JPH0619366B2 - Groundwater flow measuring device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an apparatus for directly observing and measuring the velocity and direction of groundwater flow in a borehole, and more specifically, the movement of a tracer released into flowing groundwater. It relates to a device that enables direct observation of the flow of groundwater by taking a picture with a TV camera.

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

Groundwater flow velocity = hydraulic gradient × hydraulic conductivity In the conventional groundwater flow velocity survey, the groundwater level is observed using a number of wells or boreholes, and the hydraulic gradient (distance gradient of groundwater) is obtained, as well as boring, etc. The permeability coefficient of the ground was calculated by the method, and the constant values on both sides of the coefficient were applied to the above Darcy law. In addition, the groundwater flow direction survey uses the fact that the fluid flows from the higher potential energy to the lower potential energy, arranges the observation results of the groundwater level into contour lines on a plane, and is perpendicular to the contour lines and changes from the high water level to the low water level. The direction toward the groundwater was the groundwater flow direction. Such groundwater flow measurement is a so-called indirect measurement method.

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

For example, the sensor part consisting of a disk with multiple electrodes placed around it is lowered to the bottom of the hole, and the tracer liquid having a conductivity different from that of groundwater is used to replace the groundwater of the sensor part, and the conductivity changes due to the groundwater flow. Conductivity measurement (potentiometric measurement) measuring device and the large neutron absorption cross section of boron are used to measure the change in boron concentration due to groundwater flow using water containing boron as a tracer. There is a radioisotope type (neutron counting type) measuring device that measures with a measuring instrument, or a thermal diffusion measuring type measuring device that measures the diffusion of groundwater temperature with a thermometer by putting a heat source in groundwater.

[Problems to be Solved by the Invention] Since the indirect groundwater flow measuring method as described above requires a large number of wells or boring holes because it is a porous method, the economical burden is large, and the land is not used in urban areas. Because of this, many wells cannot be used, and it is often impossible to conduct surveys with sufficient accuracy.

On the other hand, the single-hole type measuring devices have their respective characteristics, but in general, the device configuration is generally complicated and the measuring operation is often complicated, and it is difficult for a person skilled in the measurement to judge and analyze the measured data.

For example, in the case of a conductivity type measuring device, since the sensor part is filled with distilled water, repeated measurement cannot be performed, and since the earth's magnetic field is used for direction detection, the flow direction may be distorted if there is a magnetic field in the periphery. Moreover, since molecular diffusion occurs, measurement is difficult when the flow velocity is slow (10 ⁻³ cm / sec or less).
Radioisotope type measurement equipment requires knowledge of radioactivity and chemical knowledge, and measurement equipment that uses a heat source has disadvantages such as groundwater convection when the groundwater flow is very slow and the accuracy decreases. There is.

The object of the present invention is to solve the above-mentioned drawbacks of the prior art, to obtain a measurement result with high measurement accuracy and extremely high reliability, in addition to having an extremely simple structure and easy measurement operation. It is to provide a single-hole type groundwater flow measuring device capable of performing the above.

[Means for Solving Problems] The present invention that can solve the above problems is
A tubular body in which a television camera is mounted, a measurement chamber attached to the tip of the tubular body, through which ground water can freely flow, and a transparent scale plate that partitions between the tubular body space and the measurement chamber. It is a single-hole type groundwater flow measuring device provided with a tracer discharging device that discharges a tracer to a certain position inside a measuring chamber.

As the tracer releasing device, for example, a device that can drop only one drop of a 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 a liquid dye is used as a tracer, for example, a measurement chamber surrounded by a strainer is filled with transparent granules such as glass beads, and ground water can flow freely through the gaps between the granules. And In another embodiment, the measurement chamber may be composed of two plates arranged with a slight gap therebetween, and the ground water may flow between them. In such a case, not only the liquid but also the solid can be used as the tracer.

[Operation] The released tracer moves with the flow of groundwater.
Therefore, if the movement of the tracer is observed with a television camera over time, the flow condition of groundwater, that is, the flow direction and the flow velocity can be directly measured.

The transparent granular material placed inside the measurement chamber and the two closely spaced plates that make up the measurement chamber prevent tracer droplets from diffusing and prevent them from falling, and the function of moving the tracer two-dimensionally in the horizontal direction Fulfill.

The transparent scale plate arranged at the tip of the cylindrical body on which the television camera is mounted serves as a reference for reading the position of the tracer.

[Embodiment] FIG. 1 is an explanatory view showing an embodiment of the groundwater flow measuring device according to the present invention, and FIG. 2 is an illustration showing a state in which a television camera is incorporated. As is clear from these figures, the present apparatus has a cylindrical body 12 in which the television camera 10 is mounted, a measurement chamber 14 mounted at the tip thereof,
A transparent scale plate 15 for partitioning the space inside the cylinder and the measurement chamber 14 and a tracer discharge pipe 16 are provided.

The television camera mounting cylinder 12 is made of a transparent material and has a transparent scale plate 15 attached to the bottom thereof, and the inside thereof is filled with fresh water so that a good field of view can be maintained.
The upper end of the cylindrical body 12 is connected to the reducing joint 20, and the upper end of the cylindrical body 12 is further connected to a boring rod 24 via a coupling 22.
Connected to. Although not shown, the TV camera 10
Is a structure in which a lens is located at the center of the tip and a plurality of light sources are arranged around the lens, and a code 26 is provided for transmitting power for operating the light source, TV camera, etc., and for transmitting captured video signals. It is provided between the ground surface. The tracer discharge pipe 16 is also arranged along the boring rod 24 and the reducing joint 20, etc., the upper end thereof reaches the surface of the earth, and the lower end thereof penetrates the center of the transparent scale plate 15 to measure the chamber 1.
Open at the upper end of 4.

The measuring chamber 14 is surrounded by a strainer 28 and is partitioned by a bottom plate 30. The measuring chamber 14 has a fine inside (for example, a diameter of 1.
It has a structure in which a large number of glass beads 32 (about 0 to 1.5 mm) are filled.

The method of using the device thus configured is as follows. This device is inserted from the surface of the earth using a boring hole 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 by using various materials used for excavation and the like as they are. In this state, the groundwater in the hole is strainer 28
It passes through and sew the gap between the crow beads 32 to freely flow. A drop of liquid dye is dripped from the surface of the earth using the tracer discharge pipe 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 movement is prevented, so that the flow direction of the dropped liquid droplets may be somewhat increased. It spreads horizontally and moves with the flowing groundwater almost horizontally. This state is photographed by the television camera 10, and the obtained video signal is transmitted to the ground surface for monitoring or storing on a video tape. If necessary, take a picture of the monitor. At this time, since the transparent scale plate 15 is also photographed at the same time, the moved position of the dropped pigment can be accurately grasped, and the flow direction and the flow velocity of the groundwater can be obtained accordingly.

With such a device, it is possible to obtain sufficiently reliable measurement data by continuing the measurement for a long time even when the groundwater flow velocity is very low. In addition, repeating the tracer dropping makes it possible to easily perform a large number of observations.

As described above, since the measuring device can be connected to the boring rod by using the reducing joint, the load of the device is not applied to the cord from the TV camera and the device can be stably and firmly held. In addition, since it is possible to install the device at a predetermined position with a material used for a normal boring operation, it is economical and easy to handle.

FIG. 3 is a main part explanatory view showing another embodiment of the present invention.
The cylindrical body 12 on which the television camera is mounted and the upper structure thereof may be exactly the same as in the case of the embodiment shown in FIG. Therefore, in order to simplify the description, corresponding parts are designated by the same reference numerals, and description thereof will be omitted.

In this embodiment, the transparent scale plate 15 is used as the measuring chamber 44.
And a bottom plate 46 arranged with a slight gap (usually about 1 mm or less). As the bottom plate 46, it is preferable to use a white plate to facilitate the observation of the tracer. In this way, when the interval of the portion where the groundwater flows is narrow, the tracer that dripped is prevented from moving downward and moves along with the flow of groundwater flowing through the gap while maintaining the state of droplets, so that it is the same as in the case of the above embodiment The groundwater flow can be measured by observing the movement position accurately and observing it in relation to the elapsed time.

With the structure of the measurement chamber as shown in FIG. 3, not only a liquid dye but also a solid having a specific gravity equivalent to groundwater can be used as the tracer. In other words, if a solid tracer discharge means is provided at the lower center of the transparent scale plate 15, the flow of groundwater can be obtained by observing the movement of the solid. In this case, unlike droplets, it is not affected by molecular diffusion, so that it is possible to measure even when the flow velocity is extremely slow (10 ⁻³ cm / sec or less).

[Effects of the Invention] Since the present invention is configured to determine the flow direction or flow velocity of groundwater by observing the movement of the tracer with the television camera as described above, measurement can be performed with a single well, and the device can be used. It has an extremely simple structure, is easy to operate, and has an economical advantage.

In the present invention, since the flow of groundwater can be directly photographed and measured, an error in measurement or an error in interpretation of the measurement result can be prevented, and the reliability of data is extremely high, and good measurement can be performed. In addition, it has a very excellent effect in that measurement is possible even when the flow velocity is very slow.

[Brief description of drawings]

FIG. 1 is an explanatory view of essential parts showing an embodiment of a groundwater flow measuring device according to the present invention, FIG. 2 is an overall constitutional view showing an example of its usage state, and FIG. 3 is another embodiment of the present invention. It is a principal part explanatory view shown. 10 ... TV camera, 12 ... Cylindrical body, 14 ... Measuring room, 15 ... Transparent scale plate, 16 ... Tracer discharge tube,
28 ... strainer, 30 ... bottom plate, 32 ... glass beads, 44 ... measuring chamber, 46 ... bottom plate.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Uesawa 4-2-6 Kudankita 4-chome, Chiyoda-ku, Tokyo Within Geological Co., Ltd. (72) Kohei Okumura 4-26-6 Kudankita, Chiyoda-ku, Tokyo No. Geotechnical Co., Ltd.

Claims (1)

[Claims] 1. A cylindrical body in which a television camera is mounted,
A measurement chamber attached to the tip of the cylinder, through which ground water can freely flow, a transparent scale plate that partitions the space inside the cylinder and the measurement chamber, and a tracer is discharged to a fixed position inside the measurement chamber. A groundwater flow measuring device comprising a tracer discharging device.