JPS6293667A - Apparatus for measuring flow of ground water - Google Patents

Abstract

PURPOSE:To make it possible to directly measure the flow of ground water by photographing the same, by photographing the movement of the tracer discharged in flowing ground water with a TV camera. CONSTITUTION:A drop of a liquid dye is dripped from ground surface by utilizing a tracer discharge pipe 16. Whereupon, because a measuring chamber 14 is filled with a large number of glass beads, not only the diffusion of the liquid dye is suppressed but also the downward falling thereof is prevented and this liquid dye moves in an almost horizontal direction along with flowing ground water while slightly spreads in a flow direction from a dripped liquid droplet state. This state is photographed by a TV camera and the obtained image signal is transmitted to ground surface to be monitored or recorded by a video tape. At this time, because a transparent graduations plate 15 is also simultaneously photographed, the movement position of the dripped dye can be accurately recognized and the flow direction and velocity of ground water can be calculated on the basis of said position.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a device for directly observing and measuring the speed and direction of groundwater flow in a borehole, and more specifically, the present invention relates to a device for directly observing and measuring the velocity and direction of groundwater flow in a borehole, and more specifically, for monitoring the movement of a tracer released into flowing groundwater. This relates to a device that makes it possible to directly observe the flow of underground water by photographing it with a television camera.

[Prior Art] The most basic formula regarding groundwater flow is the following equation proposed by Darcy.

Groundwater flow velocity = Hydraulic gradient × Hydraulic coefficient The permeability coefficient of the ground was determined using the above method, and the constant values on both sides were applied to the above Darcy's law. In addition, groundwater flow direction surveys take advantage of the fact that fluid flows from the side with higher potential energy to the side with lower potential energy, and organize the observation results of underground wind height into contour lines on a plane. The flow direction of groundwater was defined as the direction from the ground to the low water level. Such groundwater flow measurement is a so-called indirect measurement method.

On the other hand, recently, in connection with pollution problems such as groundwater contamination, it has become necessary to accurately understand the minute flow conditions of groundwater. Several single-hole measuring devices have also been proposed for direct measurement.

For example, a sensor unit consisting of a disk with multiple electrodes arranged around it is lowered to the bottom of a hole, and a tracer liquid with a conductivity different from that of groundwater is used to replace the groundwater in the sensor unit, and the conductivity changes depending on the groundwater flow. Radioactivity can be measured using a conductivity method (potential difference measurement method) measurement device that measures the neutron concentration, and by using boron-containing water as a tracer, using boron's large neutron absorption cross section. There are measurement devices that use a radioisotope method (neutron counting method), which uses a device to measure temperature, and measurement devices that use a thermal diffusion method, which uses a thermometer to measure the diffusion of groundwater temperature by inserting a heat source into groundwater.

[Problems to be solved by the invention] The above-mentioned method for indirectly measuring groundwater flow is a porous method, so it requires a large number of wells or poling holes, which imposes a heavy economic burden, and also requires a lot of land in urban areas. Due to this, a large number of wells cannot be used, and surveys with sufficient accuracy are often not possible.

On the other hand, although each single-hole measuring device has its own characteristics, in general, the device configuration is complex and the measurement operation is often cumbersome, and it is difficult for those who are not experienced in measurement to judge and analyze the measured data.

For example, in the case of a conductivity-type measuring device, repeated measurements are not possible because the sensor part is filled with distilled water, and because the earth's magnetic field is used to detect direction, the flow direction may be distorted if there is a nearby magnetic field. Furthermore, since molecular diffusion occurs, measurement is difficult when the flow rate is slow (10''cs/sec or less).

Radioisotope measurement devices require knowledge of radioactivity and chemistry, and measurement devices that use a heat source have disadvantages such as convection of groundwater that occurs when the groundwater flow is very slow, reducing accuracy. There is.

The purpose of the present invention is to solve the above-mentioned drawbacks of the prior art, to provide extremely simple structure and easy measurement substitutes, as well as to provide highly accurate and highly reliable measurement results. The object of the present invention is to provide a single-hole groundwater flow measuring device that can be obtained.

[Means for solving the problems] The present invention, which can solve the above problems,
a cylindrical body into which a television camera is attached; a measurement chamber attached to the tip of the cylindrical body through which groundwater can freely flow; and a transparent scale plate partitioning between the space inside the cylinder and the measurement chamber; This is a single-hole groundwater flow measurement device that is equipped with a tracer release device that releases a tracer into the measurement chamber.

As the tracer release device, for example, a device that can drop a single drop of liquid dye at a predetermined timing, or a device that can release a minute solid having a specific gravity similar to that of groundwater at a predetermined timing is used.

When using a liquid dye as a tracer, for example, a measurement chamber surrounded by a strainer is filled with transparent granules such as glass beads, and the structure is such that groundwater can freely flow through the gaps between the granules. shall be. In another embodiment, the measurement chamber may be constructed of two plates placed with a slight gap between them, allowing groundwater to flow between them. In such cases, not only liquids but also solids can be used as tracers.

[Effect] The released tracer moves with the flow of groundwater.

Therefore, by observing the movement of the tracer over time using a television camera, it is possible to directly measure the flow state of groundwater, that is, the direction and velocity of the flow.

The transparent granules placed inside the measurement chamber and the two closely spaced plates that make up the measurement chamber suppress the diffusion of tracer droplets, prevent them from falling, and move the tracer horizontally and two-dimensionally. fulfill.

A transparent scale plate placed at the tip of the barrel to which the television camera is attached serves as a reference for reading the position of the tracer.

[Example] Fig. 1 is an explanatory diagram showing an embodiment of the groundwater flow measuring device according to the present invention, and Fig. 2 is an explanatory diagram showing a state in which a television camera is installed.

As is clear from these figures, this device includes a cylinder 12 into which the television camera 10 is mounted, a measurement chamber 14 attached to the tip of the cylinder, and a space within the cylinder and the measurement chamber 1.
4, and a tracer discharge tube 16.

The cylindrical body 12 for mounting the television camera is made of a transparent material, has a transparent scale plate 15 attached to the bottom, and is filled with fresh water to maintain good visibility.

The upper end of the cylindrical body 12 is connected to a reducing joint 20, and the upper end is connected to a boring rod 2 via a camp ring 22.
Connected to 4. Although not shown, TV camera 1
0 has a structure in which a lens is located at the center of the tip and multiple light sources are arranged around it. Code 26 is used for transmitting power for the light source and TV camera operation, as well as for transmitting photographed video signals. is installed between the ground and the ground. The tracer discharge pipe 16 is also installed along the boring rod 24, the reducing joint 20, etc., and its upper end reaches the ground surface, and its lower end passes through the center of the temporary transparent scale 15 and reaches the upper end of the measurement chamber 14. Open your mouth.

Now, the measurement chamber 14 is surrounded by a strainer 28 and partitioned by a bottom plate 30, and has a fine (for example, 1.5 mm diameter) inside.
The structure is filled with a large number of glass beads 32 (approximately 0 to 1.5 mm).

The method of using the device configured as described above is as follows. This device is inserted from the ground surface using a poling hole, etc., and installed at a specified depth where groundwater is flowing. At this time, since the reducing joint 20 that can be combined with the boring rod 24 is used, the present apparatus can be installed at a predetermined position using various materials used for excavation, etc. as they are. In this state, the groundwater in the hole freely flows through the strainer 28 and through the gaps between the crow beads 32. One drop of liquid dye is dropped from the earth's surface using the tracer discharge tube 16. Then, since the measurement chamber 14 is filled with a large number of glass beads as described above, the diffusion of the liquid dye is suppressed, and the downward descent is also prevented, causing the liquid dye to flow slightly from the droplet state. While expanding in the direction, it moves almost horizontally along with the flowing groundwater. This situation is photographed by a television camera 10, and the obtained video signal is transmitted to the earth's surface for monitoring or recording on videotape. Also, take a photo of the monitor if necessary. At this time,
Since the transparent scale plate 15 is also photographed at the same time, it is possible to accurately determine the position to which the dropped dye has moved, and thereby the flow direction and velocity of the groundwater can be determined.

With such a device, even when the groundwater flow velocity is very slow, it is possible to obtain sufficiently reliable measurement data by continuing measurements over a long period of time. Furthermore, by repeating the dripping of the tracer, it is possible to easily perform multiple observations.

As mentioned above, the measuring device is configured so that it can be connected to the boring rod using a reducing joint, so the device can be held stably and firmly without any load on the cord from the TV camera, etc. Furthermore, since the device can be installed at a predetermined location using materials used for normal polling operations, it is economical and easy to handle.

FIG. 3 is an explanatory diagram of main parts showing another embodiment of the present invention.

The cylindrical body 12 on which the television camera is mounted and its upper structure may be completely the same as in the embodiment shown in FIG. 2 above. Therefore, in order to simplify the explanation, corresponding parts are given the same reference numerals and the explanation thereof will be omitted.

In this embodiment, the transparent scale plate 15 serves as the measurement chamber 44.
and a bottom plate 46 arranged with a slight spacing (usually about 11 or less).

It is preferable to use a white plate as the bottom plate 46 in order to facilitate observation of the tracer. If the interval between the parts where groundwater flows is narrow in this way, the dripped tracer will be prevented from moving downward and will move along with the flow of groundwater flowing through the gap while maintaining the state of droplets, similar to the case of the previous example. It is possible to accurately determine the movement position of groundwater, and by observing it in relation to the elapsed time, it is possible to measure the flow of groundwater.

If the measurement chamber is structured as shown in FIG. 3, it becomes possible to use not only a liquid dye but also a solid having a specific gravity equivalent to that of groundwater as a tracer. In other words, if a solid tracer release means is provided at the lower central end of the transparent scale plate 15, the flow of groundwater can be determined by observing the movement of the solid. In this case, unlike droplets, it is not affected by molecular diffusion, so if the flow rate is extremely slow <
10-3cn+/sec) can also be measured.

[Effects of the Invention] As described above, the present invention detects the flow direction of groundwater or...
, j, a, so one r
Measurement can be carried out in the L well, the device has an extremely simple configuration, is easy to operate, and is highly economical.

In particular, the present invention can directly measure the flow of groundwater, thereby preventing errors in measurement or interpretation of the measurement results, making it possible to perform good measurements with extremely high reliability of data. .

Furthermore, it has an extremely excellent effect in that measurement can be performed even when the flow velocity is extremely slow.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the main part showing one embodiment of measured groundwater flow according to the present invention; Fig. 2 is an overall configuration diagram showing an example of its usage state; Fig. 3 is another embodiment of the present invention. It is an explanatory diagram of a main part showing an example. 10...TV camera, 12...Cylinder body, 14...
Measurement chamber, 15... Transparent scale plate, 16... Tracer discharge tube, 28... Strainer, 30... Bottom plate, 32
...Glass beads, 44...Measurement chamber, 46...Bottom plate. Patent Applicant: Oyoyo Geological Co., Ltd., Mr. Minoru Shigeru, Figure 1, Figure 3, Figure 2

Claims (1)

[Claims] 1. A cylindrical body into which a television camera is attached, a measurement chamber attached to the tip of the cylindrical body through which groundwater can freely flow, and a transparent scale plate that partitions the space inside the cylinder and the measurement chamber. and a tracer release device that releases a tracer into the inside of a measurement chamber.