JPH0794728B2 - Water level control method in groundwater level lowering method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a water level control method in a groundwater level lowering method for underground excavation in civil engineering and construction work.

<Prior art> When performing underground excavation, if the groundwater level is high, groundwater may be ejected to the excavation part. Therefore, assuming such a situation, the groundwater level lowering method is adopted.

The following methods are used as the conventional groundwater level lowering method.

(1) Prepare a high-performance pump, attach a water volume adjusting valve to the pump outlet, adjust the discharge water volume to the desired water level, and attach a supervisor to manage it.

(2) The water level of the observation well and pumping well is detected using a float switch or a floatless switch, and the pump is operated directly from the detection result via the electromagnetic switch of the pump power circuit. Alternatively, the pump is operated by turning on and off the electromagnetic switch through the sequencer.
After all, an observer is attached and management is carried out.

<Problems to be Solved by the Invention> The above-described conventional method has the following problems.

(1) Due to continuous operation or initial installation (fixed control) operation, it is difficult to operate within the ideal water level.

(2) The set water level cannot be changed.

(3) It is difficult to find and assume the cause of failure because it depends on people for reliability of failure.

(4) It is difficult to understand changes in water level and operating conditions.

(5) It cannot be expanded to other works.

The present invention has been made to solve the above-mentioned problems, and its purpose is to enable automatic pump operation within an ideal water level, easily change the set water level, and determine the operating status. It is to provide a water level control method in the groundwater level lowering method that is easy to use and can be diverted to other works.

<Means for Solving the Problems> As shown in FIG. 1, the present invention provides a continuous water level detector such as a pore water pressure gauge 6 for constant command and a float for emergency command in an observation well 5 or a pumping well 1. A water level detection switch such as a pressure switch 7 is installed, and a detection signal from the continuous water level detector is input to a microcomputer 8, and the pump of each pumping well 1 is controlled by the microcomputer 8 so that the detected water level becomes a set water level. 2 is operated individually, and when the detected water level in the main observation well becomes higher than the set water level, each pumping well 1 will be operated according to the preset operation priority of the pumping well.
When the detected water level in the main observation well becomes lower than the set water level, the pump 2 of each pumping well 1 is stopped in sequence in the order opposite to the above-mentioned operation priority order to keep the water level constant. However, the plurality of pumps 2 are directly controlled to be turned on / off according to the command from the water level detection switch.

<Operation> By inputting the control water level and the control water level width to the microcomputer, it is possible to operate the pump automatically within the ideal water level and operate the pumps of each pumping well individually.
In addition, by sequentially operating and stopping the pumps of each pumping well according to the operation priority, it is possible to keep the groundwater level constant with the minimum number of pumping well pumps required and the minimum pumping volume. Furthermore, since the pumps are turned on and off sequentially, it is possible to reliably respond to changes in the water level when the water permeability is very large. Further, a sudden change in water level can be dealt with by a water level detection switch.

The set water level can be changed easily by changing the variables in the program.

The change status of the water level and the operation status can be displayed on the screen, and the situation judgment becomes easy.

The number of times the pump is operated can be displayed in a graph, and the number of times the electromagnetic switch of the pump is operated and the time can be managed.

If the pump operates according to the instructions from the computer, the amount of water that should flow can be calculated from the water level and the abnormality can be easily found.

It can be applied to other works by changing the numerical values on the program and hardware adjustments, and can also be used for analysis from the examination stage such as pumping test.

<Example> Hereinafter, the present invention will be described based on an illustrated example. This is an example of deep well operation in the method of lowering groundwater level, and this system, as shown in FIG.
N submersible pumps 2 installed in the pumping well 1, submersible pump starter board 3, M collection tanks 4, pore water pressure gauges 6 and floatless switches 7 arranged in N observation wells 5, personal computer 8 The power receiving equipment 9 is provided with an automatic switching device 10 and an emergency power supply 11 so that it can be automatically backed up in the event of a power failure, and the computer 8 is also provided with a backup power supply 12 for a short time, so that electricity can be cut off instantly. Secure the absence.

The personal computer 8, as shown in FIG.
U8a, CRT display 8b, keyboard 8c, storage device 8d is a commercially available personal computer to which the printer 13 and plotter 14 are connected, and the measurement module 15 and the external output board 16 are connected.

The pore water pressure gauge 6 is a water level gauge that detects the water pressure applied to the diaphragm by the strain gauge 6a, and is input to the computer via the measurement module 15 to be constantly instructed by the submersible pump 2. The floatless switch 7 is an on / off switch using an electrode rod and is connected to the submersible pump starter panel 3 (see FIG. 1) for emergency instructions. These sensors are installed in the observation well, but can also be installed in the pumping well.

As shown in FIGS. 2 and 4, the submersible pump 2 is operated by a power circuit electromagnetic switch 18 operated by a relay switch 17 of an external output board control circuit. Further, the electromagnetic switch 18 includes one that operates immediately depending on the capacity of the generator, and one that includes a timer and operates sequentially.

In the water collection tank 4, the flow rate is measured and the personal computer 8 outputs an alarm or the like.

In the system as described above, a rapid change in the water level is dealt with by operating the submersible pump 2 directly by the floatless switch 7, and the following computer control is always performed (Figs. 5 and 6). See figure). In addition, as shown in Fig. 4, the pore water pressure gauge 6 is installed at a total of 7 locations, of which the representative No. 2 is the main observation well.

(1) Start the program and set the control water level, control water level width, pump priority, pump sequential startup time, etc.

(2) If the water level of the main observation instrument No. 2 is lower than the set value, check the water levels of other observation wells individually, and operate the corresponding submersible pumps if the water level is high, and stop it if it is low.

(3) When the water level of the main observation well No. 2 is higher than the set value, the submersible pumps are operated sequentially according to the priority order (6 → 5 → 3 → 2 → 1 → 4), and each submersible pump is operated. Check the water level in No. 2 of the main observation well. If it is higher, run the next submersible pump. If it is lower, check (2) individually.

(4) When the water level drops due to sequential operation according to the priority of each submersible pump, and the water level of the main observation well No. 2 becomes low, the submersible pumps are sequentially stopped in the reverse order of priority and each submersible pump is stopped. Check the water level of the main observation well No. 2 every time, if the water level is low, stop the next submersible pump, and if it is high (2)
Individual check.

(5) Check the water level and flow rate in the water collection tank, and check (2) above.
Repeat (4).

In addition, this system can be applied to most of the work for water level management. In this case, through field tests such as pumping tests,
It is necessary to confirm input data, etc.

Further, the present system can be applied to jack control for the work of maintaining the horizontal state by using an inclinometer, potentiometer, etc. as a sensor when installing a pier or the like using a hydraulic jack. Further, it can be applied to work for automatically moving water in and out such as floating, posture control, and sinking of a large caisson.

<Effects of the Invention> As described above, according to the present invention, a continuous water level detector and a water level detection switch are installed in an observation well or a pumping well, and a pump for each pumping well is individually calculated by a computer based on a detection signal of the continuous water level detector. When the detected water level in the main observation well becomes higher than the set water level, the pumps of each pumping well are sequentially operated according to the preset operation priority of the pumping well, and the detected water level in the main observation well is higher than the set water level. When it becomes lower, the pumps of the respective pumping wells are sequentially stopped in the order opposite to the operation priority order, and the pumps are on / off controlled by the water level detection switch, so that the following effects are obtained.

(1) The automatic pump operation within the ideal water level is possible, and the groundwater level can be kept constant with the minimum required number of pumping well pumps and the minimum required pumping volume. Furthermore, since the pumps are sequentially turned on and off, it is possible to reliably respond to changes in the water level when the hydraulic conductivity is very large. In addition, it is possible to cope with a sudden change in water level by means of an emergency water level detection switch.

(2) The set water level can be easily changed.

(3) Change status of water level, operation status, etc. can be displayed, and the situation can be easily judged and the management is facilitated.

(4) Abnormalities such as pumps can be easily found.

(5) It can be easily applied to other works.

[Brief description of drawings]

FIG. 1 is an overall flow chart of the present invention, FIG. 2 and FIG. 3 are configuration diagrams showing hardware, functional block diagrams, FIG. 4 is a block diagram showing an example of a computer system, and FIG. Flowchart, FIG. 6 is a flowchart showing an example of pump operation control. 1 ... Pumping well, 2 ... Submersible pump, 3 ... Submersible pump starter panel, 4 ... Water collecting tank, 5 ... Observation well, 6 ... Pore pressure gauge, 7 ... Floatless switch, 8 ... Personal Computer, 9 ... Power receiving equipment, 10 ...
… Automatic switching device, 11 …… Emergency power supply, 12 …… Backup power supply.

Front page continued (72) Inventor Katsuji Ikezoe 4-51 Ota-cho, Naka-ku, Yokohama, Kanagawa Kashima Construction Co., Ltd., Yokohama Branch (72) Inventor Yoshitaka Ono, 6-1, Yokodai, Isogo-ku, Yokohama, Kanagawa No. Shoken Keizai Co., Ltd. (56) Reference JP-A-3-229978 (JP, A) JP-A-54-154113 (JP, A) JP-A-54-131305 (JP, A)

Claims (1)

[Claims] 1. A continuous water level detector for constant commands and a water level detection switch for emergency commands are installed in an observation well or a pumping well, and a detection signal from the continuous water level detector is input to a microcomputer. The pumps of each pumping well are individually operated by the computer so that the detected water level becomes the set water level, and when the detected water level in the main observation well becomes higher than the set water level, the When pumping well pumps are operated sequentially and the detected water level in the main observation well becomes lower than the set water level, the pumping well pumps are sequentially stopped in the order opposite to the above-mentioned priority order to maintain a constant water level. A water level control method in a groundwater level lowering method, wherein a plurality of pumps are directly turned on / off by a command from the water level detection switch.