JPH08233745A - Abnormality detector of casing pipe for clinometer - Google Patents

Abstract

PURPOSE: To detect the torsion of a casing pipe for clinometer buried in the ground easily and correctly by observing a magnetic compass fixed in front of the forward end of a tubular probe case movable in the casing pipe by means of a TV camera. CONSTITUTION: A tubular probe case 20 is inserted into the casing pipe 10 for clinometer with the wheels 18 of the probe case 20 being fitted in the guide grooves 12 of the casing pipe 10. The case 20 descends while following the torsional state of the pipe 10 and changing the orientation thereof. A magnetic compass 22 fixed in front of the forward end of the case 20 has a pointer constantly pointing the orientation of geomagnetism and the compass 22 is observed by means of a TV camera 28 while illuminating the inside of the pipe 10 by means of a LED 26. With such arrangement, orientation of the case 20 and thereby the torsional angle of the pipe 10 can be detected surely and the error of measurement caused by torsion of the pipe 10 can be corrected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting an irregularity (in particular, a twist) of a casing pipe for an inclinometer which is buried in the ground. More specifically, it is a cylinder moving in the casing pipe for an inclinometer. The present invention relates to a device for detecting a twist of a casing pipe for an inclinometer by arranging a magnetic compass in front of the tip of the probe case and observing the magnetic compass with a television camera.

[0002]

2. Description of the Related Art Insertion-type in-hole inclinometers are conventionally known as a device for highly accurately measuring the amount of horizontal movement over time in the ground. This device installs the inclinometer casing pipe in the ground, inserts the inclinometer probe into it, and measures the inclination of the inclinometer probe (inclination of the casing pipe) at every predetermined depth. The horizontal displacement of the ground can be calculated by using the hole bottom as a fixed point. On the inner surface of the inclinometer casing pipe, a plurality of guide grooves extending along the axial direction are formed, while on the other hand,
The inclinometer probe is provided with a wheel, and the wheel is fitted into the guide groove to be guided so that the casing pipe and the inclinometer probe are always in the same direction.

Such an insertion type inclinometer is used, for example, in landslide investigation to detect the position of the slip surface and to measure the amount of displacement of the landslide in the ground, and to elucidate the landslide mechanism and design and construction of countermeasure works. It greatly contributes to management and confirmation of effects. However, when it came to be used in many landslides, some cases were also reported in which good measurement results were not always obtained. One of the reasons why good measurement results cannot be obtained is the problem of the inclinometer casing pipe, which is inserted into the boring hole and filled with liquefied grouting material on the outside to solidify the casing. Since the pipe is fixed to the ground, it is impossible to directly check the installation condition.

If, for example, a "twist" is present in the casing pipe, the twist causes a certain error in the measured values. When the tilts in the two directions are measured and the angle with the direction of the maximum tilt is obtained, no error occurs in the angle, but in the direction, the amount of twist is an error. When the direction of the inclination is specified, and the direction of the guide groove of the casing pipe is aligned with that direction for measurement, an error occurs due to the twist of the casing pipe. According to the calculation results, the relationship between the twist of the casing pipe and the error caused by it is a few percent error up to a twist angle of about 15 degrees, but the error increases sharply as the angle increases. It was found that the degree was about 13%, and the degree was about 30% at 45 degrees.

The error due to the twist of the casing pipe can be corrected if the degree of twist is known. Therefore, it is strongly desired to develop a technique for detecting the twist of the inclinometer casing pipe. For detecting the twist of the casing pipe, connect the rod, not the cable, to the inclinometer probe (only the probe case that does not have the inclinometer sensor built in) and insert the inclinometer probe into the casing pipe while adding the rod. There is a method of detecting the twist from the rotation of the rod on the ground surface.

[0006]

This method has the drawback of not being complicated in the work of inserting a large number of rods while replenishing them, but also not being able to detect an accurate twist when the joints of the rods are loosened. Further, as the casing pipe becomes longer, the work becomes more difficult, and even if the joint of the rod is not loosened, the deformation of the rod itself is accumulated and an error occurs in detecting the twist. Furthermore, if the casing pipe has a bend,
In some cases, the rod cannot be inserted, making it impossible to measure the twist.

In addition, if there is any irregularity inside the casing pipe (displacement of guide groove at joint, gap at joint, adhesion of foreign matter, corrosion or buckling of casing pipe, etc.), the inclinometer probe may come off. However, the impact cannot be ignored, such as the occurrence of an irregular error in the measured value due to the fact that a shock may be applied, an unexpected abnormal value is obtained, or the inclinometer probe fails. .
However, the conventional technique cannot detect such an abnormality on the inner surface of the casing pipe once buried in the ground.

An object of the present invention is to provide an abnormality detecting device capable of easily and accurately detecting the twist of a casing pipe for an inclinometer which is buried in the ground, and thereby correcting the measurement value by the inclinometer. is there. Another object of the present invention is to provide a device capable of observing the presence or absence of abnormalities on the inner surface of a casing pipe for an inclinometer buried in the ground simultaneously with the measurement of such twist.

[0009]

DISCLOSURE OF THE INVENTION The present invention is an abnormality detecting device for an inclinometer casing pipe buried in the ground, and is fitted in a guide groove extending in the axial direction of the inner surface of the inclinometer casing pipe, like the inclinometer probe. It has a matching wheel and has a cylindrical probe case movable in the casing pipe. A magnetic compass indicating the geomagnetic direction is attached by a support rod (including a thin wire-shaped one) so as to be located at the front of the tip of the tubular probe case with a space, and the tube is provided so as to irradiate the diagonally outward forward direction. A plurality of light emitting diodes are arranged in a ring shape at the tip of the cylindrical probe case, and a television camera is installed in the cylindrical probe case to observe the magnetic compass and the inner surface of the casing pipe.

[0010]

When the wheel of the tubular probe case is fitted in the guide groove of the inclinometer casing pipe and is inserted into the casing pipe, the tubular probe case follows the twisted state of the inclinometer casing pipe. And change the direction to descend. The magnetic compass always displays the geomagnetic direction by its magnetic needle, illuminating the inside of the casing pipe with a light emitting diode, and observing the magnetic compass with a TV camera, the direction of the cylindrical probe case at that time,
Consequently, the twist angle of the inclinometer casing pipe can be measured. The state of the inner surface of the casing pipe can also be observed together with the television camera.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall configuration diagram showing an embodiment of an anomaly detecting device for an inclinometer casing pipe according to the present invention.
The AA cross section is shown in FIG. 2, and the BB cross section is shown in FIG. This device is similar to a normal inclinometer probe in that the guide groove 1 extending in the axial direction of the inner surface of the inclinometer casing pipe 10 is used.
The casing pipe 10 is equipped with wheels 18 that fit into the casing 2.
It has a cylindrical probe case 20 that is movable inside. Then, the magnetic compass 2 indicating the geomagnetic azimuth is positioned so as to be located in front of the front end of the cylindrical probe case 20 with a space therebetween.
2 is attached by a support rod 24, and a plurality of light emitting diodes 26 are arranged in a ring shape at the tip of the cylindrical probe case 20 so as to illuminate obliquely outward and forward, and the inner surfaces of the magnetic compass 22 and the casing pipe 10 are observed. In order to do so, the television camera 28 is incorporated in the tubular probe case 20.

The inclinometer casing pipe 10 is made of resin such as metal such as aluminum and stainless steel, depending on the application and installation conditions. Usually, as shown in FIG. 2, the guide groove 12 has a long structure formed at 90-degree symmetrical positions with respect to the central axis. A large number of the inclinometer casing pipes 10 are replenished and inserted into the boring hole, and liquid grout material is filled between them to be fixed so as to be integrated with the ground. As in the case of the inclinometer probe, the wheels 18 are provided with two pairs of wheels that are inclined with respect to the axial direction of the tubular probe case 20 before and after,
One of each pair is a fixed wheel, and the other is a movable wheel, which can follow the deformation of the casing pipe 10 and can be moved without removing the wheel.

The magnetic compass 22 has a very general structure in which a sphere serving as a magnetic needle is suspended in silicone oil, and can always indicate the geomagnetic direction in any three-dimensional posture. is there. The magnetic compass 22 is supported by two support rods 24 from both sides (see FIG. 3), and is suspended in front of the tip of the cylindrical probe case 20 with a space (for example, with a distance of about 7 to 10 cm). .
Although the number and thickness of the support rods 24 are arbitrary, it is only necessary to support the magnetic compass 22 so as not to sway, and to prevent the TV camera 28 from observing the inner surface of the casing pipe, which will be described later, a thin wire shape. It is also sufficient to combine two of them.

As shown in FIGS. 4 and 5, the tip of the cylindrical probe case 20 has a truncated cone shape, and the inclined surface portion thereof has a ring shape so as to irradiate obliquely outward and forward. A number of high brightness light emitting diodes 26 are arranged. In this embodiment, twelve light emitting diodes 26 are arranged and embedded at equal intervals, and the periphery is sealed with a resin filler 30. In the present invention, the power consumption is reduced by using the light emitting diode as the lighting device. The illumination direction by the light emitting diode 26 is set to be diagonally outward and forward,
Magnetic compass 2 when facing downward (directly above the magnetic compass)
The surface of the second pipe 2 causes halation to make it difficult to observe with the TV camera 28, and the casing pipe 10.
This is because it is necessary to illuminate the surroundings because we want to observe the inner surface of the body at the same time.

Further, as shown in FIG. 4, the magnetic compass 22
Also, in order to observe the inner surface of the casing pipe 10, the television camera 28 is incorporated in the cylindrical probe case 20. The television camera 28 uses a high-sensitivity monochrome CCD as an image pickup element, and sends out a composite video signal through an ordinary inclinometer cable and connects it to a monitor device (not shown) installed on the ground surface to display an image. Can be observed. The television camera 28 is incorporated in the cylindrical probe case 20 so as to face the front end direction, and the front end opening portion of the cylindrical probe case 20 is covered by the cover glass 3.
Liquid-tightly covered with 2. The cover glass 32 is attached to the tubular probe case 20 by a screw-in member 34, and at this time, the O-ring 36 seals between the cover glass 32 and the tubular probe case 20. The front surface of the cover glass 32 is flush with the front end surface of the screw-in member 34 or the front surface of the cover glass 32 protrudes so that no bubbles remain during observation in groundwater.

As shown in FIG. 6, the light emitting diode 26 illuminates an inner surface of the casing pipe obliquely outward and frontward, and indirectly illuminates the magnetic compass 22 with reflected light. The television camera 28 projects the magnetic compass 22 in the center of the visual field at the same time as the inner surface of the casing pipe 10. With this, it is possible to clearly observe the direction of the magnetic needle of the magnetic compass 22 and the state of the inner surface of the casing pipe 10 (whether the guide groove is displaced at the joint, whether there is a gap at the joint, presence of foreign matter or corrosion). It will be possible.

The magnetic needle of the magnetic compass 22 is attached to the television camera 2.
If the casing pipe 10 is twisted as it is inserted into the casing pipe 10 while observing at 8, the direction indicated by the magnetic needle changes. This is because the device follows the twist of the casing pipe 10. Therefore, the twist of the casing pipe 10 can be detected in the opposite direction from the direction indicated by the magnetic needle of the magnetic compass 22. Since the cylindrical probe case 20 can be continuously inserted by using the inclinometer cable, the work is extremely easy. In addition, by recording the output of the television camera 28 in the VTR, it is possible to repeatedly read the twist and observe the abnormal inside surface, and it is also possible to simultaneously record the depth and the comment by voice.

[0018]

As described above, the present invention has a structure in which the interior of the casing and the magnetic compass is illuminated by the light emitting diode and the television camera is used to observe the twist of the casing pipe for the inclinometer embedded in the ground. It can be detected easily and accurately. As a result, it is possible to correct the error in the measured value due to the twist of the casing pipe. At the same time, it is possible to observe the presence or absence of abnormalities on the inner surface of the inclinometer casing pipe buried in the ground (deviation of guide grooves at joints, gaps at joints, adhesion of foreign matter, corrosion, etc.). When a measurement result other than the above is obtained, it is possible to determine whether the cause is the state of the inner surface of the casing pipe, analyze the measurement result, and determine whether or not to continue the measurement after using the casing pipe. It is also useful to do. Therefore, by regularly observing the presence or absence and the degree of abnormality of the casing pipe using the device of the present invention, the reliability of the measurement by the inclinometer can be improved and the quality of the measurement result can be improved.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of an abnormality detecting device for a casing pipe for an inclinometer according to the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a sectional view taken along line BB in FIG. 1;

FIG. 4 is an enlarged explanatory view of a tip portion of a cylindrical probe case.

FIG. 5 is a bottom view thereof.

FIG. 6 is an explanatory diagram showing a relationship between an illumination direction and a visual field in a use state.

[Explanation of symbols]

 10 Casing pipe for inclinometer 12 Guide groove 18 Wheel 20 Cylindrical probe case 22 Magnetic compass 24 Support rod 26 Light emitting diode 28 Television camera

Claims (1)

[Claims] 1. A cylindrical probe case, which is equipped with a wheel that fits in a guide groove extending in the axial direction of the inner surface of the casing pipe for the inclinometer, and is movable in the casing pipe, and in front of the tip of the cylindrical probe case. A magnetic compass indicating the geomagnetic azimuth, which is attached by a support rod so as to be positioned at intervals, a plurality of light emitting diodes arranged in a ring shape at the tip of the cylindrical probe case so as to illuminate obliquely outward and forward, and a magnetic compass. An inclinometer casing pipe abnormality detection device comprising a television camera incorporated in the cylindrical probe case for observing an inner surface of a compass and a casing pipe.