JPH0568579B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an infiltration facility that allows rainwater and various types of drainage to infiltrate into the ground.

<Conventional Technology> Currently, with the increasing use of concrete for roads and buildings, rainwater countermeasures have become an important issue.

On the other hand, as rainwater is no longer directly infiltrated into the ground, there is a tendency for groundwater to become depleted.

Furthermore, during heavy rains, large amounts of rainwater are collected that exceed the storage capacity of reservoirs and rivers, which tends to cause frequent flooding.

Based on this current situation, research and development of various infiltration facilities is currently underway to actively return rainwater to the ground while suppressing rainwater runoff.

Conventional infiltration facilities are, for example, trench type, U
There are two types, such as trench type and box type, but both have permeable pipes, U-shaped trenches, pits, etc. buried underground, and rainwater is stored inside and gradually permeates into the surrounding ground. It is a facility designed for the purpose of

Furthermore, in order to improve the permeability of rainwater, it is also known to backfill the periphery of a permeable pipe with granular material (filter material) such as quarried stone or sand to increase the permeation area.

<Problems to be Solved by the Invention> The conventional infiltration facilities described above have the following problems.

(a) Conventional infiltration facilities are prone to clogging due to the accumulation or adhesion of microscopic soil particles, sludge-forming bacteria, etc. between the particles of the filter material and around the outer periphery of the permeable pipe.

Furthermore, conventional infiltration facilities are not capable of clearing the filter material or tubing if it becomes clogged.

Therefore, when the filter material or the permeation surface becomes clogged, the permeation area shrinks and the permeation ability gradually decreases.

(b) If you are simply trying to increase the amount of water permeation,
It is sufficient to construct a large infiltration facility.

However, although this is theoretically possible, increasing the size of the infiltration facility increases construction costs, making it impractical.

<Object of the present invention> The present invention has been made to solve the above problems, and by arranging the drain material under the bottom of the infiltration facility, the infiltration ability into the ground is greatly improved, and it is simple and easy to use. The purpose is to provide an infiltration facility that can clean the inside of the infiltration facility.

<Structure of the present invention> An embodiment of the present invention will be described below with reference to the drawings.

<A> Structure of infiltration facility An example of infiltration facility according to the present invention is shown in FIGS. 1 and 3.

In the figure, 1 is a trench, 2 is a perforated pipe laid in the trench 1, 3 is crushed stone that constitutes the filter material,
4 is coarse sand, 5 is a water-permeable sheet provided on the outer peripheral side wall of crushed stone 3 and coarse sand 4, and 6 is a drain material.

The main components are detailed below.

<B> Perforated pipe The perforated pipe 2 is a PVC pipe or a concrete pipe with a large number of holes in its outer periphery.

Further, as the perforated pipe 2, it is also possible to use a pipe body made of a water-permeable material.

<C> Drain material The drain material 6 is a member whose purpose is to transfer water discharged into the trench 1 below the trench 1 so that it permeates into the ground.

FIG. 2 shows an example of the drain material 6.

The drain material 6 is made of a laminated layer of a core material 61 in which a large number of conical embossings are embossed on the surface of a cardboard board and a hole is formed at the tip of each cone, and a nonwoven fabric 62 that covers the core material 61. Consists of the body.

Further, as the other drain material 6, a known drain material used as a water collecting material can also be used.

The drain material 6 is installed along both sides of the perforated pipe 2 at a predetermined interval, passing through the crushed stone 3, the coarse sand 4, and the bottom surface of the trench 1, and facing downward in a substantially vertical direction.

The upper part of the drain material 6 is buried close to the ground surface, with the upper end of the drain material 6 protruding from the upper surface of the crushed stone 3 constituting the filter material, since water is injected from the upper end of the drain material 6 to clean the infiltration facility. Bury it to the extent that it reaches .

Further, a removable cap 63 is attached to the upper end of the drain material 6 to prevent backfilling soil 7 from entering through the upper end opening of the drain material 6.

In addition, the total length of the drain material 6 and the burial interval are appropriately selected depending on the burial ground, the planned amount of water to be treated, etc.

Further, the method of embedding the drain material 6 follows a conventional method.

<Action of the present invention> Next, the effect of penetration laying will be explained.

<A> At the time of water permeation and reduction As described above, in the present invention, the drain material 6 is buried downward in the trench 1.

Therefore, the water that permeates outside the perforated pipe 2 spreads over the entire cross section of the trench 1, passes through the water permeable sheet 5, and permeates into the side walls and bottom of the trench 1.

In addition, water in trench 1 is drained from drain material 6.
After being filtered and taken into the drain material 6, it is guided through the drain material 6 and diffuses and permeates into the ground below the trench 1.

When considering the permeability of permeated water, since the drain material 6 extends below the trench 1, the permeation area becomes significantly wider than the permeation area when only the trench 1 is used.

Since a widening of the permeation area essentially means an increase in the permeation cross section, the larger the extent of the permeation area, the better the permeability of the infiltration facility.

In addition, when considering clogging of the drain material 6, water released from the perforated pipe 2 is
After being filtered by the non-woven fabric 62 constituting the drain material 6, impurities that cause clogging are removed, so that the drain material 6 located below the trench 1 will not become clogged even after a long period of time. It's hard to wake up.

In order to confirm the above-mentioned penetration ability, the following tests were conducted. .

In the Kanto loam layer, we constructed a conventional infiltration facility in which perforated holes were buried in a trench, and an infiltration facility according to the present invention in which drain material 6 was buried below trench 1, and fresh water was poured from one side of the perforated pipe. Their penetration abilities were compared.

As a result, while the conventional facility has a rate of 0.3m ³ /hour/m, the present invention has a rate of 0.8m ³ /hour/m, which is about three times as much.
It was time/m.

Further, in order to confirm the anti-clogging effect of the infiltration facility according to the present invention, the following test was conducted.

That is, 90 kg of impurity dry loam having a particle size of 74 microns was poured into the facility of the present invention used when the above-described penetration ability was tested.

The amount of impurities injected is equivalent to the amount generated by using the infiltration facility for about 20 years.

Thereafter, fresh water was injected through the perforated pipe, and the amount of permeation in the facility of the present invention was measured.

As a result, in the infiltration facility according to the present invention, 0.36
m ³ /hour/m.

It has been demonstrated that the infiltration capacity of the cleaned and unclogged infiltration facility according to the present invention exceeds the original infiltration capacity of the conventional infiltration facility described above.

<B> Cleanliness of the infiltration facility Impurities contained in the water may accumulate between the crushed stones 3 and reduce the infiltration cross section, or may adhere to the outer periphery of the perforated pipe 2 or the drain material 6 located in the trench 1. It is predicted that clogging will occur.

Therefore, when the infiltration capacity of the infiltration facility decreases, the infiltration facility should be cleaned in the following manner.

First, backfill soil 7 is excavated until the upper end of drain material 6 is exposed.

Next, the cap 63 placed over the upper end of the drain material 6 is removed, and water is poured by applying pressure from the exposed upper end of the drain material 6.

Then, impurities adhering to the outer periphery of the drain material 6 and impurities accumulated between the crushed stones 3 are washed away.

The impurities washed away in the trench 1 are driven to the sides by the pressurized water discharged from the drain material 6 that crosses the three layers of crushed stone and the fourth layer of coarse sand, so that the permeation surface at the bottom of the trench 1 is No need to cause clogging.

<Other Examples> Although the trench method has been described above, the fourth embodiment
It is also possible to adopt a gutter type as shown in the figure.

That is, it is constructed by burying the drain material 6 vertically close to the water-permeable side gutter 8.

In this example, the same reference numerals are given to the same parts as in the above-described embodiment, and the explanation thereof will be omitted.

In addition, it can also be used for paved roads that are shaped like squares or have water permeability.

<Effects of the Present Invention> Since the present invention is as described above, the following effects can be obtained.

(b) The infiltration area of the trench can be increased by burying the drain material below the trench without increasing the size of the infiltration facility.

Therefore, the amount of water infiltration increases, and a highly efficient and economical infiltration facility can be obtained.

(b) After being filtered through crushed stone, it is filtered again through a drain material and permeates into the ground, so even if impurities accumulate at the bottom of the trench, the decline in water permeability can be suppressed.

(c) Infiltration facilities can be easily cleaned by injecting water from the top of the drain material.

Therefore, high water permeability can be maintained over a long period of time.

(d) Since the drain material does not protrude to the sides of the trench, the infiltration facility can be downsized.

Furthermore, construction is easy and construction costs can be kept low.

(e) Since it has excellent infiltration capacity, when a regulating pond is installed, the capacity of the regulating reservoir can be reduced.

(f) It can be used not only for rainwater but also as a sewage treatment facility.

[Brief explanation of drawings]

Figure 1: Explanatory diagram of one embodiment of the infiltration facility, Figure 2
Figure: Partial sectional view of drain material, Figure 3: Cross-sectional view of the infiltration facility shown in Figure 1, Figure 4: Explanatory diagram of another infiltration facility.

Claims (1)

[Scope of Claims] 1. A water-permeable pipe body, a filter material such as crushed stone or coarse sand located on the outer periphery of the water-permeable pipe body in the trench, and a filter material such as crushed stone or coarse sand that traverses the filter material and is located on the bottom surface of the trench. In an infiltration facility consisting of a drain material buried downward, the upper part of the drain material protrudes from the upper surface of the filter material, so that clean water can be injected into the drain material from the upper end of the drain material. Features: Infiltration facility.