JP2000235081A - Method and device for surveying buried transmission line or buried magnetic substance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately search a buried object generating a magnetic field in its periphery such as a buried transmission line or a buried magnetic substance, without damaging it. SOLUTION: A soil is drilled in plural sections at the same time or in order using a surveying device 1 provided with a magnetic sensor 3 in a lower end part of a drilling member 2 extended vertically, magnetism is measured continuously or intermittently in the respective drilling sections during the drilling, and the drilling by the member 2 is stopped or its drilling speed is reduced when a measured value therein reaches to predetermined magnetic intensity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for searching for a buried transmission line or a buried magnetic body and an apparatus used for the method, and more particularly to a method for generating a magnetic field around a buried transmission line or a buried magnetic body. The present invention relates to a method for searching for a buried power transmission line or a buried magnetic body capable of searching for a buried object accurately and without breaking, and an apparatus used for the method.

[0002]

2. Description of the Related Art Conventionally, attempts have been made to search for a buried transmission line or a buried magnetic body (hereinafter referred to as a buried object) in advance before excavating a ground so that the buried object is not damaged during the excavation work. I have. Examples of this search method include a magnetic search method, a radar search method, and a boring search method. In the magnetic survey method, a magnetic sensor is installed on the ground, a magnetic field formed around the buried object is measured on the ground, and the position of the buried object is specified. The radar exploration method radiates electromagnetic waves from the ground, measures reflected waves from a buried object on the ground, and specifies the position of the buried object. In the boring survey method, the ground is pierced using a boring machine, and a bit provided at the tip of a boring rod is applied to an embedded object to specify the position of the embedded object.

[0003]

However, the above-mentioned prior art has the following problems. That is, since the magnetic prospecting method is a method of exploring a buried object using a magnetic sensor installed on the ground, the explorable depth is limited, and its value is about 2 m. Further, in this method, the magnetic sensor reacts not only to the buried object but also to electric wires and magnetic materials on the ground, and it is difficult to accurately detect the buried object. The radar exploration method is a method of exploring a buried object by radiating electromagnetic waves from the ground, and thus has a limit in the explorable depth, and its value is about 3 m. Further, this method is a method of decoding a graphic image by a reflected wave on a screen of a CRT or the like, and the decoding of the image requires a high degree of know-how and a lot of time. Also, in this method, the diameter 1
It could not be detected unless it was more than 0 cm. The boring method is a method in which a bit is applied to a buried object to search for the buried object, so that the buried object is often damaged. If the transmission line is damaged, high voltage electricity will flow to the ground via bits and boring rods, which is extremely dangerous.
In addition, the repair work of the damaged electric wire required a great deal of labor. On the other hand, there are unexploded bombs in the buried magnetic material, and if such dangerous materials are damaged, there is a risk that a serious accident may occur. The present invention has been made in view of such circumstances, and has a buried transmission that can accurately and without damage cause a buried object such as a buried transmission line or a buried magnetic body to generate a magnetic field around the buried transmission line. An object of the present invention is to provide a method for searching for an electric wire or a buried magnetic body and an apparatus used for the method.

[0004]

According to the first aspect of the present invention,
The ground is excavated at a plurality of locations simultaneously or sequentially using an exploration device provided with a magnetic sensor at the lower end of the excavating member extending in the vertical direction, and at each excavation location, the magnetism is continuously or intermittently generated during excavation. When the measured value reaches a preset magnetic strength, the excavation by the excavating member is stopped or the excavating speed of the excavating member is slowed down. It is an exploration method.

According to a second aspect of the present invention, there is provided an apparatus for searching for a buried power transmission line or a buried magnetic body, wherein a magnetic sensor is provided at a lower end portion of a digging member extending in a vertical direction.

According to a third aspect of the present invention, the buried member is a boring rod, and the magnetic sensor is provided inside the boring rod. Alternatively, it is a device for searching for a buried magnetic body. By providing these inventions, the above problems are completely solved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a method for searching for a buried transmission line or a buried magnetic body (hereinafter referred to as a "buried object") and a searching device used in the method will be described with reference to the drawings. . FIG. 1 is a diagram showing a first embodiment of a device for searching for a buried object according to the present invention, and is a cross-sectional view showing a main part extracted therefrom. The embedded object search device (1) includes a rotary boring machine and a magnetic sensor (3) provided at a tip end of a boring rod (2) of the boring machine. Here, the boring rod (2) corresponds to the excavation member in the present invention. The rotary boring machine includes a boring rod (2), a motor (not shown) that rotationally drives the boring rod (2), a hoist (not shown) that moves the boring rod (2) up and down, and a boring machine. A water pump (not shown) for pumping water into the rod (2); Hereinafter, regarding these components,
It will be described in detail one by one.

The boring rod (2) corresponds to the excavating member in the present invention, and includes an outer tube (5) having a bit (4) attached to a tip thereof, and the outer tube (5).
And a swivel (7) for rotatably holding the upper part of the outer pipe (5). The outer tube (5) is rotationally driven by the motor,
Thereby, the ground can be excavated with the bit (4) attached to the tip. A magnetic sensor (3), which will be described later, is attached to the lower inner surface of the outer tube (5).

The inner tube (6) is provided with the lead wire (8) of the magnetic sensor (3). This inner tube (6)
Its upper end is fixed inside the swivel (7).
A lead wire (8) inserted from the middle of the water supply pipe (9) is provided inside the inner pipe (6). The lead (8) is connected by a coupler (10), and the lead (8) can be added by the coupler (10). Further, the inner pipe (6) communicates with a water supply pump via a water supply pipe (9), so that water pumped from the pump can be sent to the tip of the boring rod (2). A spacer (not shown) is provided between the inner pipe (6) and the outer pipe (5) so that the inner pipe (6) and the outer pipe (5) are kept at a constant distance by the spacer. Has become. The inner pipe (6) is shorter than the length of the outer pipe (5), and its tip is located above the tip of the outer pipe (5).

The swivel (7) holds the outer tube (5) rotatably as described above. The side of the swivel (7) is connected to the water pump via a water pipe (11). Thereby, the water pressure-fed from the water supply pump can be sent into the outer pipe (5). The upper part of the swivel (7) has a water pipe (9)
Through the water pump. Thereby, the water pumped from the water supply pump can be sent into the inner pipe (6).

The magnetic sensor (3) is for detecting a buried object that generates a magnetic field in the surroundings. The magnetic measurement method of the magnetic sensor (3) is not particularly limited, and for example, a search coil method, a Hall element method, a flux gate method, a magnetic oscillation method, and the like can be adopted. The magnetic measurement direction of the magnetic sensor (3) is not particularly limited, and may be any one of a uniaxial direction, a biaxial direction, and a triaxial direction. In addition, since the sensor in the uniaxial direction can be a relatively small sensor, even if the diameter of the boring rod (2) is small, it can be easily housed inside the boring rod (2). Further, the magnetic sensor (3) may be either a sensor that measures a DC magnetic field or a sensor that measures an AC magnetic field. If the magnetic sensor (3) measures a DC magnetic field, it can measure a magnetic field formed around the embedded magnetic body. If the magnetic sensor (3) measures an AC magnetic field, the AC magnetic field formed around the buried transmission line can be measured.

In the example shown in FIG. 1, the magnetic sensor (3) is a uniaxial AC magnetic sensor for measuring a longitudinal component of an AC magnetic field. Thereby, the magnetic sensor (3) in the illustrated example can measure the AC magnetic field formed around the buried transmission line.

The magnetic sensor (3) is connected to an externally provided Gauss meter (12) via a lead wire (8). Although the form of the Gauss meter (12) is not particularly limited, for example, the measurement result can be displayed numerically.

The magnetic sensor (3) is mounted on the inner surface of the distal end of the outer tube (5) via a mounting member (13). The mounting member (13) is mounted on the magnetic sensor (3) so that the magnetic sensor (3) is rotatable around its axis.
Holding. Thereby, when the outer tube (5) rotates, the magnetic sensor (3) also rotates in the mounting member (13), so that the lead wire (8) is not likely to be twisted and broken.

The buried object search device (1) has a structure in which the magnetic sensor (3) is attached to the inner surface of the tip of the outer tube (5), so that the outer tube (5) is rotated to excavate the ground. At this time, underground magnetism can be measured every moment by the magnetic sensor (3). Thus, the strength of the magnetism at an arbitrary point in the vertical direction under the ground is measured, and if the magnetism is strong to some extent, it is found that a buried object exists near bit (4). If it is known that the buried object exists near the bit (4), the digging speed can be reduced or the digging can be stopped, so that there is no danger of damaging the buried object.

FIG. 2 is a view showing a second embodiment of the apparatus for searching for a buried object according to the present invention, and is a cross-sectional view showing a main part of the apparatus. The buried object search device according to the second embodiment is also similar to the buried object search device according to the first embodiment,
An exploration device using a rotary boring machine, comprising: a boring rod (2); and the boring rod (2).
(Not shown) for rotating the motor, a hoist (not shown) for raising and lowering the boring rod (2), and a water pump (not shown) for supplying water to the inside of the boring rod (2). And a magnetic sensor (3) is provided at the tip of the boring rod (2).

The device for searching for a buried object according to the second embodiment is different from the device for searching for a buried object according to the first embodiment in that
A transmitter (14) is provided on the magnetic sensor (3), and a receiver (16) is provided on a connection (15) between the water supply pipe (9) and the boring rod (2). The point is that information is transmitted wirelessly to the upper end of the boring rod (2). Thus, by providing the transmitter (14) on the magnetic sensor (3) and providing the receiver (16) on the connection (15) between the water supply pipe (9) and the boring rod (2),
The lead wire (8) in the first embodiment becomes unnecessary, and the manufacturing cost can be reduced. Further, when the boring rod (2) is extended, the operation of extending the lead wire (8) is not required.

In the first and second embodiments, a rotary boring machine is used. However, in the present invention, an impact boring machine may be used. Also in this case, the above-described magnetic sensor (3) is mounted in a boring rod as a digging member, so that the position of the buried object can be grasped. Note that the exploration device of the present invention does not necessarily need to include a boring machine. For example, it includes a drilling blade, a rod provided to be extendable at the upper end of the drilling blade, and a manual boring device including a rotating handle provided at the upper end of the rod, and a magnetic boring device near the drilling blade. The sensor (3) may be provided. In this case, the ground is excavated by rotating the rotary handle, and the magnetism is measured during the excavation, whereby the position of the buried object can be grasped. In addition, a tubular body or a rod extending in the vertical direction is provided as a digging member, and the magnetic sensor (3) is provided at the lower end thereof, and the upper end of the tubular body or the rod is hit with a hammer or the like. It may be driven into the ground like a pile to measure the magnetism.

Hereinafter, a method for searching for a buried object using the apparatus for searching for a buried object according to the present invention will be described. 3 to 6 are views showing a first embodiment of the method for searching for a buried object according to the present invention, and are views showing one step of the method for searching. A description will be given of a case where the search device according to the first embodiment is used as an example. First, as shown in FIG. 3, one exploration device (1) for buried objects is installed on the ground using a turret (indicated by a two-dot chain line) or the like. The symbol (M) in the figure is a buried object that forms a magnetic field around it, such as a buried power transmission tube.
Next, as shown in FIG. 4, the boring rod (2) is lowered while rotating the outer pipe (5) of the boring rod (2), and excavation of the ground is started. At this time, the water pump is operated to pump water into the boring rod (2). Water flows down inside the outer tube (5) and the inner tube (6) of the boring rod (2), and the boring rod (2)
It is discharged from the tip. The discharged water is mixed with the excavated earth and sand to form mud, which rises along the boring rod (2) outside the boring rod (2) and is discharged to the surface of the earth.

During the excavation work, the magnetism is continuously or intermittently measured by the magnetic sensor (3). If there is an embedded object (M) such as an electric wire below the boring rod (2), as the bit (4) approaches the embedded object (M), the magnetic sensor (3) senses gradually larger magnetism, and the Gauss meter ( The value of the magnetism displayed in 12) increases. When measuring magnetism intermittently,
It is preferable that the measurement is performed every time a certain distance is excavated. At this time, the value of the fixed distance is not particularly limited, but can be set to, for example, 5 cm.

When the value of the magnetism displayed on the Gauss meter (12) reaches a predetermined value, excavation by the outer pipe (5) is stopped (see FIG. 5). The predetermined value is a value indicating that the magnetic sensor (3) is approaching the vicinity of the buried object (M), and its magnitude is equal to the value of the magnetic field formed around the buried object (M). It depends on conditions such as strength and the degree to which the bit (4) can be brought closer to the buried object (M). The predetermined value depends on the size and number of the buried object (M), the soil condition of the ground, and the like. However, when the buried object (M) is a 77 kV high-voltage electric wire, for example, about 1000 mG. be able to. As described above, when the value of the magnetism displayed on the Gauss meter (12) reaches a predetermined value, it is possible to know that the buried object (M) exists near the bit (4).

When the value displayed on the Gauss meter (12) reaches the predetermined value, the excavation speed may be reduced by reducing the rotation speed of the outer pipe (5). If the buried object (M) exists on the extension of the boring rod (2),
Bit (4) hits the buried object (M) slowly,
The position of the buried object (M) can be accurately grasped without damaging the buried object (M).

Then, the boring rod (2) is pulled up to the ground by operating the hoist. Then, as shown in FIG. 6, the exploration device is moved, and excavation of the ground is started again to measure the magnetism, and the boring rod (2) is pulled up. This series of operations is repeated several times to complete the exploration operation. In addition, the movement of the exploration equipment is
Is appropriately performed within a range in which is considered to exist. Although the moving distance and the number of times of movement are not particularly limited,
When the number of excavation sites per unit area is increased, the data increases, and the position of the buried object (M) can be grasped more accurately.

In the first embodiment, a plurality of locations are sequentially excavated using one exploration device (1). However, the present invention is not limited to this, and a plurality of exploration devices (1) may be used. ) May be used to excavate a plurality of locations at the same time. Specifically, first, a plurality of embedded object exploration devices (1) are installed on the ground. At this time, each exploration device (1) is installed in a range where the buried object (M) is considered to exist. Next, excavation is started by each exploration device (1), and during this excavation work, the magnetism is continuously or intermittently measured by the magnetic sensor (3) as in the first embodiment. Then
The boring rod (2) is pulled up to the ground by operating the hoist of each search device, and the search operation is completed.

According to this method for exploring a buried object, by simultaneously excavating a plurality of sites using a plurality of exploration devices (1), magnetic data at each excavation site can be obtained simultaneously, so that the buried object can be obtained. The location of (M) can be quickly grasped.

[0026]

EXAMPLES The effects of the present invention will be clarified by showing examples of the present invention. However, the present invention is not limited at all by the following examples. As shown in FIG.
Power transmission line (K) (outer diameter of the power transmission tube 175 mm, outer diameter of the power transmission cable housed inside it is 80 mm) is buried in upper and lower two stages, and two power transmission lines (K) are in the upper stage. The exploration of buried objects was conducted on the ground where four power transmission pipelines (K) were located. The equipment for exploring buried objects
The one according to the first embodiment of the present invention was used. The outer diameter of the outer tube of the boring rod (2) was 40.5 mm, and the uniaxial AC magnetic sensor shown in FIG. 1 was used as the magnetic sensor (3). Exploration was performed by using the exploration apparatus by the method according to the first embodiment of the present invention, and excavation and magnetic measurement were performed at five locations. In this example, the excavation is stopped when the measured value reaches 2000 mG. Note that in this example,
The magnetism was measured every 5 cm excavation from the ground surface. The maximum measurable value of the magnetic sensor (3) is 2000 m
G.

The results are shown in Table 1 (unit is mG). Also, from the results in Table 1, 500 mG, 750 mG, 1000 mG
The ground points at which the magnetic fields of mG, 1250 mG, and 2000 mG are considered to be generated are connected, and shown as a graph in FIG.

[Table 1] It can be seen from Table 1 and the graph in FIG. 7 that the measured value increases as the magnetic sensor (3) approaches the power transmission conduit (K). Even if the depth increases, the measured value is 2000mG
It can be seen that the power transmission line (K) does not exist in the portion where the power transmission line does not reach. As described above, excavation and magnetic measurement are performed at a plurality of points, and the depth direction distribution of underground magnetism at each excavation point is known, whereby the position of the power transmission pipeline (K) can be grasped. If the position of the power transmission line (K) can be grasped to some extent, excavation can be stopped or the excavation speed can be reduced. When the bit (4) attached to the tip of the boring rod (2) is applied to the power transmission line (K) in a state where the excavation speed is reduced, the power transmission line (K) is not damaged, and the power transmission line (K) is not damaged. The position of (K) can be specified.

[0028]

According to the method for searching for a buried transmission line or a buried magnetic body according to the present invention, a plurality of grounds are simultaneously or sequentially placed on a ground using a searching device in which a magnetic sensor is provided at a lower end of a digging member extending in a vertical direction. While excavating, at each excavation point, continuously or intermittently measure the magnetism during excavation,
When the measured value reaches a preset magnetic strength, the excavation by the excavating member is stopped or the excavating speed of the excavating member is reduced,
The following effects are obtained. That is, when the magnetic measurement value reaches a predetermined value during excavation, it can be seen that the tip of the excavation member is near the buried object. Once the position of the buried object is known to some extent, the digging member can be stopped or the digging speed of the digging member can be reduced to prevent the buried object from being damaged. Therefore, according to the exploration method of the present invention, the position of the buried object can be grasped without damaging the buried object.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of an apparatus for searching for a buried transmission line or a buried magnetic body according to the present invention, and is a cross-sectional view showing a main part extracted therefrom.

FIG. 2 is a diagram showing a second embodiment of the apparatus for searching for a buried transmission line or a buried magnetic body according to the present invention, and is a cross-sectional view showing a main part extracted therefrom.

FIG. 3 is a view showing a first embodiment of the method for searching for a buried transmission line or a buried magnetic body according to the present invention, and is a view showing one step of the method for searching.

FIG. 4 is a view showing a first embodiment of the method for searching for a buried transmission line or a buried magnetic body according to the present invention, and is a view showing one step of the searching method.

FIG. 5 is a view showing a first embodiment of the method for searching for a buried transmission line or a buried magnetic body according to the present invention, and is a view showing one step of the searching method.

FIG. 6 is a view showing a first embodiment of the method for searching for a buried transmission line or a buried magnetic body according to the present invention, and is a view showing one step of the searching method.

FIG. 7 is a diagram showing a result of a search performed by using the search device for a buried transmission line or a buried magnetic body according to the present invention.

[Explanation of symbols]

 1 ... Searching device for buried transmission line or buried magnetic material 2 ... Boring rod 3 ... Magnetic sensor

Claims (3)

[Claims] A ground is excavated at a plurality of places simultaneously or sequentially by using an exploration device having a magnetic sensor provided at a lower end of a longitudinally extending excavation member. A buried transmission line characterized by intermittently measuring magnetism and, when the measured value reaches a preset magnetic strength, stopping excavation by the excavating member or slowing down the excavating speed of the excavating member. Or how to search for buried magnetic material. 2. An apparatus for searching for a buried transmission line or a buried magnetic body, wherein a magnetic sensor is provided at a lower end of a digging member extending in a vertical direction. 3. The exploration of a buried transmission line or a buried magnetic body according to claim 2, wherein the excavation member is a boring rod, and the magnetic sensor is provided inside the boring rod. apparatus.