JPH0439889B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a device for measuring fluctuations in cracks that occur and progress due to various causes in various civil engineering and building structures. A device for measuring three-dimensional fluctuations in cracks, in which two measurement bases fixed to two structural blocks are combined so that they face each other on three or more different surfaces, and the distance between the opposing surfaces can be measured at three or more points. It is related to.

[Prior Art] In civil engineering or architectural structures, new cracks may occur due to earthquakes, ground subsidence, water pressure, deterioration of materials such as concrete, or poor construction.
Already existing cracks (including gaps, seams, etc.) may expand. Monitoring how these deformations progress and performing maintenance management to prevent structures from being destroyed is an extremely important issue in civil engineering. To this end, it is important to be able to measure crack fluctuations with extremely high accuracy of around 1/100 mm or less.

A conventional device that can measure the relative fluctuation of two structural blocks with a crack as a boundary is to fix a reference bolt, etc. to each structural block, and to stretch an Invar wire, etc. between them. It is conceivable to measure the relative displacement between the two points to which the bolt is attached based on the change in length. Such measuring devices are based on the same principles as those used, for example, in landslide monitoring.

[Problems to be solved by the invention] Problems with cracks in civil engineering and architectural structures 2
The two structural blocks do not necessarily move only in the direction in which the crack expands, but move three-dimensionally.
Therefore, if the three-dimensional behavior of the crack cannot be accurately known, proper maintenance and management of the structure cannot be performed.

However, the conventional techniques described above can only measure linear relative distance fluctuations between both reference points of two structural blocks. Therefore, there is a drawback that it is not possible to measure how much the two structural blocks have relatively moved in which direction.

In addition, since the technology measures the relative distance between two points by stretching wires, the wires are always visible on the surface of the structure, which can easily cause problems such as getting caught on something, and making management troublesome. There are some drawbacks as well.

It is an object of the present invention to solve the above-mentioned drawbacks of the prior art and to
It is an object of the present invention to provide a crack fluctuation measuring device that can measure dimensional relative displacement with high accuracy and can perform stable measurement over a long period of time.

[Means for Solving the Problems] The present invention, which can achieve the above objects, has a specific shape for each of two structural blocks bordering on cracks (including gaps, joints, etc., hereinafter the same). The measurement base is fixed to the base, and the distance between the opposing surfaces can be measured, including the inclination.

That is, the crack gauge according to the present invention includes two measuring bases, a first and a second measuring base, each of which is fixed to two structural blocks bounded by a crack.
The first measurement base has a structure having a recess or an opening, whereas the second measurement base has a structure that allows it to enter into the recess or opening of the first measurement base with a margin. The two measurement bases are combined in a relationship such that they face each other on three or more different sides. Each of the opposing portions of the first and second measurement bases is provided with a mounting portion for a displacement measuring device so that surface spacing can be measured at three or more locations that are not located on a straight line.

[Operation] Since the two measurement bases are each fixed to two structural blocks with cracks as boundaries, if the structural blocks are displaced, the measurement base will also be displaced accordingly. The two measurement bases face each other on three or more different surfaces, and the distance is measured at three or more points on each opposing surface, so the structure block (measurement base installation surface)
Even if the two structural blocks undergo angular displacement due to uplift, subsidence, etc., their relative distances and interplane angles can be determined, and thereby even complex three-dimensional changes in two structural blocks can be accurately grasped.

[Embodiment] FIG. 1 is an explanatory diagram showing an embodiment of a crack gauge according to the present invention, and FIGS. 2A and 2B are a front view and a side view showing the installed state thereof. Cracks 10 exist in civil engineering structures, etc., and 2
Assume that it is divided into two structural blocks 12 and 14. A first measuring base 16 having a recess 18 is firmly fixed to one structural mass 12 by an adhesive 20, and the other structural mass 14 has a space within the recess 18 of the first measuring base 16. A second measuring base 22, which is structured such that it can be accessed by the adhesive material 2, is
It is firmly fixed by 0. When these first and second measurement bases 16 and 22 are installed in a place where temperature changes are severe, it is preferable to make them from a material with a small coefficient of thermal expansion, such as an amber alloy or ceramic. If it is installed in a place where temperature changes are small, such as deep underground, it may be made of ordinary metal.

The first measurement base 16 consists of a standing part 24 fixed to the structural block 12, a side plate 26 extending from the side toward the structural block 14, and a top plate 28 sticking out to cover them. This is the structure in which the recess 18 is formed. In contrast, the second measurement base 22 is a rectangular block of much smaller dimensions so as to fit comfortably within its recess 18. Therefore, here, the three plate-shaped parts (standing part 24, side plate 26, and top plate 28) constituting the first measurement base 16 and the outer surface of the second measurement base 22 are arranged so that they are perpendicular to each other.
They will face each other in three directions: x, y, and z. Three or more displacement measuring device mounting holes are provided on one of these three sets of opposing surfaces so as not to be lined up in a straight line.

In this embodiment, triangular dial gauge mounting holes 34
y and 34z are arranged, and each is configured so that the tip measuring part of the dial gauge penetrates therethrough. Therefore, the orientation of the mounting holes corresponds to the xyz rectangular coordinate axes shown in FIG.

With such a configuration, for example, as shown in FIG. 3, the crack progresses and the two structural blocks 12,
Even if 4 causes a variation that involves an angular change rather than a simple translational variation, it is possible to measure the distance by inserting a dial gauge 32 at three or more points on each opposing surface as shown in Fig. 4. , it is possible to determine the distance between the opposing surfaces, including angular variations, and any changes in cracks can be determined.

FIG. 5 is an explanatory view showing another embodiment of the crack gauge according to the present invention, and FIGS. 6A and 6B are a front view and a side view thereof, respectively. The basic idea is the same as in the previous embodiment. crack 1
A first measurement base 40 is fixed to one structural block 12 bounded by 0, and a second measurement base 42 is fixed to the other structural block 14. The first measurement base 40 has two upright portions 44 and a semi-cylindrical recess 46.
On the other hand, the second measurement base 42 has an inverted L-shape, and its tip protrusion is semi-cylindrical and fits inside the recess 46 of the first measurement base 40. The structure allows for easy entry into the area.

As is clear from these figures, the first measuring base 40 is mounted in such a way that its recess 46 faces towards the structural mass 14, and the semi-cylindrical projection of the second measuring base 42 lies within said recess 46. Mounted for entry. Three displacement detection units 50 are attached to each of the curved top surface, flat bottom surface, and end surface of the first measurement base 40. In this case, the displacement measuring device mounting portions formed on the bottom surface and the end surface are not arranged in a straight line but are provided so as to constitute a triangle.

Even if the first and second measurement bases 40 and 42 have such a shape, it is possible to measure the distance between the three opposing surfaces and their inclinations as in the case of the previous embodiment, and thereby the crack 10 No. 3
It is possible to accurately grasp dimensional fluctuations.

Although two embodiments of the present invention have been described in detail above, it goes without saying that the present invention is not limited to only such configurations. It goes without saying that the shapes of the first measurement base and the second measurement base can be changed in various ways. In short, it is sufficient to combine two measurement bases that face each other in three or more different directions. In addition to dial gauges, actuating transformers and optical displacement detectors can also be used as displacement measuring instruments. In any case, as long as the measurement points on each measurement base are determined in advance, crack fluctuations can be measured very easily by bringing in one portable displacement measuring device and sequentially measuring it.

[Effects of the Invention] As described above, the present invention measures the distance between opposing surfaces at three or more points on each of three or more opposing surfaces using two measuring bases each fixed to two structural blocks bordering on a crack. Because it is configured to do so, it is possible to accurately measure the three-dimensional relative displacement of two structural blocks, including the inclination, and it is possible to accurately determine the deformation of cracks and prevent damage to civil engineering and building structures caused by cracks. This has the excellent effect of being able to properly perform maintenance and management, since it prevents damage and destruction.

In addition, since the present invention only requires two measurement bases to be installed, stable measurement is possible over a long period of time, and measurement troubles are unlikely to occur. Maintenance of the measurement bases is almost unnecessary, and Since measurements can be carried out by bringing only one displacement measuring device, the cost is low, and furthermore, it has the advantage that no skill is required for measurement.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing an embodiment of the crack gauge according to the present invention, Fig. 2 A is a front view thereof, Fig. 2 B is a side view thereof, and Fig. 3 shows the state when the crack is enlarged. An explanatory diagram, FIG. 4 is an explanatory diagram showing the measurement situation of the distance between opposing surfaces at that time, FIG. 5 is an explanatory diagram showing another embodiment of the crack gauge according to the present invention, and FIG. Figure B is a side view thereof. 10...Crack, 12,14...Structural block, 1
6... First measurement base, 18... Opening, 22
...Second measurement base, 32...Dial gauge, 34x, 34y, 34z...Hole for mounting a displacement measuring device.

Claims (1)

[Claims] 1. A first measuring base having a recess or an opening and fixed to one structural block with a crack as a boundary, and a first measuring base fixed to the other structural block with a space within the recess or opening of the first measuring base a second measurement base that enters the first and second measurement bases;
A crack gauge characterized in that the measurement bases face each other at intervals on three or more different sides, and mounting parts for displacement measuring devices are provided at three or more locations that are not in a straight line for each of the opposing parts.