JPS5942149B2 - Methods for preventing clogging of water collection pipes in landlocked areas and how to do so - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and device for preventing clogging of water collection pipes in above-ground areas.

In above-ground areas, when the water level in the underground aquifer in the area rises due to heavy rainfall, etc., the water pressure pushes up the strata above the underground aquifer, and the weight of that stratum acts downward on the slope. It is believed that this causes the earth to land.

Therefore, it has been thought to be effective to prevent the occurrence of above-ground aquifers by draining the water in underground aquifers in above-ground areas, and this has been practiced.

The groundwater intake method in the above-mentioned above-ground area is as follows:
Traditionally, the catchment well method and horizontal poling method have been mainly used.

In either method of water intake, a collection pipe is buried in an underground aquifer, and groundwater is collected through a collection hole drilled on the circumference of the pipe, stored in a well, and then discharged. Alternatively, the water can be discharged directly from the water collection pipe to the outside of the ground.

However, according to the conventional water intake method described above, although considerable water intake efficiency is exhibited at the time of construction or immediately after completion, the water intake capacity decreases significantly after several months, and in many cases, water intake becomes impossible.

In particular, in the case of water collection wells that use liner plates, there are many cases where the plate is crushed by the sliding pressure of the ground, causing the well to no longer function as a water collection well.

In addition, in the method of drilling a hole by horizontal poling and inserting a water collection pipe, the natural aquifer condition is disturbed because the excavation involves disturbing the strata within the aquifer during poling, and as a result, the first hole in the water collection pipe is removed. It was easy to wake up.

On the other hand, it was believed that draining groundwater from underground aquifers through water collection pipes would prevent water from rising above the surface, so efforts were made to lower the groundwater level below the lower part of the water collection pipes.

As a result, as can be seen from the example of water collection culverts installed along rivers, on riverbeds, or under riverbeds, when the groundwater level falls below the water collection pipe, the upper part of the water collection hole installed in the water collection pipe is almost completely covered. They become clogged with mud, garbage, and sometimes roots, and because there is no aquifer, these gradually solidify and stick to the water collection holes, making it impossible for the drainage capacity to recover even if the groundwater level rises due to rainfall. .

In addition, if forced water intake is performed when the area of the water collection hole is insufficient, groundwater will be forcibly sucked in, increasing the water flow velocity, and the movement of fine sand will be concentrated around the water collection hole, resulting in clogging. wake up

Therefore, when drawing groundwater, it is necessary to secure a water collection hole area large enough to receive the amount of water to be drawn.
For this purpose, it is necessary to know the hydraulic conductivity value of the aquifer.

Incidentally, the water intake amount Q needs to be planned and constructed according to the value obtained by multiplying the permeability coefficient K by the water collection hole area ΣaO, that is, Q=K·ΣaO.

The present invention abolishes the conventional idea of suppressing the occurrence of groundwater by completely draining the groundwater in the underground aquifer in the above-ground zone, and fundamentally changes it. Only excess groundwater is discharged so that the water in the catchment area around the buried water collection pipe is always saturated or supersaturated, and it acts as a buoyant force on the deposits that try to adhere to the water collection hole of the water collection pipe. The ultimate objective is to prevent clogging due to adhesion and hardening, maintain burial conditions that allow water to be collected at all times, eliminate any rise in groundwater level due to clogging, and thereby prevent the occurrence of water above ground. It is something to do.

That is, in the present invention, a water collection pipe with a large number of water collection holes perforated on the circumferential surface is driven horizontally into an underground aquifer in an above-ground area, and the groundwater level of the underground aquifer is lowered to The water level of the underground aquifer is maintained above the water collection pipe by overflowing at a predetermined height above the entry point, and the water collection pipe is always placed in groundwater to achieve the above objectives.

The present invention will be described below with reference to embodiments shown in the drawings.

The embodiment shown in FIG. 1 is a configuration in which a water collection well is used to cause overflow, and a water collection well 4 is established from above ground in an above-ground zone 1 to penetrate an underground aquifer 2 and reach an impermeable layer 3. The base end 5a of a water collection pipe 50, which is driven radially horizontally into the underground aquifer 2, penetrates the side wall of the water collection well 4 and is exposed inside, and a valve 6 is attached to the end.

On the other hand, an overflow pipe 70 is provided to penetrate the side wall of the water collection well 4, and the end 7a of the overflow pipe 7 is made to protrude toward the valley side of the ground, and water is drained to the outside from this end Ia. .

The opening 7b of the overflow pipe 7 that opens into the water collection well 4 is opened at a predetermined height above the buried position of the water collection pipe 5, and the water level in the water collection well 4, that is, the water level in the underground aquifer 2. is always maintained above the buried position of the water collection pipe 5.

FIG. 2 shows an embodiment in which the water collection well 4 is not used, in which the base of the water collection pipe 5 is extended to protrude outside the valley side of the earth, and an inverted U-shaped seal pipe 8 is connected to the protrusion. This seal tube 8
The water level in the underground aquifer 2 is maintained above the buried position of the water collection pipe 5 by overflowing at a water level corresponding to the bending height H of the pipe.

The water level in the underground aquifer 2 is determined by the above-ground safety factor, that is, the ratio of the moment M1 of the force resisting sliding to the moment M2 of the force trying to cause sliding, M
1/M2=Fm is thicker than 1 (1,0 to 1.1
).

The water collecting pipe 5 has a large number of water collecting holes 9 bored in its circumferential surface, and the water collecting holes 9 are formed densely on the distal end side and sparsely on the proximal end side.

This is because when the water collection pipes 5 are driven radially, the tip side gradually separates from the adjacent water collection pipe 5, so that the amount of water collected per pipe can be increased.

With the above configuration, the present invention maintains the water level of the groundwater in the underground aquifer 2 above the water collection pipe 5 at all times, so the water collection pipe 5 is always surrounded by groundwater and the water collection hole A buoyant force always acts around the tube 9 to prevent clogging substances from adhering to it, and as a result, clogging due to solidification of the adhering substances does not occur, and a decrease in water intake capacity is prevented.

Therefore, water intake in above-ground areas is always carried out accurately, and occurrence of above-ground areas due to increase in groundwater can be effectively prevented.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG. 2 is a sectional view showing the same embodiment. 1...Above ground zone, 2...Aquifer, 3...Impermeable layer, 4...Water collection well, 5...Water collection pipe, 7...Overflow pipe, 8...Seal Pipe, 9...Water collection hole.

Claims (1)

[Scope of Claims] 1. A water collection pipe with a large number of water collection holes perforated on the circumferential surface is driven horizontally into an underground aquifer in an above-ground area, and the underground aquifer O
The water level of the underground aquifer is maintained above the water collection pipe by causing the ground water level to overflow at a predetermined height above the buried position of the water collection pipe, and the water collection hole is maintained by placing the water collection pipe within the groundwater at all times. A method for preventing clogging of water collection pipes in ground-blocking areas, characterized by preventing clogging of water collection pipes. 2 A water collection pipe that is buried in an underground aquifer in an above-ground area, with water collection holes densely drilled at the tip, and a system that maintains the water level in the underground aquifer above the tip of the water collection pipe. A device for preventing clogging of a water collection pipe in an above-ground area, comprising an overflow pipe and an end of the overflow pipe exposed outside the ground.