JP3338909B2 - Layered pumping well - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stratified pumping well for individually pumping groundwater from a plurality of underground aquifers.

[0002]

2. Description of the Related Art When a plurality of aquifers exist in the ground and it is necessary to pump water separately from the plurality of aquifers, for example, a groundwater contamination survey is conducted for each aquifer. In the case where the investigation of the thermal energy possessed by groundwater for each aquifer or the case where it is necessary to drain water from a specific aquifer due to ground excavation work, the It was common to provide multiple independent wells for each aquifer.

That is, as shown in FIG. 2, when an upper aquifer 2 and a lower aquifer 3 exist above and below an impermeable layer 1 such as a viscous soil layer, for example, Book well 4
And the lower aquifer 3 penetrating through the impermeable layer 1.
The other wells 5 that reach the upper aquifer 2 are used to pump water from the upper aquifer 2 and water from the lower aquifer 3 separately. In addition, in each of the wells 4 and 5 shown in FIG. 2, reference numeral 6 denotes a well pipe installed in the wellbore 7, 8 denotes a screen formed below the well pipe 6, and 9 denotes a screen installed in the well pipe 6. The pump 10 is a pumping pipe, 11 is a filter material to be filled at least around the screen 8 in the borehole 7, and 12 is a filler material for closing the upper part in the borehole 7. Reference numeral 13 in the well 5 denotes an impermeable zone formed at the position of the impermeable layer 1 in order to prevent groundwater from the upper aquifer 2 from flowing into the well 5.

Incidentally, as described above, the plurality of wells 4, 5
Providing a separate aquifer for each aquifer 2 and 3 not only increases the cost but also requires sufficient installation space and work space because the wells 4 and 5 cannot be installed too close to each other. Therefore, for example, it is considered to adopt a stratified pumping device 15 as shown in FIG. 3 to pump water by a single well into each aquifer.

[0005] In the stratified pumping apparatus 15 shown in FIG. 3, screens 16 and 17 corresponding to the upper aquifer 2 and the lower aquifer 3 are vertically arranged in a drilling hole 7 provided through the impermeable layer 1. A well pipe 18 is provided, and a filter material 11 is filled around each of the screens 16 and 17, and a water impervious zone 13 is formed at the position of the impermeable layer 1. Then, the pump 9 is housed in the casing 19 and arranged at the position of the water-impermeable layer 1, the gap between the casing 19 and the well pipe 18 is stopped by the packer 20, and the casing 19 is closed. An upper valve 21 and a lower valve 22 that are opened and closed by remote control from the ground are attached to the upper and lower portions.

[0006] In this stratified pumping device 15, the upper aquifer 2
Groundwater flows into the well pipe 18 through the filter material 11 and the screens 16 and 17 from both the lower aquifer 3 and the lower aquifer 3, respectively. , And 3 for pumping water. That is, the upper valve 21
Is opened and the lower valve 22 is closed, only groundwater from the upper aquifer 2 passes through the upper valve 21 and the casing 19
If the upper valve 21 is closed and the lower valve 22 is opened, only groundwater from the lower aquifer 3 flows into the casing 19 through the lower valve 22. The water is pumped by the pump 9.

[0007]

By employing the above-described stratified pumping apparatus 15, stratified pumping can be performed with one well. However, the stratified pumping apparatus 15 has a casing 19 and a packer 20. , Valves 21 and 22, etc., it has a complicated and special structure, so it is costly and time-consuming to manufacture, and it is not easy to perform on-site installation work.
It has been desired to provide an effective means for performing stratified pumping more easily.

[0008]

DISCLOSURE OF THE INVENTION In view of the above circumstances, the present invention is directed to a method for separately pumping water from each aquifer which is provided on a ground where a plurality of aquifers are interposed across an impermeable layer. In a stratified pumping well, the inside of a borehole that penetrates through the impermeable layer to reach the aquifer existing thereunder is formed by a water-blocking zone made of waterproof concrete at the position of the impermeable layer. In addition to partitioning up and down so that water can be blocked, a plurality of well pipes that have a length that reaches the position of each aquifer to be pumped and that have screens are formed so that each screen is at the position of the aquifer to be pumped. And placed in the borehole
The filter material is filled around each screen, and pumps are installed in the well pipes.

[0009]

The stratified pumping well according to the present invention does not provide a plurality of wells for each aquifer to be pumped as in the prior art, and uses a plurality of aquifers without using a special stratified pumping device. Pumping water from a single well. That is, in the stratified pumping well of the present invention, a drilling hole is provided alone to reach the lowest aquifer to be pumped,
Watertight concrete is placed inside the borehole at the location of the impermeable layer.
The upper and lower sections of the excavation hole allow only groundwater from the aquifer located above it to flow upward, and the lower section below the Only groundwater from the lower aquifer flows in. Then, a plurality of well pipes corresponding to the aquifer pumping target disposed drilled hole, the periphery of the screen
The groundwater that has flowed into each well pipe from the screen through the filter material filled into the well pipes is individually pumped by a water pump installed in each well pipe.

[0010]

An embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows a schematic configuration of a stratified pumping well of the present embodiment. As in FIGS. 2 and 3, reference numeral 1 denotes an impermeable layer such as a viscous soil layer, and reference numerals 2 and 3 denote upper portions of a pumping target, respectively. Aquifer and lower aquifer.

The stratified pumping well 30 according to the present embodiment has a borehole 31 that penetrates from the surface through the impermeable layer 1 and reaches the lower aquifer 3.
Is excavated, and the inside of the excavation hole 31 is vertically divided at the position of the water-impermeable layer 1 so as to be impermeable by, for example, a water impermeable zone 32 made of watertight concrete. , 34 are arranged.

The well pipes 33, 34 have a length reaching the upper aquifer 2 and the lower aquifer 3, respectively, and have a screen 3 at their lower ends.
5 and 36 are formed, and each screen 3
5 and 36 are arranged in the excavation hole 31 so as to be located in the upper aquifer 2 and the lower aquifer 3. Then, in each of the well pipes 33, 34, groundwater flowing into the well pipes 33, 34 through the screens 35, 36 is pumped.
Pumps 39, 40 for pumping water to the surface through 8
Are installed respectively. Reference numerals 41 and 42 denote filter materials filled around the screens 35 and 36, 4
Reference numeral 3 denotes a backfill layer formed by generated soil, and reference numeral 44 denotes a sand layer.

In the stratified pumping well 30 having the above structure, the inside of the excavation hole 31 is vertically divided by the impermeable zone 32, so that the groundwater in the upper aquifer 2 flows from the screen 35 into the well pipe 33. The groundwater in the lower aquifer 3 flows from the screen 36 into the well pipe 34 and is pumped by the pump 40. Therefore, the groundwater in the lower aquifer 3 is pumped by the pump 40. Layer 2, 3
Can be pumped individually from

In this stratified pumping well 30, two well pipes 33 and 34 are arranged in a single drilling hole 31. Therefore, as shown in FIG. Although it is necessary to make the diameter of the excavation hole 31 larger than in the case where two independent wells 4 and 5 are provided, the installation space and work space are increased as compared with the case where the two wells are independently provided. It is possible to save money and to reduce the construction cost comprehensively by digging using a large excavator used for pile construction. In addition, two well pipes 3
Although three and three pumps 39 and 40 are required, complicated and special equipment is not required at all, and the well pipes 33 and 34 can be used as they are. As in the case of using the stratified pumping device 15 as shown, there is no increase in cost or time required for production, and the construction procedure on site is not different from the conventional one.

The above embodiment is an example in which the upper aquifer 2 and the lower aquifer 3 are to be pumped. Therefore, the two aquifers 2 corresponding to the upper aquifer 2 and the lower aquifer 3 are used. Well pipe 3
Although only 3, 34 are installed, the present invention can be similarly applied to a case where a larger number of aquifers are to be pumped. For example, when pumping water from three aquifers sandwiching two impervious layers, each of the impervious layers is located at the position of each impermeable layer.
2 to divide the inside of the borehole 31 into three, and to pump water from each of the three aquifers.
The number of well pipes may be set in the borehole 31. The same is true for pumping four or more aquifers.

[0016]

As described above, the stratified pumping well according to the present invention forms a drilling hole that penetrates an impermeable layer to reach an aquifer located thereunder. The inside of the hole is divided up and down by the impermeable zone made of waterproof concrete at the position of the impermeable layer, so that it can be impermeable.
It a plurality of well pipes corresponding to the aquifer pumping target their screens arranged so that the position of each aquifer
Filter material was filled around each screen, and groundwater in each aquifer that flowed into the well pipes was pumped by pumps. The pump can be pumped separately from the aquifer, thus reducing construction costs compared to the case where multiple independent wells are provided for each aquifer or a complicated and special stratified pumping system is used. This has the effect of reducing installation space and work space.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view showing an example of installation of wells in a conventional case where water is pumped by layer.

FIG. 3 is a sectional view showing a conventional example of a stratified pumping device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Impermeable layer 2 Upper aquifer (aquifer) 3 Lower aquifer (aquifer) 30 Pumping well according to stratum 31 Drilling hole 32 Watertight zone (watertight concrete ) 33,34 Well pipe 35,36 Screen 39,40 Pumps 41,42 Filter material

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Nakatsuka 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation (56) References JP-A-58-37241 (JP, A) 4-112947 (JP, U) Real opening Sho 61-80890 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) E02D 19/10 E03B 3/12 E21B 43/14

Claims (1)

(57) [Claims] 1. A stratified pumping well provided on a ground having a plurality of aquifers sandwiching an impermeable layer, for pumping water separately from each aquifer, wherein Through the excavation hole reaching through to the aquifer existing at the lower part of the excavation hole, at the position of the impervious layer, a water- shielding zone made of waterproofing concrete partitions up and down so as to be impermeable, and each of the pumping targets A plurality of well pipes each having a length reaching the position of the aquifer and having a screen formed therein are arranged in the borehole such that each screen is located at the position of the aquifer to be pumped. Fill the filter material around the
Hama to, stratification pumping apparatus characterized by comprising by installing water pumps respectively to their well pipe.