JPH06101236A - Pumping well structure - Google Patents

Abstract

PURPOSE:To reduce the amount of pumping by a method wherein strainers are provided to an outer pipe on locations where water stays, an inner pipe, smaller in diameter than the outer pipe, is provided, water collecting chambers are provided to locations where the strainers are provided and drain pumps for drainage in the water collecting chambers are provided. CONSTITUTION:A casing 2 is inserted up to a specified depth while a hole 1 is excavated, and an outer pipe 4 is buried with strainers 3a and 3b provided to water-staying layers W and W'. Then, the casing 2 and space around the locations where the strainers 3a and 3b are provided in the outer pipe 4 are filled with permeable material 5 while the outer pipe 4 in an impermeable layer Y is filled with water-expansion clay 6, and thereby water-running between the water-staying layers W and W' is stopped, and then the casing 2 is extracted. Then, the outer pipe 4 is blocked with a bottom plate 7 on a location near the strainers 3a, and water collecting chambers 10a and 10b are provided with the water pipe 4 and the bottom of an inner pipe 8 blocked with partition plates 9. As occasion demands, drain pumps 11 are installed to the water collecting chambers 10a and 10b, and drainage is made therewith. Thereby, the amount of pumping can be reduced by executing drainage as occasion arises in accordance with the degree of springwater.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a pumping well that pumps groundwater in underground construction and allows the construction to proceed smoothly.

[0002]

2. Description of the Related Art Conventionally, when the bottom surface to be excavated during underground construction extends below the groundwater level to a lower level, the water level is lowered from the bottom surface to be excavated, and the aquifer that has been previously geologically surveyed to facilitate excavation Based on the drainage plan, a pumping well is installed in advance to lower the groundwater level.

As shown in FIG. 4, in the pumping well, a casing b is inserted to a predetermined depth while excavating a drill hole a,
A well side c having a diameter smaller than that of the casing is inserted into the casing, and a strainer d is provided on the well side over the entire surface of the water collecting range. Further, a filter material e is filled between the casing and the well side,
A casing is provided with a pumping pump f inside the extraction well side to drain the water in the aquifers W and W '. G is the ground where the pumping pump is installed.

[0004]

However, according to the conventional pumping well, the drainage layer is increased because the well bottom is deeper than the bottom of the final excavation and the groundwater discharged from several aquifers is constantly drained. However, the cost of wastewater treatment facilities was high, and it was not possible to drain water from the aquifer at that depth according to the drilling depth.

The present invention has been proposed in view of the problems of the above-mentioned prior art, and the purpose thereof is to discharge the spring water from the aquifer in accordance with the excavation depth and to discharge the discharged water. The purpose is to provide a structure of a pumping well that reduces the number of wells and the number of wells, and improves drainage efficiency.

[0006]

In order to achieve the above object, a pumping well according to the present invention has a casing inserted into a required depth while excavating a drilling hole, and an outer pipe having a diameter smaller than that of the casing is inserted into the casing. In the pumping well with the
While disposing strainers respectively at a plurality of water retaining positions in the outer pipe, an inner pipe having a diameter smaller than that of the outer pipe is disposed,
Each of the strainers is provided with a water collecting chamber, and a pump for discharging water from the water collecting chamber is also provided.

According to a second aspect of the present invention, the gap between the drill hole and the outer pipe is filled with a water-permeable material around the strainer and water-expandable clay in the other impermeable layer portions.

[0008]

Since the present invention is constructed as described above,
By providing multiple water collection chambers near the strainer with an outer pipe in which a strainer is installed at each of multiple aquifers in the drill hole and an inner pipe provided in the outer pipe, At the same time, the spring water collected in each water collection chamber is pumped through a drainage pump to lower the water level.

Further, the gap between the drill hole and the outer pipe is filled with a water permeable material such as gravel around the strainer to collect spring water from the aquifer layer and expand the water in the other impermeable layer. It is possible to prevent the inflow of spring water from the aquifer, limit the amount of spring water, and prevent excessive drainage by filling with a clay.

[0010]

The present invention will be described below with reference to the illustrated embodiments. A is a pumping well, and the casing 2 is inserted to a required depth while excavating the drill hole 1, and the strainers 3a and 3 are respectively provided at the positions of the aquifers W and W'in the casing 2.
b, and an outer pipe 4 having a smaller diameter than the casing 2 is embedded, and a strainer 3 in the casing 2 and the outer pipe 4 is provided.
Water-permeable material 5 such as pea gravel around the positions of a and 3b
The water impermeable layer Y other than the aquifers W and W'is filled with the water-expandable clay 6 in the outer tube 4 to stop running water between the aquifers W and W '. Then, the casing 2 is pulled out.

In the vicinity of the strainer 3a, the outer pipe 1 is closed by a bottom plate 7, the bottoms of the outer pipe 4 and the inner pipe 8 are closed by a partition plate 9, and the first water collecting chamber 10a and the second water collecting chamber 10a are closed. Water room 10
b is provided. A pumping pump 11 is installed in each of the water collecting chambers 10a and 10b as needed, and the pump 11 drains water. In the case of a deep well with a deep excavation depth, the inner pipe 8 and the outer pipe 4 are inserted while being connected.

Reference numeral 12 in the figure is a reinforcing member for connecting the inner pipe 8 and the outer pipe 4. According to the above-described embodiment, the strainers 3a, 3 are located at the positions corresponding to the aquifers W, W'according to the geological survey in advance.
b, the aquifers W, W'and the strainers 3a, 3b
By filling the water-permeable material 5 between them and collecting spring water in each of the water collecting chambers 10a, 10b partitioned by the outer pipe 4 and the inner pipe 8, the excavation depth and the degree of spring water are increased. The pumping pump 11 is installed in each of the water collecting chambers 10a and 10b to pump water, and the groundwater level is lowered to provide a strainer under the well side as in the conventional case to constantly pump spring water. Unlike in the case, draining as needed significantly reduces the amount of pumped water.

[0013]

As described above, according to the present invention, the strainer is provided at the position corresponding to the aquifer, and the water collecting chambers for the outer pipe and the inner pipe are provided so that the spring water from each aquifer is affected. It is possible to smoothly carry out the excavation work after lowering the groundwater level by installing a pumping pump in the water collection chamber and pumping water by monitoring the depth of excavation and the degree of spring water. Since the groundwater is not drained as necessary, the scale of the wastewater treatment facility can be reduced, and a single well can serve as multiple wells, which is a great economic effect.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a pumping well according to the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

3 is a view taken along the line EE in FIG.

FIG. 4 is a vertical sectional view showing a conventional structure.

[Explanation of symbols]

 A Pumping well G Ground W Aquifer W'Aquifer Y Impermeable layer 1 Drilling hole 2 Casing 3a Strainer 3b Strainer 4 Outer pipe 5 Water permeable material 6 Water-expandable clay 7 Bottom plate 8 Inner pipe 9 Partition plate 10a First Water collection chamber 10b Second water collection chamber 11 Pumping pump

Front page continuation (72) Inventor Keiji Furuta 4-6-15 Sendagaya, Shibuya-ku, Tokyo Fujita Co., Ltd.

Claims (2)

[Claims] 1. A pumping well in which a casing is inserted into a required depth while excavating a drilling hole, and an outer pipe having a diameter smaller than that of the casing is embedded in the casing, and the outer pipe has a plurality of water-storing positions respectively. In addition to disposing a strainer, disposing an inner pipe having a diameter smaller than that of the outer pipe, providing a water collecting chamber in each disposing portion of each strainer, and a pumping pump for draining water from each water collecting chamber as needed. The structure of a pumping well characterized by being provided. 2. The structure of a pumping well according to claim 1, wherein the clearance between the drill hole and the outer pipe is filled with a water-permeable material around the strainer and water-expandable clay in the other impermeable layer portions.