JPS6144385A - Detection of radiation absorber in structure - Google Patents

Abstract

PURPOSE:To make it possible to rapidly and simply measure an accurate position and to enable detection without receiving the limit due to the thickness of a structure, by irradiating the structure with radioactive rays and measuring the position and shape of the radiation absorber embedded in the structure from the projection chart projected to a film. CONSTITUTION:A radiation absorber 2 such as reinforcement is embedded in a structure 1 such as a concrete wall body. A marking wire 3 such as a lead wire material is horizontally adhered to the radioactive ray irradiation surface A of the structure 1 and an insert hole 4 is horizontally provided to the side surface of the structure 1 crossing the irradiation surface A at right angles at the same height Z as the marking line 3 and the film cassette, wherein a film F1 is inserted in a container F2, is inserted in said hole 4. When X-rays are irradiated from the X-ray source 5 on the extension from the center point of the marking line 3, the projection chart of the embedded object 2 and marking line 3 can be formed on the film F1. By this method, the position or shape of the embedded object 2 can be detected.

Description

[Detailed description of the invention] Industrial field of application The present invention relates to a method for detecting radiation absorbers in a structure, which detects the position of pipes, reinforcing bars, etc. in a structure by irradiating them with radiation. This method is particularly aimed at structures whose thickness exceeds the radiation transmission limit.

<37> Conventional technology When diagnosing an Ff4 earthquake of an existing concrete building or renovating a building, it is possible to ascertain in advance the positive lIπ position of reinforcing bars and piping placed inside concrete walls, columns, beams, etc. There is a need to.

Therefore, conventionally, electromagnetic induction methods and radiation irradiation methods have been devised as methods for non-destructively detecting the position of buried objects buried inside concrete walls 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, and the reaction of the magnetic force to the buried object is sensed.

In addition, a method 15 has recently been developed in which the concrete 1 to wall of the object is irradiated with radiation to search for buried objects buried within a structure.

In other words, a marker line with known dimensions is pasted on the irradiation surface of a structure where buried objects such as reinforcing bars are buried, and a film that senses the transmitted intensity of radiation is attached to the back surface, and radiation is emitted from the source side. The marker lines and j! [! This is a method of calculating the position of a buried object by actually measuring the relative position and dimensions of the projected view of the object.

<[[>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 the measurement error is large.Also, when the buried object is buried in a complicated manner within the wall, it is difficult to judge the measured value. requires 14 degrees of skill.

(b) In the method of irradiating with radiation, there is a limit to the thickness of the structure to be irradiated.

In other words, there is a limit to the distance that radiation can penetrate.

Therefore, if the structure is thicker than this, the radiation will not reach the film attached to the back side opposite to the radiation source side, and no projection will appear on the film.

The present invention solves the above-mentioned drawbacks, and provides a method for searching for radiation absorbers inside a structure, which enables quick and easy measurement of a more positive 111f position, and allows exploration without being limited by the thickness of the structure. The purpose is to provide.

<IV>Means for solving the problems In the present invention,
An insertion hole is opened in the target structure as a film insertion space in the direction intersecting the radiation to be irradiated and before the radiation transmission limit, and after eight cassettes containing radiation film are placed there, the structure is inserted. By employing a method of irradiating radiation to the area and measuring the position and shape of buried objects in the radiation absorber from the projection image projected on film, it has become possible to search for buried objects in structures that are thicker than the penetration limit. .

KU V:〉Example Next, one embodiment of the present invention will be described based on the drawings.

(B) Positional relationship of each device used in the present invention [Structure and 8X line] In Fig. 1, structure 1 is a wall made of concrete, etc., or a column, a beam, etc., and has radiation absorbing material such as reinforcing steel inside. Buried object 2 is buried.

In addition, 3 is a marker line 3 made of lead or tungsten, etc.
and is attached horizontally to the irradiation surface A of the structure 1.

(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.

The position is a point at an arbitrary distance on a line extending perpendicularly from a point that divides the marker line 3 of the structure 1 into three equal parts.

[Film Insertion Space] In the structure 1, for example, an insertion hole 4 is surrounded as a film insertion space from a side surface B perpendicular to the irradiation surface A on the side where radiation is irradiated r8.

The insertion hole 4 is a hole into which a film cassette F, which will be described later, is inserted.

Its position and direction are as follows.

(1) The center of the insertion hole 4 is at the same height Z as the marker line 3.

(2) Direction intersecting the irradiating radiation.

(3) Parallel and horizontal to marker line 3 on irradiation surface A.

Furthermore, the depth of the insertion hole 4 from the structure 1 irradiation point A is set to a range through which the radiation used at that time can pass through.

Note that the insertion hole 4 should be aligned with (1
It is also conceivable that 17il HQ "j be parallel to the marker line 3 on the α plane A and diagonally in the longitudinal direction of the structure 1.

If two marker lines are pasted in parallel in the vertical direction, it becomes possible to simultaneously search for buried objects in the vertical direction such as main reinforcements and at the same time to search for buried objects in the horizontal direction such as hoop reinforcements.

In this embodiment, the insertion hole 4 is 1°J wide, and the size of the insertion hole 4 is as small as possible within the range in which the Noilm cassette F can be inserted.

In some cases, slits etc. may be carved in addition to the J5 drill hole.

In this case, the container for the film cassette F, which will be described later, is not cylindrical, but a commonly used plate-shaped film cassette can be used. .

[Film Cassette Co Film cassette F is a film cassette F in which a rectangular and elongated film F1 is inserted into a cylindrical container F2 made of plastic, aluminum, etc., and is sized so that it can be inserted into the above-mentioned insertion hole 4.

The film cassette F is inserted into the insertion hole 4 with the photosensitive surface of the film F1 facing the X-ray source 5 side.

(b) Irradiation of X-rays Next, X-rays are irradiated from XI[5 toward the irradiation surface A of the structure 1.

The film F1 is located in the insertion hole 4, which is provided at a depth 17fl that does not exceed the radiation transmission limit.

Therefore, a projected view of the buried object 2 and the marker 113 is formed on the film F1 in the insertion hole 4 by the X-rays transmitted through the structure 1.

(c) Wlfr principle Next, the analysis principle for searching the position and shape of the buried object 2 from the projection view projected on the film F will be explained.

L actual measurement and measurement] Measure the two projections of buried object 2 and marker line 3 and find the IC value,
The position of the buried object 2 can be determined from the irradiation surface A, the distance between the insertion hole 4 and the X-ray source 5, the dimensions of the marker line, and the like based on the triangular proportionality formula.

In FIG. 2, D indicates the diameter of the buried object 2 having a diameter d projected onto the film F1, and D indicates the length of the marker line 3 of the diameter β projected onto the film F1.

Furthermore, FWD is the distance from the XPA source 5 to the irradiation surface A of the structure 1, and F F D is the distance from the X-ray source 5 to the film F1.

Also, X indicates the buried object 2 and the marker line 3 projected on the film F1.
is the distance between the respective centers of .

Since the buried object 2 is a standard product, the diameter d of the buried object 2 can be determined from drawings at the time of construction of the structure or by projecting a part of it.

Here, as shown in Figure 2, the distance from the irradiation surface A of the structure 1 to the buried object 2 is y, and from the Mikasa equinox of the marker line 3 to the structure 1
Letting X be the horizontal distance to the center of the buried object 2 on the irradiation surface, the position of the buried object 2 within the structure 1 can be determined by finding the distance between X and y.

First, for y, the following formula holds true, and the value is found (1),
If FFD is deleted from (2), then by substituting the respective numerical values into the equation (3), y, that is, the distance from the irradiation surface A of the structure 1 to the center of the buried object 2, is determined.

Next, the formula for X is as follows.

Therefore sign II! On the irradiation surface A of structure 1 from the point that bisects 3, the distance -L to the center of buried object 2 divided by l13 is 〒
11 dawn.

Furthermore, the following formula is derived from the above formula, so the irradiation surface A
When the distance from the film E1 in the insertion hole 4 to the film E1 is -[, the T can also be determined by the following equation (5).

[Position confirmation by drawing] (Figure 3) Let the X-ray source 5 set on the drawing be S, and extend a straight line from S to the irradiation surface A of the actually measured structure 1 with a distance of ill F l/V D. Let one end be $-, and let P and P' be points on a line that intersects the straight line SS'' at right angles, and that are half the distance β/2 of the mark PA3 on the left and right from the intersection.

Next, draw a line connecting the XFA source 5 and P and P-.

A straight line connecting points r and r' on the extensions of the core wires sp and sp-, which is parallel to the straight line PP- and whose length is the length l projected onto the film F1 of the marker line 3.1. : The straight line rr- becomes the projected marker line portion.

Next, a straight line connecting the point 11- on the straight line connecting the irradiation source S and both ends CIQ- of the projected view of the buried object 2 appearing on the marker line 81S obtained above, and parallel to the straight line PP'. The buried position of the buried object 2 is a circle whose diameter is the straight line 11', which is the diameter distance d of the buried object.

(E) Other Embodiments 1 In the above embodiments, the insertion space was opened horizontally, but it goes without saying that the above analysis principle can also be applied to drilling holes in an oblique direction.

The diagonal direction herein includes diagonal directions in both a plan view and a side view.

Furthermore, the irradiation of radiation is not limited to the orthogonal direction.

(v) Other Embodiment 2 (FIG. 4) In the above embodiment, the marker lines were attached horizontally, but it is also possible to attach two marker lines in parallel in the vertical direction.

In this case, the marker line must be pasted in a range that intersects the height position of the insertion hole, and the irradiation source is placed at a constant position on a line perpendicular to the irradiation surface from the midpoint between both marker lines. Exploration of buried objects can be performed using the same analytical principle.

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

(b) Rather than attaching a radiation film to the back of the structure, the film was inserted into a penetration hole opened at a depth within the radiation penetration limit.

Therefore, it has become possible to search for buried objects even in thick structures.

Since it becomes possible to use radiation with less radiation, shadows caused by radiation)j rays are reduced, and work safety is improved.

(0) Holes are drilled into the structure for the film insertion space, but there is no need to remove the finishing material, so the trench structure will not be damaged during the lifting work, and the minimum number of holes can be drilled.

Furthermore, repairs after completion of the work can be as simple as filling the hole with mortar or the like.

(c) (14) Since the position of an object within a structure is displayed as a clear numerical value, it is much more accurate than methods such as electromagnetic induction, and the position of buried objects can be determined without the need for skill.

(d) Since the present invention allows the positions of reinforcing bars and the like within a structure to be measured in advance, there is no need to waste effort, time, and expense when, for example, extending or renovating a concrete house.

(E) The piping, reinforcement, etc. inside the structure are displayed numerically, so you can clearly see the reinforcement condition of the structure and improve its earthquake resistance! It is possible to improve the workability of inspections etc. that recognize 1.

[Brief explanation of drawings]

Figure 1: Explanatory diagram of one embodiment of the present invention Figure 2: Explanatory diagram of measured values Figure 3: Explanatory diagram of position confirmation by drawing two diagrams Figure 4: Explanatory diagram of other embodiments 1° Structure 2: Buried object 3: Sign line 5: X-ray source Fl: Film

Claims (1)

[Claims] A marker line with known dimensions is affixed to the irradiated surface of a structure in which a radiation absorber is buried, and a film is inserted into the structure at a depth within the radiation penetration limit from the irradiated surface. A space is opened, a film that senses the intensity of transmitted radiation is inserted into the film insertion space, radiation is irradiated from outside the structure, and the position and dimensions of the marker line and radiation absorber projected on the film are determined. A method for detecting a radiation absorber in a structure, the method comprising: actually measuring and calculating the position of the buried radiation absorber.