JPH0340839B2 - - Google Patents

Description

[Detailed Description of the Invention] <> Industrial Application Field The present invention relates to a method for detecting radiation-absorbing objects within a structure, in which the positions of pipes, reinforcing bars, etc. within the structure are probed by irradiation with radiation. This is especially applicable to parts with complex shapes such as columns and beams.

<> Conventional technology When conducting seismic diagnosis of existing concrete buildings or remodeling buildings, it is necessary to accurately determine in advance the locations of reinforcing bars and piping installed inside concrete walls, columns, beams, etc. .

Therefore, conventionally, electromagnetic induction methods and radiation irradiation methods have been devised as a so-called non-destructive method of detecting the position of buried objects buried inside concrete walls, columns, etc. of buildings.

In the electromagnetic induction method, a measuring device containing an electromagnetic coil is moved while touching the surface of the wall to be inspected.
This method detects the reaction of magnetic force to buried objects.

In addition, a method has recently been developed in which the concrete wall of the target object is irradiated with radiation to detect buried objects buried within a structure.

That is, first, a marker line with known dimensions is pasted on the irradiation surface of the structure where buried objects such as reinforcing bars are buried.
On the other hand, a film that is sensitive to the transmitted intensity of radiation is attached to the back side.

Next, radiation is irradiated from the radiation source side to project the buried object and the marker line onto the film placed parallel to the marker line.

Then, the position of the buried object is calculated by actually measuring the relative positional relationship and dimensions of the projected view.

<> Problems to be Solved by the Present Invention The above method has the following problems.

(b) The electromagnetic induction method has the disadvantage that the depth and size of the buried object cannot be determined, and that there is a large measurement error. In places with complex systems, highly skilled techniques are required to measure and judge measured values.

(b) In the method of irradiating with radiation, differences in density occur in the film in places where there are complicated pillars, beams, etc.

In other words, for example, as shown in Fig. 5, for pillar a where marker line b and film f cannot be installed on parallel surfaces such as the front and back sides, when searching for the position of buried object c at the corner, etc., the adjacent The surface must be used as the irradiation surface and the film installation surface.

In such a situation, since the marker line b and the mounting surface of the film f are not parallel, the thickness through which the radiation passes differs, creating shading in the image, making measurement impossible.

The present invention solves the above-mentioned drawbacks, and provides a method for detecting radiation-absorbing objects inside complex structures, which allows for quick and easy measurement of more accurate positions, and enables exploration without being restricted by the shape of the structure. The purpose is to provide

<> Means for Solving the Problems The present invention uses a block made of a material with a radiation absorption coefficient equivalent to that of the structure to be surveyed, and a state in which this block is brought into surface contact with a convex portion of the structure. At the same time, a marker and a film are placed on each opposing surface of this block, and radiation is irradiated from the side where the marker is attached, thereby projecting the image onto the projection surface facing opposite to the surface on which the marker is installed. The position of the radiation absorbing object within the structure is determined by eliminating the density gradient of the projected image.

<> Example Next, an example of the present invention will be described based on the drawings.

(a) Each device used in the present invention (FIG. 1) [Structure] In FIG. 1, a structure 1 is a wall made of concrete or the like, or a column, a beam, or the like.

Due to the structure, the marking line 3 and the radiation film F, which will be described later, cannot be installed parallel to each other in a plan view, for example, in a state where only two sides, the adjacent irradiation source side surface 11 and the film side surface 12, are exposed. It's summery.

Further, a radiation absorbing object 2 such as a reinforcing bar is buried in a corner 13 formed by two adjacent sides, the irradiation source side surface 11 and the film side surface 12.

[Block] B is a block made of a material having the same radiation absorption coefficient as structure 1.

Further, the block B has a recess B1 formed in a shape that is in surface contact with two surfaces of the irradiation source side surface 11 and the film side surface 12 of the corner portion 13 of the structure 1, respectively.

Further, block B has two facing surfaces, one of which forms a sign line installation surface B2, and the other surface of which a projection surface B2 is formed.
form 3.

A marker line 3, which will be described later, is attached to the marker line installation surface B2, and a radiation-reactive film F, etc., for example, is attached to the projection surface B3.

Instead of the film F, a known image forming body such as a fluorescent screen may be provided on the projection surface B3 so that the image can be read electrically.

In addition, it is possible to use a material with an absorption coefficient for radiation equivalent to that of Structure 1, such as aluminum in addition to the same concrete as the structure, or a liquid such as barium or iodine if the thickness is adjusted to be radiologically equivalent to that of concrete. May be used.

[Signer] Reference numeral 3 is a wire rod made of lead or tungsten, etc., which acts as a marker and is pasted horizontally on the marker line installation surface B2 of block B.

[Irradiation Source] For example, the X-ray source 5 is used as the radiation irradiation source, but it is of course possible to use radiation other than X-rays.

And the X-ray source 5 is located on the marker line installation surface B of block B.
2 side, at an arbitrary distance on a line extending perpendicularly from the point that bisects the marker line 3.

Next, using each of the above devices, the corner 1 of the structure 1 is
A method for investigating the positions of the three parts of the buried object 2 will be explained.

(b) Installation of blocks Place recess B1 of block B in corner 13 of structure 1.
Place the block B in surface contact with the structure 1.

Then, the marker line 3 is pasted on the marker line installation surface B2, and the film F is set on the projection surface B3.

(b) Irradiation of X-rays Next, X-rays are irradiated from the X-ray source 5 toward the irradiation source side surface 11 of the structure 1 and the marking wire installation surface B2 of the block B.

(c) Condition of X-ray transmission As shown in Figure 2, the radiation absorption coefficient of block B is set to be the same as that of structure 1.
For X-rays, the radiation side 11, the marking line installation surface B2,
This is the same as irradiating an integral structure surrounded by the projection plane B3, the film side surface 12, etc.

Furthermore, since the marking line installation surface B2 and the projection surface B3, which face each other in the integrated structure, are substantially parallel, the opposing distances between the marking lines 3 installed on each of these surfaces B2 and B3 and the film F are equal.

Therefore, a projected image of the marker line 3 and the buried object 2 is clearly projected on the film F on the side of the projection surface B3.

(C) Analysis principle [Position confirmation by drawing] (Fig. 3) Let S be the X-ray source 5 set on the drawing, and extend a straight line from S to the actually measured marker line installation surface B2 of block B with distance FWD. One end of the line is S', and points P and P' are on a line that intersects the straight line SS' at right angles, and are half the distance l/2 of the marker line 3 on the left and right from the intersection.

Next, draw a line connecting the point S representing the X-ray source 5 with P and P'.

A straight line connecting points r and r' on the extension lines of straight lines SP and SP', parallel to straight line PP' and whose length is the length L projected on film F of marker line 3.
rr′ becomes the projected marker line portion.

Next, both ends qq' of the projected view of the buried object 2 appearing in the marker line portion determined above and the irradiation source S
A straight line connecting points tt′ on the straight line connecting
A straight line that is parallel to PP′ and has a diameter distance d of buried object 2
A circle with a diameter of tt' is the buried position of the buried object 2.

(e) Other embodiments (Fig. 4) In the above embodiment, the case where a linear marker line 3 is used for the marker body is explained, but a lead plate N etc. is embedded in the block B parallel to the projection plane B3. It is also possible to use this lead plate N as a marker.

In short, it is sufficient that the marker is located approximately parallel to the projection plane B3.

<> Effects of the Invention Since the present invention has been described above, the following effects can be expected.

(b) By installing the block in surface contact with the corner of the structure, the sign on the block and the projection surface facing the sign are almost parallel in the plan view. Become.

Therefore, the transmission distance of the radiation becomes uniform, and the image of the radiation-absorbing object can be clearly projected on the projection plane of the block.

This makes it possible to accurately search for buried objects without destroying the structure, even if the object to be searched is a part with a complex shape, such as the corner of a column or beam.

(b) Since the position of an object within a structure is displayed as a clear numerical value, it is much more accurate than electromagnetic induction methods, and the position of buried objects can be determined without requiring much skill.

(c) Generally, finishing materials are attached to concrete surfaces to give the interior a beautiful finish, but according to the method of the present invention, there is no need to peel or paste these interior materials, and they can be left as they are. Internal inspection is possible.

(d) Since the pipes, etc. inside the structure are displayed numerically, the reinforcing condition of the structure can be clearly seen, making it possible to improve the efficiency of safety inspections to confirm seismic performance.

[Brief explanation of drawings]

Figure 1: Perspective view of one embodiment of the present invention, Figure 2: Plane view during irradiation, Figure 3: Explanatory diagram of position confirmation by drawing, Figure 4: Explanatory diagram of other embodiments, Figure 5
Figure: Explanatory diagram of conventional irradiation method, 1: Structure,
2: buried object, 3: marker line, 5: X-ray source, F: film.

Claims (1)

[Claims] 1. A block made of a material with a radiation absorption coefficient equivalent to that of the structure and having a shape that is in contact with the corner surface of the structure is used, and the corner of the structure of this block is A marker with known dimensions is affixed to one of the two opposing surfaces that are not in contact with each other, a radiation projection surface is formed on the other of the two opposing surfaces, and the above block is attached to the corner of the structure. radiation is irradiated from the side to which the marker is attached, and each image of the marker and radiation absorbing object is projected onto a projection surface facing opposite to the installation surface of the marker. A method for exploring a radiation-absorbing object in a structure, the method comprising: actually measuring the position and dimensions, and calculating the position of the buried radiation-absorbing object.