JPH0410272Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] The present invention relates to drainage ditches laid on soft ground, particularly drainage ditches laid on soft ground areas such as agricultural drainage channels and reclaimed land. [Prior art] Conventionally, agricultural waterways, drainage ditches, etc. have been constructed with U-shaped gutter bodies made of concrete, etc., but such U-shaped gutter bodies weigh, for example, 68.6 kg/1 m width, and When the groove body is full of water, the weight of the water is
56kg/1m width, so if this is installed on soft ground, the U-shaped groove will sink due to lack of support in the ground, causing the waterway to bend in a wavy manner, and some of the U-shaped grooves will shift. There was a drawback that water leaked out. Such soft ground improvement methods include replacement, embankment,
There are over 20 construction methods, including slow construction, vertical drain, sand compaction, and quicklime pile. Even now, improvement of conventional construction methods and development of new construction methods are active, and soft ground improvement methods are being attempted (Japanese Patent Application Laid-open Nos. 50-161016, 52-80605, 50-
No. 86809, No. 48-49233, Special Publication No. 53-37107,
58-33328, 49-49056). however,
At present, neither method has become a definitive improvement method. The insulation construction method and the Latofil construction method, which have recently been attracting attention for roads, etc., use foamed polystyrene blocks or plate-like materials with a compressive strength of 0.9 to 3.0 kg/ ^cm2 as the laying material, and after excavating the existing road surface, the foamed This is a construction method in which a concrete surface is placed on top of the pavement and new pavement is constructed on top of it, and it is attracting attention as a powerful construction method, especially in Northern Europe. [Problems that the invention aims to solve] However, this construction method is also not a definitive solution to soft ground. In other words, the foamed polystyrene blocks of this construction method do not have sufficient shear strength, compressive strength, tensile strength, frictional strength, restoring performance, etc., so they are not useful for strengthening the bearing capacity of the ground, and as a result, the U-shaped groove structure is The weight of the water causes material destruction, causing the waterway to cave in or take on a wavy shape.
In addition, since it does not have a drainage function, groundwater etc. tend to accumulate in the ground, and it is easy to freeze up in the winter, so it is not a fundamental solution to soft ground. The purpose of this invention is to solve these conventional problems, and the present invention combines an insulating plastic foam with high compressive strength and high shear strength with a lightweight foamed polystyrene material of low density and buoyancy as the insulating foam to be installed. Furthermore, the present invention provides a drainage ditch for improving soft ground, which is further provided with a plastic foam having a drainage function so that the maximum weight of the U-shaped ditch body is smaller than the weight of natural soil. In this invention, the load is transferred from the U-shaped groove to the supporting layer under the soft ground using a heat insulating plastic foam material that has high compressive strength and high shear force that can withstand heavy loads without using crushed stone or concrete. Natural ground soil is saved by the volume of the foam, and the load applied to the soft ground due to the weight of laying the U-shaped gutter is reduced. Furthermore, the plastic foam with a drainage function installed on the underside of this lightweight material actively drains groundwater, etc. that cause soft ground, reducing moisture in the ground and improving the support strength of soft ground. be. [Means for solving the problem] That is, the present invention provides a structure in which the lower surface of the U-shaped groove body 2 to be laid has a compressive strength of 3.5 Kg/cm ² or more and a shear strength of 20 Kg/cm ² or more and a thickness of 20 mm or more. A lightweight material 4 made of polystyrene foam with a density of 0.018 to 0.05 g/cc and a compressive strength of 0.9 to 3.0 Kg/cm ² is provided on the lower surface of the insulating plastic foam 3. This drainage ditch is characterized in that a water-permeable plastic foam 5 having a drainage function and having a porosity of 5 to 65% is provided on the lower surface of the material 4. [Operation] In the ground 1, groundwater is drained through the permeable plastic foam 5. Further, the U-shaped groove body 2 and its water are firmly supported by the buoyancy of the strong heat insulating plastic foam 3 and the lightweight polystyrene foam 4. Furthermore, the lower part of the U-shaped groove 2 on the ground 1 is made of heat-insulating plastic foam 3 and lightweight material 4.
It is insulated from the ground by a plastic foam body 5 having a drainage function. [Example] Hereinafter, an example of the present invention will be described in detail based on the drawings. In FIG. 1, 1 is soft ground, and 2 is a U-shaped groove made of concrete, plastic, metal, etc., provided on the soft ground 1. The U-shaped groove body 2 has a height of 240 mm, an outer width of 360 mm at the top, an inner width of 300 mm, and an inner width of 260 mm at the bottom. In addition, the weight of this U-shaped groove body 2 per 1 m is 68.0 kg, the buried capacity per 1 m is 0.084 m ³ , and the maximum effective water capacity per 1 m is 0.056.
m ³ , the weight of water per 1 m when full is 56.0
Kg, the maximum weight at full water per 1m is 124.0Kg, and the soil weight per 1m is 0.108t. A heat insulating plastic foam 3 is provided below this U-shaped groove 2. The heat insulating plastic foam 3 is a foamed polyolefin having a width of 370 mm and a thickness of 50 mm or more and having a compressive strength of 3.5 Kg/cm ² or more and a shear strength of 20 Kg/cm ² or more. This insulating plastic foam 3 has a weight of 3.5Kg/cm ²
(Measurement method JIS K-6767) or higher compressive strength and 20Kg/
cm ² (Measurement method JIS K-7214) or higher, and preferably extrusion-crosslinked polyolefin foam (USP
4552708, patent application No. 57-225295, patent application No. 58-119643)
Apparent density 40-320Kg/ ^m3 (Measurement method JIS K-6767)
is preferred. More preferably, a cross-linked high-density polyethylene foam [for example, Yukafoam manufactured by Mitsubishi Yuka Co., Ltd.
HD-1000 (trade name)] is preferred. The physical properties of this Yukaform HD-1000 are as follows.

【table】

[Table] Foams with a compressive strength of less than 3.5 kg/cm ² , such as polystyrene foam, are flexible and conform too well to the ground 1, making the surface more likely to wave.
Foams with a shear strength of 20Kg/cm2 or ^less are more likely to be cut by ground displacement (vertical movement), and the cut areas lose their insulation properties.
It becomes easier to freeze. Apparent density of polyolefin foam 40-320
The reason for choosing the Kg/ ^m3 range is that if it is less than 40Kg/ ^m3 , the compressive strength and shear strength will be weak.
This is because if it exceeds Kg/ ^m3 , the insulation performance will be poor. A more preferable apparent density is 45 to 195 Kg/m ³ . The reason why the thickness of this polyolefin foam is set to be 20 mm or more is that if it is less than this, the heat insulation properties and shear resistance will be poor, and the load applied to the plastic foam 5 below will increase. The thickness of the insulating plastic foam 3 varies depending on the local freezing index and the required shear strength, but is approximately 50 mm in the Tohoku region. Lightweight material 4 has a density of 0.018 to 0.05g/cc and compressive strength
It is made of expanded polystyrene with a weight of 0.9 to 3.0 kg/cm and is 400 mm wide and 100 mm thick. Insulating plastic foam 3 having the above performance
The lightweight material 4 and the plastic foam 5 having a drainage function have the effect of preventing the temperature of the ground 1 below from decreasing and maintaining it at a temperature that is difficult to freeze. The plastic foam 5 with drainage function has a width
150mm Thickness 150mm This structure is shown in the enlarged view in Figure 2. In Figure 2A, foamed particles 13, 13, . It has an easy structure. Furthermore, it is desirable that the granules 13 have cutting performance, and are preferably made of hardened plastic, wood chips, or the like. More preferably, asphalt and a polymer adhesive are sprinkled on spherical foam particles made of thermoplastic resin such as foamed polystyrene, foamed polypropylene, and foamed polyethylene, and mixed to form a water-permeable gap. 15 is
A 25-60% foamed insulation material is preferred (the foamed insulation material is manufactured by Mitsubishi Yuka Verdice Co., Ltd. and Kitanihon Kagaku Kogyo Co., Ltd. under the trade name Styrodren). The styro drain has both heat insulation and waterproof properties, and exhibits an excellent drainage effect without clogging. The physical properties of this styrodrain are as follows.

[Table] Instead of the foamed granules 13, foam chips 16 made of polystyrene, polypropylene, etc. as shown in FIG. 2, or irregularly shaped chips 1 as shown in FIG.
9 may also be used. 17 is the adhesive surface of the foam chip 16, and 18 is a hole for water passage. These chips 16 and 19 are welded to each other by melting their surfaces with pressurized steam in a mold. The plastic foam 5 having a drainage function has a heat insulation function and a pressure resistance function. As shown in the first diagram, objects 6, 6 for draining water overflowing from the ground 1 and the drainage ditch are also located on both sides of the U-shaped gutter body 2.
It is a good idea to provide The objects 6, 6 are also preferably made of the same material as the plastic foam 5, and more preferably a styro drain having heat insulating properties. The styro drain has approximately 30% of the pore volume for continuous water flow, allowing smooth drainage without clogging over a long period of time.
This is because even when frozen, expanded styrene absorbs frost heaving pressure due to its excellent physical properties as a buffer material. The dimensions of the object 6 also vary depending on the region, but are approximately 30 mm wide x 200 mm deep and 35 to 70 mm thick. [Effects of the invention] The drainage ditch according to the invention quickly drains pore water and turbid water through the action of the plastic foam that has a drainage function, lowers the groundwater level, lowers the moisture content of the ground, and improves ground support. Strengthen the force and stabilize the U-shaped groove. Furthermore, by supplementing the shear force with the insulating plastic foam, it is possible to reduce or eliminate the use of crushed stone and concrete as ground reinforcement materials, and the buoyancy of lightweight materials reduces weight and strengthens soft ground. It is possible to reduce the sinking of the U-shaped groove, which is a noticeable phenomenon in Furthermore, if expanded polystyrene is used as a lightweight material, it has heat insulating properties, and together with insulating plastic foam, frost heaving of the ground can be further prevented.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of one embodiment of the drainage channel according to the present invention, Fig. 2 (a) and (b) are enlarged views of the structure of the plastic foam having a drainage function, and (c) is a perspective view showing another example of the chip used therein. It is a diagram. 1... Ground, 2... U-shaped groove body, 3... Heat insulating plastic foam, 4... Light weight material, 5... Water permeable plastic foam.

Claims (1)

[Scope of utility model registration request] A heat-insulating plastic foam with a thickness of 20 mm or more and a compressive strength of 3.5 Kg/cm ² or more and a shear strength of 20 Kg/cm ² or more is provided on the lower surface of the U-shaped groove to be laid.
Density on the underside of this insulating plastic foam
A polystyrene foam with a compressive strength of 0.018 to 0.05 g/cc and a compressive strength of 0.9 to 3.0 Kg/cm ² is provided, and a water permeable plastic foam with a porosity of 5 to 65% that has a drainage function is provided on the underside of this lightweight material. Drainage ditch characterized by: