well

Abstract

To increase functions of a well for construction work which is used in underground construction involving ground excavation.SOLUTION: A well for construction work is used in ground construction involving ground excavation and includes: a casing pipe including a water collection pipe which collects ground water; a submerged pump including a drain pipe disposed at the water collection pipe in the casing pipe; and an underground heat exchanger which is disposed so as to enclose the submerged pump and includes multiple heat collection pipes in which a heat medium circulates. The casing pipe is provided within a wall of an earth-retaining wall or in the ground on the back surface side.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a well for construction work used in underground work involving ground excavation. [Background technology]

[0002] Geothermal energy utilization systems have been developed that utilize geothermal energy, which is a renewable energy source, for building air conditioning, hot water supply, etc. For example, Patent Document 1 discloses a heat exchange system that uses deep wells and water storage holes constructed underground.

[0003] Specifically, a circulation pipe through which liquid from a heat pump installed above ground is circulated is inserted into the reservoir, and groundwater pumped from a deep well is injected into the shallow part of the reservoir, while the groundwater stored in the reservoir from a deeper part is drained. In this way, the system exchanges heat between the groundwater that generates convection from top to bottom in the reservoir and the liquid in the circulation pipe.

[0004] According to Patent Document 1, the water level in the reservoir can be maintained constant at all times without being affected by fluctuations in the groundwater level, so the liquid flowing down the circulation pipe inserted into the reservoir can stably exchange heat with the groundwater. However, when building a heat exchange system, the work of constructing a deep well and a reservoir in the ground requires a large initial cost.

[0005] In this context, for example, Patent Document 2 discloses a groundwater utilization method in which a groundwater utilization system is constructed that obtains thermal energy through heat exchange with groundwater using a casing pipe installed in the ground where the groundwater level is to be lowered during construction, and the thermal energy obtained by this groundwater utilization system is supplied to a structure after construction is completed.

[0006] Specifically, a casing pipe equipped with a strainer is installed within an area enclosed by an earth retaining wall, and during construction, a pump is inserted into the casing pipe to drain the groundwater and lower the groundwater level while the structure is constructed. After construction is completed, the pump is removed from the casing pipe and a heat collection pipe is inserted to create a groundwater utilization system. The heat exchange medium supplied to the heat collection pipe exchanges heat with the groundwater inside the casing pipe, then further exchanges heat in a heat pump installed above ground, and is used in the air conditioning of the completed structure. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 5959035 [Patent Document 2] Patent No. 6907596 Summary of the Invention [Problem to be solved by the invention]

[0008] According to Patent Document 2, a groundwater utilization system is constructed that obtains thermal energy through heat exchange with groundwater by utilizing a casing pipe in which a pumping pump was inserted during construction. In this way, if the work of drilling the ground can be omitted, the construction costs associated with constructing a groundwater utilization system can be significantly reduced. However, because the pumping pump is removed when constructing the groundwater utilization system, even though the casing pipe has the ability to collect groundwater, this collection capacity cannot be utilized after construction is completed. For this reason, there is a need to further utilize the water collection capacity of construction wells made of casing pipes.

[0009] The present invention has been made in view of the above problems, and its main object is to provide a multi-functional construction well for use in underground construction work involving ground excavation. [Means for solving the problem]

[0010] In order to achieve this object, the well of the present invention is a well for construction work used in underground work involving ground excavation, and is characterized in that it comprises a casing pipe with a water collection section for collecting groundwater, a submersible pump with a drainage pipe placed in the water collection section within the casing pipe, and a geothermal heat exchanger arranged to surround the submersible pump and having a plurality of heat collection pipes through which a heat medium circulates, and the casing pipe is installed underground within the wall or on the back side of the retaining wall. Height range and a ground heat exchanger that is arranged to surround the submersible pump and has a plurality of heat collection pipes through which a heat medium circulates, the casing pipe being installed within the wall or in the ground on the back side of the retaining wall. The plurality of heat collection pipes are spaced apart from one another. It is connected to the submersible pump via a spacer that holds the It is characterized by:

[0011] According to the well of the present invention, the casing pipe is installed underground within the wall or behind the wall so as not to interfere with new structures constructed within the wall, and a submersible pump and a geothermal heat exchanger are installed inside the casing pipe. This allows the well to be used for construction work during the construction period and also serves as a geothermal heat utilization system equipped with a geothermal heat exchanger. After the construction is completed, the well can be used not only for the geothermal heat utilization system but also as a pumping well. This allows the well to be converted into an emergency disaster well, for example, making it possible to realize the multi-functionality of the construction well.

[0012] Furthermore, if a water injection well used in the recharge method, which is known for using a large-diameter, long casing pipe to increase water injection capacity, is used as the well for construction work, it will be possible to increase the number of heat collection pipes placed inside the casing pipe and to lengthen the pipes. This will enable more efficient heat exchange with groundwater in a geothermal energy utilization system equipped with a geothermal heat exchanger.

[0013] Furthermore, the geothermal energy utilization system using the geothermal heat exchanger can be used not only for the new structure and surrounding structures after construction is completed, but also for heating, cooling, and hot water in the construction office and work station that are open during construction. This means that it will be possible to enjoy the power and energy saving effects and CO2 emission reduction effects of using the geothermal energy utilization system even during construction.

[0014] In addition, by combining a heat pump with the drainage pipe attached to a submersible pump, it is possible to create a so-called direct pumped geothermal energy system, in which groundwater pumped by the submersible pump is heat-exchanged with the heat pump. This makes it possible to use both an indirect circulation geothermal energy system using a geothermal heat exchanger and a direct pumped geothermal energy system side by side and simultaneously.

[0015] The well of the present invention is characterized in that a water injection pipe branching off from the drainage pipe is installed in the drainage pipe, and the open end of the water injection pipe is positioned at the upper end of the casing pipe.

[0016] According to the well of the present invention, groundwater pumped by a submersible pump can be injected into the vicinity of the upper end of the casing pipe through a water injection pipe, which causes convection in the groundwater from the upper end to the lower end of the casing pipe, thereby further improving the heat exchange efficiency between the heat transfer medium circulating in the heat extraction pipe and the groundwater.

[0017] In addition, if the water injection pipe is blocked, the well can be cleaned by repeatedly operating the submersible pump to pump groundwater from the casing pipe and then stopping the submersible pump. Therefore, by performing these operations periodically, it is possible to prevent clogging of the strainer and the fill gravel. [Effects of the Invention]

[0018] According to the present invention, by installing a casing pipe equipped with a submersible pump and a geothermal heat exchanger inside the wall or underground on the back side of the retaining wall, the construction well can be used for construction work during the construction period and also serves as a geothermal heat utilization system equipped with a geothermal heat exchanger.After the construction is completed, the construction well can be converted into a pumping well using a submersible pump, such as an emergency disaster well, making it possible to realize multi-functionality of the construction well. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a diagram showing an outline of a water injection well according to an embodiment of the present invention. [Figure 2] FIG. 10 is a diagram showing the state in which a water injection well after construction is completed in an embodiment of the present invention is converted into a geothermal energy utilization system and an emergency disaster well. [Figure 3] 1 is an enlarged view of an upper portion of a water injection well (part B in FIG. 1) in an embodiment of the present invention. [Figure 4] FIG. 2 is an enlarged view of a lower portion (part A in FIG. 1) of a water injection well in an embodiment of the present invention. [Figure 5] FIG. 2 is a diagram showing a centralizer of the underground heat exchanger according to the embodiment of the present invention. [Figure 6] FIG. 3 is a diagram showing a spacer of the underground exchanger in the embodiment of the present invention (in the case of four heat collection pipes). [Figure 7] This is a diagram showing an example in which a deep well constructed using the deep well construction method on the back side of a retaining wall in an embodiment of the present invention is converted into a geothermal energy utilization system and an emergency disaster well. [Figure 8] This is a diagram showing an example in which a deep well constructed using a deep well method is converted into a geothermal energy utilization system and an emergency disaster well within a retaining wall in an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] The present invention aims to realize multi-functionality for construction wells used in underground construction work involving ground excavation, by converting them into emergency wells or using them in conjunction with geothermal energy utilization systems, and to utilize them effectively not only during construction but also after the work is completed. Below, we will explain the details by taking a water injection well used in the recharge method as an example of a construction well.

[0021] << ... As shown in Figure 1, at an underground construction site where the recharge method is used as a supplementary method for water replacement work, a pumping well 2 for pumping groundwater Gw is installed in an excavation area S surrounded by an earth retaining wall R. In addition, a water injection well 1 for forcibly returning the pumped groundwater Gw to the ground is installed behind the earth retaining wall R.

[0022] The pumping well 2 comprises a casing pipe 21 placed in an underground hole H2 formed in the ground, a pumping pump 24 inserted into the casing pipe 21, and a pumping pipe 25 connected at its base end to the pumping pump 24. The casing pipe 21 is provided with a strainer section 22 within a height range where it contacts the permeable layer P2, and the outer periphery of the strainer section 22 is covered with packed gravel 23. In addition, the pumping pipe 25 has a drainage port 251 at its tip inserted into the water injection well 1 so as to discharge the groundwater Gw sucked up by the pumping pump 24 into the water injection well 1.

[0023] << ... The water injection well 1 includes a casing pipe 11 placed in a borehole H1 provided in the ground, and a strainer section 12 is provided in the casing pipe 11 at least in the height range where it contacts the permeable layer P1. The outer circumferential surface of the strainer section 12 is covered with packed gravel 13. Thus, when groundwater Gw pumped by the pumping well 2 is supplied into the casing pipe 11 from the outlet 251 of the pumping pipe 25, the water injection well 1 can inject the water into the permeable layer P1 through the strainer section 12 and packed gravel 13.

[0024] <<Well cleaning equipment>> 1, the casing pipe 11 is also provided with a submersible pump 14 and a drain pipe 15. The drain pipe 15 extends vertically within the casing pipe 11, with a drain outlet 151 at its upper end positioned outward from the upper end of the casing pipe 11 and its lower end connected to the submersible pump 14. The submersible pump 14 is positioned within the height range of the strainer section 12 (including its vicinity), and the submersible pump 14 and drain pipe 15 function as a cleaning device in the water injection well 1 by forcibly draining the strainer section 12 and filling gravel 13.

[0025] This procedure involves repeatedly operating the submersible pump 14 to pump the groundwater Gw in the casing pipe 11 and then stopping the operating submersible pump 14. This causes water to alternately flow in both directions inside and outside the casing pipe 11, making it possible to remove substances that cause clogging in the strainer section 12 and the filling gravel 13. At this time, the electromagnetic valve 16a installed in the drain pipe 15 is open, and the electromagnetic valve 16b installed in the water injection pipe 17 is closed. These electromagnetic valves 16a, 16b and the water injection pipe 17 will be described later.

[0026] <<Facilities for using groundwater as a water resource (emergency wells)>> The water injection well 1 having such a configuration is installed on the rear side of the earth retaining wall R, so even if a new structure is constructed in the excavation area S within the earth retaining wall R, it will not interfere with this new structure. Therefore, as shown in Figure 2, by leaving the submersible pump 14 and drainage pipe 15 used as cleaning equipment for the water injection well 1 in place without blocking them after construction is completed, it is possible to convert the well into an emergency disaster well, for example, even while the building is in use after construction work is completed.

[0027] For example, the drain outlet 151 provided at the upper end of the drain pipe 15 is positioned opposite the water storage facility 18, as shown in Figure 1. In this way, by operating the submersible pump 14, the groundwater Gw in the casing pipe 11 is drained into the water storage facility 18 via the drain pipe 15, and this groundwater Gw can be used as a water resource.

[0028] <<Equipment for convection of groundwater>> An electromagnetic valve 16a is attached to the drain pipe 15, and a water injection pipe 17 is provided upstream of the electromagnetic valve 16a, branching off from the drain pipe 15. The tip opening of the water injection pipe 17 is inserted near the upper end of the casing pipe 11, and an electromagnetic valve 16b is attached to the pipe.

[0029] 3, the solenoid valves 16 including the solenoid valves 16a and 16b are provided with a control panel 161 that controls them, and the control panel 161 is capable of transmitting data to and from a control server 30 on a computer system or cloud and an administrator terminal 40 via a communication network 20 such as the Internet or a dedicated communication line. In addition, the administrator terminal 40 is capable of communicating data with the control server 30 via the communication network 20.

[0030] This allows the site manager and facility manager to remotely control the opening of the electromagnetic valve 16a using the manager terminal 40, thereby adjusting the flow rate in the drain pipe 15. In other words, when the site manager and facility manager input adjustment information related to the flow rate into the manager terminal 40, the adjustment information is sent from the control server 30 to the control panel 161 via the communication network 20. The control panel 161 controls the opening of the electromagnetic valve 16 based on this adjustment information. This allows the flow rate in the drain pipe 15 to be remotely controlled so as not to exceed the normal pumping amount set by the government.

[0031] In addition to the above-described flow rate adjustment, by inputting information related to the opening and closing operation of the electromagnetic valve 16 into the administrator terminal 40, it is also possible to open and close the electromagnetic valves 16a and 16b, for example, by opening the drain outlet 151 side or the water injection pipe 17 side, in the same manner as described above. In this way, the site manager and facility manager can remotely operate the electromagnetic valve 16 by using the administrator terminal 40. Note that the administrator terminal 40 may be any device, such as a laptop computer, tablet terminal, or smartphone, as long as it is capable of data communication with the control server 30 via the communication network 20.

[0032] With regard to these electromagnetic valves 16, when the electromagnetic valve 16a of the drain pipe 15 is closed and the electromagnetic valve 16b of the water injection pipe 17 is open and the submersible pump 14 is operated, the groundwater Gw that has flowed into the drain pipe 15 is injected from the water injection pipe 17 into the vicinity of the upper end of the casing pipe 11. Then, as shown in Figure 2, convection from above to below occurs in the groundwater Gw that is stagnating inside the casing pipe 11.

[0033] This makes it possible to improve the heat exchange efficiency between the groundwater Gw stagnating in the casing pipe 11 of the water injection well 1 and the heat medium F circulating in the geothermal heat exchanger 42 inserted in the casing pipe 11. Next, an indirect circulation type geothermal heat utilization system 4 using the geothermal heat exchanger 42 inserted in the casing pipe 11 and a direct pumped-storage geothermal heat utilization system 3 using the drainage pipe 15 will be described.

[0034] <<Facilities for using groundwater as a heat resource>> <Direct pumped water use> As shown in Figures 2 and 3, the drainage pipe 15 attached to the water injection well 1 is equipped with a heat pump 31 installed in the pipeline just before the drain outlet 151, forming a direct pumped geothermal energy utilization system 3. The heat pump 31 is a device that exchanges heat with the groundwater Gw pumped through the drainage pipe 15, and makes the exchanged heat available for use in living environment facilities 8 such as air conditioning and heating, and hot water supply. This allows the heat of the groundwater Gw to be used as a thermal resource.

[0035] ≪Indirect circular use≫ A geothermal heat exchanger 42 is inserted into the casing pipe 11 of the water injection well 1, which is filled with groundwater Gw, and is arranged to surround the submersible pump 14 and drainage pipe 15. Together with a heat pump 41 installed above ground, this constitutes an indirect circulation geothermal heat utilization system 4. The heat pump 41 is installed above ground and is a device that exchanges heat with the heat medium F circulating within the geothermal heat exchanger 42, making the exchanged heat available for use in living environment facilities 8, such as air conditioning and heating, and hot water supply.

[0036] In other words, the water injection well 1 is equipped with a direct pumped-water geothermal energy utilization system 3 that exchanges heat with the groundwater Gw flowing down the drainage pipe 15, and an indirect circulating geothermal energy utilization system 4 that exchanges heat with a heat medium F that circulates within the geothermal heat exchanger 42 and has exchanged heat with the groundwater Gw.

[0037] ≪Ground heat exchanger≫ As shown in Figure 4(a), the geothermal heat exchanger 42 used in the indirect circulation geothermal heat utilization system 4 adopts a so-called branch pipe type and is equipped with multiple heat collection pipes 43 arranged in parallel and a connecting jig 44 provided at the lower end of the heat collection pipes 43.

[0038] The heat collection pipes 43 form a circulation flow path for the heat transfer medium F, which is a fluid such as water, antifreeze, or air. Any number of heat collection pipes 43 may be used, but here, as shown in the cross-sectional views of Figures 4(b) to (d), an example is given in which three heat collection pipes 43 are used. Of the three heat collection pipes 43, one is a return pipe 43a that returns the heat transfer medium F to the heat pump 41 located on the ground, and the other two are used as feed pipes 43b that send the heat transfer medium F from the heat pump 41 to the borehole H1. The lower ends of these pipes are connected together in a communicating state by a connecting jig 44.

[0039] The connecting jig 44 is a cone-shaped hollow body arranged so that it is convex downward, and the lower ends of the feed pipe 43b and the return pipe 43a are inserted through the flat surface of the cone (generally corresponding to the bottom surface). Therefore, the heat transfer medium F that flows down the two feed pipes 43b join together in the hollow part of the connecting jig 44 and then flows into the return pipe 43a. In this way, the heat transfer medium F exchanges heat with the groundwater Gw that fills the casing pipe 11 while circulating through the heat collection pipe 43 via the connecting jig 44.

[0040] It is known that the feed pipes 43b of the heat collection pipes 43 have a higher heat collection efficiency than the return pipes 43a. For this reason, by combining more feed pipes 43b than return pipes 43a, the flow rate of the return pipes 43a is increased, thereby improving the heat collection efficiency of the entire heat collection pipes 43.

[0041] 4(a), in the branch pipe type geothermal heat exchanger 42, a plurality of spacers 6 are installed at intervals of, for example, 1 to 2 m to maintain the distance between the return pipe 43a and the feed pipe 43b, thereby improving the heat extraction efficiency by keeping the distance between the return pipe 43a and the feed pipe 43b constant. In addition to these plurality of spacers 6, a centralizer 5 that positions the geothermal heat exchanger 42 approximately in the center of the casing pipe 11 and a weight member 7 that prevents the geothermal heat exchanger 42 from floating up are installed, and the geothermal heat exchanger 42 is installed inside the casing pipe 11.

[0042] This allows the submersible pump 14 to be positioned approximately in the center of the casing pipe 11 while maintaining an appropriate distance (not necessarily an even distance) between the return pipe 43a and the feed pipe 43b. Details of the centralizer 5 and spacer 6 will be explained below, but it is preferable to use rust-proofed metal material, stainless steel, or non-metallic material such as FRP (fiber reinforced plastic).

[0043] <<<Centralizer>> As shown in Figures 4(a) and (d), the centralizer 5 is a component that bundles the heat extraction pipes 43 and places them approximately in the center of the casing pipe 11, and is placed above the connecting jig 44. As shown in Figure 5(a), it comprises two semicircular divided pieces 51 and fasteners 53 such as bolts. When the two divided pieces 51 are joined via the fasteners 53, a doughnut-shaped disk is formed as shown in Figure 4(d). Its outer diameter is slightly smaller than the inner diameter of the casing pipe 11, and the inner diameter is large enough to accommodate three heat extraction pipes 43 and rod-shaped weight members 7.

[0044] 5(a) and 5(b), each divided piece 51 has a continuous rising portion 52 on its opposing surface, and a through hole is formed in this rising portion 52. Therefore, as shown in FIG. 5(b), the three heat extraction pipes 43 bundled around the weight member 7 are sandwiched between two divided pieces 51 and joined with fasteners 53 using the through holes in the opposing rising portions 52. In this way, the centralizer 5 is attached to the three heat extraction pipes 43 in a sandwiched manner. The rising portions 52 also function as protective members for the heat extraction pipes 43, and attaching the centralizer 5 prevents the heat extraction pipes 43 from being bent or damaged.

[0045] <<Spacer>> The spacer 6 comprises a drain pipe spacer 63 as shown in Figure 3(b), and a pump spacer 62 and a lower spacer 61 as shown in Figures 4(b) and (c), and also has the function of holding the submersible pump 14 and drain pipe 15 depending on the height position at which the underground heat exchanger 42 is installed.

[0046] <Lower spacer> As shown in Figure 4(c), the lower spacer 61 is a ring-shaped member that is arranged above the centralizer 5 and below the submersible pump 14, and on its outer periphery, clamping portions 611 that clamp the feed pipe 43b and the return pipe 43a are arranged at equal intervals in the circumferential direction, the number of which is equal to the number of heat collection pipes 43.

[0047] <Pump spacer> As shown in Figure 4(b), the pump section spacer 62 is a component that holds the submersible pump 14 in the center and holds the heat extraction pipes 43 at equal intervals around its outer periphery, and is equipped with a pair of half bands 621 that surround the submersible pump 14 from the outside.

[0048] The pair of half bands 621 are joined via fasteners 624 such as bolts, and are formed into a ring shape when attached to the outer circumferential surface of the submersible pump 14. Furthermore, clamping sections 622 that clamp the heat extraction pipe 43 at equally spaced positions are provided on the outer circumferential surface of the half band 621 via connecting members 623 when the half band 621 is in the ring shape. Furthermore, a protective cover 625 that protects the heat extraction pipe 43 is provided in a removable manner to prevent the heat extraction pipe 43 from coming into contact with the hole wall or the like when clamped by the clamping sections 622 and being damaged.

[0049] <Drainage pipe spacer> 3(b), the drain pipe spacer 63 has the same structure as the pump spacer 62, and includes a pair of half bands 631 and a fastener 634 that joins the half bands 631. The outer peripheral surface of the half bands 631 is also provided with a clamping portion 632 that clamps the heat extraction pipe 43, and a connecting member 633 that connects the half bands 631 and the clamping portion 632.

[0050] Both the pump section spacer 62 and the drain pipe section spacer 63 have clamping sections 622, 633 attached to half bands 631, 632 via connecting members 623, 633. By providing the connecting members 623, 633 in this way, it is possible to adjust the distance between adjacent heat collection pipes 43 and the distance between the heat collection pipe 43 and the submersible pump 14 or the drain pipe 15 by appropriately changing their lengths.

[0051] <<<How to install a geothermal heat exchanger and submersible pump>> The underground exchanger 42 fitted with the spacer 6 and centralizer 5, and the submersible pump 14 equipped with the drain pipe 15 are placed inside the casing pipe 11 in the following procedure. Any size is acceptable, but in the example shown in Figures 1 and 2, the casing pipe diameter is 400 mm, the submersible pump 14 outer diameter is 270 mm, the drain pipe diameter is 89 mm, and the heat collection pipe 43 diameter is 25 mm.

[0052] First, the heat collection pipe 43 is fitted with the centralizer 5 and lower spacer 61 and is then inserted stepwise into the casing pipe 11. Next, when it reaches a predetermined depth, the pump section spacer 62 and drainage pipe section spacer 63 are attached, and the heat collection pipe 43 is combined with the submersible pump 14 and drainage pipe 15. These are then inserted to a predetermined depth into the underground hole H1, and the submersible pump 14, drainage pipe 15 and underground exchanger 42 are installed in the casing pipe 11.

[0053] Alternatively, the centralizer 5 and lower spacer 61 can be attached to the heat collection pipe 43 above ground in advance, and the submersible pump 14 and drain pipe 15 can also be attached via the pump section spacer 62 and drain pipe section spacer 63. After combining the submersible pump 14 and drain pipe 15 with the underground exchanger 42 in this way, they can be inserted into the casing pipe 11 and installed at a predetermined depth.

[0054] In this way, the underground exchanger 42 and the submersible pump 14 equipped with the drain pipe 15 can be easily positioned and installed approximately in the center of the casing pipe 11 by using the spacer 6 and the centralizer 5, and both the pump section spacer 62 and the drain pipe section spacer 63 can be removed from the submersible pump 14 and the drain pipe 15 by removing the fasteners 624, 634. Therefore, if the submersible pump 14 malfunctions or requires inspection, the submersible pump 14 equipped with the drain pipe 15 can be pulled out from the casing pipe 11 together with the underground exchanger 42, and the pump section spacer 62 and the drain pipe section spacer 63 can be removed.

[0055] <<How to use a well>> Thus, the water injection well 1 equipped with the submersible pump 14 with the underground exchanger 42 and the drainage pipe 15 can be used as follows during and after the construction work is completed:

[0056] <<During construction period>> As shown in Figure 1, when groundwater Gw is discharged from pumping well 2 to water injection well 1 via pumping pipe 25, water injection well 1 can inject this groundwater Gw into permeable layer P1 via strainer 12 and packed gravel 13. In addition, by periodically cleaning the inside of the well using a submersible pump 14 equipped with drainage pipe 15 according to the procedure described above, clogging of strainer 12 and packed gravel 13 can be prevented. At this time, electromagnetic valve 16 is operated so that the drain outlet 151 side of drainage pipe 15 is open.

[0057] In addition, the heat obtained using the indirect circulating geothermal energy utilization system 4 can be used for living environment facilities 8 such as heating, cooling, and hot water in the construction office and work area. This makes it possible to enjoy the power and energy saving effects and CO2 emission reduction effects of using the geothermal energy utilization system even during the construction period.

[0058] <<After construction is completed>> After the underground construction work in the excavation area S is completed, the pumping well 2 is blocked, but as mentioned above, the water injection well 1 is located behind the retaining wall R and does not interfere with the new structures constructed in the excavation area S. Therefore, as shown in Figure 2, the submersible pump 14 and drainage pipe 15 are left in place along with the underground heat exchanger 42 without being blocked.

[0059] Since the casing pipe 11 of the water injection well 1 remains filled with groundwater Gw even after construction is complete, heat can be extracted from the groundwater Gw using the indirect circulation geothermal heat utilization system 4. Therefore, the heat obtained from the groundwater Gw can be used for living environment facilities 8, such as heating and cooling and hot water supply, in new structures constructed in the excavation area S or in buildings near the excavation area S.

[0060] At this time, the electromagnetic valve 16 is operated so that the water injection pipe 17 side of the drain pipe 15 is opened, and the submersible pump 14 is operated. In this way, the groundwater Gw in the casing pipe 11 is convected in the vertical direction as described above, improving the heat exchange efficiency between the heat medium F circulating in the underground heat exchanger 42 and the groundwater W.

[0061] Furthermore, while the submersible pump 14 is running, the electromagnetic valve 16 is periodically switched to open the outlet 151 side of the drain pipe 15, and the inside of the well is cleaned. This ensures that the water injection well 1 remains in a healthy state without clogging even after construction is complete. Therefore, in an emergency, the submersible pump 14 and drain pipe 15 are operated as pumping equipment, and the well can be used as an emergency disaster well.

[0062] The groundwater Gw pumped by the submersible pump 14 and the drain pipe 15 is supplied to the water storage facility 18 by operating the electromagnetic valve 16 so that the drain outlet 151 side of the drain pipe 15 is open. Therefore, the groundwater Gw supplied to the water storage facility 18 can be used as general purpose water or cooling water for generators for new structures constructed in the excavation area S or buildings near the excavation area S.

[0063] Furthermore, while the submersible pump 14 and drain pipe 15 are being used as pumping equipment, the direct pumping geothermal energy utilization system 3 using the drain pipe 15 and heat pump 31 is in operation. Therefore, the heat obtained from the groundwater Gw using this geothermal energy utilization system 3, together with the heat obtained by the indirect circulating geothermal energy utilization system 4, can be used for living environment facilities 8 such as heating and cooling and hot water supply in new structures constructed in the excavation area S or in buildings near the excavation area S.

[0064] In this way, by using the water injection well 1, it is possible to construct a direct pumped geothermal energy utilization system 3, an indirect circulating geothermal energy utilization system 4, and even an emergency disaster well, while omitting the process of drilling a hole in the ground, thereby making it possible to significantly reduce installation costs. Therefore, it is possible to maximize the economic effect of installing the geothermal energy utilization systems 3 and 4 and the emergency disaster well.

[0065] Furthermore, the water injection well 1 of the recharge method given as an example of a well for construction work often uses a large-diameter and long casing pipe 11 for the purpose of increasing water injection capacity, and for example, the diameter of the casing pipe 11 may be about 400 to 600 mm, and the pipe length may reach about 100 m. If the casing pipe 11 is long, then the heat extraction pipe 43 of the underground exchanger 42 placed inside it can also be made long, making it possible to improve heat exchange efficiency.

[0066] Furthermore, when a large-diameter casing pipe 11 is used, it is possible to increase the number of heat collection pipes 43. FIG. 6 shows an example in which the number of heat collection pipes 43 has been increased from three to four, but it is also possible to increase the number further depending on the diameter of the casing pipe 11. In this way, when the number of heat collection pipes 43 is increased from three to four, it is advisable to use one as a return pipe 43a and the remaining three as feed pipes 43b. Furthermore, as shown in FIGS. 6(a) to 6(c), the drain pipe spacer 63, the pump spacer 62, and the lower spacer 61 are provided with additional clamping portions 611, 622, and 632 that clamp the heat collection pipe 43, and as shown in FIG. 6(d), the centralizer 5 is attached in a manner in which it is clamped between the four heat collection pipes 43.

[0067] <<<Examples of using deep wells using the deep well construction method>>> In this embodiment, the water injection well 1 used in the recharge well construction method is used as an example, but the present invention is not limited to this. Any well for construction work installed on the earth retaining wall R or on the back side of the earth retaining wall R can be used, and for example, the pumping well 2 used in the deep well construction method can also be used.

[0068] Figure 7 shows an example of a pumping well 2 located behind the retaining wall R, in which a geothermal heat exchanger 42 is inserted into the casing pipe 21 and is arranged to surround the pumping pump 24 and the lifting pipe 25, and together with a heat pump 41 installed above ground, this constitutes an indirect circulation geothermal heat utilization system 4. In addition, a heat pump 31 is installed in the pipeline of the lifting pipe 25, forming a direct pumped geothermal heat utilization system 3.

[0069] An electromagnetic valve 26a is attached to the pumping pipe 25, and a water injection pipe 27 is provided upstream of the electromagnetic valve 26a, branching off from the pumping pipe 25. The tip opening of the water injection pipe 27 is inserted near the upper end of the casing pipe 21, and an electromagnetic valve 26b is attached to the pipe. The pumping well 2 thus equipped can be used as follows during and after construction is completed.

[0070] <<During construction period>> As shown in Figure 7, by pumping up groundwater Gw via the pumping pump 24 and the lifting pipe 25, the groundwater level G in the adjacent excavation area S across the retaining wall R is lowered. At this time, the electromagnetic valves 26, including the electromagnetic valve 26a of the lifting pipe 25 and the electromagnetic valve 26b on the water injection pipe 27 side, are operated so that the drain outlet 251 side of the lifting pipe 25 is open.

[0071] Furthermore, the groundwater Gw that flows into the pumping pipe 25 passes through the heat pump 31 on its way to the drain outlet 251, causing heat exchange and enabling the direct pumped water geothermal energy utilization system 3 that utilizes the pumping pipe 25 to function. Therefore, together with the indirect circulating geothermal energy utilization system 4 equipped with the geothermal heat exchanger 42, the heat obtained from the groundwater Gw can be used for living environment facilities 8 such as air conditioning, heating, and hot water in the construction office and work area.

[0072] <<After construction is completed>> After the underground construction work in the excavation area S is completed, as explained using the example of the water injection well 1, the pumping well 2 is not blocked off and the pumping pump 24 and pumping pipe 25 are left in place along with the geothermal heat exchanger 42. This allows the heat obtained from the groundwater Gw in the indirect circulation geothermal heat utilization system 4 to be used for living environment facilities 8 such as heating and cooling and hot water supply in new structures constructed in the excavation area S or in buildings near the excavation area S.

[0073] At this time, the electromagnetic valve 26 is operated to open the water injection pipe 27 side of the water lift pipe 25, and the water lift pump 24 is operated to convect the groundwater Gw in the casing pipe 21 in the vertical direction. Furthermore, while the water lift pump 24 is operating, the electromagnetic valve 26 is periodically switched to open the drain outlet 251 side of the water lift pipe 25, thereby cleaning the inside of the well. Then, in an emergency, the water lift pump 24 is operated to use the well as an emergency disaster well.

[0074] The pumped groundwater Gw is supplied to the water storage facility 28 by operating the electromagnetic valve 26 so that the drain outlet 251 side of the pumping pipe 25 is opened. Therefore, the groundwater Gw supplied to the water storage facility 28 can be used as general service water or cooling water for generators for new structures constructed in the excavation area S or buildings near the excavation area S.

[0075] The pumping well 2 shown in FIG. 8 has the same structure as the pumping well 2 shown in FIG. 7, except that it is installed inside the retaining wall R.

[0076] According to the present invention, construction wells such as water injection well 1 and pumping well 2 installed underground within or behind the retaining wall R can be used during construction as a direct pumped geothermal heat utilization system 3 or an indirect circulating geothermal heat utilization system 4. After construction is completed, the wells can also be converted into emergency disaster wells, making it possible to multi-function the construction wells.

[0077] The well of the present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the present invention.

[0078] For example, in this embodiment, only one branch pipe type underground heat exchanger 42 is provided, but if the diameter of the casing pipe 11 is large enough, a plurality of underground heat exchangers 42 may be provided.

[0079] Furthermore, the underground heat exchanger 42 is not limited to the branch pipe type, but any type may be used as long as it has a structure that is generally used in borehole-type underground heat utilization systems that use boreholes H, such as U-tube type heat collection pipes, and is capable of circulating heat medium F, and there is no restriction on the number of such pipes.

[0080] Furthermore, by using an underwater pump 14 with a slim outer diameter, such as a multi-stage pump, the spacing between the heat collection pipes 43 and between them and the underwater pump 14 can be properly ensured, improving thermal efficiency and also making it possible to increase the number of heat collection pipes 43. [Explanation of symbols]

[0081] 1. Water injection well 11 Casing pipe 12 Strainer section (water collection section) 13 Filler gravel 14 Submersible pump 15 Drain pipe 151 Drain 16 Solenoid valve 16a Solenoid valve (for drain pipe) 16b Solenoid valve (for water injection pipe) 161 Control Panel 17 Water injection pipe 18 Water storage facilities 2. Pumping wells 21 Casing pipe 22 Strainer section (water collection section) 23 Filler gravel 24 Water pump (submersible pump) 25. Water pumping pipe (drainage pipe) 251 Drain 26 Solenoid valve 26a Solenoid valve (for drain pipe) 26b Solenoid valve (for water injection pipe) 27 Water injection pipe 28 Water storage facilities 3 Geothermal energy utilization system (open loop) 31 Heat Pump 4. Geothermal energy utilization system (closed loop) 41 Heat Pump 42 Geothermal heat exchanger 43 Heat collection tube 43a Return pipe 43b Feed pipe 44 Connection jig 5 Centralizer 51 Split piece 52 rising part 53 Fasteners 6 spacers 61 Lower spacer 611 Clamping part 62 Pump spacer 621 Half Band 622 Clamping part 623 Connecting members 624 Fasteners 625 Protective Cover 63 Drain pipe spacer 631 Half Band 632 Clamping part 633 Connecting members 634 Fasteners 7 Weight member 8 Living environment facilities 20. Communication Networks 30 Control Server 40 Administrator terminal H1 underground hole H2 underground hole Gw Groundwater S Excavation area R retaining wall F Heat medium P1 Permeable layer P2 Permeable layer

Claims

1. A well for construction work used in underground construction involving ground excavation, a casing pipe provided with a water collection section for collecting groundwater; a submersible pump having a drain pipe disposed in the water collecting section within the casing pipe; a geothermal heat exchanger arranged to surround the submersible pump and having a plurality of heat collection pipes through which a heat medium circulates; A well characterized in that the casing pipe is installed underground within the wall or behind the retaining wall.

2. A well for construction work used in underground construction involving ground excavation, a casing pipe provided with a water collection section for collecting groundwater; a submersible pump having a drain pipe disposed within the height range of the water collecting section within the casing pipe; a geothermal heat exchanger arranged to surround the submersible pump and having a plurality of heat collection pipes through which a heat medium circulates; The casing pipe is installed inside the earth retaining wall or underground on the back side thereof, A well characterized in that the heat collection pipes are connected to the underwater pump via spacers that maintain the spacing between the heat collection pipes.

3. 3. The well according to claim 1 or 2, A water injection pipe branching from the drain pipe is installed in the drain pipe, A well characterized in that the open end of the water injection pipe is positioned at the upper end within the casing pipe.

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