KR100796161B1 - Apparatus for measuring convergence and ceiling subsidence using fiber bragg grating sensor - Google Patents

Abstract

The present invention relates to a device for measuring the pore displacement and tip settlement using a fiber bragg grating (FBG) sensor, the measurement point along the cross section of the structure from the FBG strain sensor and the FBG angle displacement sensor attached to the structure surface One strain rate by attaching a sensor attachment mechanism to the sensor and installing two or three sensors on the same measurement surface and then measuring the small length change and the angular displacement to calculate the two-dimensional or three-dimensional internal displacement of the structure. The sensor can be attached along the cross section of the structure, and one or two angular displacement sensors can be installed on the same measuring surface. The sensor can provide a method for measuring the two-dimensional or three-dimensional cavity displacement without any complicated mathematical calculations. .

Fiber Optic Grating Sensor, FBG Sensor, FBG Strain Sensor, FBG Angle Displacement Sensor

Description

FIELD OF MEASURING CONVERGENCE AND CEILING SUBSIDENCE USING FIBER BRAGG GRATING SENSOR}

Figure 1a is a front view of the two-dimensional hole displacement and hem settlement measurement device for the present invention.
Figure 1b is a front view of the three-dimensional hole displacement and hem settlement measurement device for the present invention.
Figure 1c is a front view showing an example of installing the three-dimensional hole displacement and hem settlement measurement device for the present invention.

Figure 2 is a side view showing an example of installing the three-dimensional internal displacement and hem settlement measurement device according to the present invention of Figure 1c.

Figure 3 is a configuration diagram extending the hole displacement and hem settlement measurement device of the present invention.

Figure 4 is a view showing another embodiment of the pore displacement and shear settlement measurement apparatus of the present invention installed separately the FBG strain sensor and the FBG angle displacement sensor.

5 is a schematic view showing a state in which the present invention is installed in the tunnel for the measurement of tunnel internal displacement and sedimentary settlement.

Figure 6 is a view of the measurement example of the vector dx, dy by the tunnel internal displacement and the tip settlement.

7 is a measurement principle diagram of the lining internal displacement and the shear settlement absolute coordinate method in the present invention.

8 is a measurement principle diagram of the lining internal displacement and the shear settlement relative coordinate system in the present invention.

■ Explanation of symbols used in main part of drawing ■

1: FBG Sensor Module 2: FBG Strain Sensor 3: FBG Angle Displacement Sensor 4: Protective Tube 5,5 ': Base 6: Connecting Shaft

 7: Tunnel 8: Temple of Heaven 100,100 ': Fixed piece

The present invention relates to a pore displacement and a tip settlement measurement apparatus using a fiber bragg grating (FBG) sensor for the measurement of pore displacement and tip settlement of a tunnel, and more specifically, to a hole displacement during tunnel construction and maintenance. And it relates to a measuring device that can measure the zenith settlement in real time.

When measuring only the change in the longitudinal direction on the cross section of the tunnel in the measurement of the hole displacement of the tunnel, it is not possible to know the directionality of the coordinate after deformation due to the deformation characteristics of the lining. Hard.
Therefore, the tunnel displacement and hem settlement measurement devices using the conventional sensors are embedded in the tunnel lining to determine the expansion or contraction by embedding the length change measurement sensor or the length variation using the displacement sensor and the angle sensor to measure the displacement. After measuring the angle change and the angle, combine the two measurement results to convert into the internal displacement.
However, since the conventional electric sensor system measures two values of the length change and the angle by different measuring methods, the accuracy of the hole displacement is determined by the different measurement accuracy of the two sensors. The data collection device is complicated and its measurement cost is relatively high.The accuracy of the sensor is 1 / 100mm and the angle is 1 / 100degree. Not only there is a problem in the measurement of the deformation, but above all, there is a very weak problem that can not measure when the subway is running because the measurement reliability is affected by a lot of electromagnetic waves.

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The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to measure the internal displacement and sedimentary settle, which has no influence of electromagnetic waves, and has very high measurement resolution and high measurement reliability. It provides a method for measuring the hole displacement and the tip settlement by using the strain sensor and the FBG angle displacement sensor, so that the safety diagnosis can be performed at all times and the air gap using the optical fiber grating sensor that can measure the length displacement and the angle displacement simultaneously with one system. It is to provide a displacement and tip settlement measurement device.

The object of the present invention,
In the apparatus for measuring the hole displacement and tip settlement of a structure using an optical fiber grating sensor, the fixing pieces at both ends of the FBG sensor module are connected to the base by a fastening member; Both ends of the protective tube are installed on the fixing piece; An FBG strain sensor is installed in the longitudinal direction between the fixing pieces in the protective tube; At least one FBG angle displacement sensor is installed on the outside of the protective tube by means of a connecting shaft to measure the pore displacement and the tip settlement using the optical fiber grating sensor, which can always measure two-dimensional or three-dimensional pore displacement and tip settlement. It can be achieved by the device.
Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.
Figure 1a is a front view of the two-dimensional hole displacement and hem settlement measurement device for the present invention, Figure 1b is a front view of the three-dimensional hole displacement and hem settlement measurement device according to the present invention, Figure 1c Front view showing an example of installing the three-dimensional hole displacement and the hem settlement measurement device according to the present invention, Figure 2 is a side view showing an example of installing the three-dimensional hole displacement and hem settlement measurement device according to the present invention of Figure 1c 3 is a configuration diagram in which the hole displacement and hem settlement measurement apparatus of the present invention is extended.
As shown in Figure 1a to 2, the present invention is composed of a unit FBG sensor module (1) having a predetermined length and can be used continuously connected.

That is, the FBG sensor module 1 has a FBG strain sensor 2 made of a pipe such as a square or a circle, a protective tube 4 into which the FBG strain sensor 2 is inserted, and the FBG strain sensor 2. It is installed in the FBG angle displacement sensor 3 for measuring the angular displacement, and is composed of fixing pieces (100, 100 ') provided at both ends of the protective tube (4).

As shown in FIG. 2, a plurality of bases 5 and 5 ′ are installed in the tunnel so that the fixing pieces 100 and 100 ′ at both ends of the FBG sensor module 1 can be attached using a fastening member. By installing the bases 5 and 5 ', a plurality of FBG sensor modules 1 are continuously installed adjacent to each other (see Fig. 3).
The FBG angular displacement sensor 3 having a resolution of 1 / 1,000 degrees is installed on the upper portion of the protective tube 4 of the FBG strain sensor 2 by a connecting shaft 6, and the length displacement measurement is performed inside the protective tube 4. An FBG strain sensor 2 having a resolution of 1 / 10,000,000 for connecting is connected in the longitudinal direction between the stationary piece 100 and the stationary piece 100 '.
And, the FBG sensor module 1 is continuously attached to the base (5), one FBG sensor module 1 is to be installed independently of the internal cross-section of the tunnel, etc., each having independent coordinates.

3 and 5, the FBG sensor module 1 of the present invention having such a constructional characteristic is provided at the base 5, 5 'portion to measure the internal displacement and the tip settlement of the tunnel 7. The FBG strain sensor 2 is configured to perform the phase clock side by successively connecting adjacent to each other in the longitudinal direction.

Reference numeral 8 in FIG. 5 shows the heaven end of the tunnel 7.

When using the FBG sensor module 1 of the present invention that can be configured as described above to measure the internal displacement and the tip settlement of the tunnel (7), as shown in Figure 5, the end (8) of the tunnel (7) Accordingly, the FBG sensor module 1 is connected and extended in the longitudinal direction as shown in FIG.

The FBG sensor module 1 is approximately 1 m in length, and as shown in FIG. 2, point a is an observation point and point b is a measurement point.
That is, referring to FIG. 7, when B is a measurement point, A is an observation point, and when B is an observation point, C is a measurement point.
Therefore, when deformation occurs in the lining and the B to D points move, the new coordinates B 'to D' are configured, and the A coordinate is invariant.

The basic principle of measuring the deformation of the lining in the FBG sensor module 1 of the present invention, there are 'absolute coordinate method' and 'relative coordinate method' according to the method of obtaining the internal displacement.

In the absolute coordinate measuring method, the internal displacement is a moving distance between the midpoint coordinates after deformation (A-B'-C'-D'-E ') and the midpoint coordinates before deformation (A-B-C-D-E). Therefore, you must know the coordinates of the previous measuring point according to the deformation.

) 값을 내공변위로 놓는다. On the other hand, in the relative coordinate method, as shown in FIG. 8, the curvature change due to the trigonometric function for a change in time regardless of the coordinates using the length deformation and the angle deformation generated by the deformation (

) Is set to internal displacement.

Absolute coordinate method prevents the generation of new coordinates when the FBG sensor module (1) in the middle of the continuous FBG sensor module (1) in one section fails, or the error value due to malfunction of the FBG sensor module (1). There may be a problem with the delivery.

On the other hand, in the case of the relative coordinate method, since each FBG sensor module 1 independently measures, the internal displacements can be obtained with respect to the normal FBG sensor module 1, but when the angular deformation is minute due to the formal value reduction. To have that accuracy.

Hereinafter, the measurement method based on the absolute coordinate method will be described in detail;

The FBG sensor module 1 for measuring the cross-sectional deformation of a tunnel is a cross-sectional deformation that occurs when the FBG sensor module 1 is installed from S1 to S4 section along the top end 8 of the cross section of the tunnel 7 as shown in FIG. 7. In this case, the movement of the coordinate point is represented by B 'to D' coordinates, and is affected by the coordinate movement of the preceding FBG sensor module 1.

Looking at the case of the FBG sensor module 1 installed in the S1 section, since there is no preceding FBG sensor module 1, the movement from B to B 'can be represented only by the dx (b) and dy (b) components.

와

에 의한 삼각 함수에 의하여 구할 수 있다. Each installation coordinate point (A to D) is already known by the installation point design of the FBG sensor module (1), the deformation coordinate point B '(Xb', Yb ') is

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It can be obtained by trigonometric function by.

,

이다.here

,

to be.

Therefore, dx and dy can be obtained using B (Xb, Yb) and B '(Xb', Yb ').

와

를 구하여 얻을 수 있다.As a result, the cross-sectional change of the tunnel 7 at point B is

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Obtained by

The pure deformation of the FBG sensor module 1 installed in the S2 section is the movement from C to C ', and the C' coordinate is the dx (b) and dy (b, which are the components of the movement from S to B 'of S1 on the C' coordinate. ).

You can get the point C 'as shown in the above formula, and the rest of the D' and E 'coordinates are obtained in the same way.

And using the FBG sensor module 1 of the present invention the measurement method of the lining deformation by the relative coordinate method is as follows.

와 h', h 는 다음 수식과 같으며 이를 내공변위로 하여 축력 및 휨모멘트를 구하게 된다. 즉, 각

와

을 구하면 각 FBG 센서모듈(1)에서 각 좌표와 독립적인 내공변위값을 구하게 된다. Curvature change in FIG. 8

And h 'and h are as follows, and the axial force and the bending moment are obtained by using the internal displacement. That is, each

Wow

If we obtain, we obtain the internal displacement value independent of each coordinate in each FBG sensor module (1).

와

을 구하면 된다.The measuring principle of absolute coordinate method and relative coordinate method results in each FBG sensor module (1).

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You can find

는 도 1c와 같이, FBG 센서모듈(1)의 양단은 각각 고정편(100,100')에 설치되되, 일단은 볼트 등의 체결부재를 사용하여 A의 베이스(5)와 일체로 고정되며,

As shown in Figure 1c, both ends of the FBG sensor module 1 is installed on each of the fixing piece (100, 100 '), one end is fixed integrally with the base (5) of A using a fastening member such as a bolt,

값을 정밀하게 구하게 된다.The other end is a connection structure which can slide each other only in the longitudinal direction while being inserted into the base 5 of A`, and the movement distance of the coordinate point due to the cross-sectional deformation is determined by the FBG strain sensor 2.

The value is calculated precisely.

값을 구하게된다.In addition, the front and rear movement by the cross-sectional deformation is performed by the FBG angle displacement sensor (3).

Get the value.

In addition to the two-dimensional hole displacement measuring apparatus described above, if necessary, a three-dimensional hole displacement can be measured by a similar device.
That is, as shown in Figure 1a, by installing only one FBG angle displacement sensor (3) can be measured two-dimensional internal displacement, as shown in Figure 1b, the FBG angle displacement sensor (3) at different angles Installation of a plurality of three-dimensional pore displacement measurement is possible.
For example, the upper FBG angle displacement sensor (3) is installed to face the front, the lower FBG angle displacement sensor (3 ') is switched to the direction of 90 degrees with the upper FBG angle displacement sensor (3) To install it.
Therefore, two FBG angle displacement sensors 3 and 3 'are installed at 90 ° angles to each other to measure the three-dimensional internal displacement.
Therefore, if the FBG angular displacement sensor is additionally installed in the state of being installed for the existing two-dimensional pore displacement measurement, the three-dimensional pore displacement measurement becomes possible.

On the other hand, Figure 4 attached is a view showing another embodiment of the pore displacement and shear settlement measurement apparatus of the present invention installed separately the FBG strain sensor and the FBG angle displacement sensor.
As shown in FIG. 4, the FBG angular displacement sensor 3 is separated from the protective tube 4 in which the FBG strain sensor 2 is installed, and the pair of bases 5 and 5 in which a pair of fixing pieces 100.100 'are installed. A separate support is formed on '), and both ends thereof are fixed to the bases 5 and 5', and at least one FBG angle displacement sensor 3 is installed at the outside of the support by the connecting shaft 6. The two-dimensional or three-dimensional pore displacement and the tip settlement can be measured at all times.
One end of the support installed on the pair of bases 5 and 5 'is fixed to the base 5 by a fastening member so as to be integrated with the base 5, and the other end to the base 5'. It has a connection structure that can slide each other only in the longitudinal direction.

As described in detail above, the present invention provides an FBG sensor module for measuring the tunnel internal displacement and the tip settlement, and simultaneously installs the FBG strain sensor and the FBG angle displacement sensor on the protective tube to accurately measure the length and angle of the measurement point. Sensing and completely overcoming the influence of electromagnetic waves, which is a disadvantage of the conventional electric system, has the effect of constantly measuring the tunnel displacement of the subway in operation which has been impossible.
In addition, the precision of the optical fiber grating sensor can be improved, and up to 40 sensors can be connected in series with one strand of optical fiber, which requires much less space than the conventional electric system. Since the measurement of one reflection wavelength is the same, the same measurement method can be used for one-time safety diagnosis, and the cumulative deformation compared to the initial value of civil engineering structures can be measured.

The present invention described above is limited to the above-described embodiments as various substitutions, modifications, and alterations are possible within the scope of the present invention without departing from the technical spirit of the present invention. It is not.

Claims (4)

The fixing pieces 100, 100 'at both ends of the FBG sensor module 1 are connected to the bases 5, 5' by fastening members; Both ends of the protective tube 4 are installed on the fixing pieces 100 and 100 '; An FBG strain sensor (2) is installed in the longitudinal direction between the fixing pieces (100, 100 ') inside the protective tube (4); One or more FBG angular displacement sensors 3 are installed at the outside of the protective tube 4 by the connecting shaft 6 so that the two-dimensional or three-dimensional internal displacement and the hem settlement can be measured at all times. One end of the protective tube (4) installed on the fixing piece (100, 100 ') is fixed to the fixing piece (100) by a fastening member to operate integrally, the other end is installed in the fixing piece (100') in the longitudinal direction only An apparatus for measuring displacement and shear settling using an optical fiber grating sensor, characterized by having a connection structure that can slide with each other. delete The method of claim 1, The FBG angular displacement sensor 3 is separated from the protective tube 4 in which the FBG strain sensor 2 is installed, and is separated on a pair of bases 5 and 5 'in which a pair of fixing pieces 100.100' are installed. Constructing a support to fix both ends to the base (5,5 '); One or more FBG angular displacement sensors 3 are installed on the outside of the support by the connecting shaft 6 to measure the two-dimensional or three-dimensional pore displacement and the tip settlement. Internal displacement and hem settlement measurement device. The method of claim 3, wherein One end of the support installed on the pair of bases 5 is integrally fixed to the bases 5 and 5 'by the fastening member so as to be integrated with the base 5, and the other end thereof is the base 5 and 5'. A device for measuring the displacement and pore settling using an optical fiber grating sensor, characterized in that it has a connection structure that can slide each other only in the longitudinal direction.

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