JPS6283667A - Method for measuring flow speed of ground water - Google Patents

Abstract

PURPOSE:To make it possible to instantaneously measure water stream distribution at each depth, by a simple operation such that vibration generated by a ground water stream flowing through the outside of a boring hole and the periphery thereof is detected and detection output is operated to be converted to the speed of the ground water stream. CONSTITUTION:Vibration generated in the ground by a ground water stream 8 is transmitted to a vibration detector 2 through water in a boring hole 7. The detector 2 compares the kind or indivisual characteristic of vibration with reference output from a reference voltage generator 3 to perform correction. The detection output thereof is supplied to an operation means (computer) 4 and the signal operated by the computer programmed so as to satisfy the function relation of the speed of an output voltage water stream by a practical test is supplied to a recording apparatus 6. As a result, the speed of the ground water stream is measured with the elapse of time.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for measuring groundwater flow velocity by detecting vibrations caused by groundwater flow.

Conventional technology Conventional methods for measuring groundwater flow velocity include placing a propeller-type current meter in a borehole and measuring the water flow velocity directly;
There is a method of injecting a conductive substance such as salt into a borehole, diluting the salt water with flowing water, and calculating the groundwater flow rate a+rr from the resulting change in conductivity.

Problems to be Solved by the Invention The above-mentioned conventional method of measuring water flow velocity using a propeller-type current meter is effective when there is no hole maintenance pipe in the borehole because the water flow velocity directly rotates the propeller. When a pipe is inserted into a borehole, even if the storage pipe has many holes, the water flow velocity inside the pipe is significantly attenuated compared to the water flow velocity outside the pipe, and furthermore, the water flow diffuses inside the pipe after entering the pipe. Therefore, the water flow velocity inside and outside the pipe cannot be the same.

In addition, with the method of measuring changes in conductivity, if there is a water vein, the salt concentration will decrease, so it is possible to estimate the water flow, but the correlation between the conversion result to groundwater flow velocity and the true water flow velocity is poor. In many cases, the water velocity is unknown, making it impossible to obtain reliable water flow velocity values. Furthermore, it is difficult and labor-intensive to inject salt water into the borehole and manipulate it to make the salt concentration uniform within the borehole, and it is difficult to determine the change in salt concentration σ1 for a considerable period of time. There were disadvantages such as having to do
The present invention has been made to solve the above problems. Means for Solving the Problems The present invention installs a vibration detector (2) in the borehole (7) to detect vibrations caused by underground water flow. extracting the acoustic energy as an electrical output and inputting the output to the calculation means (4);
This is a method of measuring groundwater flow velocity by calculating the groundwater flow velocity, recording it in a recording device (6) as a time-lapse record as the water flow velocity in the underground, and simultaneously displaying it on a digital display device (5) so that it can be read directly.

Function The present invention provides a vibration detector (
2), convert the energy into electrical output and take it out, calculate the electrical output using the calculation means (4) programmed with a conversion function, convert it to water flow velocity and output it, and output it using the output recording device (6). Embodiment 0 Recording as time-lapse data and continuously measuring FIG. 1 is a schematic groove diagram of an embodiment of the present invention.

(2) in the figure is a vibration detector. This vibration detector (2) senses vibrations and acoustic vibration energy from the ultra-low frequency range to the ultra-audible range generated by the underground water flow (8), captures the energy as mechanical vibration, and further obtains an electrical output. . Although this conversion element uses a piezoelectric element, the same effect can be obtained using an electromagnetic conversion element. If the output of this vibration detector (2) is subjected to external electrical noise interference, it will cause an error in the measured value, so the calculation means ( 4). The insulated signal wire (1) is equipped with a length measuring tape because it is necessary to know the distance to the vibration detector (2) in the borehole that can be suspended from the ground surface.

This distance is indispensable for determining the position of groundwater veins from the ground surface and for creating 15 depth observation data of flow velocity.

Therefore, a length measurement tape measure is attached to the insulated signal wire (1) and it is hung down into the borehole, but it is also possible to attach length measurement marks to the outer sheath of the signal wire, for example every meter. Of course, it would be even better if the scale 0:0 could be printed directly on the 4th scale as shown in FIG. As mentioned above, underground water flow (
The underground vibrations generated by 8) are transmitted to the vibration detector (2) via the water in the borehole, and an electrical output that is related to the water flow velocity can be obtained. The relationship is determined through field tests, and the functional relationship between output voltage and water flow rate is specified.
Since the output of the vibration detector (2) varies depending on its type or individual characteristics, it is compared with the reference output output from the basic candy five-pressure generator (3) and corrected. It is a vibration detector (2
) is applied with a known vibration and the electrical output from the vibration detector (2) is compared with the reference output. It consists of a combi coater programmed to satisfy the relationship between The calculation output obtained by the calculation means (4) is outputted as an electric signal and is automatically recorded in the recording device (6), so that the groundwater flow velocity can be measured over time. At the same time, the analog output of the calculation result is converted into digital data and inputted to a numerical display device (5) using liquid crystal or light emitting diode, and the water flow velocity can be directly read from the numerical display.

Effects of the Invention The method for measuring groundwater flow according to the present invention has the above-described configuration.According to the present invention, an existing borehole (7) containing a hole storage pipe (J The vibration generated by the groundwater flow (8) flowing outside and around the borehole is detected by a vibration detector (2) suspended in the borehole, and the output is calculated and converted into water flow velocity. Since the measurement can be performed regardless of the movement of the water, the problem of the propeller method is solved, and the concentration can be made uniform using a method similar to the method of injecting salt into a hole and determining the water flow velocity from the change in conductivity caused by the water flow. There is no need to
Disadvantages such as the long time it takes to change the salt concentration are also eliminated.
It has the advantage of being able to instantly measure water flow distribution at each depth with simple operations. Further, according to the present invention, as mentioned above, it is extremely effective in the exploration of underground water veins, and measures to effectively remove groundwater and thereby prevent landslides can be implemented quickly, and conversely, it is also effective in the exploration of water veins for the utilization of water resources. It is.

[Brief explanation of drawings]

FIG. 1 is a functional diagram showing the configuration of the present invention, and FIG. 2 is an explanatory diagram showing an insulated signal wire with a length measurement scale. In the figure (1)...Insulated signal wire (2)...Vibration detector (3)...Reference voltage generator (4)...Calculating means/computer (5)...Digital display device ( 6)...Recording device (7)...Borehole (8)...Groundwater flow (9)...Ground surface ilG...Underground 0])...Borehole storage pipe αa...Insulated signal wire outer cover surface (1)...Length measurement scale

Claims (1)

[Claims] 1. A vibration detector (2) to which an insulated signal wire (1) is connected and a calculation means (4) are provided, and the vibration detector (2) is installed in a borehole (7). , the vibration detector output is calculated by means (
4) A groundwater flow velocity measuring method characterized by inputting the following. 2. The groundwater flow rate measuring method according to claim 1, wherein the outer cover surface (12) of the insulated signal wire (1) has a length measurement scale (13).