JP3176319U - Drainage well - Google Patents

Abstract

An object of the present invention is to expand a well range in a drainage well in which a large number of drainage pipes are buried in an aquifer, groundwater is sucked from a catchment hole of the catchment pipe, collected in a well, and pumped from within the well. A drainage well that aims to improve water collection capacity while preventing clogging of the water collection hole is provided.
[MEANS FOR SOLVING PROBLEMS] A plurality of water collecting pipes (10) communicating with a well for pumping (1) are embedded in an aquifer formation (3), and flow into the water collecting pipes from a number of water collecting holes (4) opened in the peripheral surface of each water collecting pipe. The water collecting well that collects groundwater to be collected in the well and pumps the water from the well. The opening area is gradually increased from the base side to the tip side so as to work equally in the entire region.
[Selection] Figure 2

Description

  The present invention relates to a well for collecting groundwater.

  Conventionally, as shown in FIG. 4, as a method of taking groundwater, a large number of water collecting pipes 2, 2,... Are buried radially in the underground aquifer 3 from a well-shaped well 1. It is sucked from the well 1 by a pump, so that ground water is sucked from a large number of water collecting holes 4 (or winding screens, etc.) drilled in the peripheral surface of the water collecting pipes 2, 2,. The wells (known as Manchu wells) made in the past are known, and the well area is expanded to improve the water collection efficiency.

  However, when the water collecting pipes 2, 2,... Are embedded in a radial manner in this way, the distance between the water collecting pipes 2, 2,. The ground water in the gap portion a is less likely to be absorbed, and is collected from the water collecting holes of the base portion close to the well 1 of the water collecting pipes 2, 2. The problem of being unable to absorb water efficiently has been pointed out.

  That is, for example, when the construction length of one water collecting pipe is 10 m, the pumping test after completion of the pumping water level 6 in the well 1 and the tip 2a of the water collecting pipe 2 as shown schematically in FIG. Since a large loss head 7 is generated at the water level, the effect of the construction length of 10 m is not actually obtained.

  As means for solving these problems, there is one in which water collecting holes on the front end side of the water collecting pipe are closely opened so that water is sufficiently absorbed from the front end side (Patent Document 1).

  However, in the means described in the above-mentioned document, even if it is intended to collect groundwater between the tips of the water collecting pipes 2, 2,..., The groundwater flowing into the water collecting hole has a base portion where the suction force of the pump is greatly affected. If the water collecting hole concentrates in the region indicated by (8) in FIG. 5 and the suction force of the pump is increased to absorb water from the entire area of the water collecting pipe 2, the water collecting hole at the base of the water collecting pipe 2 Since it is sucked at a high flow rate, the sediments are sucked, resulting in the problem of clogging the water collecting holes and significantly reducing the water collecting ability.

Japanese Examined Patent Publication No. 46-26307

  The present invention has a problem with the above-mentioned conventional technology, that is, the amount of groundwater flowing into the water collection pipe is made uniform in the entire area of the water collection pipe, thereby preventing clogging of the water collection hole of the water collection pipe and entering the well. The purpose of this project is to make the inflow of groundwater smooth, increase the operating efficiency of the pump, and improve the water intake efficiency.

  As a means for solving the above-mentioned problems, the present invention has a structure in which a plurality of water collecting pipes communicating with a well for pumping are embedded in an aquifer and water is collected from a number of water collecting holes opened on the peripheral surface of each water collecting pipe. A water collection well that collects groundwater flowing into the pipe into the well and pumps the water from the well. The water collection hole of the water collection pipe has a suction force from the inside of the well from the base of the water collection pipe. The opening area is formed so as to gradually increase from the base side to the tip side so as to work equally in the entire region up to the tip.

  The water collecting pipes are preferably embedded radially from the well into the aquifer formation.

  As the water collecting hole opened in the water collecting pipe, a means comprising a plurality of circular holes or elliptical holes, or a slit-shaped water collecting hole opened in the circumferential direction of the water collecting pipe can be adopted.

  The increase / decrease of the opening area of the water collecting hole of the water collecting pipe can be selected from means based on the opening area of each water collecting hole and means based on the number of water collecting holes.

  According to the present invention, the suction force by the pump is not concentrated on a part of the pump, and it is possible to avoid sucking earth and sand and to be sucked in equally from the water collecting holes in the entire longitudinal direction of the water collecting pipe. As a result, the pumped water level in the well and the water level at the tip of the water collection pipe are at a substantially constant level, the diameter of the well can be effectively increased, and the water collection capacity can be greatly increased.

The top view which shows an example of the water collecting pipe in this invention. Sectional drawing which shows the construction example of the drainage well by this invention. Explanatory drawing of the water collection situation of the water collection well by this invention. The horizontal sectional view which shows the construction example of the water collection pipe | tube in FIG. Explanatory drawing of the water collection situation by the conventional water collection well.

  FIG. 1 shows an example of a water collecting pipe 10 used for a water collecting well according to the present invention. When the pipe is buried in the aquifer 3 radially from the well 1 as shown in FIGS. Water collecting holes 4, 4... Are opened on the peripheral surface from 10a to tip 10b.

  The water collecting holes 4, 4... Are formed in the water collecting holes 4 from the base 10 a to the tip 10 b so that the suction force by the pump from the inside of the well 1 works equally in the entire area 9 from the base 10 a to the tip 10 b. The opening area of 4... Is gradually increased.

  The means for gradually increasing the opening area by the water collecting holes 4, 4... Depends on the individual opening area of the water collecting holes 4, 4,. It can be determined by the opening area based on.

  When the water collecting pipe 10 configured in this way is radially embedded in the aquifer 3 and sucked by the pump, it reaches the water collecting hole 4 on the tip 10b side of the water collecting pipe 10 as schematically shown in FIG. The amount of inflow becomes linear, the flow velocity does not become uneven in the water collection pipe 10, and it smoothly flows into the well 1 so that the pumped water level 6 in the well 1 and the water level on the tip 10b side of the water collection pipe 10 are substantially the same level. Therefore, the loss head 7 is remarkably reduced, so that the well diameter L is greatly expanded, and the amount of water intake can be increased accordingly.

  Further, in the present invention, the water collecting holes 4, 4... Of the water collecting pipe 10 are arranged so that the suction force from the well 1 to the pumping pump acts equally in the entire region from the base 10 a to the tip 10 b of the water collecting pipe 10. The opening area is gradually increased from the 10a side to the tip 10b side. Here, it is more accurate to determine the extent to which the opening area by the water collecting holes 4, 4... Gradually increases to the tip 10 of the water collecting pipe 10. It is preferable to take into consideration the characteristics of the third, for example, the flow speed and flow direction of groundwater.

  In addition, when the water collection pipe | tube 10 is radiated | emitted radially like FIG. 4, the loss head 7 will arise only by the space | interval a of the water collection pipes 10 and 10, but by increasing the construction number of the water collection pipe | tube 10, a loss head It is possible to reduce the difference.

  As shown in FIG. 1, the water collecting hole 4 opened in the water collecting pipe 10 divides the entire length of the water collecting pipe 10 into a plurality of areas A, B, C, and D, and from the A area on the tip 10b side to the base 10a side. If the openings are divided into sections so that the opening area gradually decreases over the area C, the areas A to D are formed by individual members, and the water collecting pipe 10 is configured by connecting them by welding or the like. It is preferable from the viewpoint of ease.

  In FIG. 1, for example, the region A of the tip 10b is 1.5 times as long as the region B of the intermediate portion, and the region B of the intermediate portion has a length equal to the region C on the base 10a side. The end region D has half the length of the intermediate region B and the region C on the base 10a side. Further, for example, the density at which the water collecting holes 4, 4,... Are provided is 2 in the intermediate region B and 3 in the region A of the tip 10b, where the region C on the base 10a side is 1. And 0 in the region D at the base end.

Next, the principle of the drainage well for increasing the well diameter L will be exemplified.
The amount of water intake is Q, the water permeability coefficient is K, and the sum total of the water collection hole areas of all the water collection pipes 10 is Σa ₀ . Moreover, since not all water collection holes are effective, the safety factor is set to 1.1.
Water collecting hole area Σa ₀ is Σa ₀ = Q / K × 1.1
It becomes.

As an example, if the daily amount is 5000 m ³ , the water intake per second is 0.05787 m ³ / sec.

Next, the number of construction points of the water collecting pipe 10 necessary for taking the water intake amount Q of 0.05787 m ³ / sec is obtained.
According to an empirical rule as the value of the water permeability coefficient K, for example, when the water permeability coefficient K = 5.0 × 10 ⁻³ m / sec, the water collection hole area Σa ₀ is
Water collecting hole area Σa ₀ = 0.05787 ÷ 5.0 × 10 ³ × 1.1 = 12.73 m ²
It becomes.
Water collecting hole area a ₀ (total area of water collecting holes) of one water collecting pipe 10 = 0.3 m ²
And That is, the total area of the water collecting holes in the regions A, B, C, and D of the water collecting pipe 10 shown in FIG. 1 is set to 0.3 m ² . Here, as shown in FIG. 1, the total area of 0.3 m ² has the number distribution of the water collecting holes set over the regions A, B, C, and D.

The number of construction water collecting pipes is Σa ₀ / a ₀ = 12.73 ÷ 0.3≈43.

  When the calculation formula is used, the water collecting hole area corresponding to the water intake Q is sufficiently provided, so that a large amount of water is taken in at a value equal to the flow velocity of groundwater flowing in the aquifer 3. However, there is no movement of fine sand and the like, and it does not accumulate around the well 1 and does not flow into the well 1, so that clogging is eliminated.

  The water collecting pipe may be constituted by a so-called winding screen, and the water collecting hole may be constituted by a spiral groove of the winding type screen, and the width of the groove may be increased from the base end to the tip end of the water collecting pipe. By expanding the width of the groove from the proximal end of the water collecting pipe toward the distal end, it becomes possible to cause the suction force from the well pump 1 to work equally in the entire area from the base to the distal end of the water collecting pipe. Become.

DESCRIPTION OF SYMBOLS 1 Well 2, 10 Water collecting pipe 3 Aquifer 4 Water collecting hole 6 Water level in well pipe 7 Loss head 10a Water collecting pipe base 10b Water collecting pipe tip

Claims (6)

A plurality of water collecting pipes communicating with the well for pumping are buried in the aquifer, and groundwater flowing into the water collecting pipes from the many water collecting holes opened in the peripheral surface of each water collecting pipe is collected in the well. It is a drainage well that pumps water from the inside of the well,
The water collection hole of the water collection pipe is formed with an opening area gradually increasing from the base side to the tip side so that the suction force by the pump from the inside of the well tube works equally in the entire region from the base part to the tip of the water collection pipe. A drainage well characterized by   The drainage well according to claim 1, wherein the drainage pipe is radially embedded from the well into the aquifer formation.   The water collection well according to claim 1 or 2, wherein the water collection hole opened in the water collection pipe is composed of a plurality of circular holes or elliptical holes.   The water collection well according to claim 1 or 2, wherein the water collection hole opened in the water collection pipe is configured by a slit opened in a circumferential direction of the water collection pipe.   The catchment well according to any one of claims 1 to 4, wherein the increase or decrease in the opening area of the water collecting hole of the water collecting pipe is determined by the opening area of each water collecting hole.   The catchment well according to any one of claims 1 to 4, wherein an increase or decrease in the opening area of the catchment hole of the catchment pipe is determined by the number of catchment holes.

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