Drainage device and construction method thereof

Abstract

To provide a drainage device which is extremely easy to handle during storage and transportation, and which can be extremely easily constructed, and a construction method for the drainage device.SOLUTION: A drain device according to the present invention is formed by combining a waterproof sheet 2 and a water-permeable material 3, wherein the waterproof sheet 2 is a polyethylene sheet molded by blending a powder of cross-linked high density polyethylene as an auxiliary raw material and an antifogging agent which is a functional agent for plastic molding, the waterproof sheet 2 has a thickness of 1.8 to 2. 5mm, and at least two linear thin portions are formed along a longitudinal direction. The water-permeable material 3 is characterized in that a plurality of monofilaments made of a synthetic resin are randomly curved or bent in a three dimensional direction to be entangled with each other, and formed into a rectangular parallelepiped shape in a state of having a large number of continuous voids inside. A plurality of water permeable materials are connected so as to be foldable in the longitudinal direction by a binding band.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a drainage device that is buried underground to discharge water that has seeped into the ground due to rainfall or underground spring water to the outside, or that is used to drain water from slopes or embankments, and to a construction method for the same. [Background technology]

[0002] In drainage devices that are buried underground for the purpose of discharging seepage water and spring water from the ground to the outside, a permeable material with many continuous voids is placed inside the drainage device to prevent foreign matter from entering the device and to ensure space to serve as a drainage channel.

[0003] There are various types of permeable materials that can be installed in drainage devices, including, for example, materials in which multiple synthetic resin monofilaments are randomly curved or bent in three dimensions and entangled, forming an integrated structure with continuous voids inside. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-275876 [Patent Document 2] Japanese Patent Publication No. 2022-141015 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional permeable materials using monofilament and the gutters in which they are placed are often long (e.g., 2 to 4 m), making them difficult to handle during storage and transportation, and also making them difficult to handle during installation, often requiring cumbersome work.

[0006] The present invention seeks to solve the problems associated with the prior art, and aims to provide a drainage device and an installation method therefor that are extremely easy to handle during storage and transportation, and that can be installed very simply. [Means for solving the problem]

[0007] The drainage device of the present invention is a combination of a waterproof sheet and a water-permeable material.The waterproof sheet is a polyethylene sheet molded by blending cross-linked high-density polyethylene powder as a secondary raw material and an anti-fogging agent, which is a functional agent for plastic molding.The waterproof sheet has a thickness of 1.8 to 2.5 mm and has at least two linear thin-walled sections formed along the longitudinal direction.The water-permeable material is a rectangular parallelepiped made of multiple synthetic resin monofilaments that are randomly curved or bent in three dimensions and entangled, and have a large number of continuous voids inside.The multiple water-permeable materials are connected by cable ties so that they can be folded in the longitudinal or width direction.

[0008] In addition, in this drainage device, it is preferable that the entire surface of the waterproof sheet has minute irregularities equivalent to the coarseness of sandpaper, and it is also preferable that the thin-walled portions of the waterproof sheet are formed 50 mm or more from the left and right side edges of the waterproof sheet.

[0009] The method for constructing a drainage device according to the present invention comprises forming a trench at the planned installation location of the drainage device, placing a waterproof sheet at the bottom of the trench, making a valley fold in the thin portion of the waterproof sheet, raising the flaps outside the thin portion, placing a permeable material on the center of the width of the waterproof sheet, and pouring soil outside the flaps and above the permeable material to backfill the trench. Note that when backfilling with soil, the soil can be placed directly on top of the permeable material. [Effects of the Invention]

[0010] The drainage device of the present invention has high drainage capacity, and since the waterproof sheet can be rolled up and the permeable material can be folded, it is extremely easy to handle during storage and transportation.It is also easy to handle during installation, so it does not require skilled techniques and can be installed very easily. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view of a waterproof sheet 2 that constitutes a drainage device according to a first embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged view of a part (the part surrounded by the dashed circle) of the waterproof sheet 2 shown in FIG. [Figure 3] Figure 3(1) is a plan view of the water-permeable material 3 that constitutes the drainage device of the first embodiment of the present invention, Figure 3(2) is a side view thereof, and Figure 3(3) is a side view of the water-permeable material 3 in a state in which the cable ties 32 are tightened. [Figure 4] FIG. 4 is a diagram showing the water-permeable material 3 shown in FIG. 3 in a folded state. [Figure 5] FIG. 5 is an explanatory diagram of a construction method for a drainage device according to a second embodiment of the present invention, showing a cross section (cross section perpendicular to the longitudinal direction) of a groove 4 formed at a planned installation position of the drainage device. [Figure 6] FIG. 6 is an explanatory diagram of a construction method for a drainage device according to a second embodiment of the present invention, showing cross sections (cross sections perpendicular to the longitudinal direction) of a groove 4, a waterproof sheet 2, and a water-permeable material 3. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention can be embodied not only as a “drainage device” but also as a “construction method for a drainage device.” These embodiments will be described below.

[0013] The drainage device (first embodiment) of the present invention is formed by combining a waterproof sheet 2 shown in Fig. 1 with a water-permeable material 3 shown in Fig. 3. Of these, the waterproof sheet 2 is made of polyethylene, and is made by mixing powder or pellets of linear low-density polyethylene (LLDPE), which is the main raw material, with secondary raw materials (additives) such as cross-linked high-density polyethylene powder (sized to pass through a mesh with 1.5 mm openings), fatty acid ester, antioxidant (phenolic, amine, sulfur-based, and / or phosphorus-based compound), and anti-fogging agent (functional agent for plastic molding, main component: surfactant), and forming the mixture into a sheet with a thickness of 2 mm (preferably 1.8 to 2.5 mm), width of 300 mm, and length of your choice (for example, 10 m).

[0014] 1 and 2, this waterproof sheet 2 has two (or three or more) linear thin-walled portions 21 (0.5 mm thick) formed along the longitudinal direction. These thin-walled portions 21 are formed 50 mm (or more than 50 mm) from each of the left and right side edges 25 of the waterproof sheet 2. The distance between these two thin-walled portions 21 is set larger than the width of the water-permeable material 3 shown in FIG. 3.

[0015] This waterproof sheet 2 is molded using cross-linked high-density polyethylene powder as a secondary ingredient, creating minute irregularities across the entire surface, equivalent to the coarse grain of sandpaper (#60-280). This allows it to capture minute particles like sand and prevent them from flowing away, allowing only the inflowing water to flow smoothly. Additionally, an anti-fogging agent, a functional agent used in plastic molding, is blended as a secondary ingredient. The anti-fogging agent's main component, surfactants, bleed out, making the surface of the waterproof sheet 2 hydrophilic and reducing its water-repellent properties. This improves its compatibility with water and is expected to improve drainage.

[0016] After being formed, the waterproof sheet 2 can be wound up around an axis perpendicular to the longitudinal direction as shown in FIG. 1 to form a roll, which makes it easier to handle during storage and transportation.

[0017] The water-permeable material 3 is a rectangular parallelepiped (length 300 mm, width 200 mm, thickness 40 mm) formed from a plurality of synthetic resin monofilaments (diameter 1.5 to 2.5 mm, preferably 2 mm) that are randomly curved or bent in three dimensions and entangled, with numerous internal continuous voids. This water-permeable material 3 can be produced by extruding linear synthetic resin (monofilaments) with a diameter of 2 mm (or 1.5 to 2.5 mm) downward from the downward-facing die of an extrusion molding machine and feeding the extruded linear synthetic resin (monofilaments) onto a conveyor whose transport speed is set to be slower than the extrusion speed of the monofilaments.

[0018] In this embodiment, high-density polyethylene (HDPE) powder is used as the main raw material of the water-permeable material 3 (monofilament), and cross-linked high-density polyethylene and an anti-fogging agent (functional agent for plastic molding, main component: surfactant) are blended as powders as auxiliary raw materials. The blending ratio of these main raw materials and auxiliary raw materials is preferably 60 to 80 parts by weight (preferably 70 parts by weight) of high-density polyethylene, 20 to 40 parts by weight (preferably 30 parts by weight) of cross-linked high-density polyethylene, and 4 to 10 parts by weight (preferably 7 parts by weight) of anti-fogging agent.

[0019] Since cross-linked high-density polyethylene has different properties (fluidity, etc.) from high-density polyethylene, when cross-linked high-density polyethylene (auxiliary material) is blended with high-density polyethylene (main material) in the above-mentioned ratio and extrusion molding is performed, the cross-linked high-density polyethylene in the synthetic resin material is extruded from the die of the extruder in a stretched molecular state. When the synthetic resin (monofilament) extruded from the die comes into contact with air, partial "shrinkage" occurs due to the temperature difference, resulting in the formation of numerous small irregularities on the surface (the difference between adjacent protrusions and recesses is about 0.1 to 0.5 mm), making the surface not smooth overall but rough and randomly twisted, which can be expected to improve the tensile strength and compressive strength of the molded monofilament.

[0020] Furthermore, when 4 to 10 parts by weight of an anti-fogging agent, which is a functional agent for plastic molding, is blended as an auxiliary raw material, the blended surfactants and other additives can bleed out, making the surface of the monofilament that constitutes the water-permeable material hydrophilic and reducing its water repellency. Therefore, when a water-permeable material is manufactured using monofilaments blended with an anti-fogging agent, it can be expected that the material will have better compatibility with water and better drainage performance.

[0021] As shown in FIG. 3, a plurality of water-permeable materials 3 (for example, 4 to 7 pieces, total length 1200 to 2100 mm) are connected in series in the longitudinal direction by plastic binding bands 32 (with latches).

[0022] A hole penetrating in the vertical direction (thickness direction) is formed at the end of each water-permeable material 3, and each cable tie 32 is inserted into the hole of two adjacent water-permeable materials 3. These water-permeable materials 3 are connected with a sufficient gap between adjacent water-permeable materials 3 (more specifically, so that the circumference of the loop of the cable tie 32 is four to five times the thickness of one water-permeable material 3), so that they can be folded and stacked as shown in Figure 4, and folding makes them easy to handle during storage and transportation.

[0023] In this embodiment, the water-permeable materials 3 are connected in series in the longitudinal direction as shown in Figure 3 (i.e., so that the longitudinal ends of each water-permeable material 3 are close to each other), but the orientation of each water-permeable material 3 can also be changed by 90° and they can be connected in parallel in the width direction (i.e., so that the side edges of each water-permeable material 3 are close to each other).

[0024] The drainage device according to the present invention can be constructed by the following method (second embodiment): First, as shown in Fig. 5, a groove 4 is formed at the planned installation position of the drainage device, and a waterproof sheet 2 is placed at the bottom of the groove 4. The width of the groove 4 is about 300 mm when one row of water-permeable material 3 is arranged, and about 500 mm when two rows are arranged, and the depth is about 100 mm (preferably at least twice the thickness of the water-permeable material 3).

[0025] The waterproof sheet 2 is unfolded from the roll shape shown in Fig. 1, the thin-walled portion 21 is folded in a valley, and the portion (flap 22) (preferably 50 mm or more in height) outside the thin-walled portion 21 is raised as shown in Fig. 5. Then, large-head nails (not shown) are driven from the top side (above) to fix the waterproof sheet 2 to the ground.

[0026] Next, as shown in Figure 6, the water-permeable material 3 is placed on the widthwise center of the waterproof sheet 2. At this time, the water-permeable material 3, which is folded as shown in Figure 4, is unfolded in the longitudinal direction as shown in Figure 3(2), and further, as shown in Figure 3(3), each binding band 32 is tightened to make the loop smaller, so that the ends of adjacent water-permeable materials 3 are close to each other.

[0027] Once the permeable material 3 has been placed, soil (soil excavated when forming the trench 4) (or crushed stone, etc.) is poured outside the flap 22 and above the permeable material 3 to backfill the trench 4. When pouring soil outside the flap 22, it is necessary to keep the flap 22 in a vertical position, but in the present invention, since the waterproof sheet 2 has thin portions 21, the flap 22 can be kept in a vertical position by simply pressing down on a few points, allowing the backfilling work to be carried out smoothly.

[0028] Furthermore, when backfilling soil and sand, conventional methods often involve placing a nonwoven permeable sheet or the like on top of the permeable material placed in the trench to prevent the intrusion of soil and sand. However, in the present invention, there is no need to place a permeable sheet or the like on top of the permeable material 3 placed in the trench 4, and even if soil and sand are placed directly on top of the permeable material 3, the drainage function can be sufficiently achieved. [Explanation of symbols]

[0029] 2: waterproof sheet, 21: Thin-walled section, 22: Flap, 25: Lateral edge, 3: Permeable material, 32: Cable ties, 4: Ditch,

Claims

1. A drainage device that combines a waterproof sheet and a water-permeable material, The waterproof sheet is a polyethylene sheet formed by blending cross-linked high-density polyethylene powder as a secondary raw material and an anti-fogging agent, which is a functional agent for plastic molding. It has a thickness of 1.8 to 2.5 mm and has at least two linear thin-walled sections formed along the longitudinal direction. The water-permeable material is a rectangular parallelepiped formed material in which multiple synthetic resin monofilaments are randomly curved or bent in three dimensions and entangled, with numerous continuous voids inside. A drainage device characterized in that a plurality of permeable materials are connected by cable ties in a manner that allows them to be folded in the longitudinal direction or width direction.

2. 2. The drainage device according to claim 1, wherein the waterproof sheet has minute irregularities on the entire surface thereof, the irregularities corresponding to the coarseness of sandpaper.

3. 2. The drainage device according to claim 1, wherein the thin-walled portions of the waterproof sheet are formed at positions 50 mm or more from the left and right side edges of the waterproof sheet.

4. A method for installing the drainage device according to any one of claims 1 to 3, A groove is formed at the planned location for installing the drainage device. Place a waterproof sheet at the bottom of the trench, Fold the thin part of the waterproof sheet in half and raise the outer flaps. Place a water-permeable material on the center of the width of the waterproof sheet, A method for constructing a drainage system, characterized by filling the trench with soil outside the flap and above the permeable material.

5. 5. The method for constructing a drainage system according to claim 4, wherein earth and sand are directly placed on the permeable material.

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