional shapes may be wrapped around each other and wound.

FIG. 26 shows a helical gap member 70 having the same cross section.
This is an example in which a plurality of (two in the figure) are overlapped in the radial direction (A direction) and wrapped with different diameters on the inside and outside. According to this example, a wider gap space can be ensured between the outermost water-permeable sheet and the perforated pipe without providing a flange or a projection as shown in FIG. It is also useful for adjusting the porosity.

FIG. 27 shows a plurality of spiral gap members 71 having the same cross section in the axial direction (direction B in FIG. 26).
This is an example in which they are wrapped side by side and wound approximately the same diameter. According to this example, the connection of the gap material can be easily performed at the connection portion of the perforated pipe, and no particular connection component is required.
Further, the porosity and strength can be adjusted according to the degree of wrap.

FIGS. 28 and 29 are views showing examples in which members having different cross sections are combined and wound. 28. That is, the members shown in FIG.
This is an example in which the diameter is changed so as to overlap inside and outside and spirally wound. According to this example, when the cross section of the member is H-shaped, U-shaped, inverted U-shaped, or the like, by wrapping in a staggered manner, adjacent spiral fins are connected by inner and outer members. Can fit. By this effect, unnecessary elongation in the tube axis direction can be suppressed, leading to an increase in strength. Also, connection is easy as in the case of FIG.

FIG. 29 shows an example in which members 73a and 73b having different cross sections are spirally wound while being wrapped in the tube axis direction. This embodiment also has the same effect as that of FIG. Further, the lapping method described with reference to FIGS. 26 to 29 can be applied to not only the spiral gap material but also the bellows gap material.

In FIGS. 26 to 29, two members are wound, but three or more members may be wound. Further, the plurality of members may be made of the same material or different materials. By changing the material, the strength, flexibility, water permeability and the like can be changed as required.

[0055]

As described above, according to the present invention, the gap material according to the present invention has a much larger sectional modulus than the conventional wire material such as fiber, so that it has sufficient strength. Is easy and the manufacturability is excellent. for that reason,
Manufacturing time is reduced and manufacturing costs are much lower.

Further, when the blind drainage pipe is buried in the ground, it can be buried in the ground as it is without filling the surrounding area with crushed stone or the like due to the sufficient strength of the gap material and the air permeability and water permeability. Therefore, unlike the related art, a curing material such as crushed stone is not required around the pipe to be buried.

Also, due to the excellent water permeability and air permeability of the gap material, rainwater and the like are collected in the perforated pipe and quickly drained. Therefore, the construction period can be shortened, the ground can be easily drained, and the ground excellent in maintenance can be formed by an easy operation with low cost.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a spiral gap member having a large radial section coefficient according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an example of a spiral gap member having a shaft according to the present invention.

FIG. 3 is a perspective view showing an example of a gap member having a large axial section modulus in the present invention.

FIG. 4 is a perspective view showing an example of a fin-shaped gap member having a shaft according to the present invention.

FIG. 5 is a perspective view showing an example in which a slit is formed in a fin-shaped gap member according to the present invention.

FIG. 6 is a perspective view showing an example in which a hole is formed in a fin-shaped gap member according to the present invention.

FIG. 7 is a perspective view showing an example of a gap member formed with a radial rod according to the present invention.

FIG. 8 is a perspective view showing an example of a gap member obtained by bending a fin-shaped body in the present invention.

FIG. 9 is a perspective view showing an example of a gap material in which waves are applied to a fin-like body in the present invention.

FIG. 10 is a perspective view showing an example of a gap member connecting adjacent fin-shaped bodies in the present invention.

FIG. 11 is a perspective view showing an example of a gap member having a square fin attached to a square axis in the present invention.

FIG. 12 is a perspective view showing an example of a gap member having a plurality of fins attached to a plurality of shafts according to the present invention.

FIG. 13 is a perspective view showing an example of a gap member having various fins attached to a square axis in the present invention.

FIG. 14 is a perspective view showing an example of a gap member in which the fin-shaped body according to the present invention is erected in parallel with the longitudinal direction of the shaft.

FIG. 15 is a perspective view showing an example of a gap member having a large number of holes formed in a fin-like body according to the present invention.

FIG. 16 is a perspective view showing an example of a gap member in which a slit is formed in a fin-like body according to the present invention.

FIG. 17 is a cross-sectional view illustrating an example of a gap member having a bellows structure according to the present invention.

FIGS. 18A and 18B are schematic diagrams illustrating another example of the gap member according to the present invention, wherein FIG. 18A illustrates a cross-sectional shape of a bellows structure, and FIG.

FIG. 19 is a schematic cross-sectional view showing an example of a gap member having a cover in an outer peripheral groove in the present invention.

FIG. 20 is a schematic cross-sectional view showing an example of a gap material in which the opening of the outer peripheral groove is narrowed in the present invention.

FIG. 21 is a schematic cross-sectional view showing another example of the gap member in which the opening of the outer peripheral groove is narrowed in the present invention.

FIG. 22 is a cross-sectional view showing an example of a gap member having an outer circumferential groove adapted to soil conditions in the present invention.

23A and 23B are schematic cross-sectional views showing examples of a gap material having a protruding portion between the pipe and a perforated pipe according to the present invention, in which FIG.

FIG. 24 is a cross-sectional view illustrating an example of a gap member that engages with a perforated pipe outer circumferential groove according to the present invention.

FIG. 25 is a perspective view showing an example of a blind drainage pipe to which a gap material according to the present invention is applied.

FIG. 26 is a perspective view showing another embodiment of the present invention and showing an example of a spiral gap material in which a plurality of pieces having the same cross section are combined in the radial direction.

FIG. 27 shows another embodiment of the present invention, and is a perspective view showing an example of a spiral gap material in which a plurality of pieces having the same cross section are combined in the axial direction.

FIG. 28 is a perspective view showing another embodiment of the present invention and showing an example of a spiral gap member in which a plurality of pieces having different cross sections are combined in a radial direction.

FIG. 29 shows another embodiment of the present invention, and is a perspective view showing an example of a spiral gap material in which a plurality of pieces having different cross sections are combined in the axial direction.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 spiral gap material 2 plate-shaped cross section 3 gap material center opening 5 shaft 6 gap material 8 disk-shaped member 9 pipe 10 fin gap material 11 fin 13 fin 14 hole 18, 19, 20 fin body 23 gap material 24 Fin-like body 25 Hole 26 Slit 30 Perforated pipe 33 Porous material 40 Porous material 41 Sediment 45 Porous material 46 Projection 50 Perforated pipe 51 Groove 52 Porous material 60 Blind drain pipe 61 Perforated pipe 62 Porous material 63 Water permeable sheet 64 water holes

Claims (11)

[Claims] 1. A perforated pipe having a plurality of water holes formed in a pipe wall, a water-permeable and resilient gap material mounted on an outer peripheral portion of the perforated pipe, and an outer peripheral portion of the gap material. In a blind drainage pipe comprising a water-permeable covering material for covering and draining infiltration water buried in the ground, the gap material has one or more cross-sectional shapes having a larger sectional modulus than the fibrous gap material. A blind drainage pipe characterized by being formed from the member of (1). 2. A perforated pipe having a large number of water holes formed in a pipe wall, and a water-permeable and elastic gap material attached to an outer peripheral portion of the perforated pipe, and buried in the ground. In the blind drain pipe that drains the permeated water, the gap material is formed from one or more members having a cross-sectional shape having a larger sectional modulus than the fibrous gap material, and the water-permeable portion having the water permeability. A blind drainage pipe having shielding means for preventing intrusion of earth and sand. 3. The blind drainage pipe according to claim 1, wherein the gap member is formed by spirally forming a member having a sectional shape having a larger sectional modulus than the fibrous gap member. And blind drainage pipe. 4. The blind drainage pipe according to claim 1, wherein the gap member is formed in a bellows shape with a member having a sectional shape having a larger sectional modulus than the fibrous gap member. And blind drainage pipe. 5. The blind drainage pipe according to claim 1, wherein the gap member has a hollow shaft portion. 6. The blind drainage pipe according to claim 1, wherein the gap member has a shaft portion formed of a core material. 7. The blind drainage pipe according to any one of claims 1 to 4, wherein the gap member has a shaft formed of a hollow pipe. 8. The blind drainage pipe according to claim 1, wherein the gap member includes a plurality of members, and has a same or different cross-sectional shape with a larger section modulus than that of the fibrous gap member. A blind drainage pipe characterized by being formed in combination. 9. The blind drainage pipe according to claim 1, wherein the gap material is wound around an outer circumference of the perforated pipe. 10. The blind drainage pipe according to claim 1, wherein the gap member is arranged in the same direction as the perforated pipe. 11. The blind drainage pipe according to claim 1, wherein the perforated pipe is penetrated through a shaft of the gap material.