KR20090060111A - Burying type optical fiber sensor - Google Patents

Abstract

A buried optical fiber sensor is provided, which enables to conveniently and exactly measure the deformation or other conduct of the underground or the structure. A buried optical fiber sensor comprises the main body and the optical fiber sensing part. The main body(100) is formed of the optical fiber mounting unit(110) in the side of the top and bottom and left and right in the longitudinal direction. The optical fiber sensing part(200) is mounted on the optical fiber mounting unit. The main body is made of synthetic resin material having the elasticity. The optical fiber sensing part is equipped with the optical fiber protector(220).

Description

Buried Fiber Optic Sensors {BURYING TYPE OPTICAL FIBER SENSOR}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of construction measurement, and more particularly, to a sensor embedded in a ground or a structure to measure deformation, leak detection, and the like.

Measuring deformations and other behaviors in the ground or inside a structure has become a very important task in that it is possible to predict the slope or the collapse of the structure in advance.

In particular, the deformation of the ground occurs through natural causes such as fine earthquake and heavy rain or artificial causes such as civil engineering.

Ground deformation caused by such cause causes accidents such as damage of pipes and buried structures due to settlement of ground, collapse of slope, and collapse of tunnel in tunnel construction.

Conventionally, as a means for measuring this, a method of predicting the deformation of the ground through the change in the length of the wire by connecting the pile to the ground at a predetermined interval, and the wire has been used.

However, such a technique was able to measure the behavior of the surface of the earth, and had a problem that the measurement of the ground is fundamentally impossible.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a buried optical fiber sensor that can accurately and conveniently measure the deformation or other behavior of the underground or inside the structure.

The present invention, in order to achieve the object as described above, the main body 100, the optical fiber mounting portion 110 is formed in the longitudinal direction on the sides of the top, bottom, left and right; The optical fiber sensor 200 mounted on the optical fiber mounting unit 110 is provided.

The main body 100 is preferably formed of a synthetic resin material having elasticity and restoring force so as to be buried in the ground or structure.

The optical fiber sensing unit 200 is an optical fiber 210; And an optical fiber protection unit 220 mounted around an outer surface of the optical fiber 210 to behave together with the optical fiber 210.

The optical fiber protection unit 220 preferably includes a reinforcing material 221 formed of a synthetic resin material having elasticity and restoring force to behave together with the main body 100.

The reinforcing material 221 is a circular cross-sectional structure, the optical fiber mounting portion 110 is preferably a groove structure in which the reinforcing material 221 is fitted.

In the state where the optical fiber sensing unit 200 is fitted to the optical fiber mounting unit 110, the embedded optical fiber sensor preferably has a substantially circular cross section.

The optical fiber protective part 220 is formed of a metallic material and includes a metallic protective material 222 mounted between the reinforcing material 221 and the optical fiber 210 to behave together with the optical fiber 210. It is preferable.

The metallic protective material 222 is preferably formed by a structure to maintain a cross section of a certain shape even when bending occurs.

It is preferable that a frictional force increasing structure is formed on the outer surface of the metallic protective material 222.

The metallic protective material 222 is preferably mounted as a braided structure by a metal yarn.

The metallic protective material 222 is preferably formed of at least one material selected from the group consisting of silver, copper, aluminum, gold, and platinum.

The optical fiber protection unit 220 may further include a coating material 223 mounted between the reinforcing material 221 and the metallic protection material 222 to behave together with the metallic protection material 222.

The coating material 223 is preferably a heat resistant material capable of resisting high temperatures of 200 ° C or higher.

The coating material 223 is preferably a synthetic resin material.

The coating material 223 is preferably formed of a Teflon material.

A coupling member mounting groove 120 formed in a longitudinal direction in an area between the optical fiber mounting portions 110 of the main body 100; A coupling member 300 that is commonly mounted in the coupling member mounting groove 120 and the coupling member mounting groove 120a of the main body 100a of the other embedded optical fiber sensor; It is preferable that the fixing member 310 to further secure the coupling member 300 to the main body 100;

The width of the lateral opening of the coupling member mounting groove 120 is preferably smaller than the width of the coupling member 300.

The fixing part 310 is installed on the outside of the coupling member 300, it is preferable that the width of the head includes a bolt member 311 larger than the width of the side opening of the coupling member mounting groove 120. Do.

The present invention provides a buried optical fiber sensor that can accurately and conveniently measure the deformation or other behavior in the ground or inside the structure.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in Figure 1, the embedded optical fiber sensor according to the present invention, basically, the optical fiber mounting portion 110 is formed in the longitudinal direction on the sides of the top, bottom, left and right; And an optical fiber sensing unit 200 mounted on the optical fiber mounting unit 110.

Optical fiber refers to a thin fiber having a diameter of about 0.1 mm formed so that the refractive index of light is high inside and low outside, so that total reflection optical phenomenon occurs inside the fiber.

In order to reduce light loss when transmitting light using the above phenomenon, highly transparent material is required, and high purity quartz or polymer material having excellent optical properties is used.

The structure has a double cylinder shape in which a core called a core is wrapped around a portion called cladding. The outside is coated with one or two coats of synthetic resin to protect it from impact.

The total size excluding the protective coating is 100 to several hundred μm in diameter (1 μm is 1/1000 mm), and the refractive index of the core portion is higher than the refractive index of the cladding, so that the light is focused on the core portion so that the light can proceed without escaping well. have.

Optical fiber is mainly used in the communication field, but when the optical fiber is stretched by the temperature and pressure, it detects the interference pattern of the light passing through the inside and can measure the temperature and pressure. The sensor is called an optical fiber sensor.

Recently, various attempts have been made to utilize such optical fiber sensors in the field of construction measurement, and in detail, measurement of displacement (sag, deformation) of structures due to pressure changes, leak detection due to temperature changes, and the like.

As in the present invention, when mounting the optical fiber sensing unit 200 having the characteristics as described above to the optical fiber mounting portion 110 of the main body 100, and embedded in the underground or structure, at the end of the optical fiber exposed to the outside Since accurate measurement is possible, it is possible to obtain the effect of measuring the deformation and behavior of the ground or the structure conveniently and accurately in real time.

In addition, the optical fiber sensor according to the present invention, since the optical fiber sensing unit 200 is mounted in the longitudinal direction on the side of the top, bottom, left and right (four rooms) of the main body 100, displacement and bending displacement in all directions of the parent to be measured. This has the effect of accurately measuring.

That is, as shown in Figs. 3 and 4, when the optical fiber sensor causes the bending deformation due to the displacement of the parent, a negative value may be obtained by subtracting the changed length of the lower optical fiber from the changed length of the upper optical fiber. It can be seen that the mother had a deformation in the downward direction.

On the contrary, if a positive value is obtained, it can be seen that the mother has been deformed upward.

Due to the characteristics of the optical fiber, the point at which the displacement occurs can be measured. Therefore, in combination with the above description, it is possible to accurately measure that the mother caused the settlement behavior at a specific site.

In addition, since the optical fiber sensing unit 200 is also mounted on the left and right sides of the optical fiber sensor, the displacement and the bending displacement in the left and right directions can be measured by the above principle.

In case of embedding such buried fiber optic sensor on dangerous slope and ceiling surface of tunnel under construction, it is possible to accurately grasp the behavior of the mother earth in real time, and to prevent large accidents caused by collapse of slope, tunnel, etc. in advance. have.

Since the main body 100 is buried in the ground or the structure to be integrally formed, the main body 100 is preferably formed of a synthetic resin material having elasticity and restoring force.

In addition, in order to be buried in the ground or the structure to exhibit performance for a long time, it is preferable to use a material (such as ABS) having excellent physical properties such as rigidity, chemical resistance, impact resistance.

Since the optical fiber is fragile and easily broken, protection means must be taken to prevent it.

That is, the optical fiber sensing unit 100 is an optical fiber 210; And an optical fiber protection unit 220 mounted around the outer surface of the optical fiber 210 to behave together with the optical fiber 210. The optical fiber protection unit 220 is configured to the optical fiber mounting unit 110 of the main body 100. It is desirable to take the mounted configuration.

Since the optical fiber protection unit 220 also needs to behave together with the parent to be measured, it is preferable to take a configuration including a reinforcement 221 formed of a synthetic resin material having elasticity and restoring force to behave together with the main body 100.

Since the reinforcing material 221 serves to protect the optical fiber 210 of the core part by being mounted on the main body 100, it is preferable that the reinforcing material 221 is formed of a material having excellent rigidity and bonding property with the main body (FRP, etc.).

The mounting structure between the optical fiber protection unit 220 and the optical fiber mounting unit 110 of the main body 100 may take a bonding method of mutually independent structures, but in order to achieve a more stable behavior structure, the optical fiber protection unit 220 ), The reinforcing material 221 has a circular cross-sectional structure, and the optical fiber mounting portion 110 preferably has a groove structure into which the reinforcing material 221 is fitted.

In the state where the optical fiber sensing unit 200 is fitted to the optical fiber mounting unit 110, it is preferable to allow the embedded optical fiber sensor to have a substantially circular cross section in that the integrated behavior with the mother can be made smoother.

Between the reinforcing member 221 of the optical fiber protection unit 220 and the optical fiber 210, as shown in FIG. 5 or less, the metal protective material 222 is formed by a metallic material and behaves together with the optical fiber 210. It is preferred to be mounted.

Since the metal material has excellent strength, thereby protecting the outer surface of the optical fiber 210, it is possible to prevent the breakage of the optical fiber 210, and has flexibility (flexibility), so that the displacement of the structure to be the parent If is generated, the displacement is transmitted to the optical fiber 210 as it is to enable accurate measurement.

In addition, in order for the optical fiber sensor to accurately measure the change in ambient temperature and perform a role such as leak detection (the leaking section uses the principle that the temperature decreases compared to the surroundings), the sensor itself may generate a certain amount of heat. By having, it is necessary to maintain a constant temperature.

If the temperature of the sensor itself changes with the change in the ambient temperature, since the reference temperature is changed, it is impossible to measure the change in temperature.

Since the metal material is basically not only excellent in thermal and electrical conductivity, but also finely adjusts the resistance value by the inclusion of impurities, the present invention forms a sensor by surrounding the protective material 222 on the outer surface of the optical fiber 210. In the case of taking the structure of, the optical fiber sensor can be maintained at a constant temperature, thereby obtaining the effect that accurate measurement of the ambient temperature change is possible.

It is preferable that the structure of the metallic protective material 222 satisfy | fills the following requirements.

First, since it serves to protect the internal optical fiber 210, even when bending occurs due to deformation of the parent structure, it is good to take a structure that always maintains a cross section (for example, a circular shape) of a constant shape.

For example, a corrugated pipe structure as shown in FIGS.

Second, in order to firmly bond with the reinforcing material 221 or the coating material 223 described later, it is preferable that a frictional force increasing structure is formed on the outer surface of the metallic protective material 222.

For example, it is an embossing structure (structure in which a plurality of protrusions are formed) as shown in FIG.

The metallic protective material 222 is preferable in that the braided structure by the metal yarn can naturally meet all of the above requirements, as shown in FIGS. 9 and 10.

Here, the braided structure refers to a structure in which a metal yarn (processed with metal in the shape of a thin thread) is woven into a net structure diagonally with respect to the longitudinal direction of the optical fiber sensor, so that a cavity is naturally formed. .

As described above, it is possible to protect the optical fiber 210 inside due to the rigidity of the metal while maintaining a constant circular cross section at all times when bending occurs.

Furthermore, since it takes a net structure, when the coating operation is performed, a part of the metallic protective material 222 is naturally embedded in the reinforcing material 221 or the coating material 223 to be described later, it is possible to obtain a very good bonding force. have.

As described above, the metallic protective material 222 may be made of a material having excellent flexibility, thermal and electrical conductivity, and controllability of resistance values.

Examples include silver, copper, aluminum, gold, platinum, and the like, specifically, silver has been shown to most certainly meet the above requirements.

As shown in FIG. 11, the optical fiber protection unit 220 of the optical fiber sensing unit 100 further includes a coating material 223 mounted around the outer surface of the metallic protection material 222 to behave together with the metallic protection material 222. It is desirable to take one structure.

After the coating of the metallic protective material 222 on the optical fiber 210, once the outer surface of the metallic protective material 222 is coated with a coating material 223 to fix the metallic protective material 222, and inserted into the reinforcing material 221 This is because it is advantageous in terms of efficiency and ease of manufacturing.

The coating material 223 is coated around the outer surface of the metallic protective material 222, and is preferably formed of a material having excellent flexibility in order to behave together with the reinforcing material 221.

Since the metallic protective material 222 inside the coating material 223 serves as a heating element as described above, the coating material 223 mounted on the outside of the coating material 223 is formed of a heat resistant material capable of resisting a high temperature of about 200 ° C. or more. It is preferable.

In order to satisfy such conditions, it is preferable to employ synthetic resin as the material of the coating material 223, and more specifically, to use teflon.

On the other hand, when it is necessary to use a plurality of embedded optical fiber sensor according to the present invention, it can take the following configuration.

That is, as shown in Figure 12, 13, the coupling member mounting groove 120 formed in the longitudinal direction in the region between the optical fiber mounting portion 110 of the main body 100; A coupling member 300 commonly mounted to the coupling member mounting groove 120 and the coupling member mounting groove 120a of the main body 100a of the other embedded optical fiber sensor; It is a structure further provided; fixing portion 310 for fixing the coupling member 300 to the main body 100.

In this case, the coupling member 300 is mounted on the coupling member mounting grooves 120 and 120a of both main bodies 100 and 100a and has a merit that the connection structure can be easily achieved by fixing it by the fixing part 310. have.

In order to facilitate insertion of the coupling member 300 into the coupling member mounting grooves 120 and 120a, the width of the side opening of the coupling member mounting groove 120 is smaller than that of the coupling member 300, It is preferable that the coupling member 300 does not deviate laterally from the coupling member mounting groove 120.

Fixing unit 310 may be implemented by a variety of structures, but when the coupling member mounting groove 120 has the above configuration, the width of the head is larger than the width of the side opening of the coupling member mounting groove 120 By installing the bolt member 311 outside the coupling member 300, the coupling member 300 and the main body 100 may be coupled by tightening the bolt member 311.

Since the above is merely described with respect to some of the preferred embodiments that can be implemented by the present invention, the scope of the present invention, as is well known, should not be construed as limited to the above embodiments, the present invention described above All of the technical ideas together with the technical idea of the base will be included in the scope of the present invention.

1 to 11 show an embodiment of an optical fiber sensor according to the present invention,

1 is a perspective view of a first embodiment.

2 is a cross-sectional view of the first embodiment.

3 is a first state diagram of the first embodiment;

4 is a second state diagram of the first embodiment;

5 is a cross-sectional view of a second embodiment of the optical fiber sensing unit.

6 is a first state diagram of a second embodiment of a metallic protective material.

Fig. 7 is a second state diagram of the second embodiment of the metallic protective material.

8 is a side view of a third embodiment of a metallic protective material.

9 is a first state diagram of the fourth embodiment of the metallic protective material.

10 is a second state diagram of the fourth embodiment of the metallic protective material.

11 is a sectional view of a third embodiment of an optical fiber sensing unit.

12 is a partial perspective view of a state before coupling;

13 is a partial perspective view of a state after coupling.

** Description of the symbols for the main parts of the drawings **

* 100: main body 110: optical fiber mounting part

120: coupling member mounting groove 200: optical fiber sensing unit

210: optical fiber 220: optical fiber protection unit

221: reinforcing material 222: metallic protective material

223 coating material 300 coupling member

310: fixing part 311: bolt member

Claims (18)

Body 100 is formed with the optical fiber mounting portion 110 in the longitudinal direction on the upper and lower left and right sides; An optical fiber sensing unit 200 mounted on the optical fiber mounting unit 110; Embedded optical fiber sensor. The method of claim 1, The main body 100 is a buried optical fiber sensor, characterized in that formed by a synthetic resin material having elasticity and restoring force to be buried in the ground or structure. The method of claim 1, The optical fiber sensing unit 200 Optical fiber 210; An optical fiber protection unit 220 mounted around an outer surface of the optical fiber 210 to behave together with the optical fiber 210; Buried optical fiber sensor, characterized in that provided. The method of claim 3, The optical fiber protection unit 220 Buried optical fiber sensor, characterized in that it comprises a reinforcement (221) formed by a synthetic resin material having elasticity and restoring force to behave with the main body (100). The method of claim 4, wherein The reinforcing material 221 is a structure of a circular cross section, The optical fiber mounting portion 110 is a buried optical fiber sensor, characterized in that the groove structure in which the reinforcing material (221) is fitted. The method of claim 5, In the state in which the optical fiber sensing unit 200 is fitted to the optical fiber mounting portion 110, the embedded optical fiber sensor is a buried optical fiber sensor, characterized in that it comprises a substantially circular cross section. The method of claim 4, wherein The optical fiber protection unit 220 The buried optical fiber sensor is formed of a metallic material and includes a metallic protective material 222 mounted between the reinforcing material 221 and the optical fiber 210 to behave together with the optical fiber 210. . The method of claim 7, wherein The metallic protective material 222 is a buried optical fiber sensor, characterized in that formed by the structure to maintain a constant cross-section even when bending occurs. The method of claim 7, wherein Embedded optical fiber sensor, characterized in that the friction increase structure is formed on the outer surface of the metallic protective material (222). The method of claim 8, The metallic protective material 222 is A buried optical fiber sensor characterized in that it is mounted as a braided structure by metal yarn. The method of claim 7, wherein The metallic protective material 222 is A buried optical fiber sensor, characterized in that formed by at least one material selected from the group consisting of silver, copper, aluminum, gold, platinum. The method of claim 7, wherein The optical fiber protection unit 220 And a coating member 223 mounted between the reinforcing member 221 and the metallic protective member 222 to behave together with the metallic protective member 222. The method of claim 12, The coating material 223 is a buried optical fiber sensor, characterized in that the heat-resistant material capable of resisting high temperatures of 200 ℃ or more. The method of claim 12, The coating material 223 is Buried optical fiber sensor, characterized in that the synthetic resin material. The method of claim 14, The coating material 223 is A buried optical fiber sensor, characterized in that formed by Teflon material. The method according to any one of claims 1 to 15, Coupling member mounting groove 120 formed in the longitudinal direction in the region between the optical fiber mounting portion 110 of the main body 100; A coupling member 300 that is commonly mounted in the coupling member mounting groove 120 and the coupling member mounting groove 120a of the main body 100a of the other embedded optical fiber sensor; Fixing portion 310 for fixing the coupling member 300 to the main body 100; A buried optical fiber sensor further comprising. The method of claim 16, The width of the side opening of the coupling member mounting groove 120 is smaller than the width of the coupling member 300, embedded optical fiber sensor. The method of claim 17, The fixing part 310 is It is installed on the outside of the coupling member 300, buried optical fiber sensor, characterized in that the width of the head includes a bolt member (311) larger than the width of the side opening of the coupling member mounting groove (120).

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