JP4140733B2 - Recharge method, water injection control method and water injection control system - Google Patents

Description

  The present invention relates to a recharge method, a water injection control method thereof, and a water injection control system, and more particularly, to a technique for returning groundwater pumped up during excavation in a ground having a high groundwater level to the ground.

  When excavating the ground to construct an underground structure, if the groundwater level is high, countermeasures such as a groundwater level lowering method or a chemical injection method are implemented. The groundwater level lowering method is a method for stabilizing the ground by pumping water from the ground and lowering the groundwater level at the necessary construction site. This groundwater level lowering construction method is a reliable groundwater countermeasure construction method against the waterstop construction method such as the chemical solution injection construction method, and is therefore excellent in safety especially in the construction under the railway.

  By the way, if the groundwater pumped up by the groundwater level lowering method is discharged into the sewers and rivers as it is, it will cause damage such as subsidence of the surrounding ground and lowering of the water level of the wells. For this reason, a method of returning the pumped groundwater to the ground, that is, a recharge method is widely implemented.

FIG. 11 shows a conventional recharge method, in which a pumping well 21 is installed near a construction site 20 where excavation is performed, and a condensate well 22 is installed around the pumping well 21. Natural groundwater level L ₀ by pumping groundwater from pumping well 21 drops to L _1, it is possible to drill construction in construction sites. The groundwater pumped from the pumping well 21 is returned to the ground through natural water injection at a natural head pressure through the condensate well 22. In addition, in FIG. 11, the code | symbol 23 is a water-impermeable layer and 24 has shown the water-permeable layer.

  However, in this recharge method, clogging occurs in the pore wall and filter of the condensate well due to suspended suspended solids, bacteria, and dissolved iron oxides contained in the groundwater. For this reason, the return efficiency is deteriorated, and in some cases, it may be forced to drain into a sewer or a river.

For this reason, various methods for preventing clogging due to suspended matter have been proposed (see, for example, Patent Document 1). In addition, a method has been proposed in which groundwater that has been pumped is pressurized and returned to shut off the groundwater from the atmosphere and prevent oxidation of iron dissolved in the groundwater (see Patent Document 2).
JP-A-6-193041 JP 2002-256538 A

The present invention has been made based on the technical background as described above, and achieves the following object.
The purpose of the present invention is to eliminate the need for filtration facilities such as filters and screens in condensate wells where clogging is unavoidable, and to reliably return groundwater without draining even when the amount of pumped water is large The purpose is to provide.

  Another object of the present invention is to return almost all of the pumped-up groundwater to the ground while reducing the groundwater level at the required site such as excavation site while preventing the surrounding groundwater level environment from being affected. It aims at providing the water injection control method and control system which can implement | achieve the complete recharge construction method.

The present invention employs the following means in order to achieve the above object.
That is, the invention reduces the natural groundwater level of required site by pumping groundwater from pumping well, the recharge method to return the groundwater pumped by water injection into the ground through the recovery fluid well,
As the condensate well, a shallow portion condensate well in which the water injection portion is located in a shallow portion that causes the natural groundwater level above the impermeable layer, and a deep layer in which the water injection portion is located in a deep portion below the impermeable layer Set up a part condensate well,
In the recharge method, groundwater is returned by performing pressurized water injection at a low pressure from the shallow layer condensate well and at a high pressure from the deep layer condensate well.

  Here, the deep layer refers to a depth region in which, even if water is injected at a pressure significantly higher than the groundwater level, there is no influence such as reverse flow of groundwater to the ground surface or floating of the ground surface. For example, a depth region that is deeper than the impermeable layer and does not cause damage to the impermeable layer even when water is injected at a pressure significantly higher than the groundwater level, and as a result does not affect the ground surface. The shallow layer means a depth region other than the deep layer. Specifically, it is a depth region where water can be injected only at a pressure equivalent to or slightly higher than the natural groundwater level. The shallow part.

The present invention also includes a pumping well, a shallow condensate well where the water injection part is located in the shallow part, and a deep condensate well where the water injection part is located in the deep part, and pumps groundwater from the pumping well. In the recharge method of lowering the groundwater level of the required site by pressing the groundwater pumped up and returning the groundwater through the shallow condensate well and the deep condensate well,
Monitor whether the difference between the pumped amount and the total amount of water injected into the shallow condensate well and the deep condensate well and the groundwater level in the shallow layer are within the set range.
Based on this monitoring result, the water injection control method in the recharge method is characterized in that the water injection amount is changed mainly based on the water injection to the shallow condensate well and the water injection to the deep condensate well. is there.

  More specifically, when the difference between the pumped water amount and the total water injection amount is not within the set range, the water injection amount to the shallow condensate well is changed, and the groundwater is changed by the change in the water injection amount to the shallow condensate well. When the position reaches the upper and lower limit set values, the amount of water injected into the deep condensate well is changed.

  In addition, when the difference between the pumped amount and the total water injection amount is within the set range and the groundwater level is not within the set range, the amount of water injected into the shallow condensate well is changed, and the injection into the shallow condensate well is changed. When the difference between the pumped water amount and the total water injection amount reaches the upper and lower limit set values due to the change in the water amount, the water injection amount to the deep layer condensate well is changed.

The present invention further includes a pumping well, a shallow condensate well where the water injection part is located in the shallow part, and a deep condensate well where the water injection part is located in the deep part, and pumps groundwater from the pumping well. A water injection control system for carrying out a recharge method for reducing groundwater level at a required site and pressurizing pumped groundwater and returning groundwater through the shallow condensate well and deep condensate well,
A water receiving tank for receiving groundwater pumped from the pumping well;
A shallow layer return conduit and a deep layer return conduit for returning groundwater from the water receiving tank to the shallow portion condensate well and the deep portion condensate well, respectively.
A shallow layer pumping device and a deep layer pumping device, which are respectively provided in the shallow layer return conduit and the deep layer return conduit, and pressurize and return the groundwater;
A water amount difference detecting means for detecting a difference between the pumped amount and the total water injection amount to the shallow part condensate well and the deep part condensate well;
Groundwater level detection means for detecting the groundwater level in the shallow layer,
A control device for controlling each operation of the shallow layer pumping device and the deep layer pumping device based on the detection results of the water amount difference detecting means and the groundwater level detecting means. For the water injection control system.

More specifically, the control device includes:
Water amount difference determining means for determining whether or not the water amount difference is within a set range;
A groundwater level determination means for determining whether or not the groundwater level is within a set range;
And a pumping device control unit that controls each operation of the shallow layer pumping device and the deep layer pumping device based on the determination results of the water amount difference determination unit and the groundwater level determination unit.

  Further, when the water amount difference is not within a set range, the pumping device control means controls the operation of the shallow layer pumping device to change the amount of water injected into the shallow layer condensate well, and the shallow layer condensate well. When the groundwater level reaches the upper and lower limit set values due to the change in the amount of water injected into the water, the operation of the deep layer pumping device is controlled to change the amount of water injected into the deep layer condensate well.

  The pumping device control means controls the operation of the shallow layer pumping device when the water amount difference is within a set range and the groundwater level is not within the set range to control the amount of water injected into the shallow layer condensate well. And when the water amount difference reaches the upper and lower limit set values due to the change in the amount of water injected into the shallow layer condensate well, the amount of water injected into the deep layer condensate well is controlled by controlling the operation of the deep layer pumping device. To change.

  Moreover, the said water amount difference detection means consists of a water level sensor provided in the said water-receiving tank. The groundwater level detection means comprises a water level sensor provided in an observation well installed in a shallow layer. The shallow layer pumping device and the deep layer pumping device are variable speed pumps.

  The shallow layer return pipe and the deep layer return pipe are a common pipe connected to the water receiving tank, and a branch pipe branched from the common pipe and extending to the shallow layer condensate well and the deep layer condensate well. The shallow layer pumping device and the deep layer pumping device can adopt a configuration including a variable speed pump provided in the common pipe and an electromagnetic valve provided in each branch pipe. .

  According to the present invention, clogging can be prevented from occurring by pressurizing the pumped-up groundwater, thereby eliminating the need for filtration equipment such as filters and screens, washing pumps, and the like. Therefore, the pipe for the condensate well needs only a small diameter.

  The condensate well consists of a deep condensate well and a shallow condensate well, and groundwater is returned from the shallow condensate well to prevent a decrease in the groundwater level outside the area where the groundwater level should be lowered. When the amount is large, the groundwater can be reliably returned without draining by returning it from the deep condensate well.

  Further, according to the present invention, the difference between the pumped water amount and the total water injection amount and the groundwater level are monitored, and based on the monitoring results, the water injection amount to the shallow condensate well is first increased or decreased. Water injection control is performed to increase or decrease the amount of water injected into the deep condensate well when the treatment cannot cope. For this reason, it is possible to realize a complete recharge method in which almost all of the pumped-up groundwater is returned to the ground without greatly affecting the surrounding groundwater level environment.

  FIG. 1 is a cross-sectional view showing an embodiment of the present invention. It is the same as before that the pumping well 2 is installed at or near the construction site 1 where excavation is performed. In this invention, the condensate well consists of two types of condensate wells, a shallow layer condensate well 3a and a deep layer condensate well 3b.

  The shallow layer condensate well 3a is a condensate well in which the water injection part 4 is located in the shallow layer part, in this embodiment, the permeable layer 7 above the impermeable layer 5, and a plurality of condensate wells are installed around the construction site 1. . Moreover, the deep layer condensate well 3b is a condensate well in which the water injection part 4 is located in the deep layer part, in this embodiment, the water permeable layer 6 below the impermeable layer 5, and a plurality of condensate wells are installed around the construction site 1. .

By pumping groundwater from pumping wells 2, natural groundwater level L ₀ drops to L _1, allowing drilling in construction site 1. The groundwater pumped up is pressurized and injected into the ground at a low pressure from the water injection section 4 through the shallow condensate well 3a. The return of the groundwater from the shallow layer portion condensate fluid well 3a, the groundwater level in the region other than the construction site 1 is maintained at L _2, lowering of groundwater level is prevented. When the amount of pumped water is large, groundwater is pressurized and injected into the ground at a high pressure from the water injection section 4 through the deep condensate well 3b. By returning the groundwater from the deep condensate well 3b, the groundwater can be reliably returned to the ground without draining the groundwater.

  The injection of groundwater from the shallow part condensate well 3a and the deep part condensate well 3b is a pressurized water injection that causes splitting of the ground. This eliminates the need for filtration equipment such as filters and screens, cleaning pumps, etc., where clogging is unavoidable. Therefore, both the shallow layer condensate well 3a and the deep layer condensate well 3b can reduce the pipe diameter.

  The conventional clogging problem can be avoided by water injection under pressure. Here, if groundwater is returned only by the shallow condensate well 3a, since it is returned at a low pressure, the return amount per condensate well cannot be increased, and as a result, the number of condensate wells is reduced. I have to do more. On the contrary, when the groundwater is returned only by the deep condensate well 3b, the return amount can be increased because it is returned at a high pressure, but the groundwater level in the region other than the construction site 1 is lowered. Become. The present invention is a rational system that not only avoids the conventional clogging problem but also enables reliable return of groundwater while preventing a decrease in groundwater level in a region other than the construction site.

  FIG. 2 is a cross-sectional view showing details of the deep layer condensate well 3b. A casing pipe 10 is installed in the deep condensate well 3b, and a water injection pipe 12 having a strainer 11 at the tip is installed in the casing pipe 10. In order to prevent the reverse flow of the return water to be injected under pressure, a water stop material 13 is provided between the water injection pipe 12 and the hole wall above the strainer 11. The structure of the shallow layer condensate well 3a is substantially the same except that the installation depth is different.

  FIG. 3 is a functional block diagram showing an embodiment of the water injection control system according to the present invention. In the figure, a region A is a region where the groundwater level is lowered, for example, a region including the excavation site 1 of the ground under the track. In this region A, a plurality of pumping wells 2 are installed. Area B is an area around area A where it is not desired to lower the groundwater level L of the shallow layer. In this area B, a plurality of shallow layer condensate wells 3a that can control the groundwater level are installed. Is done. In addition, although the several deep layer condensate well 3b is installed in the area | region B, you may install in the area | regions other than the area | region B, since it hardly affects the groundwater level of a shallow layer part. A plurality of observation wells 50 for measuring the shallow groundwater level L are installed in or near the region B, and water level sensors 51 are provided in these observation wells 50. The measurement signal of the water level sensor 51 is input to the control device 60.

  Groundwater pumped up from the pumping well 2 is received by a receiving tank 53 through a pumping pipe 52. The water receiving tank 53 is connected with a shallow layer return conduit 54a and a deep layer return conduit 54b, respectively, and variable speed pumps 55a and 55b are provided in the return conduits 54a and 54b, respectively. The groundwater is pressurized by the variable speed pumps 55a and 55b, supplied to the shallow layer condensate well 3a and the deep layer condensate well 3b via the return pipes 54a and 54b, and pressurized and injected into the ground.

  The pumping pipe 52 is provided with a flow rate sensor 56 for detecting the pumping amount, and the measurement signal is input to the control device 60. The shallow layer return conduit 54a and the deep layer return conduit 54b are provided with flow sensors 57a and 57b for detecting the amount of water injection and pressure sensors 58a and 58b for detecting the water injection pressure (pump pressure), respectively. These measurement signals are input to the control device 60. The water receiving tank 53 is provided with a water tank water level sensor 59 for detecting the water level of the groundwater being received, and the measurement signal is input to the control device 60.

  The control device 60 includes water amount difference determination means 61, groundwater level determination means 62, and pumping device control means 63. The water amount difference determining means 61 is based on the measurement signal of the tank water level sensor 59 and the difference between the pumped water amount and the total water injection amount (the sum of the water injection amount to the shallow layer condensate well 3a and the water injection amount to the deep layer condensate well 3b). Is for determining whether or not is within the set range. Here, the set range is a range between the upper limit water level where the water level has risen above the basic water level and the lower limit water level, as shown in FIG. In FIG. 9, when the water volume difference is zero (pumped water amount = total water injection amount), the aquarium water level is at the basic water level, and when there is a water volume difference and the pumped water amount> total water injection amount, the water tank water level is at the upper water level side (+ side). ), And when the pumping amount <total water injection amount, the water level of the tank changes to the lower limit water level side (-side).

  The groundwater level determination means 62 is for determining whether or not the groundwater level is within the set range based on the measurement signal of the water level sensor 51 provided in the observation well 50. Here, the set range is a range between the upper limit water level in which the groundwater level has risen above the basic water level in a steady state and the lower limit water level that has fallen. The basic water level and the upper and lower limit water levels of the groundwater level are set in consideration of soil data and soil permeability.

  The pumping device control means 63 is for controlling the operation of the variable speed pumps 55a and 55b based on the determination results of the water amount difference determination means 61 and the groundwater level determination means 62. That is, when the water volume difference or the groundwater level is not within the respective setting ranges, a control signal is sent to the variable speed pumps 55a and 55b, and the number of revolutions is changed, so Change the amount of water.

  Next, the operation of the control system will be described with reference to the flowcharts shown in FIGS. As shown in FIG. 4, during the execution of the recharge method, the control device 60 determines whether or not the water tank water level is within the upper and lower limit setting range shown in FIG. 9 (step S1). If the aquarium water level is within the set range, the control device 60 determines whether or not the groundwater level is within the upper and lower limit set range (step S2). If the groundwater level is within the set range, it is determined whether the operation is continued (step S3). If the operation is continued, the process returns to step S1.

  Here, when it is determined in step S1 that the aquarium water level is not within the set range, the control device 60 determines whether the fluctuation of the aquarium water level is the upper limit side (+ side) or the lower limit side (− side) shown in FIG. (Step S4) If the upper limit side (+ side), that is, the pumping amount> the total water injection amount, a process of increasing the water injection amount is performed (step S5). Moreover, if the water tank level fluctuation is the lower limit side (− side), that is, the pumping amount <the total water injection amount, the water injection amount is reduced (step S6).

  FIG. 5 is a flowchart showing details of the water injection amount increasing process (step S5). As described above, the control device 60 executes this when the pumping amount> the total water injection amount and when the water tank level is determined to exceed the upper limit set water level. 9) (step S5-1), and if the warning water level is exceeded, an alarm is issued (step S5-2), and then the variable speed pump of the shallow return line 54a The rotation speed of 55a is increased, and the amount of water injected into the shallow layer condensate well 3a is increased (step S5-3). At that time, the control device 60 uses the measurement data of the flow rate sensor 56 provided in the pumping pipeline 52 and the measurement data of the flow rate sensors 57a and 57b provided in the shallow layer return pipeline 54a and the deep layer return pipeline 54b. The necessary increased water injection amount is processed, and the water injection amount to the shallow condensate well 3a is increased stepwise based on the required increased water injection amount data.

  This water injection amount increasing operation is performed while checking each measurement data of the pressure sensor 58a of the shallow layer return conduit 54a, the groundwater level sensor 51 of the observation well 50, and the water level sensor 59 of the water receiving tank 53 (step S5-4). , S5-5, S5-6). That is, the control device 60 determines that the water injection pressure (pump pressure) is within the upper limit set value in step S5-4, and if the groundwater level is determined to be within the upper limit set value in step S5-5, step S5. -6, gradually increase the amount of water injected into the shallow condensate well 3a until it is determined that the tank level has changed to the-side.

  Due to an increase in the amount of water injected to the shallow condensate well 3a, the controller 60 has reached the upper limit set value in step S5-4, or the groundwater level has reached the upper set value in step S5-5. If it judges that it has performed, the control apparatus 60 will increase the rotation speed of the variable speed pump 55b of the deep layer return pipeline 54b, and will increase the amount of water injection to the deep layer condensate well 3b (step S5-7).

This water injection amount increasing operation is performed while checking each measurement data of the pressure sensor 58b of the deep layer return conduit 54b and the water level sensor 59 of the water receiving tank 53 (steps S5-8, S5-9). That is, if the water injection pressure (pump pressure) is within the upper limit set value as a result of the determination in step S5-8, the control device 60 does not continue until it determines that the water tank water level has changed to the negative side in step S5-9. The amount of water injected into the partial condensate well 3b is increased stepwise.
.

  If the controller 60 determines that the water injection pressure (pump pressure) has reached the upper limit value in step S5-8 due to the increase in the amount of water injected into the deep condensate well 3b, an alarm is issued (step S5-10). In this case, it is difficult to return the total pumped amount, and a part of the pumped amount is discharged (step S5-11).

  FIG. 6 is a flowchart showing details of the water injection amount reduction process (step S6). As described above, the control device 60 executes this when the pumping amount is less than the total water injection amount and it is determined that the aquarium water level is lower than the lower limit set water level. 9) (step S6-1), and if it is below the warning water level, an alarm is issued (step S6-2), and then the variable speed pump of the shallow part return conduit 54a The rotational speed of 55a is reduced, and the amount of water injected into the shallow layer condensate well 3a is reduced (step S6-3). At that time, as in the case of the above-described increase in the water injection amount, the control device 60 calculates the necessary reduced water injection amount from the pumped water amount data and the total water injection amount data, and gradually reduces the amount of water injection based on the necessary reduced water injection amount data. Reduce the amount of water injected into the stratum condensate well 3a.

  This water injection amount reduction operation is performed while checking each measurement data of the ground water level sensor 51 of the observation well 50 and the water level sensor 59 of the water receiving tank 53 (steps S6-4 and S6-5). That is, when the control device 60 determines that the groundwater level is within the lower limit value in step S6-4, the control device 60 recovers the shallow layer until it determines that the water tank level has changed to the + side in step S6-5. The amount of water injected into the well 3a is decreased stepwise.

  If the control device 60 determines that the groundwater level has reached the lower limit value in step S6-4 due to a decrease in the amount of water injected into the shallow condensate well 3a, the control device 60 determines that the variable speed pump 55b in the deep layer return conduit 54b. And the amount of water injected into the deep condensate well 3b is reduced (step S6-6).

This water injection amount reduction operation is performed while checking the measurement data of the water level sensor 59 of the water receiving tank 53 of the deep layer return conduit 54b (step S6-7). That is, the controller 60 reduces the amount of water injected to the deep condensate well 3b in a stepwise manner until it is determined in step S6-7 that the water tank water level has changed to the + side.
.

  By the water injection amount increasing process (step S5) or the water injection amount decreasing process (step S6) as described above, the water level of the aquarium is maintained within the set range, and the water amount difference between the pumped water amount and the total water injection amount is maintained within the set range. Both the water injection volume increasing process and the water injection volume decreasing process are performed by increasing or decreasing the water injection volume to the shallow condensate well 3a while checking the groundwater level, and only when the increase / decrease process cannot cope with it. This is a process of increasing or decreasing the amount of water injected into 3b. For this reason, all the groundwater pumped up at the construction site is returned to the ground without any significant impact on the groundwater level environment around the construction site and without being discharged to the outside unless a special situation occurs. A complete recharge method can be realized.

  In the present invention, as described above, while checking the groundwater level, the water injection control to the shallow condensate well 3a is mainly performed, and the water injection control is performed according to the water injection control to the deep condensate well 3b. If maintained within the set range, it is normally considered that the groundwater level is maintained within a range that does not reach the warning water level even if the groundwater level is outside the set range or set range. However, even if the aquarium water level is maintained within the set range, it is not impossible for the groundwater level to change unexpectedly in the area around the construction site due to changes in the groundwater flow. Therefore, in the present invention, even in such a case, processing for maintaining the groundwater level within the set range is performed.

  That is, in the flowchart shown in FIG. 4, even if it is determined in step S1 that the aquarium water level is within the set range, as described above, the control device 60 determines whether the groundwater level is in the set range in step S2. Judging. As a result, if it is determined that the groundwater level is not within the set range, the control device 60 determines whether the fluctuation of the groundwater level is the upper limit side (+ side) or the lower limit side (− side) (step S7). If it is (-side), the process which increases the amount of water injection will be performed (step S8). Moreover, if the fluctuation | variation of a groundwater level is an upper limit side (+ side), the process which reduces the amount of water injection will be performed (step S9).

  FIG. 7 is a flowchart showing details of the water injection amount increasing process (step S8). As described above, the control device 60 executes this when the groundwater level is determined to be below the lower limit set water level, and first checks whether the groundwater level is within the lower warning water level (step S8-1) If the alert water level is below the alert water level (step S8-2), the rotational speed of the variable speed pump 55a in the shallow layer return conduit 54a is increased, and the shallow layer condensate well 3a The amount of water injected into the water is increased (step S8-3). At that time, the control device 60 calculates the required increased water injection amount from the relationship of the water injection amount with respect to the fluctuation amount of the groundwater level set in advance, and step by step based on the required increased water injection amount data to the shallow condensate well 3a. Increase water injection volume.

  This water injection amount increasing operation is performed while checking each measurement data of the pressure sensor 58a of the shallow layer return conduit 54a, the water level sensor 59 of the water receiving tank 53, and the groundwater level sensor 51 of the observation well 50 (step S8-4). , S8-5, S8-6). That is, the control device 60 issues an alarm when it is determined in step S8-4 that the water injection pressure (pump pressure) is not within the upper limit set value (step S8-7). If the tank water level is within the lower limit in step S8-5, the amount of water injected into the shallow condensate well 3a is stepwise until it is determined in step S8-6 that the groundwater level has changed to the + side. increase.

  When the controller 60 determines that the water tank level has reached the lower limit in step S8-5 due to an increase in the amount of water injected into the shallow condensate well 3a, the controller 60 adjusts the variable speed pump 55b of the deep section return conduit 54b. , And the amount of water injected into the deep condensate well 3b is decreased (step S8-8). This water injection amount reduction operation is performed while checking the measurement data of the water level sensor 59 of the water receiving tank 53 (step S8-9), and the control device 60 changes the water level of the water tank to the + side as a result of the determination in step S8-9. Until it is determined that the water has been injected, the amount of water injected into the deep condensate well 3b is reduced stepwise.

  If it is determined in step S8-9 that the water level of the tank has changed to the + side due to a decrease in the amount of water injected into the deep condensate well 3b, the amount of water injected into the shallow condensate well 3a within the set range of the aquarium water level Will be possible again. Therefore, the control device 60 returns to step S8-6 to check whether or not the groundwater level has changed to the + side, and if it has not changed, the amount of water injected into the shallow condensate well 3a is increased again (step). S8-3).

  FIG. 8 is a flowchart showing details of the water injection amount reduction process (step S9). As described above, the control device 60 executes this when the groundwater level is determined to exceed the upper limit set water level. First, it is checked whether the groundwater level is within the upper warning water level (step S9-1) If the warning water level is exceeded, an alarm is issued (step S9-2), and the rotational speed of the variable speed pump 55a of the shallow layer return conduit 54a is decreased, and the shallow layer condensate well 3a The amount of water injected into the water is reduced (step S9-3). At that time, the control device 60 calculates the required reduced water injection amount from the relationship of the water injection amount to the preset groundwater level fluctuation amount, and calculates the water injection amount to the shallow condensate well 3a based on the necessary reduced water injection amount data. Decrease in steps.

  This water injection amount reduction operation is performed while checking each measurement data of the water level sensor 59 of the water receiving tank 53 and the groundwater level sensor 51 of the observation well 50 (steps S9-4 and S9-5). That is, if the water tank level is within the upper limit value in step S9-4, the control device 60 will note to the shallow condensate well 3a until it is determined in step S9-5 that the groundwater level has changed to the-side. Reduce the amount of water step by step.

  When the controller 60 determines that the water level in the aquarium has reached the upper limit value in step S9-4 due to a decrease in the amount of water injected into the shallow condensate well 3a, the controller 60 determines the variable speed pump 55b of the deep layer return conduit 54b. Is increased to increase the amount of water injected into the deep condensate well 3b (step S9-6). This water injection amount increasing operation is performed while checking each measurement data of the pressure sensor 58b of the deep layer return conduit 54b and the water level sensor 59 of the water receiving tank 53 (steps S9-7, S9-8). That is, if the water injection pressure (pump pressure) is within the upper limit set value as a result of the determination in step S9-7, the control device 60 will continue until it determines in step S9-8 that the aquarium water level has changed to the-side. The amount of water injected into the partial condensate well 3b is increased stepwise.

  If the controller 60 determines that the water injection pressure (pump pressure) has reached the upper limit value in step S9-7 due to the increase in the amount of water injected into the deep condensate well 3b, an alarm is issued (step S9-9). In this case, depending on an increase in the amount of water injected into the deep condensate well 3b, it is difficult to reduce the amount of water injected into the shallow condensate well 3a while maintaining the tank level within the set range. Part is discharged (step S9-10).

  If it is determined in step S9-8 that the aquarium water level has changed to the-side due to an increase in the amount of water injected into the deep condensate well 3b, a decrease in the amount of water injected into the shallow condensate well 3a within the setting range of the aquarium water level Will be possible again. Therefore, the control device 60 returns to step S9-5 to check whether or not the groundwater level has changed to the-side, and if not, again reduces the amount of water injected into the shallow layer condensate well 3a (step S9-5). S9-3).

  By the water injection amount increasing process (step S8) or the water injection amount decreasing process (step S9) as described above, the groundwater level changes due to changes in the groundwater flow while the difference between the pumped water amount and the total water injection amount is within the set range. Even if it occurs, the groundwater level can be maintained within the set range.

  FIG. 10 is a functional block diagram showing another embodiment of the control system. In this embodiment, the return pipe for returning groundwater from the water receiving tank 53 to the shallow part condensate well 3 a and the deep part condensate well 3 b branches from the common pipe 64 connected to the water receiving tank 53 and the common pipe 64. It consists of branch pipes 64a and 64b. A variable speed pump 65 is provided in the common pipe 64, and electromagnetic valves 66a and 66b are provided in the branch pipes 64a and 64b, respectively.

  Accordingly, the shallow layer pumping device is constituted by the variable speed pump 65 and the electromagnetic valve 66a provided in the shallow layer returning conduits 64 and 64a, and the deep layer pumping device is provided in the deep layer returning conduits 64 and 64b. The variable speed pump 65 and the electromagnetic valve 66b. In the case of this embodiment, the operation of increasing or decreasing the amount of water injected into the shallow condensate well 3a and the deep condensate well 3b is performed by changing the rotational speed of the variable speed pump 65 and the opening degree of the electromagnetic valves 66a and 66b. Is called.

  The above embodiments are merely examples, and the present invention can take various forms. For example, in the embodiment of the control system described above, the water amount difference between the pumped water amount and the total water injection amount is detected by the measurement data obtained from the water level sensor 59 provided in the water receiving tank 53, but the present invention is not limited to this. That is, the amount of pumped water and the total amount of water injected from the measurement data of the flow rate sensor 56 provided in the pumping pipe 52, the flow rate sensors 57a and 57b provided in the shallow layer return pipe 54a and the deep layer return pipe 54b, respectively. It is also possible to adopt a configuration in which the difference is calculated and used as a detected water amount difference.

It is sectional drawing which shows embodiment of the recharge construction method by this invention. It is sectional drawing which shows the detail of a deep layer condensate well. It is a functional block diagram showing an embodiment of a water injection control system. It is a flowchart for demonstrating operation | movement of a control apparatus. It is a flowchart for demonstrating the water injection amount increase process when a water tank water level fluctuates. It is a flowchart for demonstrating the water injection amount reduction process when an aquarium water level fluctuates. It is a flowchart for demonstrating the water injection amount increase process when a groundwater level fluctuates. It is a flowchart for demonstrating the water injection amount reduction process when a groundwater level fluctuates. It is a figure which shows the setting range of an aquarium water level It is a figure which shows another embodiment of a water injection control system. It is sectional drawing which shows a conventional construction method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Construction site 2 Pumping well 3a Shallow part condensate well 3b Deep part condensate well 4 Injection part 5 Impervious layer 6 Permeable layer 7 Permeable layer 10 Casing pipe 11 Strainer 12 Injection pipe 13 Water stop material 50 Observation well 51 Groundwater level sensor 52 Pumping pipe 53 Water receiving tank 54a Shallow layer return pipe 54b Deep layer return pipe 55a, 55b Variable speed pump 56 Flow rate sensor 57a, 57b Flow rate sensor 58a, 58b Pressure sensor 59 Aquarium water level sensor 60 Controller 61 Water difference judgment means 62 Groundwater level judgment means 63 Pumping device control means 64 Common pipes 64a, 64b Branch pipes 65 Variable speed pumps 66a, 66b Solenoid valve A Area where the groundwater level is lowered B Area where the groundwater level is not desired to be lowered

Claims (12)

Lowering the natural groundwater level of required site by pumping groundwater from pumping well, the recharge method to return the groundwater pumped by water injection into the ground through the recovery fluid well,
As the condensate well, a shallow portion condensate well in which the water injection portion is located in a shallow portion that causes the natural groundwater level above the impermeable layer, and a deep layer in which the water injection portion is located in a deep portion below the impermeable layer Set up a part condensate well,
A recharge method for returning groundwater by performing pressurized water injection at a low pressure from the shallow condensate well and at a high pressure from the deep condensate well. Groundwater at the required site by installing a pumping well, a shallow condensate well where the water injection part is located in the shallow part, and a deep condensate well where the water injection part is located in the deep part, and pumping groundwater from the pumping well In the recharging method of lowering the position, pressurizing the groundwater pumped up and returning the groundwater through the shallow condensate well and the deep condensate well,
Monitor whether the difference between the pumped amount and the total amount of water injected into the shallow condensate well and the deep condensate well and the groundwater level in the shallow layer are within the set range.
A water injection control method in the recharge method, characterized in that, based on this monitoring result, water injection into the shallow layer condensate well is mainly performed, and water injection amount is changed according to water injection into the deep layer condensate well. When the difference between the pumped water volume and the total water injection volume is not within the set range, change the water injection volume to the shallow condensate well,
The recharge method according to claim 2, wherein when the groundwater level reaches an upper and lower limit set value due to a change in the amount of water injected into the shallow condensate well, the amount of water injected into the deep condensate well is changed. Water injection control method. When the difference between the pumped water amount and the total water injection amount is within the set range, and the groundwater level is not within the set range, the water injection amount to the shallow condensate well is changed,
When the difference between the pumped water amount and the total water injection amount reaches an upper and lower limit set value due to a change in the water injection amount to the shallow layer condensate well, the water injection amount to the deep layer condensate well is changed. A water injection control method in the recharge method according to claim 2. Groundwater at the required site by installing a pumping well, a shallow condensate well where the water injection part is located in the shallow part, and a deep condensate well where the water injection part is located in the deep part, and pumping groundwater from the pumping well A water injection control system for carrying out a recharge method for reducing ground pressure and pressurizing the pumped-up groundwater and returning groundwater through the shallow condensate well and the deep condensate well,
A water receiving tank for receiving groundwater pumped from the pumping well;
A shallow layer return conduit and a deep layer return conduit for returning groundwater from the water receiving tank to the shallow portion condensate well and the deep portion condensate well, respectively.
A shallow layer pumping device and a deep layer pumping device, which are respectively provided in the shallow layer return conduit and the deep layer return conduit, and pressurize and return the groundwater;
A water amount difference detecting means for detecting a difference between the pumped amount and the total water injection amount to the shallow part condensate well and the deep part condensate well;
Groundwater level detection means for detecting the groundwater level in the shallow layer,
A control device for controlling each operation of the shallow layer pumping device and the deep layer pumping device based on the detection results of the water amount difference detecting means and the groundwater level detecting means. Water injection control system for. The controller is
Water amount difference determining means for determining whether or not the water amount difference is within a set range;
A groundwater level determination means for determining whether or not the groundwater level is within a set range;
6. A pumping device control unit that controls each operation of the shallow layer pumping device and the deep layer pumping device based on the determination results of the water amount difference determination unit and the groundwater level determination unit. Water injection control system for implementation of the recharge method described.   When the water amount difference is not within a set range, the pumping device control means controls the operation of the shallow layer pumping device to change the amount of water injected into the shallow layer condensate well, and to the shallow layer condensate well. The amount of water injection to the deep layer condensate is changed by controlling the operation of the deep layer pumping device when the groundwater level reaches an upper and lower limit set value due to a change in water injection amount. Water injection control system for the implementation of the recharge method.   When the water amount difference is within a set range and the groundwater level is not within the set range, the pumping device control means controls the operation of the shallow layer pumping device to change the water injection amount to the shallow layer condensate well. When the difference in water amount reaches the upper and lower limit set values due to changes in the amount of water injected into the shallow section condensate well, the operation of the deep section pumping device is controlled to change the amount of water injected into the deep section condensate well. The water injection control system for carrying out the recharge method according to claim 6.   The water injection control system for carrying out the recharge method according to any one of claims 5 to 8, wherein the water amount difference detecting means comprises a water level sensor provided in the water receiving tank.   The water injection control system for carrying out a recharge method according to any one of claims 5 to 8, wherein the groundwater level detection means comprises a water level sensor provided in an observation well installed in a shallow layer.   The water injection control system for carrying out a recharge method according to any one of claims 5 to 8, wherein the shallow layer pumping device and the deep layer pumping device comprise variable speed pumps. The shallow layer return pipe and the deep layer return pipe are a common pipe connected to the water receiving tank, and a branch pipe branched from the common pipe and extending to the shallow layer condensate well and the deep layer condensate well. And consists of
The shallow layer pumping device and the deep layer pumping device are each composed of a variable speed pump provided in the common pipe and an electromagnetic valve provided in each branch pipe. A water injection control system for carrying out the recharge method according to any one of the above.

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