JP2015166546A - Underground water control method and system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and system capable of economically controlling underground water levels in the same aquifer.SOLUTION: There is provided an underground water control method for forming a water flow in underground aquifer 8 by: inserting a pipe 12 having a pair of water conduction holes 14, 16 that face in directions reverse to each other and are bored at aquifer depth parts into a pit 10 drilled from the ground E to the underground aquifer 8; installing, inside the pipe 12, a water barrier member 20 with an aperture 22 for partitioning the inside of the pipe 12 into a space 24 communicating with one water conduction hole 14 and a space 26 communicating with the other water conduction hole 16; and transmitting underground water W from one of the spaces 24, 26 to the other by using a water pump 30 fitted or inserted in a watertight manner into the aperture 22 of the water barrier member 20.

Description

  The present invention relates to a groundwater control method and system, and more particularly to a method and system for controlling a groundwater level in an underground aquifer.

  As shown in FIG. 7, in the construction of excavating the ground 1 to construct an underground structure or the like, the upward pressure of the groundwater W existing below the bottom surface (excavation bottom surface) of the excavation area 2 surrounded by the retaining wall 3 Since there is a risk of boiling on the bottom of the excavation or the floor of the excavation may be lifted, a pumping well 51 can be provided inside the retaining wall 3 to pump the groundwater W below the bottom of the excavation and reduce the lifting pressure. Yes (groundwater level lowering method). The pumped-up groundwater W can be discharged into sewage, etc., but in order to avoid fluctuations in the groundwater level (ground subsidence, etc.) in the surroundings during construction, as shown in FIG. A recharge method (condensate method) has been developed in which a condensate well 52 (or 53) is provided and a part or all of the groundwater W once pumped is returned to the ground via the condensate well 52 (or 53) (Patent Document 1). , 2). The condensate well 52 in the illustrated example shows a case where the groundwater W pumped from the aquifer (sandy soil) 8 below the bottom of the excavation by the pumping well 51 is returned to the same aquifer 8, and the condensate well 53 in the illustrated example is The case where it returns to the aquifer 6 (sandy soil above the impermeable layer 7) different from the aquifer 8 which pumped up the groundwater W is shown.

  Moreover, instead of the recharge method using the pumping well 51 and the condensate well 52 (or 53) as shown in FIG. 7 (A), the pumping and condensing of the groundwater W can be carried out as a single well (see FIG. 7B). A recharge method using a vertical hole 55 has also been developed (see Patent Documents 3 to 5). In the recharge method shown in FIG. 7B, water holes are provided in the depth portion corresponding to the aquifer 6 above the impermeable layer 7 and the depth portion corresponding to the aquifer 8 below. The casing pipe is inserted into a single well 55, and a partition member (packer or the like) 56 is disposed at a depth corresponding to the impermeable layer 7 between the two water passage holes in the pipe. The pump 57 is disposed above (or below). Then, a condensate pipe 58 passing vertically through the partition member 56 is connected to the pump 57, and the groundwater W pumped from the lower aquifer 8 is returned to the upper aquifer 6. It reduces the lifting pressure and prevents ground subsidence. Contrary to the illustrated example, there may be a method of pumping water from the upper aquifer 6 and returning the groundwater W to the lower aquifer 8 via the condensate pipe 58. Note that the groundwater level lowering method as shown in the illustrated example is not limited to excavation work, but may be implemented, for example, as a countermeasure against liquefaction.

JP 2006-077567 A JP2012-092514A Japanese Patent Publication No. 4-000128 JP-A-6-088327 Japanese Patent Laid-Open No. 10-259798

  According to the recharge method shown in FIG. 7, it is possible to prevent ground subsidence and the like while suppressing the discharge amount to the sewage and the like in the groundwater level lowering method. However, the recharge method shown in FIG. 7 (A) using the pumping well 51 and the condensate well 52 (53) requires a large site area and a large installation cost to install two or more wells, and the construction period becomes longer. There are problems. On the other hand, according to the recharge method of FIG. 7 (B) in which pumping and condensing water are performed in a single well 55, the installation cost can be reduced and the construction period can be shortened.

  However, the recharge method shown in FIG. 7 (B) also requires energy (pump power, etc.) for pumping and transferring groundwater W between the aquifers 6 and 8 in the ground. Although the initial cost of installation can be kept low, there is a problem that requires a relatively large running cost. In addition, it may not be possible to return all of the groundwater W pumped from one of the aquifers 6 and 8 to the other, and the excess groundwater W will be uneconomical that must be pumped to the ground and discharged into sewage. There is also. Furthermore, the construction method is based on the premise that there are a plurality of aquifers 6 and 8, and when there is only a single aquifer at the site of excavation work or liquefaction countermeasures, as shown in Fig. 7 (A) There is also a problem that the recharge method using the pumping well 51 and the condensate well 52 is unavoidable. There is a demand for the development of a technology that can economically control the groundwater level even in the site of excavation work or liquefaction countermeasures where only a single aquifer exists.

  Accordingly, an object of the present invention is to provide a method and system that can economically control the groundwater level within the same aquifer.

  Referring to the embodiment of FIG. 1, the groundwater control method according to the present invention includes a pair of oppositely facing water holes 14 in a vertical hole 10 excavated from the ground E to the underground aquifer 8 (or aquifer 6). 16 is inserted into a depth of the aquifer, and a pipe 24 is inserted into a space 24 that leads to one water passage hole 14 and a space 26 that leads to the other water hole 16. An aquifer 8 is formed by installing a water shielding member 20 with an opening 22 for partitioning and sending groundwater W from one of the spaces 24 and 26 to the other with a water pump 30 fitted or inserted into the opening 22 of the water shielding member 20 in a watertight manner. It is formed by forming a water flow.

  Referring also to the block diagram of FIG. 1, the groundwater control system according to the present invention is inserted into a vertical hole 10 excavated from the ground E into the underground aquifer 8 (or the aquifer 6) and has a pair of oppositely facing passages. A space in which the water holes 14, 16 are installed in the pipe 12, which is drilled in the deep part of the aquifer, and the space 12 communicates with the one water hole 14 and the other water hole 16 through the pipe 12. A water-impervious member 20 having an opening 22 that is divided into 26 and a water-feed pump 30 that is fitted or inserted into the opening 22 of the water-impervious member 20 in a water-tight manner and sends ground water W from one of the spaces 24 and 26 to the other. The water flow is formed in the aquifer 8 by water supply.

  Preferably, as shown in FIG. 1C, a pair of water passage holes 14 and 16 are provided at different depths of the pipe 12, and the water shielding member 20 with an opening 22 is formed between the water passage holes 14 and 16. In addition, it is installed in a direction crossing the pipe central axis, and groundwater is sent in parallel to the pipe central axis by the water pump 30 in the opening 22 of the water shielding member 20. Alternatively, as shown in FIG. 2 (B), the water-impervious member 20 with the opening 22 is installed from the inside of the pipe 12 so as to cover one water passage hole 16 (or 14). It is also possible to send groundwater in a direction intersecting the pipe central axis by the water supply pump 30. As shown in FIG. 8, the water-impervious member 20 with the opening 3 includes a cylindrical member 20e installed in the pipe 12 so as to be aligned with the center axis of the pipe, and a pair of water passage holes on the peripheral wall of the cylindrical member 20e. 14 and 16 is provided with a pair of openings 22 and 29 and partitions the outer wall outer space in the pipe 12 into a space 24 that communicates with one water passage hole 14 and a space 26 that communicates with the other water passage hole 16. 20 f may be provided, and the intake port and discharge port of the water supply pump 30 disposed in the hollow portion of the cylindrical member 20 e may be inserted into the one 22 and the other 29 of the opening.

  More preferably, as shown in FIG. 1 (B), a plurality of vertical holes 10A to 10L excavated along the periphery of the predetermined area on the ground E, respectively, a pair of water passage holes facing inward and outward of the predetermined area, respectively. 14 and 16 are inserted into pipes 12 drilled at the depth of the aquifer, and a water shielding member 20 with an opening 22 is installed in each pipe 12, and a water feed pump 30 at the opening 22 of each water shielding member 20 is used. The groundwater level of the aquifer inside the predetermined area is lowered from the outside by sending groundwater from the inside to the outside of the predetermined area.

  The groundwater control method and system of the present invention can economically control the groundwater level within the same aquifer.

Hereinafter, embodiments and examples for carrying out the present invention will be described with reference to the accompanying drawings.
It is a block diagram of one Example of the groundwater control system of this invention. It is explanatory drawing of the other Example of the groundwater control system of this invention. It is explanatory drawing of the filter material with which it fills between the internal peripheral surface of a vertical hole, and the outer surface of a casing pipe in this invention. It is explanatory drawing of the flow of groundwater formed in an aquifer by the control method of this invention. It is explanatory drawing of one Example which provided the water stop wall which prevents local circulation of groundwater between a pair of water flow holes of a casing pipe in this invention. It is explanatory drawing of the other Example which provided the water stop wall which prevents local circulation of groundwater between a pair of water flow holes of a casing pipe in this invention. It is explanatory drawing of the conventional groundwater level fall construction method. It is explanatory drawing of the further another Example of the groundwater control system of this invention.

  FIG. 1 shows an embodiment in which the groundwater control system of the present invention is applied to excavation work on the ground 1 similar to FIG. As shown in FIG. 1 (B), the earth retaining wall 3 is formed along the periphery of the predetermined excavation area 2 on the ground E, and a plurality of vertical holes 10A to 10L arranged in a ring shape along the outer side of the mountain retaining wall 3 are formed on the ground E. The excavation area 2 is excavated while lowering the groundwater level below the excavation area 2 by installing the groundwater control system of the present invention inside each of the vertical holes 10A to 10L. FIG. 1 (A) shows a vertical cross-sectional view perpendicular to the ground surface including the vertical holes 10A and 10G in the excavation area 2 of FIG. 1 (B).

  As shown in FIG. 1 (C), the groundwater control system of the present invention includes a casing pipe 12 inserted into each vertical hole 10, a water shielding member 20 with an opening 22 installed in the pipe 12, and the water shielding member. The water supply pump 30 is fitted or inserted into the 20 openings 22 in a watertight manner. The groundwater control system according to the present invention does not pump or transfer the groundwater W of the aquifer 8 as shown in FIG. 7, but in a desired direction (in the illustrated example, from the inside to the outside of the excavation zone 2). By creating a flow of groundwater W (in the direction), the water level in the upstream area (the water level P1 inside the water level P2 outside the cut area 2) is lowered relative to the downstream area of the water flow. The retaining wall 3 is constructed so that the groundwater W of the aquifer 8 can flow through the bottom so that the inner groundwater level can be controlled from the outside.

  The casing pipe 12 in the illustrated example has a pair of water holes 14 and 16 formed at a depth corresponding to the underground aquifer 8. The water passage holes 14 and 16 are formed in opposite directions as viewed from the center axis of the pipe. In the illustrated example, one water passage hole 14 faces the inside of the retaining wall 3 and the other water passage hole 16 faces the retaining wall. 3 is inserted toward the outside. For example, a casing pipe 12 is formed by inserting a hollow pipe of a predetermined length made of iron pipe, stainless steel pipe or synthetic resin into the vertical hole 10 while being connected in the direction of the central axis, and has a depth corresponding to the aquifer 8. A hollow pipe in which a pair of strainers facing each other across the central axis is connected to the part is connected in the opposite direction, and a hollow pipe without a water passage hole is connected to the other part and the bottom part. The cross-sectional shape of the water flow holes 14 and 16 can be arbitrarily selected from a circular shape, a slit shape, and other shapes.

  The pair of water passage holes 14 and 16 of the casing pipe 12 both face the same underground aquifer 8, for example, as shown in FIGS. 2 (B) and 4 (C). It can be provided at a depth site. However, it is not always necessary to have the same depth as long as it is within the range facing the aquifer 8. For example, as shown in FIG. 1 (C) and FIGS. 4 (A) and 4 (B), It is also possible to make the depth slightly different. Further, one water passage hole 14 and 16 is sufficient, but as shown in FIG. 4 (D), any one or both of the water passage holes 14 and 16 can be provided as necessary. .

  Desirably, as shown in FIG. 5, a water blocking wall 11 is provided between the water flow holes 14, 16 of the casing pipe 12 to prevent local circulation of the ground water W between the water flow holes 14, 16. . For example, as shown in FIG. 5A, a high-pressure injection device (not shown) is inserted along the central axis of the vertical hole 10 excavated from the ground E to the underground aquifer 8, as shown in FIG. By using a method (high pressure jet agitation method) that mixes and agitates while cutting the ground by injecting cement-based ground improvement material at high pressure from the central axis of the vertical hole 10 toward both sides in the predetermined vertical direction (radial direction). As shown in (C), the water blocking walls 11 extending in a desired direction (direction parallel to the earth retaining wall 3 in the illustrated example) can be formed on both sides of the vertical hole 10. If necessary, the thickness of the water blocking wall 11 can be adjusted appropriately by high-pressure injection of the improved material while rotating the high-pressure injection nozzle by a desired angle θ. After forming a water blocking wall 11 in a desired direction at a depth facing the aquifer 8 in the vertical hole 10, a casing pipe 12 is inserted inside the vertical hole 10, as shown in FIG. It installs so that the water flow holes 14 and 16 may be located on the opposite side across the water blocking wall 11.

  As will be described later, the groundwater control system of the present invention partitions the inside of the casing pipe 12 into a space 24 that communicates with one water passage hole 14 and a space 26 that communicates with the other water passage hole 16. The flow of the groundwater W from the space 24 toward the other space 26 is created, but the local circulation of the groundwater W outside the pipe 12, for example, an undesired circulation flow from the water passage 16 to the water passage 14. If this occurs, the flow of groundwater W cannot be created efficiently. As shown in FIG. 5, by providing a water blocking wall 11 that prevents local circulation between the water flow holes 14 and 16 on the outside of the casing pipe 12, the flow of the groundwater W in a desired direction can be efficiently performed with small energy. Can be expected to produce. FIG. 5C shows a longitudinal sectional view of the vertical hole 10 as viewed from the water passage hole 14 side of the casing pipe 12, and the flow of the groundwater W is created so as to go from the front side to the back side of the drawing.

  As shown in FIGS. 1 and 3, at least the outer surface of the water flow holes 14 and 16 of the casing pipe 12 and the inner peripheral surface of the vertical hole 10 are filled with a filter material 32 such as gravel to ensure water permeability. However, it is desirable to prevent clogging with sediment and inflow of sediment into the pipe 12. FIGS. 3A to 3C show the arrangement of the filter material 32 when the water holes 14 and 16 are provided at different depths, and the outer surface of the pipe 12 without the water holes and the inner peripheral surface of the vertical hole 10. It indicates that cement bentonite or other water shielding material 34 is filled in between. 3 (D) to 3 (F) show the arrangement of the filter material 32 when the water holes 14 and 16 are provided at the same depth, and the entire outer peripheral surface of the pipe 12 facing the underground aquifer 8 is filtered. The filling of the material 32 is shown. However, from the viewpoint of ease of construction, the filter is always applied to the entire outer peripheral surface facing the aquifer 8 as shown in FIGS. 3D to 3F regardless of the depth of the water holes 14 and 16. It is advantageous to arrange the material 32.

  The water blocking wall 11 as shown in FIG. 5 can be formed by a method (injection method) for injecting an improved material such as a water glass system or a suspension system instead of the high-pressure jet agitation method. In order to form the water blocking wall 11 in a desired direction, it is desirable to use a construction method that can inject improvement material with directivity. Further, as shown in FIG. 6, projecting blades 18 projecting radially (in the radial direction) are provided on the outer surface between the water passage holes 14, 16 of the casing pipe 12, and the projecting blade 18 passes through the water holes 14, 16. It is also possible to use the water blocking wall 11 that prevents local circulation of the groundwater W between them. When the casing pipe 12 with protruding blades 18 as shown in FIG. 6 is used, it is not necessary to form the water blocking wall 11 by a high-pressure jet stirring method or the like, and the protruding blades 18 are in the desired direction (in the example shown in the figure). The water stop wall 11 as shown in FIG. 5 can be formed simply by inserting the casing pipe 12 so as to be in a direction parallel to the earth retaining wall 3, thereby simplifying the construction and shortening the construction period. it can. FIGS. 6A to 6F correspond to FIGS. 3A to 3F, respectively, and FIGS. 6A to 6C show the case where the water holes 14 and 16 are provided at different depths. 6 (D) to 6 (F) show a case where the water holes 14 and 16 are provided at the same depth.

  As shown in FIG. 1C, an opening that partitions the inside of the pipe 12 into a space 24 that communicates with one water passage hole 14 and a space 26 that communicates with the other water passage hole 16 is formed inside the casing pipe 12 of the illustrated example. The water impervious member 20 with 22 is disposed, and the water pump 30 is fitted or inserted into the opening 22 of the water impervious member 20 in a watertight manner so that the water intake port of the water pump 30 faces the one space 24 and the water pump 30 discharges. The exit faces the other space 26. Desirably, the water-impervious member 20 is detachable, and after inserting the pipe 12 into the vertical hole 10, the water-impervious member 20 is suspended by a wire (not shown) or the like to a predetermined position on the inner peripheral surface of the pipe 12. Install in close contact. However, if necessary, the water shielding member 20 can be fixed inside the casing pipe 12 in advance before being inserted into the vertical hole 10. The cross-sectional shape of the opening 22 of the water shielding member 20 can be arbitrarily selected from a circular shape, a slit shape, and other shapes.

  1C and 1D show an embodiment in which an annular packer member 20a that can be expanded and contracted is used as the water-impervious member 20 with the opening 22. FIG. The annular packer member 20a in the illustrated example has an annular rubber hollow ring, and the peripheral side surface of the cylindrical water pump 30 is fitted into the central opening 22 in a watertight manner. First, the rubber ring of the annular packer member 20a in which the water pump 30 is fitted into the opening 22 is contracted, and in the contracted state, the pipe is brought from the ground to a depth between the water flow holes 14 and 16 in the pipe 12. Suspend horizontally in a direction that intersects the central axis. Thereafter, as shown in FIGS. 1 (C) and 1 (D), an appropriate pressurized fluid is supplied from the ground to expand the rubber ring, thereby bringing the annular packer member 20a into close contact with the inner peripheral surface of the pipe 12. The one space 24 and the other space 26 in the pipe 12 are cut off. In this state, the water pump 30 fitted horizontally in the opening 22 is driven, the groundwater W in one space 24 is taken in from the intake port of the pump 30, and the predetermined distance in parallel to the central axis of the pipe is passed from the discharge port to the other space 26. By sending it out with water pressure, a flow of groundwater W directed from the inside to the outside of the excavation zone 2 is created inside the aquifer 8 (see the flow of groundwater W in FIG. 4A).

  In FIG. 1, even when the groundwater W in the underground aquifer 8 is flowing, the water pressure of the water pump 30 is appropriately adjusted to adjust the water pressure in the space 26 leading to the water passage hole 16 in the casing pipe 12 to the fluid pressure. By making it higher, the flow of groundwater W in the direction opposite to the flow direction can be created in the aquifer 8, and the groundwater level inside the excavation zone 2 can be lowered from the outside in FIG. However, as shown in FIG. 1C, when the water pressure in the space 26 in the pipe 12 is increased, the water surface level also increases. FIG. 2A shows an embodiment in which a water level control packer 28 is disposed in the space 26 above the water-impervious member 20, and the water pressure in the space 26 can be increased while suppressing an increase in the water level in the pipe 12. Show. By suppressing the rise in the water level in this way, the energy (pump power, etc.) necessary to create the desired flow of groundwater W can be reduced. The water shielding member 20a and the water pump 30 in FIG. 2A can also be installed by being hung inside the casing pipe 12 with a wire or the like, but may be inserted into the vertical hole 10 after being fixed inside the casing pipe 12 in advance. Is possible.

  FIG. 2C shows an embodiment in which an annular seal member 20b with an opening 22 is used instead of the annular packer member 20a. The annular seal member 20b in the illustrated example is an annular water shielding member in which a shield packing that slides in close contact with the inner peripheral surface of the pipe 12 is attached to the outer peripheral edge. The surrounding side is fitted in a watertight manner. The annular seal member 20b is lowered while sliding the shield packing on the inner peripheral surface of the pipe 12 from the ground, and is lowered to the depth between the two water flow holes 14 and 16, and is brought into close contact with the pipe central axis. As a result, the one space 24 and the other space 26 in the pipe 12 are blocked. In this state, the water pump 30 fitted horizontally in the opening 22 is driven, and the groundwater W in one space 24 is sent to the other space 26 at a predetermined water pressure in parallel with the central axis of the pipe. A flow of groundwater W is created inside (see the flow of groundwater W in FIG. 4A). Also in this case, as shown in FIG. 2D, it is desirable to arrange a water surface level control packer 28 in the space 26 above the water shielding member 20. 2C and 2D can be inserted into the vertical hole 10 after being fixed inside the casing pipe 12 in advance.

  FIG. 2E shows a water shielding member 20 having a water shielding plate 20c with an opening 22 that is fixed in advance to the pipe cross section at a depth between the two water flow holes 14 and 16 of the casing pipe 12 in a direction crossing the pipe central axis. Examples are shown. In this case, after inserting the pipe 12 into the vertical hole 10, the water pump 30 is suspended from the ground by a wire or the like and is seated on the water shielding plate 20 c fixed in the pipe 12, and the discharge port (or water intake) of the pump 30 is placed. Mouth) is inserted into the opening 22 of the water shielding plate 20c. It is desirable to provide a check valve 23 for ensuring water tightness in the opening 22 of the water shielding plate 20c into which the pump 30 is inserted. In this state, the water pump 30 is driven, and the groundwater W in one space 24 is sent to the other space 26 at a predetermined water pressure in parallel with the central axis of the pipe, thereby creating a flow of the groundwater W in the underground aquifer 8. (See the flow of groundwater W in FIG. 4B). Also in this case, as shown in FIG. 2 (F), it is desirable to dispose a water surface level control packer 28 in the space 26 above the water shielding member 20. 2 (E) and 2 (F), the water pump 30 can be inserted into the vertical hole 10 after being fixed inside the casing pipe 12 in advance.

  In the embodiment of FIG. 2 (E), the water shielding plate 20c with the opening 22 is fixed in a direction crossing the central axis of the pipe, but as shown in FIG. It is also possible to fix the water shielding plate 20d with the opening 22 so as to cover the water passage hole 16 (or the water passage hole 14). Also in this case, after inserting the pipe 12 into the vertical hole 10, the water pump 30 is suspended from the ground with a wire or the like and is seated on the water shielding plate 20d in the pipe 12, and the discharge port (or water intake port) of the pump 30 is provided. It is inserted into the opening 22 of the water shielding plate 20d. It is desirable to provide a check valve 23 for ensuring water tightness in the opening 22 of the water shielding plate 20c into which the pump 30 is inserted. In this state, the water pump 30 is driven, and the groundwater W in one space 24 is sent to the other space 26 at a predetermined water pressure in a direction crossing the central axis of the pipe, so that the flow of the groundwater W into the underground aquifer 8. (See the flow of groundwater W in FIG. 4C). Also in this case, the water level control packer 28 can be disposed in the space 26 above the water shielding member 20 as in the case of FIG.

  As described above, in the groundwater control method and system of the present invention, a pair of oppositely directed water holes 14 and 16 are formed in the aquifer depth region in the vertical hole 10 excavated from the ground E to the underground aquifer 8. After the perforated pipe 12 is inserted and the water-impervious member 20 with the opening 22 is divided into the space 24 communicating with the one water passage hole 14 and the space 26 communicating with the other water passage hole 16 in the pipe 12, Since the water flow is formed in the aquifer 8 by sending the groundwater W from one of the spaces 24 and 26 to the other with the water pump 30 fitted or inserted into the opening 22 of the water shielding member 20 in a watertight manner, the following effects are obtained. Play.

(A) A water flow in a predetermined direction can be generated in the aquifer 8 by the vertical hole 10 excavated in the aquifer 8, and the water level in the upstream region can be lowered relative to the downstream region of the water flow.
(B) For example, by generating a water flow from the inside to the outside by the plurality of vertical holes 10A to 10L excavated along the periphery of the predetermined area of the aquifer 8, the predetermined area is obtained similarly to the conventional groundwater level lowering method. The groundwater level inside can be lowered than outside.
(C) Since the water level is controlled by generating a water flow in the aquifer 8 without pumping up the groundwater W of the aquifer 8, only a single aquifer that has been difficult with the conventional groundwater level lowering method can be used. It is possible to control the level of groundwater that is not pumped at the site of non-existent excavation work or liquefaction countermeasures.
(D) In addition, the groundwater level can be controlled with less energy compared to the conventional groundwater level lowering method in which the groundwater W in the aquifer 8 is pumped and transferred.
(E) Further, since the groundwater W is not required to be pumped when controlling the groundwater level of the aquifer 8, it is possible to avoid the inconvenience of generating excessive groundwater W that needs to be discharged into sewage or the like.

  Thus, the provision of “a method and system capable of economically controlling the groundwater level within the same aquifer”, which is an object of the present invention, can be achieved.

  In the illustrated example, the groundwater control system of the present invention is applied to lowering the groundwater level in excavation work. However, the present invention is not limited to the application to excavation work, and various groundwater level controls are required. It is also possible to apply to civil engineering works such as liquefaction countermeasures. That is, similarly to the case of FIG. 1B, a plurality of vertical holes 10A to 10L are excavated in a ring shape along the peripheral edge of a predetermined area where the liquefaction of the ground E is concerned, and each of the vertical holes 10A to 10L is drilled. The pipe 12 in which the pair of water flow holes 14 and 16 facing inward and outward is formed in the aquifer depth part is inserted. Then, the above-described water-impervious member 20 with the opening 22 (see FIG. 2) is installed in each pipe 12, and the water-feeding pump 30 fitted or inserted into the opening 22 of each water-impervious member 20 from the inside to the outside respectively. By sending the groundwater, the groundwater level inside the predetermined area is lowered from the outside, thereby preventing liquefaction in the predetermined area.

  FIG. 8 shows another embodiment of the water shielding member 20 with the opening 22 arranged inside the casing pipe 12. The water shielding member 20 in the illustrated example includes a cylindrical member 20e that is installed inside the pipe 12 so as to be aligned with the center axis of the pipe, and a pair of openings 22 and 29 are provided on the peripheral wall of the cylindrical member 20e. A water-impervious protrusion 20f in contact with the inner surface of the pipe 12 is provided at an intermediate portion between the openings 22 and 29 on the outer surface of the peripheral wall. 8A is a perspective view showing the inner cylindrical member 20e by partially cutting the pipe 12, FIG. 8B is a vertical sectional view thereof, and FIG. 8C is a horizontal sectional view thereof. . In the illustrated example, the openings 22 and 29 are circular in cross section, but may be slits, and the cross-sectional shapes of the openings 22 and 29 can be arbitrarily selected.

  As shown in FIG. 8 (A), the pair of openings 22 and 29 on the peripheral wall of the cylindrical member 20e are installed so as to face the pair of water passage holes 14 and 16 of the pipe 12, and shown in FIG. 8 (C). As described above, the space 26 communicating with one water passage hole 14 and the space 26 communicating with the other water passage hole 16 through the outer wall outer space (gap between the outer surface of the peripheral wall and the pipe inner surface) in the pipe by the water shielding protrusions 20f on the outer wall surface. And partition. The cylindrical member 20e is installed by, for example, inserting the casing pipe 12 into the vertical hole 10 and then suspending it from the ground with a wire or the like in the pipe 12 or by fixing it in the casing pipe 12 in advance and inserting it into the vertical hole 10 Can be installed.

  After installing the cylindrical member 20e in the casing pipe 12, as shown in FIG. 8 (B), the water supply pump 30 is suspended from the ground with a wire or the like and disposed in the hollow portion of the cylindrical member 20e. The intake port is inserted into one opening 22 of the cylindrical peripheral wall, and the discharge port of the pump 30 is inserted into the other opening 29 of the cylindrical peripheral wall. A plurality of openings 22 and 29 in the cylindrical peripheral wall can be provided. In this case, as shown in the example, the intake port of the pump 30 and the plurality of openings 22 are connected via a branched intake pipe 35 to branch off. The discharge port of the pump 30 and the plurality of openings 29 can be connected via the discharge pipe 36. In FIG. 8 (B), the water pump 30 is previously placed in the hollow portion of the cylindrical member 20e and then inserted into the casing pipe 12, or the cylindrical member 20e in which the water pump 30 is placed in the hollow portion is preliminarily casing. It is also possible to insert into the vertical hole 10 after being fixed in the pipe 12.

  As shown in FIG. 8B, the water supply pump 30 is driven in a state where the water intake port and the discharge port are connected to the openings 22 and 29 of the cylindrical peripheral wall, and the ground water W in one space 24 outside the peripheral wall is kept at a predetermined water pressure. By sending it out to the other space 26 outside the peripheral wall, a flow of groundwater W as shown in FIG. 4C can be created inside the underground aquifer 8. As shown in FIG. 8, it is expected that a relatively strong flow of the groundwater W can be created by sending the groundwater W through the plurality of openings 22 and 29 in the cylindrical peripheral wall. In order to efficiently create the flow of groundwater W, as shown in FIG. 8 (B), it is necessary to provide a water shielding lid or packer member 20g, 20h that tightly closes the upper and lower ends of the gap between the outer surface of the peripheral wall and the inner surface of the pipe. desirable.

DESCRIPTION OF SYMBOLS 1 ... Ground 2 ... Cut-off area 3 ... Earth retaining wall 6 ... Aquifer (sandy soil)
7 ... Impervious layer (viscous soil) 8 ... Aquifer (sandy soil)
9 ... Impermeable layer (cohesive soil)
DESCRIPTION OF SYMBOLS 10 ... Vertical hole 11 ... Water stop wall 12 ... Casing pipe 14 ... 1st water flow hole (intake hole)
16 ... 2nd water flow hole (discharge hole) 18 ... Projection blade | wing (water blocking wall)
DESCRIPTION OF SYMBOLS 20 ... Water-impervious member 20a ... Annular packer member 20b ... Annular seal member 20c ... Water-impervious plate 20d ... Water-impervious plate 20e ... Hollow cylinder 20f ... Water-impervious projection 20g, 20h ... Water-impervious lid or packer member 22 ... Opening 23 ... Check valve 24 ... first space 26 ... second space 28 ... water level control packer 29 ... opening 30 ... water pump 32 ... filter material 34 ... water blocking material 35 ... intake pipe 36 ... discharge pipe 51 ... pumping well 52, 53 ... Condensate well 55 ... Well 56 ... Partition member 57 ... Pump 58 ... Condensate piping E ... Above ground W ... Groundwater

Claims (10)

Insert a pipe with a pair of oppositely facing water holes drilled in the depth of the aquifer into a vertical hole excavated from the ground into the underground aquifer, and insert one pipe into the pipe. A water-impervious member with an opening that divides into a space communicating with the other water passage hole and a water pump fitted or inserted in the water-tight member in a water-tight manner into the opening of the water-impervious member to supply groundwater from one of the two spaces to the other. A groundwater control method that forms a water stream in an aquifer by sending it. The method according to claim 1, wherein the pair of water passage holes are provided at different depths of the pipe, and the water shielding member with an opening is installed at a depth between the water passage holes in a direction intersecting with the pipe central axis. A groundwater control method in which groundwater is sent in parallel with the central axis of a pipe by a water pump at the opening of the water shielding member. 2. The method according to claim 1, wherein the water-impervious member with an opening is installed so as to cover one water passage hole from the inside of the pipe, and groundwater is sent in a direction crossing the central axis of the pipe by a water pump at the opening of the water-impervious member. A groundwater control method. The method according to claim 1, wherein the water-impervious member with an opening includes a cylindrical member installed in the pipe so as to be aligned with the center axis of the pipe, and a pair of opposed water-permeable holes on the cylindrical peripheral wall. A water supply pump disposed in a hollow portion of the cylindrical member is provided with an opening and a water shielding projection for partitioning a space outside the peripheral wall in the pipe into a space communicating with one water passage hole and a space communicating with the other water passage hole. A groundwater control method in which a water intake port and a discharge port are inserted into one and the other of the openings. The method according to any one of claims 1 to 4, wherein a pair of water-holes facing inward and outward of the predetermined area are respectively formed in a plurality of vertical holes excavated along the periphery of the predetermined area on the ground. By inserting pipes drilled in the site, installing the water-impervious members with openings in the pipes, and sending groundwater from the inside to the outside of the predetermined area by the water pumps at the openings of the water-impervious members, respectively. A groundwater control method in which the groundwater level of an aquifer inside a predetermined area is lowered from the outside. A pipe inserted into a vertical hole excavated from the ground into the underground aquifer and having a pair of oppositely oriented water holes drilled in the depth region of the aquifer, installed in the pipe and passing through one of the pipes A water-impervious member with an opening that partitions into a space that communicates with the water passage hole and a space that communicates with the other water passage hole, and water supply that fits or inserts water-tightly into the opening of the water-impervious member and sends ground water from one of the two spaces to the other A groundwater control system comprising a pump, wherein a water flow is formed in the aquifer by water supplied from the water pump. The system according to claim 6, wherein the pair of water passage holes are provided at different depths of the pipe, and the water shielding member with an opening is installed at a depth between the water passage holes in a direction intersecting with the pipe central axis. A groundwater control system in which groundwater is sent in parallel with the central axis of the pipe by a water pump at the opening of the water shielding member. 7. The system according to claim 6, wherein the water-impervious member with an opening is installed so as to cover one water passage hole from the inside of the pipe, and groundwater is sent in a direction crossing the central axis of the pipe by a water pump at the opening of the water-impervious member. A groundwater control system. 7. The system according to claim 6, wherein the water-impervious member with an opening includes a cylindrical member installed in the pipe so as to be aligned with the center axis of the pipe, and a pair of opposed water-permeable holes on the cylindrical peripheral wall. A water supply pump disposed in a hollow portion of the cylindrical member is provided with an opening and a water shielding projection for partitioning a space outside the peripheral wall in the pipe into a space communicating with one water passage hole and a space communicating with the other water passage hole. A groundwater control system in which a water intake and a discharge port are inserted into one and the other of the openings. The system according to any one of claims 6 to 9, wherein a pair of water-holes facing inward and outward of the predetermined area are respectively formed in a plurality of vertical holes excavated along the periphery of the predetermined area on the ground. By inserting pipes drilled in the site, installing the water-impervious members with openings in the pipes, and sending groundwater from the inside to the outside of the predetermined area by the water pumps at the openings of the water-impervious members, respectively. A groundwater control system that lowers the groundwater level of the aquifer inside the specified area from the outside.