JPH04103Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] This invention is a culvert that improves water drainage by excavating a U-shaped trench in areas where wastewater treatment is required, such as agricultural land, and burying drainage pipes with numerous through holes. The present invention relates to a drainage structure, and in particular to an underdrain drainage structure in which a water brushing medium is filled between the wall of an excavated trench and a drainage pipe. [Prior Art] Conventionally, in order to manage and improve the soil of farmland that requires irrigation, such as greenhouse cultivation, a frame-shaped culvert 2 has been constructed around a farmland area 1, as shown in Fig. 3.
Efforts are being made to provide drainage means leading to rivers, etc. The general structure is to excavate a trench with a U-shaped or rectangular cross section, and install a cylindrical pipe with a perforated circumferential surface at the bottom of the trench.The water that collects through the hole flows through the pipe and exits. However, if you simply backfill the excavated soil after installing a cylindrical pipe, the soil will clog the pipe's holes, causing problems over time. Since this often leads to poor drainage over time, attempts have been made to fill the gap between the wall surface of the groove bottom and the pipe surface with gravel as a water-scanning medium. However, gravel is heavy;
It is difficult to transport, lacks workability, and has faced the challenge of rising prices in recent years. [Problems to be solved by the invention] In view of the above-mentioned problems, the purpose of the invention is to develop an underdrain drainage structure that uses a water brushing medium that is light, easy to handle, inexpensive, and has drainage capacity and durability. The aim is to provide effective soil management and improvement. [Means and effects for solving the problems] In order to achieve the above object, the present invention focuses on the bulk density, cushioning properties, fluidity, and water repellency of a synthetic resin foam molded product, and uses it in an underdrain drainage structure. The molded article is characterized in that it is used as a water-brushing medium, and the molded article has an S-shape or pseudo-S-shape as the most effective shape for its use. [Examples] Hereinafter, the present invention will be explained in detail with reference to Examples and drawings. FIG. 1 is a configuration diagram showing a preferred example of an underdrain drainage structure implementing the present invention. In the figure, the culvert drainage structure is a U-shaped trench 2 excavated in contact with a field 1.
A hollow cylindrical drainage pipe 3 is laid at the bottom of the groove,
After filling the space between the peripheral surface of the drainage pipe 3 and the wall surface 2a of the groove bottom with a synthetic resin foam molded body 4 having a closed cell structure as a water brushing medium, the surface layer of the U-shaped groove is backfilled with soil 5. ,It is configured. The structure of the present invention may be achieved by simply stacking both layers between the synthetic resin foam molded body 4 and the soil 5, but in this embodiment, a net 2b is interposed between the layers to facilitate mixing of both layers. This makes the work easier and convenient when replacing the water brushing medium or repairing the drain pipe. The cross-sectional shape of the drain pipe 3 is not specified as long as it is a hollow cylindrical pipe, but from the viewpoint of strength, a circular cross-section is preferable, and a large number of through holes 3a for collecting water are bored on the circumferential surface. . Water leaking from the soil into the foam molded layer is drained through the through holes 3a.
The water is collected into a cylindrical pipe, flows through the pipe, and is poured into the drain. The cylindrical pipe, ie, the drain pipe 3, is connected to a water storage layer 7 via an on-off valve 6. The on-off valve 6 is opened and closed by a control means 10. The water storage layer 7 is equipped with a drainage pump 8, and the water in the tank can be drained into the water channel 9 whenever necessary. The synthetic resin foam molding 4 used as a water brushing medium is heated and melted to foam, and then the density is reduced.
A material that can be expanded to 0.05 to 0.005 g/cm ³ is satisfactory from the standpoint of cushioning properties, but polyethylene foam or polystyrene foam usually has a low density and tends to develop steel properties. It is desirable because it is lightweight and has good fluidity during filling work, and also because it forms a thin skin layer on the surface of the molded product and does not absorb water. In order to increase the compressive strength after filling and the fluidity during filling, an S-shape or pseudo-S-shape (described later) is used. FIGS. 2A and 2B are perspective views showing a preferred example of the shape of the foam molded product used in the present invention, and FIG. 2B is a partially sectional perspective view taken along the line -' in FIG.
In both figures, the foamed molded body is formed in an S-shape,
The ratio of the dimensions of the S-shaped length L, overall width C, wall thickness T, molded body width W, and curved part thickness (number within the wall thickness) is C/L: 0.55 to 0.3, T/L :0.46~0.15,
W/L: 0.35~0.15, C/W: 2.8~1.3, R/
W: limited to 0.6 to 0.1. The actual length L is 75-15mm, and the density is 0.05-15mm as mentioned above.
It is 0.005g/ ^cm3 . If it is S-shaped like this,
After being filled as a water brushing medium, they intertwine with each other and increase pressure resistance. When the C/L value exceeds 0.55, the filling workability deteriorates, and when it is less than 0.3, the pressure resistance and cushioning properties after filling are slightly impaired. If T/L and W/L are too large, it will be difficult to adjust the packing density, resulting in non-uniform filling, while if they are too small, the repeated impact resistance will decrease and the product will be susceptible to damage during transportation. Furthermore, even if the above conditions are met, if the R/W value exceeds 0.6, the repeated impact resistance will still decrease, and the C/W value will decrease.
The same applies even if it exceeds 2.8. When the C/W is less than 1.3, the bulk density increases, leading to uneconomical results.
If the S-shape satisfies the above values, the rigidity and strength of the foam itself will harmonize with the structural mechanical rigidity and strength of the shape and dimensions to strengthen bending rigidity, and further reduce each slip and Entanglement is also involved, increasing pressure resistance and cushioning properties after filling while maintaining workability. If the shape is similar to this S-shape, it is possible to achieve the same or similar effects as above, and in particular, the water repellency and corrosion resistance that the synthetic resin foam itself has as a closed cell can be improved. It doesn't change. As mentioned above, the water repellency of the synthetic resin foam can be improved by filling the S-shaped or quasi-S-shaped synthetic resin foam molding as a water brushing medium around the water collection pipe buried at the bottom of the excavated trench. Use it for water brushing,
The pressure resistance and durability provided by the S-shaped ties and slides and the corrosion resistance of the synthetic resin itself prevent deterioration over time, making it possible to construct an underdrain drainage structure that does not cause clogging. It goes without saying that synthetic resin foam is lightweight and convenient for transportation and filling operations. Note that this culvert drainage structure can be applied not only to the above-mentioned frame-like arrangement method as shown in FIG. It is applicable. In the present invention, the on-off valve 6 is closed and the field 1 is closed.
The field can be easily converted into a paddy field by storing water therein, and after the paddy field is harvested, an on-off valve 6 is opened to drain the water and the field can be used again as the original field. That is, it is possible to make the soil compatible with fields and paddy fields, and to actively promote the effective use of the soil. (Experiment example) A styrene resin with a cross section of S
It is extruded from a shaped extruder for primary foaming, and then for secondary foaming.

[Table] Molded products according to the present invention shown in Table 1 were made by foaming. Comparative products 1 and 2 were also made for comparison. These molded products were packed into columns and their porosity was examined. The results were as shown in Table-2.

[Table] Furthermore, as a material corresponding to the filled hydrophobic material disclosed in Japanese Utility Model Application Publication No. 55-113740, both ends have a shape that is more swollen than the middle part, and the length is 20 mm.
mm, width at both ends 10mm, width at the middle 5mm, thickness 5mm
A molded product (comparative product 3) with a density of 0.008 g/cm ³ was made using the following methods. The porosity of Comparative Product 3 was also examined in the same manner as above and was found to be 22%. Thus, it can be seen that while the comparative product is not much different from rice husk, the product of the present invention exhibits sufficient porosity and can exhibit excellent drainage ability. [Effects of the invention] As explained above, according to the invention, a synthetic resin foam molded product is used, which is lightweight, easy to handle,
An inexpensive drainage medium is filled around the water collection hole of a buried drainage pipe to create an underdrainage structure with high drainage capacity and durability, which effectively contributes to soil management and modification. It is.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the underdrain drainage structure according to the present invention, Fig. 2 is a perspective view illustrating the shape of the foam molding used in the present invention, and Figs. 3 and 4 are examples of the arrangement of the underdrain. FIG. 1... Field, 2... Culvert, 2a... Wall, 2b
...Net, 3...Drainage pipe, 3a...Through hole,
4...Synthetic resin foam molded product, 5...Soil, 6...
Opening/closing valve, 7... Water tank, 8... Drain pump, 9...
...Waterway, 10...Control means, L...Length, C...
Overall width, T...wall thickness, W...molded body width, R...
Thickness of curved part.

Claims (1)

[Scope of utility model registration request] At the bottom of a U-shaped trench excavated in an area that requires wastewater treatment, a drainage pipe formed by drilling a hole in the circumferential surface of a cylindrical pipe is laid to allow water to flow to the outlet. An underdrain drainage system in which a synthetic resin foam molded body with a closed cell structure is filled as a water brushing medium between the circumferential surface of the cylindrical pipe and the wall surface of the U-shaped groove, and the surface layer of the U-shaped groove is backfilled with soil. The structure is such that a synthetic resin foam molded body as a water-brushing medium is formed into an S-shape or a pseudo-S-shape, and the length L, overall width C, wall thickness T, and molded body width W of the S-shape or pseudo-S shape. , the ratio of the thickness R of the curved portion is C/L: 0.55 to 0.3, T/L: 0.46 to
0.15, W/L: 0.35 to 0.15, and furthermore, C/L:
W: 2.8 ~ 1.3, R/W: 0.6 ~ 0.1, and the actual length L is 75 ~ 15 mm, and the density is 0.05 ~
An underdrain drainage structure characterized by being filled with 0.005g/ ^cm3 .