JPH06146257A - Device for pumping and restoring underground water - Google Patents

Abstract

PURPOSE:To ensure water permeabilities of a foundation and a strainer part of a protecting pipe for reduction, by restraining iron oxide from being produced during water pumping or water discharge. CONSTITUTION:A water pumping protecting pipe 1 inserted in a water pumping well J has a strainer part 2 in the lower side section thereof, and the upper end thereof is hermetically closed. A pumping pipe 4 is inserted into the water pumping protecting pipe through the intermediary of a cover B, and a water pumping pump 6 is provided at the lower end thereof. A protecting pipe 7 for restoration adapted to be inserted in a protecting well K for restoration, has a strainer 8 in the lower part thereof, and is hermetically closed at its upper end by a cover 7B. An air chamber 10 is provided between the cover 7B and a free underground water level B. A water drain pipe 13 inserted in a drain pipe 13 is inserted into the protecting pipe 7 through the intermediary of the cover 7B, and the lower end thereof is extended downward from the free underground water level B. An air separating and discharging device 14 is connected to the upper ends of the water pumping pipe 4 and the drain pipe 13. A water blocking packer 18 is laid in annular gap M between the protecting well K and the protecting pipe 7 at a position above the free underground water level B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a groundwater pumping and reducing drainage device for draining and reducing groundwater and miscellaneous drainage pumped up in root cutting work and the like.

[0002]

2. Description of the Related Art Generally, in the construction of an underground structure, when the excavation bottom is lower than the groundwater, it is necessary to temporarily discharge the groundwater level below the excavation bottom by draining some water. For this reason, conventionally, groundwater has been pumped up by a well pumping method, a well point method, a deep well method or the like, and after removing a sand content through a sand settling tank, it is discharged to a water supply or a river.

However, if groundwater (hereinafter referred to as pumped water) pumped up during the root cutting work is discharged to the sewer, the total amount of drainage becomes enormous, and a considerable discharge fee is required. In addition, in some regions, discharge is not possible due to lack of discharge pipe capacity, and river discharge is often subject to regulations due to environmental issues.

Therefore, a method of inserting a reduction protection tube into a reduction well drilled near the excavation site and injecting drainage, or, as disclosed in Japanese Patent Laid-Open No. 3-257220, pumping water is introduced into a basin. By using the permeation type recharge drainage method, etc., in which the water is drained and returned to the ground via the method, the discharge amount to sewage and the like is reduced, and the discharge fee is reduced.

[0005]

By the way, when the pump is forcibly pumped up from the pumping well, the groundwater level in the well further decreases, and the groundwater flows into the protection pipe through the strainer portion of the pumping protection pipe into the protection pipe. At this time, groundwater and air are agitated, and air is mixed into the groundwater in the form of bubbles,
Iron contained in groundwater and oxygen in bubbles combine to produce iron oxide. As a result, iron oxide may crush the strainer part of the reduction protection tube or the void in the ground to which the drainage should penetrate, resulting in a decrease in drainage efficiency or an increase in the drainage along the protection tube, causing it to spring above the ground. There is a situation where water cannot be returned.

However, in the conventional method using the protective tube for reduction, there is no means for preventing air from being mixed into the pumped water or for actively separating and discharging the mixed air. It was

The above-mentioned infiltration type recharge drainage method is intended for shallow strata, and since it is a pressureless water injection method utilizing gravity, the injection amount per hour is limited, and finally, It has the drawback that it often becomes impenetrable.

Further, in the reduction well, in general, drainage spouts to the ground along the protection pipe or permeates to the excavation side and flows out, resulting in a phenomenon that the injection efficiency is lowered. Therefore, conventionally, a method of sealing the inside of the annular gap between the reduction well and the protection pipe for pumping with clay and a method of injecting grout material into the gap have been adopted.

However, since the clay cannot be completely compacted from the construction conditions, sufficient sealing performance cannot be obtained, and since the specific gravity of grout material is heavier than groundwater, it flows down to the strainer side. As a result of crushing the eyes of the strainer section and the filter material, there are drawbacks such that the drainage efficiency is reduced and drainage becomes impossible.

The present invention has been made in view of the above-mentioned drawbacks and problems of the prior art. It prevents generation of air during air pumping and separates and releases the mixed air to generate iron oxide. An object is to provide a groundwater pumping and reduction drainage device that can be suppressed. It is another object of the present invention to provide a groundwater pumping and reduction drainage device capable of preventing drainage injected into a reduction well from spouting to the ground or flowing out to the excavation side.

[0011]

SUMMARY OF THE INVENTION The present invention, which is constructed to solve the above-mentioned problems, has a strainer portion formed axially midway in a pumping protection pipe inserted in a pumping well. , A sealing portion is provided at the upper end in the axial direction, and a pumping pipe is inserted from the upper end side to the inner lower end side in the pumping protection pipe, and the pumping pump is located at the lower end of the pumping pipe below the strainer part. A strainer is located at the lower end in the axial direction on the reducing protection tube that is inserted into the reducing well, and a strainer is formed at the upper end in the axial direction to define an air chamber between it and the free groundwater level. A drainage pipe is inserted from the outside upper end side so that the lower end side is located below the free groundwater level in the reduction protection pipe, and the upper end of the drainage pipe and the upper end of the pumping pipe are communicated with each other by air flow. A separate discharge device is provided, and the reduction well and the protection tube for reduction are provided. Made from those disposed water stop packer in the annular space formed between the.

The water blocking packer has a packer grout portion which is located above the strainer portion and is filled with grout material through a filling pipe into a grout filling bag fitted to the reducing protection tube. An injection grout portion formed by injecting and solidifying the grout material above the packer grout portion via an injection pipe is preferable.

[0013]

Since the inside of the protection pipe for pumping water is shielded from the outside air, the mixing of air into the pumping water is suppressed, and a negative pressure is exerted to exert suction force. Since the drainage pipe drains into the water below the free groundwater level, air is not mixed in the drainage. The air chamber keeps the drainage input constant. The air is separated and discharged while the pumped water stays in the air separating and discharging device for a certain period of time. The packer grout part and the injection packer part reliably seal the annular gap.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings. In the figure, A is a work site, B is a free groundwater level, C is an impermeable layer, and the work site A is provided with an impermeable wall D such as a continuous wall from the surface to the impermeable layer C. One side of the impermeable wall D is a non-excavation site F and the other side is an excavation site G. The excavation site G is provided with a pumping well J deeper than the root cutting bottom H. On the other hand, in the non-excavation area F, a reduction well K having the same depth as the pumping well J is bored from the ground surface to above the impermeable layer C.

In the figure, reference numeral 1 denotes a pumping protection pipe inserted into the pumping well J. The pumping protection pipe 1 is a hollow straight pipe 1A.
And a lid 1B that closes the axial upper end of the straight pipe 1A in a gas-liquid tight manner via a seal member. The straight pipe 1A is provided with a strainer portion 2 formed from a large number of small holes located downward from the middle in the axial direction, and the lid body 1B is provided with a pipe insertion hole 3 in the axial direction.

A pumping pipe 4 is inserted into the pumping protection pipe 1 through the pipe insertion hole 3, and an upper end side 4A of the pumping pipe 4 protruding outward from the lid 1B is bent into a substantially L shape. And extends in the horizontal direction, and the lower end side 4B extends below the strainer portion 2. 5 is a flow control valve provided at the upper end side 4A of the pumping pipe 4, 6 is a pumping pump provided at the lower end side 4B end of the pumping pipe 4, and the pumping pump 6 is at the bottom side of the pumping well J. It is arranged.

On the other hand, 7 indicates a drainage protection tube. The protection pipe 7 is composed of a hollow straight pipe 7A and a lid 7B that closes the axial upper end of the straight pipe 7A in a gas-liquid tight manner via a seal member. A strainer portion 8 composed of a large number of small holes is formed from the bottom to the lower end, and a tube insertion hole 9 is formed in the lid body 7B in the axial direction. Then, by inserting the drainage protection tube 7 having the closed upper end into the reduction well K as described above, an air chamber 10 is defined in the protection tube 7 between the lid 7B and the free ground water level B. Is made. 11
Is a pressure gauge for detecting the pressure in the air chamber 10, and 12 is a pressure adjusting valve in the air chamber 10.

Reference numeral 13 is a drainage pipe inserted into the reduction protection pipe 7 through the pipe insertion hole 9, and the upper end side 13A of the drainage pipe 13 protruding outward from the lid 7B is bent into a substantially L shape. The length L from the lid 7B to the lower end is set so that the lower end side 13B is located below the free groundwater level B and extends horizontally.

Next, reference numeral 14 denotes an air separating / releasing device for separating the air mixed when pumping the ground water through the pumping pipe 4 and discharging the separated air to the outside. Reference numeral 15 denotes a gas-liquid separation tank that constitutes the air separation / release device 14, and an inlet 15 connected to the pumping pipe 4 is provided on the upper side of the gas-liquid separation tank 15.
A is provided, an outlet 15B connected to the drain pipe 13 is provided on the lower side, and a gas-liquid flow port 15C is provided on the upper side.
And an air outlet 15D are provided.

Reference numeral 16 denotes an automatic valve closing type air vent valve provided at the upper end of the gas-liquid separation tank 15. The air vent valve 16
Is a valve casing 16A communicating with the gas-liquid flow port 15C
And a valve seat 16B provided in the valve casing 16A
And a float valve body 16C which is supported by the valve casing 16A via a valve arm so as to be able to swing upward and downward, and which is seated on and off the valve seat 16B from below, and an exhaust gas which is opened at the upper end of the valve casing 16A. It is composed of a mouth 16D.

Reference numeral 17 denotes a manual auxiliary air vent valve provided in the gas-liquid separation tank 15 in communication with the air flow port 15D. The auxiliary air vent valve 17 mixes a large amount of air with the groundwater pumped up. It is for auxiliary valve opening operation when there is.

Thus, the air separating / releasing device 1 of the present embodiment.
4 is a gas-liquid separation tank 15 and an automatic valve closing type air vent valve 16
And a manual auxiliary air vent valve 17.

Next, in FIGS. 1 and 3, reference numeral 18 denotes a water blocking packer provided in an annular space M formed between the reduction well K and the reduction protection tube 7. Reference numeral 19 denotes the water blocking packer 18, which is located above the free groundwater level B and is liquid-tightly fitted in the annular space M. The lower packer grout portion 19 is non-permeable. A grout filling bag 19A made of an aqueous cloth material and fitted to the outside of the drainage protection pipe 7, and a filling pipe 2 inserted into the annular space M.
And the chemical liquid type grout material 19B filled in the grout filling bag 19A through the gap 0.

On the other hand, reference numeral 21 denotes an upper packer grout portion which is liquid-tightly fitted in the annular space M at a predetermined distance from the lower packer grout portion 19. The upper packer grout portion 21 is, like the lower packer grout portion 19, a grout filling bag 21A made of a water-impermeable cloth material, and a chemical liquid grout filled in the grout filling bag 21A via another filling pipe 22. It is composed of a material 21B.

Reference numeral 23 denotes an injection grout portion formed in the annular space M between the upper packer grout portion 21 and the lower packer grout portion 19, and the injection grout portion 23 is provided on the upper packer grout portion 21. It is formed by injecting the liquid cement-based grout material 23A through the injecting pipe 24 inserted into the annular space M in the inserted state and solidifying the liquid.

In the water-stopper packer 18 described above, the grout filling bag 19A to which the filling pipe 20 is connected is inserted to a predetermined position in the annular space M, and the grout material 19B is pressure-filled through the pipe 20 to lower the bag. After forming the side packer grout portion 19, the upper packer grout portion 21 is formed in the same manner as the lower packer grout portion 19. After that, the grout material 23A is injected through the injection pipe 24 to form the injection grout portion 23, and then the injection grout portion 23 is disposed. In addition, 25 is a filter material.

Further, in this embodiment, the water stop packer 18 is arranged above the free groundwater level B, but it may be below the free groundwater level B as long as it is above the strainer section 8.

This embodiment is constructed as described above. When the groundwater on the excavation site G side is pumped up and the pumping pump 6 is driven to reduce the drainage to the non-excavation site F side, it is pumped up via the strainer section 2. The pumped water that has flowed into the protection pipe 1 is pumped up to the air separation / release device 14 via the pumping pipe 4. Since the upper end of the pumping protection pipe 1 is closed, when the water level in the pumping well J decreases due to pumping, a negative force, that is, a suction force is applied to the protection pipe 1, so that a suction force also acts in the pumping well J. As a result, the water collection effect is increased, and the rate of decline of groundwater can be promoted.

Further, since the air is not supplied from the upper side of the pumping protection pipe 1, the amount of air mixed into the groundwater can be reduced and the generation of iron oxide can be suppressed as compared with the prior art.

In the pumping operation, when the pumping capacity of the pumping pump 6 is smaller than the pumping capacity of the pumping well, the pumping pump 6 may idle and suck a large amount of air together with the groundwater. Adjust the pumping volume by squeezing 5.

The pumped water is introduced into the air separating / releasing device 14 to separate the air mixed in the pumped water as bubbles. That is, the pumped water is temporarily stored in the gas-liquid separation tank 15, air bubbles are diffused during this time, and the air is discharged to the outside through the normally open air vent valve 16. The air vent valve 16 has a float valve body 16C, and closes the pumped water when it flows into the valve casing 16A to prevent the pumped water from flowing out.

The size of the gas-liquid separation tank 15 varies depending on the pumping capacity, but it is preferable to use a tank having a volume capable of retaining pumped water for 10 to 30 seconds or more. Further, when the amount of air mixed is large, the manual auxiliary air vent valve 17 is opened to promptly discharge the air to the outside.

The pumped water from which the air has been removed by the air separation / release device 14 is discharged as drainage into the reduction protection pipe 7 via the drain pipe 13. Since the tip end side 13B of the drainage pipe 13 is located below the free groundwater level B and is inserted in water, it is possible to prevent air from being mixed in when drainage is discharged.

In addition, the air chamber 10 formed between the freezing water level B and the inside of the reducing protection pipe 7 functions as an air chamber, and when the air chamber 10 becomes excessive due to long-term water injection. The pressure can be adjusted to an appropriate pressure by the pressure adjusting valve 12. This makes it possible to suppress the turbulent flow of the drainage and to inject water into the ground at a constant flow rate and a constant pressure. As a result of the drainage being injected at a stable flow velocity, the water injection effect can be enhanced.

Moreover, the water blocking packer 18 provided in the annular space M between the reduction well K and the protection pipe 7 for pumping water has a pair of lower and upper packer grout parts 1 which are spaced upward and downward.
9 and 21 and the injection grout portion 23, and the reduction well K and the reduction protection tube 7 are liquid-tightly sealed, so that the drainage flows out to the ground through the annular gap M. It can be prevented. Further, by providing the lower packer grout portion 19, it is possible to prevent a situation in which the grout material 23A flows out to the strainer portion 8 side and crushes the strainer portion 8 and the ground, thereby lowering the water injection efficiency.

Furthermore, the grout materials 19B and 21B of the packer grout portions 19 and 21 are made of a cement-based grout material having high strength and fast curability, and the injection grout portion 23 has high strength and durability. By using the grout material 23A, a high water blocking effect can be obtained at an early stage.

Next, FIG. 4 shows a modification of this embodiment. When the reduction well N is drilled down to below the impermeable layer C, and the reduction protection pipe 31 whose upper end is closed by the lid 31A is inserted into the reduction well N, the water blocking packer 18 is used as the impermeable layer. It may be located at C and provided in the annular space M. By doing so, it is possible to prevent the drainage injected into the ground from flowing into the excavation site G side. Further, the impermeable wall P may have a length that does not reach the impermeable layer C.

Further, FIG. 5 shows a second embodiment, and the feature of this embodiment is that the air separation / release device 31 is arranged in the protection pipe 1 for pumping water. That is, reference numeral 32 in the drawing denotes a suction pipe that constitutes the air separation / release device 31, and the suction pipe 32 communicates with a pumping port of the pumping pump 6 and is projectingly provided at the lower end of the pumping pump 6, and the lower end side opening is Suction port 32
It is A. Reference numeral 33 denotes a gas-liquid separation tube that is fitted and fixed to the outside of the suction tube 32. The gas-liquid separation tube 33 is the suction tube 3
2, and a closing lid 33B that closes the upper end of the tube body 33A fitted to the suction tube 32.
And a gas-liquid flow port 33C formed in the closing lid 33B.
And a bottom plate 33E that closes the lower end of the pipe body 33A and a strainer portion 33D that is circumferentially provided at an intermediate position in the axial direction of the pipe body 33A. The lower part is the liquid retaining part 34, and the upper part is the air chamber 35 above the strainer part 33D.

Reference numeral 36 is an automatic valve closing type air vent valve provided on the outer surface of the closing lid 33B in communication with the gas / liquid flow port 33C. The air vent valve 36 is the air vent valve 16 of the first embodiment.
Similarly to the above, it has a structure having a float valve element 36A. An air vent pipe 37 is connected to the exhaust port 36B of the air vent valve 36, and the upper end of the air vent pipe 37 is located above the strainer portion 2 of the water pump protection pipe 1 and inside the water pump protection pipe 1. It is open to.

The air separating / releasing device 31 of the present embodiment is constructed as described above, and the air separating / releasing device 14 of the first embodiment.
Instead of the above, the pumping protection pipe 1 is inserted at the lower end side. Then, the groundwater flowing into the pumping protection pipe 1 via the strainer portion 2 is sucked into the gas-liquid separation pipe 33 via the strainer 33D and temporarily stays in the liquid retaining portion 34. During this time, the air mixed as air bubbles in the groundwater is discharged into the air chamber 35, and the air vent pipe 36 is used to pass the air vent pipe 37.
Is discharged into the protection pipe 1 for pumping water.

The ground water from which air has been separated is sucked into the suction pipe 32 through the suction port 32A as pumped water, and is sucked toward the pumping pipe 4 side.

According to this embodiment, since the air is preliminarily separated from the groundwater before the pumping by the pumping pump 6, the pumping efficiency can be improved and the water without iron oxide can be sucked up. You can

[0043]

Since the present invention is constructed as described above in detail, it has the following effects.

(1) Since the upper end of the pumping pipe for protection of water is closed by a sealing portion to prevent air from being mixed into the pumping water, the amount of pumping water can be increased and iron oxide is generated in the pumping water. Can be prevented.

(2) Since a negative force (suction force) acts in the pumping protection pipe with the upper end sealed, the efficiency of collecting water from the ground is high and the rate of decrease of groundwater can be promoted.

(3) Since the upper end of the reducing protection pipe is closed by a closed portion and an air chamber is formed between it and the free groundwater level, turbulent flow of drainage can be suppressed and the water injection pressure to the ground is kept constant. It becomes possible to adjust, and water injection efficiency can be improved.

(4) The drain pipe is set so that the lower end side is located below the free groundwater level, and it is possible to reliably prevent the phenomenon that the drainage is discharged into the reducing protection pipe in a waterfall shape and air is mixed. Therefore, the generation of iron oxide can be suppressed, and the reduction of water injection efficiency due to the inclusion of air can be prevented.

(5) Since the air separation / release device is provided between the pumping pipe and the drainage pipe to positively remove the air in the pumping water, the production of iron oxide can be effectively suppressed. it can.

(6) Since the water blocking packer is composed of the packer grout portion and the injection grout portion, the annular gap can be reliably sealed and a high water blocking effect can be exhibited.

(7) Since the packer grout portion can be accurately positioned, the injection grout portion can be arranged at the designed position, and as a result, the water blocking effect can be reliably obtained.

(8) According to the device of the present invention, the above (1),
As described in (4) and (5), since the air is removed from the pumped water and drainage to suppress the generation of iron oxide, it is necessary to prevent the strainer of the reduction protection pipe and the ground from clogging. You can As a result, the drainage efficiency can be maintained for a long period of time, and maintenance work such as cleaning for removing clogging, which is conventionally required, can be eliminated.

(9) According to the present invention, there is no loss of water to the outside during the process from pumping to drainage, and the amount of drainage does not decrease with respect to the amount of pumped water. No subsidence.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an overall configuration of a groundwater pumping and reduction drainage device according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of an air separation / emission device that constitutes an example device.

FIG. 3 is an enlarged vertical sectional view of a water blocking packer used in the apparatus of the embodiment.

FIG. 4 is a vertical cross-sectional view showing an overall configuration of a groundwater pumping and reduction drainage device according to a modification of the embodiment.

FIG. 5 is a cross-sectional view showing the air separation / release device according to the second embodiment connected to a pump.

[Explanation of symbols]

 1 Protective Pipe for Pumping Water 1B Lid Body 2 Strainer Part 4 Pumping Pipe 6 Pumping Pump 7 Protective Tube for Reduction 7B Lid Body 8 Strainer Part 10 Air Chamber 13 Drain Pipe 14, 31 Air Separation and Release Device 18 Water Stop Packer 19 Lower Packer Grout Part 21 Upper packer grout part 23 Injection grout part B Free groundwater level J Pumping well K Reduction well M M Annular cavity

Claims (2)

[Claims] 1. A strainer section is formed at an intermediate position in the axial direction on a pumping protection pipe inserted into a pumping well, and
A sealing portion is provided at the upper end in the axial direction, and a pumping pipe is inserted from the upper end side outer side to the inner lower end side in the pumping water protection pipe, and a pumping pump is positioned at the lower end of the pumping pipe below the strainer part. The strain reducing protection tube installed in the reduction well has a strainer portion located on the lower end side in the axial direction, and a sealing portion that defines an air chamber between the free upper ground water level and the free groundwater level. The drainage pipe is inserted from the outside upper end side so that the lower end side is located below the free groundwater level in the reduction protection pipe, and the upper end of the drainage pipe and the upper end of the pumping pipe are communicated with each other to separate air. A pumping and reducing drainage device for groundwater, comprising a discharging device, and a water blocking packer provided in an annular space formed between the reduction well and the protection tube for reduction. 2. The water blocking packer comprises a packer grout portion formed by filling a grout filling bag, which is located above the strainer portion and fitted into the reduction protection pipe, with a grout material through a filling pipe. 2. The groundwater pumping and reduction drainage device according to claim 1, further comprising: an injection grout portion formed by injecting and solidifying the grout material above the packer grout portion through an injection pipe.