JPH0357432B2 - - Google Patents

Description

[Detailed Description of the Invention] <> Industrial Application Field 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 is especially aimed at structures with a thickness that exceeds the radiation transmission limit.

<> 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.

In other words, a marker line with known dimensions is pasted on the irradiation surface of a structure in which 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. In this method, the position of the buried object is calculated by actually measuring the relative positional relationship and dimensions between the marker line projected on the film and the projected view of the buried 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 highly skilled technology.

(b) In the method of irradiating 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 in a structure, which allows for quick and easy measurement of more accurate positions, and allows exploration without being limited by the thickness of the structure. The purpose is to

<> 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 the radiation After installing a cassette containing a film of It has also become possible to search for buried objects in structures that are thicker than the limit.

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

(b) Positional relationship of each device used in the present invention [Structures and sign lines] In Fig. 1, a structure 1 is a wall made of concrete, etc., or a column, a beam, etc., and has radiation absorbing materials such as reinforcing bars inside it. Buried object 2 is buried.

Reference numeral 3 denotes a marker line 3 made of lead, tungsten, or the like, and is attached horizontally to the irradiation surface A of the structure 1.

[Irradiation source]

5 uses, for example, an X-ray source 5 as a radiation 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 the point bisecting the marker line 3 of the structure 1.

[Film insertion space]

Irradiation surface A on the side that irradiates the structure 1 with radiation
For example, an insertion hole 4 is opened as a film insertion space from a side surface B perpendicular to .

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 irradiation surface A of the structure 1 is set to a range through which the radiation used at that time can pass through.

In addition, insert the insertion hole 4 into the structure 1 in a direction intersecting the radiation to be irradiated and parallel to the marker line 3 on the irradiation surface A.
It is also possible to open it diagonally in the vertical direction.

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 a drilled hole, and its size is made as small as possible within the range into which the film cassette F can be inserted.

Note that slits etc. may be carved in addition to drill holes.

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

[Film cassette]

The film cassette F is a film cassette F in which a long, rectangular film F1 is inserted into a cylindrical container F2 made of plastic, aluminum, etc.
The size should be such that it can be inserted into the

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 applied to the irradiation surface A of the structure 1 from the X-ray source 5.
Irradiate towards.

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

Therefore, the buried object 2 and the marker line 3 are exposed to the film F1 in the insertion hole 4 by the X-rays transmitted through the structure 1.
A projection diagram can be created.

(c) Principle of Analysis Next, the principle of analysis for detecting the position and shape of the buried object 2 from the projection map projected on the film F will be explained.

[Actual measurements and calculations]

The values obtained by actually measuring the two projected views of the buried object 2 and the marker line 3, together with the irradiation surface A, the distance between the insertion hole 4 and the X-ray source 5, the dimension of the marker line, etc., are used to determine the buried object using a triangular proportional formula. You can know the location of 2.

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

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

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

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 the distance from the bisecting point of the marker line 3 to the center of the buried object 2 on the irradiation surface of the structure 1 is y. If the horizontal distance is x,
By determining the distance between x and y, the position of the buried object 2 within the structure 1 can be determined.

First, the following formula holds true for y, and the value can be found.

L/l=FFD/FWD...(1) D/d=FFD/FWD+y...(2) When FFD is deleted from (1) and (2), y=(Ld/lD-1)×FWD... (3), and by substituting each numerical value into the formula (3), y, that is, the irradiated surface A of structure 1
The distance from to the center of the buried object 2 is determined.

Next, the formula for x is as follows.

x=X×d/D...(4) Therefore, from the point that bisects marker line 3, structure 1
The distance to the center of the buried object 2 on the irradiation surface A is determined.

Furthermore, since the following equation is derived from the above equation, when the distance from the irradiation surface A to the film F1 in the insertion hole 4 is T, that T can also be determined by the following equation (5).

T=FFD-FWD=(L/l-1)×FWD...(5) [Position confirmation by drawing] (Figure 3) The X-ray source 5 set on the drawing is S, and from S, the actually measured structure Distance to irradiation surface A of object 1
Extend the straight line of FWD, let one end be S′, and
On the line that intersects perpendicularly to SS', P,
Let it be P′.

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

A straight line rr' is projected, which is a straight line connecting points r and r' on the extension lines of the straight lines SP and SP', and is parallel to the straight line PP' and whose length is the length L projected on the film F1 of the marker line 3. This is the marked line part.

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

(E) Other Examples 1 In the above example, the insertion space was opened horizontally, but
Of course, the above analysis principle can also be applied to drilling 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.

(c) Other Embodiments 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.

<> 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 an insertion 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 a small amount of radiation, the effects of radiation are reduced and work safety is improved.

(b) A hole is drilled into the structure for the film insertion space, but there is no need to remove the finishing material, and the structure is not damaged during the lifting process, so the minimum amount of drilling is required.

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

(c) 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 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) Since the piping, reinforcement arrangement, etc. in the structure are displayed numerically, the reinforcement arrangement condition of the structure can be clearly understood, and workability such as inspections to confirm seismic performance can be improved.

[Brief explanation of drawings]

Figure 1: An explanatory diagram of an embodiment of the present invention, Figure 2:
Explanatory diagram of measured values, Figure 3: Explanatory diagram of position confirmation by drawing, Figure 4: Explanatory diagram of other examples 1: Structure, 2: Buried object, 3: Sign line, 5: X
Source, F1: film.

Claims (1)

[Claims] 1. A marker line with known dimensions is affixed to the irradiation surface of a structure in which the radiation absorber is buried, and a film insertion hole is provided in the structure at a position within the radiation transmission limit from the irradiation surface. A film that detects the transmitted intensity of radiation is inserted into the film insertion hole, radiation is irradiated from outside the structure, and the position of the marker line projected on the film and the depth of the radiation absorber are determined. A method for exploring a radiation absorber in a structure, the method comprising: actually measuring dimensions, and calculating the position of the radiation absorber buried in the structure based on the measured data.