JP3178324B2 - Water leakage prevention method and water leakage prevention structure at waste disposal site - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a structure for preventing water leakage at a waste disposal site.

[0002]

2. Description of the Related Art A landfill-type waste disposal site, which is a facility for dumping industrial waste and general waste, is one in which a recess formed in a mountainous area is leveled and used. It is known that a new concavity is excavated and formed in a plain area to be used as a landfill.However, in such a final waste disposal site, leachate leaching from the waste dumped at the disposal site is known. In order to prevent the soil from penetrating into the ground and contaminating the surrounding ground, it is mandatory to install a seepage control on the bottom of these disposal sites.

[0003] From the viewpoints of certainty, safety, workability, economy and the like, such water shielding works mainly include:
A method of laying a soft synthetic resin-based or rubber-based waterproof sheet at the bottom of a waste disposal site has been adopted. Also,
Such a water shielding work may be performed using an asphalt coating, a synthetic fiber sheet, or the like.

[0004] On the other hand, according to such a landfill type waste disposal site, groundwater may be present in the ground surrounding the landfill, and if the groundwater level is too high, the laid and installed shielding is required. The waterworks receive a large water pressure from the lower surface side, which causes adverse effects such as floating of the water-impervious works by the water-impervious sheet and the collapse of the slope of the disposal site.

Accordingly, a waste disposal site formed on the ground in which such groundwater exists is generally laid and installed at the deepest part of the waste disposal site 30, as shown in FIG. 3, for example. A groundwater drainage device 33 composed of a groundwater drainage pipe 32 and the like is provided in the ground further below the water shield work 31, and groundwater is pumped up through the groundwater drainage device 33 so that the water level of the groundwater is laid. Lower than the level of the water-blocking work, thereby preventing the rising of the water shield 31 and the collapse of the slope.

[0006]

However, according to the above-mentioned conventional method for preventing the rise of the water shield and the collapse of the slope, etc., the water level of the groundwater is set higher than the laying level of the water shield such as a water shield sheet. Although it is easy to lower it, on the other hand, if the impervious work is damaged or a defective part occurs due to some kind of obstacle, the internal There has been a problem that the leachate is easily diffused into the surrounding ground, which may cause a risk of contaminating groundwater and the surrounding environment.

Therefore, the present invention has been made in view of such a conventional problem, and it is possible to easily prevent the rise of the impermeable work due to the groundwater in the surrounding ground, the collapse of the slope, and the like. Water leakage prevention at waste disposal sites that can easily prevent leachate from confining inside the disposal site and spreading to the surrounding ground, even if there is a damaged or defective part in the impermeable structure It is an object to provide a method and a water leakage prevention structure.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned object, and the gist of the invention is to provide a pit for collecting groundwater on the outer ground of a waste disposal site provided with a seepage control. Is provided, groundwater flows into the pit, and by pumping it, the level of the surrounding groundwater is maintained slightly higher than the level of the leachate in the waste disposal site, and the interception work is interposed. A method for preventing water leakage at a waste disposal site, comprising preventing the leachate from leaking to the outside through a seepage control due to a head difference between inside and outside.

Another aspect of the present invention is to provide a groundwater collecting pit formed on the outer ground of a waste disposal site provided with a seepage control, and a pit along the seepage control of the waste disposal site. In this way, the groundwater drain pipe connected to the pit at the lower end of the groundwater collecting pit and the groundwater flowing into the groundwater collecting pit are disposed in the ground below the groundwater collecting pit. the waste this water level pumped up
Keeping the leachate water level slightly higher in the landfill
And a drainage control means for controlling the water leakage in the waste disposal site.

[0010] Further, another gist of the present invention is to provide a groundwater collecting pit formed on the outer ground of a waste disposal site provided with a seepage control, and to follow the seepage control at the waste disposal site. As described above, the pit is disposed in the ground under the pit, and is extended and installed in a plurality of steps in the height direction so as to communicate with the pit through the plurality of openings formed in the pit for collecting groundwater. A water leakage prevention structure in a waste disposal site, comprising: a groundwater drainage pipe; a drainage means for pumping groundwater flowing into the groundwater collecting pit; and a lid member for appropriately closing the opening. It is in.

According to the present invention, the groundwater is appropriately pumped from the pit for collecting groundwater and the surrounding groundwater level is kept slightly higher than the leachate water level in the waste disposal site, thereby blocking the groundwater. The water pressure applied to the impervious works from the underside of the constructor is kept low to prevent the impervious works from rising and the slopes from collapsing, etc. The impeller is constantly loaded with water pressure heading in the direction to contain the leachate that has accumulated and accumulated inside the disposal site and prevents it from leaking outside.

The above-mentioned slightly high water level means a water level at which a head difference between the inside and outside is obtained so as to produce the above-described action.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments, ie, embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a water leakage prevention structure 10 according to a first embodiment of the present invention.
Is a groundwater collecting pit 13 formed in the ground located on the outside of a waste disposal site 12 in which a water-blocking sheet 11 is laid on the bottom as a water-blocking work; 11 along the groundwater collecting pit 13 at the lower end of the groundwater collecting pit 13.
And a drainage control device 15 for pumping groundwater flowing into the groundwater collecting pit 13 and controlling the water level in the pit 13.

Here, the waste disposal site 12 is formed by excavating a concave valley, for example, in a mountainous region, etc., and forming a large concave portion formed by partitioning the downstream side of the valley with an embankment structure 16. And waste 1
After a base material is appropriately provided on the bottom surface of the concave portion into which the cooling water is injected, a water-impervious sheet 11 is laid, and a protective mat, for example, a sand mat, is laminated thereon. The waste 18 is dumped and landfilled. The water-impervious sheet 11 is manufactured using, for example, a soft synthetic resin-based or rubber-based sheet member.
Since it is difficult to cover the entire bottom surface area at once, a unit water-impervious sheet of a predetermined size suitable for construction is laid at the laying work site, for example, by heat welding or crimping via adhesive. The waste disposal site 12 is laid in a state of being integrated so as to be able to cover the bottom surface of the waste disposal site 12 by being overlapped and joined.

The pit 13 for collecting groundwater formed outside the waste disposal site 12 is, for example, formed by a shaft excavated and constructed in the embankment structure 16 that partitions the downstream side of the waste disposal site 12. The bottom of this is a waste disposal site 12
And a connection opening 17 is provided at the lower end thereof, and a groundwater drainage pipe 14 is connected therewith.

On the other hand, the groundwater drainage pipe 14 is a perforated pipe made of, for example, vinyl chloride or PC concrete, and its surroundings are covered with a filter layer 25 made of crushed stone, gravel or the like, thereby preventing clogging thereof. At the same time, by extending along the lower end face of the waste disposal site 12 and the surrounding slopes over a considerable height difference, it is present in the ground from the lower end surface level of the waste disposal site 12 to the upper end level. Pit 13 for collecting groundwater
It can be made to flow into.

Further, the water leakage prevention structure 10 according to this embodiment is provided with a drainage control device 15 for pumping groundwater flowing into the pit 13 for collecting groundwater and controlling the water level in the pit 13. That is, the drainage control device 1
5 is a drainage pump 2 provided in the pit 13 for collecting groundwater.
6. A float 27 for detecting the water level in the pit 13
A sensor 28 for detecting the water pressure on the impermeable sheet 11 due to the leachate 19, a control device 29 for comparing the detection results of the float and the sensor to control the operation of the drainage pump 26, and the like. The level of the water level in 13, that is, the level of the groundwater level in the ground around the periphery of the waste disposal site 12 can be adjusted and maintained at an arbitrary height.

The water leakage prevention structure 1 of the first embodiment
According to No. 0, the groundwater flowing through the groundwater drainage pipe 14 is appropriately pumped and discharged from the pit 13 for collecting groundwater, and the groundwater level in the ground surrounding the disposal site 12 is still discarded. Waste 18 inside the disposal site 12
While not dumped, below the lower end surface of the disposal site 12, since it has been dumped, the water level of the leachate 19 leached from the waste 18 and accumulated and stored inside the disposal site 12 is slightly higher, In addition, it can be adjusted and held at a position lower than the landfill level, whereby the water pressure applied to the impermeable sheet from the lower surface side of the impermeable sheet 11 can be suppressed and held low, so that the rising of the impermeable sheet 11 In addition to preventing the collapse of the surface, the small head difference h between the inside and the outside always applies the water pressure from the outside toward the inside of the disposal site 12 to the impermeable sheet, thereby sealing the leachate 19 accumulated and retained inside. To prevent this from leaking out.

FIGS. 2A and 2B show a water leakage prevention structure 20 according to a second embodiment of the present invention.
As in the case of the first embodiment, the water leakage prevention structure 20 is formed in the embankment structure 16 which is located outside the waste disposal site 12 where the impermeable sheet 11 is laid and constructed on the bottom surface. According to the water leakage prevention structure 20, the groundwater collecting pit 13 includes a plurality of connection openings 21 that are opened in a plurality of steps in the height direction. Has a water-impervious sheet 1
It is arranged in the ground below it along 1
Groundwater drainage pipes 22 extended and installed in a plurality of stages in the height direction are connected to each other. Further, the groundwater collecting pit 13 is provided with, for example, a drainage pump 23 as a drainage means. A closing lid 24 capable of closing these openings is provided.

Here, the groundwater drainage pipe 2 extended and installed in a plurality of stages in the height direction, ie, three stages in the second embodiment.
2 is laid in substantially the same configuration as the groundwater drainage pipe 14 of the first embodiment, but at the respective laying heights, except for the groundwater drainage pipe 22 located at the lowest level,
1 is extended annularly along the lower peripheral portion of the impermeable sheet 11 without penetrating therethrough (see (b)), whereby groundwater located at the level of each step or higher is collected into groundwater, respectively. It can be made to flow down to the pit 13 for use.

The water leakage prevention structure 2 of the second embodiment
According to 0, according to the level of the leachate 19 sequentially accumulated and retained inside the disposal site 12, the lowermost connection opening 21 is sequentially closed using the closure lid 24,
Only groundwater located above the level of the connection opening 21 located immediately above the groundwater will flow into the groundwater collecting pit 13, and if the flowing groundwater is discharged, the level of the groundwater will be reduced to the level of the connection opening 21. Level, or at the laying level of each groundwater drainage pipe 22 connected thereto, so that the drainage pump 23
The water level of the surrounding groundwater can be set slightly higher than the water level of the leachate 19 in the waste disposal site 12 without controlling the amount of water discharged from the waste disposal site 12, and a small head difference h can be easily maintained. In the second embodiment as well, the amount discharged by the drainage pump 23 may be automatically controlled in relation to the level of the leachate 19 in the disposal site 12.

It should be noted that the present invention is not limited to the embodiments of the above-described embodiments, but can be variously modified and adopted within the scope of the structure described in each claim. That is, for example, the water leakage prevention method of the present invention can be used without being limited to the case where the water leakage prevention structure of each embodiment is adopted, and the water leakage prevention method and the water leakage prevention structure of the present invention The present invention can be applied to a waste disposal site provided with a seepage control other than the seepage control sheet. Further, the closing lid 24 in the second embodiment is used.
The groundwater drainage pipe 22 need not necessarily be provided in the uppermost connection opening 21, and the groundwater drainage pipe 22 does not necessarily have to be annularly extended as long as it can be provided without penetrating the impermeable sheet 11.

[0023]

As described above in detail, according to the water leakage prevention method and the water leakage prevention structure in a waste disposal site of the present invention, groundwater is appropriately pumped from a pit for collecting groundwater and the level of the surrounding groundwater is raised. Is maintained slightly higher than the leachate water level in the waste disposal site, and the water pressure applied to the seepage control from the underside of the seepage control is kept low. The slope can be easily prevented from collapsing, etc., and due to this slight head difference, the water pressure flowing from the outside to the inside of the disposal site is constantly applied to the impervious works, and the leaching accumulated and accumulated inside the disposal site Even if the water impregnation part has a damaged part or a defective part by containing the water, it is possible to easily prevent the leachate from diffusing into the surrounding ground.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view illustrating a configuration of a water leakage prevention structure in a waste disposal site according to a first embodiment of the present invention.

FIGS. 2A and 2B are schematic cross-sectional views and a schematic plan view, respectively, illustrating a configuration of a water leakage prevention structure in a waste disposal site according to a second embodiment of the present invention.

3A and 3B are schematic cross-sectional views illustrating a conventional method for preventing water leakage at a waste disposal site, and FIG. 3B is an enlarged cross-sectional view of a groundwater drainage facility.

[Explanation of symbols]

 10, 20 Water leakage prevention structure 11 Water shielding sheet (water shielding work) 12 Waste disposal site 13 Groundwater collecting pit 14, 22 Groundwater drainage pipe 15 Drainage control device 16 Embankment structure 17, 21 Connection opening 18 Waste 19 Leaching Water 23 Drainage pump (drainage means) 24 Blocking lid h Head difference

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B09B 1/00

Claims (3)

(57) [Claims] 1. A pit for collecting groundwater is provided on the outer ground of a waste disposal site provided with a seepage control, and groundwater flows into the pit and is pumped up. Is maintained slightly higher than the level of leachate in the waste disposal site, and due to the head difference between the inside and outside across the seepage control, the leachate tries to leak to the outside through the seepage control. A method for preventing water leakage at a waste disposal site, characterized by preventing water leakage. 2. A groundwater collecting pit formed on the outer ground of a waste disposal site provided with a water shield, and a pit formed along the water shield of the waste disposal site. A groundwater drainage pipe disposed in the ground and communicating with the pit at a lower end portion of the pit for collecting groundwater,
The groundwater that has flowed into the groundwater collecting pit is pumped up and the level of the groundwater is determined as the level of leachate in the waste disposal site.
And a drainage control means for controlling the drainage so as to keep it slightly higher than at a waste disposal site. 3. A groundwater collecting pit formed on the outer ground of a waste disposal site provided with a seepage control, and a ground below the waste disposal site along the seepage control of the waste disposal site. A groundwater drainage pipe, which is disposed inside and communicates with the pit through a plurality of openings formed in the groundwater collecting pit, the groundwater drainage pipe being extended in a plurality of stages in the height direction, and A water leakage prevention structure in a waste disposal site, comprising: a drainage means for pumping groundwater flowing into a water pit; and a lid member for appropriately closing the opening.