JP2022027194A - Structure management method and structure management device - Google Patents

Abstract

To provide a structure management method and a structure management device which can grasp a behavior in a wide part of a plurality of blocks, and can easily perform installation operation.SOLUTION: A structure management method that is used for constructing a structure including a plurality of blocks 5 by gradually constructing the blocks 5 includes the steps of: preparing an optical fiber 11 for detecting distortion; constructing the blocks 5; installing the optical fiber 11 on the constructed blocks 5 while leaving an extra length 11g; and detecting the distortion of the constructed blocks 5 by the optical fiber 11. The structure is constructed by repeating the steps of constructing the blocks 5, installing the optical fiber 11 thereon while leaving the extra length 11g, and detecting the distortion of the blocks 5 by the optical fiber 11.SELECTED DRAWING: Figure 11

Description

The present disclosure relates to a structure management method and a structure management device for a structure constructed by block construction.

Conventionally, various structure management methods and structure management devices for managing structures in the middle of construction have been known. Japanese Unexamined Patent Publication No. 2017-210754 describes a caisson skeleton sunk device and a sunk method. In the method of submerging the caisson skeleton, the peripheral friction of the caisson skeleton is controlled to adjust the inclination of the caisson skeleton and sunk the caisson skeleton.

The caisson skeleton subsidence device includes a plurality of injection nozzles arranged so as to be arranged along the circumferential direction and the vertical direction of the caisson skeleton, and a plurality of peripheral friction meters arranged in the vicinity of any of the plurality of injection nozzles. , A loose area measuring means for measuring a loose area formed on the peripheral surface of the caisson skeleton is provided.

Each peripheral friction meter measures the frictional force on the outer peripheral surface of the caisson skeleton. Then, by injecting the liquid from the discharge port near the peripheral friction meter that measures the high frictional force, the caisson skeleton is promoted to be sunk and the inclination of the caisson skeleton is corrected. A plurality of loose area measuring means are arranged so as to be arranged along the circumferential direction and the vertical direction of the caisson skeleton. The caisson skeleton has a plurality of blocks arranged along the vertical direction, and a discharge port, a peripheral friction meter, or a loosening area measuring means is arranged in each of the plurality of blocks.

Japanese Unexamined Patent Publication No. 2017-210754

In the above-mentioned subsidence device and subsidence method, a large amount of equipment is required because a plurality of injection nozzles, a peripheral friction meter, or a loosening area measuring means are arranged in each of a plurality of blocks of the caisson skeleton, and the device configuration is required. There is the problem of complexity. In addition, since a measuring instrument such as a peripheral friction meter can only measure the location where the measuring instrument is placed, many measuring instruments are used to grasp the behavior of a wide area (for example, the whole) of a plurality of blocks. Must be placed. Therefore, in order to measure a wide range of a plurality of blocks, many measuring instruments must be arranged at many places, and there is also a problem that the installation work is complicated.

It is an object of the present disclosure to provide a structure management method and a structure management device capable of grasping the behavior of a wide range of a plurality of blocks and easily performing installation work.

The structure management method according to the present disclosure is a structure management method used when constructing a structure including a plurality of blocks by constructing blocks step by step, and prepares an optical fiber for detecting strain. A block is constructed by including a process, a process of constructing a block, a process of installing an optical fiber in the constructed block while leaving an extra length, and a process of detecting the distortion of the constructed block by the optical fiber. The structure is constructed by repeating the process of installing the optical fiber while leaving a surplus length, and the process of detecting the distortion of the block by the optical fiber.

In this structure management method, an optical fiber is installed in each of a plurality of blocks, and the strain of the plurality of blocks is detected by the installed optical fiber. Therefore, by installing the linear optical fiber over a plurality of blocks, it is possible to detect distortion in a wider area with a small number of optical fibers. Therefore, since it is possible to measure the strain by installing an optical fiber in each of the plurality of blocks while constructing each of the plurality of blocks, the behavior of a wide area of the plurality of blocks can be grasped by a small number of optical fibers. can do. Further, in this structure management method, an optical fiber is installed while leaving an extra length in the constructed block, and the structure is repeatedly constructed by constructing the block, installing the optical fiber in the block, and detecting the distortion of the block by the optical fiber. Build things. Therefore, it is possible to install the optical fiber in the block while leaving a surplus length for each construction of the block, and to construct the structure while repeating the construction of the block and the installation of the optical fiber. Since the optical fiber may be installed by fixing one optical fiber to the block while leaving an extra length, it can be easily performed without the need for connecting the optical fiber. Therefore, since a small number of optical fibers can be constructed together with the construction of the block, the installation work can be easily performed and a wide range of distortion can be efficiently detected.

In the step of detecting the distortion of the block by the optical fiber, the distortion of the block may be detected by Rayleigh measurement. Rayleigh measurement measures block distortion by detecting Rayleigh backscattered light in light propagating through an optical fiber. The light intensity of Rayleigh backscattered light is weaker than the light intensity of the input measured light. Therefore, by detecting this change in light intensity, the magnitude of strain generated in the optical fiber can be obtained. Therefore, Rayleigh measurement using Rayleigh backscattered light has the advantages of high accuracy and resistance to light loss.

The block may be a reinforced concrete block, and the structure may be a reinforced concrete structure. In this case, it is possible to easily measure the strain in a wide range of the reinforced concrete structure gradually constructed for each block.

The structure may be a caisson containing reinforced concrete blocks. In this case, for example, one optical fiber can be installed for each constructed block for a caisson that is gradually constructed for each block by the pneumatic caisson method. Therefore, the strain generated in each of the plurality of blocks of the caisson can be measured by one optical fiber. Therefore, it is possible to easily measure the strain of a wide range of caisson with a small number of optical fibers.

The structure management method described above includes a step of identifying a location where a frictional force is generated on the outer peripheral surface of the caisson from the detected strain, and a step of injecting a lubricant into the location where the frictional force is generated. May be good. In this case, it is possible to measure the frictional force on the outer peripheral surface of the caisson from the strain and identify the location where the frictional force is generated. By identifying the points where the frictional force is concentrated, it is possible to take necessary measures before the quality of the caisson deteriorates. That is, since the lubricant is injected into the place where the frictional force is generated, it is possible to inject as much lubricant as necessary into the required place. Therefore, since the lubricant can be injected efficiently, pinpointly and promptly, a high-quality caisson can be efficiently constructed. In addition, it is possible to reduce the influence on the surroundings due to the sudden subsidence.

The structure management device according to the present disclosure is a structure management device used when constructing a structure including a plurality of blocks by constructing blocks step by step, and includes an optical fiber for detecting strain. Each time a block is constructed, the optical fiber is installed while leaving an extra length in the constructed block, and the optical fiber installed in each of the plurality of blocks detects distortion.

In this structure management device, an optical fiber is installed in each of a plurality of blocks, and the distortion of the plurality of blocks is detected by the optical fiber. By installing the linear optical fiber over a plurality of blocks while leaving an extra length, it is possible to detect distortion in a wider range with a small number of optical fibers. Therefore, since it is possible to install an optical fiber in each block and measure strain while constructing each of the plurality of blocks, it is possible to grasp the behavior of a wide area of the plurality of blocks with a small number of optical fibers. It becomes. In this structure management device, the optical fiber is installed in each of the plurality of blocks while leaving an extra length, and the strain is measured. Therefore, as in the structure management method described above, it is possible to construct the structure while repeating the construction of the block, the installation of the optical fiber on the block, and the detection of the distortion of the block by the optical fiber. The optical fiber can be easily installed while constructing. That is, the installation of the optical fiber can be easily performed because one optical fiber may be fixed to the block while leaving an extra length. Therefore, since a small number of optical fibers can be constructed together with the construction of the block, the installation work can be easily performed and the distortion in a wide range can be efficiently detected. Further, by evaluating the detected strain, it is possible to efficiently inject the lubricant, ensure the quality of the skeleton, and reduce the influence of the surroundings due to the sudden subsidence.

According to the present disclosure, the behavior of a wide range of a plurality of blocks can be grasped, and the installation work can be easily performed.

It is a vertical sectional view which shows an exemplary caisson which shows the structure which concerns on one Embodiment. (A) is a vertical sectional view schematically showing a normal caisson state. (B) is a vertical cross-sectional view schematically showing a state in which a high frictional force acts on the outer peripheral surface of the caisson. (C) is a vertical cross-sectional view schematically showing a state in which the caisson is cracked as a result of a high frictional force acting on the outer peripheral surface of the caisson. It is a top view schematically showing the structure of the caisson and the structure management apparatus of FIG. It is a perspective view which shows typically the arrangement of the caisson of FIG. 3 and the optical fiber of the structure management apparatus. (A) is a sectional view of an exemplary optical fiber. (B) is a diagram schematically showing the surface of an optical fiber. (C) is a cross-sectional view of an optical fiber according to a modified example. It is a perspective view which shows typically the mode of the optical fiber for temperature compensation. It is a graph which shows the example of the simulation result of the structure management apparatus of FIG. It is a graph which shows the example of the simulation result of the structure management apparatus of FIG. It is a graph which shows the example of the simulation result of the structure management apparatus of FIG. It is a graph which shows the example of the simulation result of the structure management apparatus of FIG. (A), (b) and (c) are vertical sectional views schematically showing each procedure of the structure management method according to one embodiment. It is a flow diagram which shows the example of the process of the structure management method which concerns on one Embodiment. (A), (b) and (c) are vertical sectional views schematically showing each procedure of the structure management method according to another embodiment. It is a flow diagram which shows the example of the process of the structure management method which concerns on another form. Each of (a) and (b) is a plan view and a vertical sectional view showing an installation example of an optical fiber according to another embodiment. Each of (a) and (b) is a plan view and a vertical sectional view showing an installation example of an optical fiber according to still another embodiment. (A), (b), (c) and (d) are diagrams schematically showing a procedure of a structure management method when constructing a structure according to another form.

Hereinafter, embodiments of the structure management device and the structure management method according to the present disclosure will be described with reference to the drawings. In the description of the drawings, the same or corresponding elements are designated by the same reference numerals, and duplicate description will be omitted as appropriate. In addition, the drawings may be partially simplified or exaggerated for the sake of easy understanding, and the dimensional ratios and the like are not limited to those described in the drawings.

FIG. 1 is a vertical sectional view schematically showing a caisson 1 and a structure management device 10 as an example of a structure. The caisson 1 is a pneumatic caisson and includes a caisson skeleton 2. The caisson skeleton 2 has a side wall 3 having a blade edge 3b at the lower end. The caisson 1 is constructed by the pneumatic caisson method. The structure management device 10 includes, for example, a plurality of optical fibers 11 installed on the inner peripheral surface 3d (surface) of the side wall 3, and a lubricant injection device 15 for injecting a lubricant into the outer peripheral surface 3c of the side wall 3. ..

In the pneumatic caisson method, a block 5 which is a reinforced concrete skeleton is constructed on the ground surface G, and for example, a work room 4 is provided below the lowermost block 5. By sending compressed air corresponding to the groundwater pressure into the working room 4, the infiltration of groundwater into the working room 4 is prevented. Excavation and excavation are performed inside the work room 4 to sink the caisson skeleton 2, and the caisson skeleton 2 can be used as the foundation of a building such as a bridge, a sewage pumping station, an underground adjustment pond, a shield tunnel vertical pile, or a road. It is used as a structure such as a tunnel T of.

For example, the construction of the caisson 1 is performed by dividing it into 7 lots. Specifically, the block 5 including the bottom wall 6 of the caisson skeleton 2 is constructed in the first lot, and the block 5 on the bottom wall 6 is constructed in the second lot. The height of the block 5 for each lot is, for example, 4 m or more and 5 m or less, but can be changed as appropriate. Then, from the third lot onward, the block 5 is sequentially constructed on the block 5 for each lot, and the uppermost block 5 is constructed on the seventh lot. However, the number of lots is not limited to 7, and may be 6 or less or 8 or more, and can be appropriately changed.

2 (a), 2 (b) and 2 (c) are vertical cross-sectional views schematically showing the side wall 3 of the caisson skeleton 2 and the ground B around the caisson skeleton 2. As shown in FIG. 2A, when the frictional force (peripheral frictional force) acting between the outer peripheral surface 3c of the side wall 3 and the ground B is small, the blade edge 3b of the caisson skeleton 2 becomes the ground B. Sink. At this time, by excavating the earth and sand (ground B) inside the work room 4, the caisson skeleton 2 sinks into the ground B due to the subsidence force, and the caisson skeleton 2 is in a state where a compressive force acts on the whole.

On the other hand, when the frictional force acting between the outer peripheral surface 3c of the side wall 3 and the ground B becomes high, the blade edge 3b of the caisson skeleton 2 does not sufficiently sink into the ground B as shown in FIG. 2B. When a frictional force acts on the outer peripheral surface 3c, the frictional force becomes an upward resistance force, so that the caisson skeleton 2 may try to tilt or may not sink.

At this time, a tensile force may act on the caisson skeleton 2 depending on the position and magnitude of the frictional force. In addition, the frictional force acting on the outer peripheral surface 3c of the caisson skeleton 2 may cause the caisson skeleton 2 to tilt or not sink to the ground B. Therefore, when the caisson skeleton 2 is laid down, the posture of the caisson skeleton 2 is grasped. However, it is necessary to ensure the accuracy of the sunk.

Further, when a large frictional force is locally generated between the outer peripheral surface 3c of the side wall 3 and the ground B, the cutting edge 3b of the caisson skeleton 2 floats from the ground B as shown in FIG. 2 (c). As a result, the reaction force of the ground B to the cutting edge 3b becomes smaller (eliminates), and the caisson skeleton 2 hangs from the position where the frictional force is generated. As a result, a tensile force acts on the caisson skeleton 2, and if the tensile force on the caisson skeleton 2 becomes large, there is a concern that the quality may deteriorate due to problems such as cracks X in the caisson skeleton 2.

Further, when the frictional force acts on the outer peripheral surface 3c until the reaction force from the ground B to the blade edge 3b of the caisson skeleton 2 disappears, the lubricant is injected into the outer peripheral surface 3c. However, the caisson skeleton 2 may fall when the lubricant is injected to reduce the frictional force of the outer peripheral surface 3c. When the caisson skeleton 2 falls, the impact of the fall is transmitted to the surroundings, which may cause shaking or the like.

Conventionally, the injection of the lubricant into the outer peripheral surface 3c of the caisson skeleton 2 using the lubricant injection device 15 may be performed by the sense of the operator, and the accuracy of the injection of the lubricant depends on the skill level of the operator. There was a current situation of doing. However, even a skilled worker may not be able to determine which position of the caisson skeleton 2 the large frictional force is acting on, so that the lubricant cannot be injected into an appropriate position, and the lubricant is wasted. It was sometimes uneconomical because it was injected into.

On the other hand, in the structure management device 10 according to the present embodiment, the lubricant can be injected pinpointly at an appropriate position by the lubricant injection device 15, which enables efficient injection of the lubricant. FIG. 3 is a plan view schematically showing the caisson 1 and the structure management device 10. FIG. 4 is a perspective view schematically showing the arrangement of the optical fiber 11 of the structure management device 10.

As shown in FIG. 3, a steel sheet pile 7 is provided on the outside of the caisson 1 in a plan view, and a structure management device 10 is provided around the caisson 1. The structure management device 10 includes an optical fiber 11 that detects the distortion of the caisson 1, a temperature-correcting optical fiber 12, and a control device 13 to which each of the optical fiber 11 and the temperature-correcting optical fiber 12 is connected. The control device 13 is provided on the ground surface G, for example, and outputs measurement light to each of the optical fiber 11 and the temperature compensation optical fiber 12.

The optical fiber 11 is, for example, a distributed optical fiber sensor, and detects the distortion of the caisson 1. By using a distributed optical fiber sensor, the detailed distribution of strain can be grasped, and if there is a singular point in the magnitude of strain, the position of occurrence of deformation or the degree of deformation in the entire caisson skeleton 2 Can be grasped in detail.

As shown in FIGS. 3 and 4, the structure management device 10 includes a plurality of optical fibers 11 as optical fiber cables, and each optical fiber 11 is fixed to the inner peripheral surface 3d of the caisson 1. In a plan view, the plurality of optical fibers 11 are arranged so as to be arranged along the circumferential direction D of the caisson 1.

As an example, four optical fibers 11 are arranged so as to be arranged at equal intervals along the circumferential direction D. The end of the optical fiber 11 is connected to the control device 13, and the optical fiber 11 extends vertically downward from one side of the circumferential direction D of the caisson 1 extending from the control device 13 and extends vertically downward from the bottom wall of the caisson 1. 6 (near the bottom wall 6) is bent along the circumferential direction D.

For example, the optical fiber 11 is installed so as to extend from the upper end to the lower end of the caisson 1. This makes it possible to detect strain at all points of the caisson 1 in the vertical direction. Further, by attaching the optical fiber 11 so as to extend along the vertical direction, it is possible to detect the distribution of the strain of the caisson 1 in the vertical direction.

The optical fiber 11 bent along the circumferential direction D in the bottom wall 6 is bent vertically upward on the other side of the circumferential direction D, extends from the caisson 1, and is connected to the control device 13. As an example, the control device 13 includes one end and the other end of an optical fiber 11 extending vertically downward from the north side of the caisson 1 and extending vertically downward from the northwest side of the caisson 1, extending vertically downward from the west side of the caisson 1 and south of the caisson 1. One end and the other end of the optical fiber 11 extending from the west side, one end and the other end of the optical fiber 11 extending vertically downward from the south side of the caisson 1 and extending vertically downward from the southeast side of the caisson 1, and vertically downward from the east side of the caisson 1. One end and the other end of the optical fiber 11 that extends and extends from the northeast side of the caisson 1 are connected. The number of optical fibers 11 and the arrangement mode of the optical fibers 11 are not limited to the examples of FIGS. 3 and 4, and can be appropriately changed.

The structure management device 10 detects the distortion of the caisson 1 by Rayleigh measurement using, for example, an optical fiber 11. For example, when the control device 13 inputs the measurement light to the optical fiber 11, Rayleigh backscattered light is generated in the optical fiber 11. The spectrum of Rayleigh backscattered light (intensity per frequency) varies with distortion, pressure or temperature.

Also, the intensity of Rayleigh backscattered light is smaller than the intensity of the measured light. In Rayleigh measurement, the distortion generated in the optical fiber 11 is detected by measuring the change in the spectrum of the backscattered light. Rayleigh measurement using Rayleigh backscattered light has the advantages of high accuracy and resistance to light loss.

In the optical fiber 11, for example, the strain of concrete can be detected with an accuracy of 1μ. Therefore, it is possible to detect crack generation strain (about 100 μ) that may occur in a concrete structure such as a caisson 1 and prevent cracks that deteriorate the quality of the caisson skeleton 2.

FIG. 5A shows an example of a cross-sectional view of an optical fiber 11 which is an optical fiber cable, and FIG. 5B is a diagram showing an example of the surface of the optical fiber 11. As shown in FIGS. 5A and 5B, an exemplary optical fiber 11 comprises an optical fiber core wire 11b, a tension member 11c, and a sheath 11d covering the optical fiber core wire 11b and the tension member 11c. Be prepared. As an example, the sheath 11d is composed of an insulator.

For example, the optical fiber 11 has a flat plate shape and a long shape, and the cross section of the optical fiber 11 has a flat shape (for example, a rectangular shape with rounded corners). As a result, the contact area of the optical fiber 11 with respect to the installation target location such as the inner peripheral surface 3d of the side wall 3 can be increased to easily install the optical fiber 11, and the optical fiber 11 can detect distortion with high accuracy. It will be possible to do.

The optical fiber 11 has, for example, a pair of tension members 11c arranged along the longitudinal direction of the cross section (the left-right direction in FIG. 5A), and a pair of optical fiber core wires 11b are placed between the pair of tension members 11c. It will be provided. The tension member 11c makes it possible to protect the optical fiber core wire 11b from the tension applied to the optical fiber 11. The surface of the optical fiber 11 (sheath 11d) is, for example, embossed. Concavities and convexities are formed on the surface of the optical fiber 11, for example, the irregularities formed on the surface of the optical fiber 11 are arranged in a grid pattern.

In the above, an example of the shape of the optical fiber 11 and the like has been described. However, the shape and structure of the optical fiber 11 are not limited to the above examples and can be appropriately changed. As shown in FIG. 5C, the optical fiber 11A provided with the core wire 11f having a circular cross section can be used instead of the optical fiber 11. As a specific example, when fixing to the concrete surface (inner peripheral surface 3d), the optical fiber 11A of FIG. 5 (c) may be used.

The structure management device 10 includes, for example, one temperature compensation optical fiber 12. As shown in FIGS. 3 and 6, the end portion of the temperature compensating optical fiber 12 is connected to the control device 13. For example, the temperature compensating optical fiber 12 has an optical fiber core wire 12b and an optical fiber core wire 12b. The tubular member 12c comprising the surrounding tubular member 12c is, for example, a steel pipe. As an example, the material of the tubular member 12c is a hard material (as an example, SUS: Steel Use Stainless).

Since the optical fiber core wire 12b of the temperature compensation optical fiber 12 is surrounded by the tubular member 12c, it is not affected by the distortion of the caisson 1 but only by the temperature change. That is, when the caisson 1 is distorted and the temperature is changed outside the temperature-correcting optical fiber 12, the optical fiber core wire 12b is only affected by the temperature change.

On the other hand, when the caisson 1 is distorted and the temperature is changed outside the optical fiber 11, the optical fiber core wire 11b is affected by both the strain and the temperature change. Therefore, the control device 13 cancels the distortion of the cason 1 in the optical fiber 11 and the change in the light intensity due to the temperature change with the change in the light intensity due to the temperature change in the cason 1 in the temperature correction optical fiber 12. It is possible to detect the distortion of the light with high accuracy.

The control device 13 calculates the distortion value of the caisson 1 at the location where the optical fiber 11 is installed by using the light propagating through the optical fiber 11. For example, the control device 13 may calculate the amount of distortion of the caisson 1 from the amount of change (difference) in the intensity peak of the Rayleigh backscattered light. In this case, the control device 13 changes the intensity peak between the optical information obtained in the n-1th measurement and the optical information obtained in the nth measurement in the nth measurement (n is a natural number of 2 or more). The amount is calculated to calculate the amount of distortion of the caisson 1.

Next, an example of the mode of strain detected by the optical fiber 11 of the structure management device 10 will be described with reference to FIGS. 7 to 10. First, as shown in FIG. 7, in the steady state (normal state), a vertically upward frictional force F2 acts on the outer peripheral surface 3c of the caisson 1 with respect to the load F1 of the caisson 1 acting vertically downward. , The reaction force F3 acting on the cutting edge 3b from the ground B acts, and the load F1 is in a state of being balanced with the frictional force F2 and the reaction force F3. The reaction force F3 referred to here also includes a force due to the pressure in the pressure chamber.

Then, it is detected by the optical fiber 11 that a uniform frictional force F2 acts on the outer peripheral surface 3c of the caisson 1 along the vertical direction, and for example, the tensile force and the compressive force with respect to the caisson 1 are close to zero. To. In FIG. 7 and the graphs on the right side of FIGS. 8, 9 and 10 described later, the vertical axis indicates the depth (height from the bottom wall 6), and the horizontal axis indicates the tensile force acting on the caisson 1. And the compressive force.

As shown in FIG. 8, when the frictional force F2 acting on the outer peripheral surface 3c of the caisson 1 is uniform along the vertical direction and larger than the steady state, the reaction force F3 becomes smaller and the optical fiber 11 acts on the caisson 1. Tensile force is detected. At this time, it is detected by the optical fiber 11 that the tensile force with respect to the caisson 1 increases as the caisson 1 becomes deeper.

As shown in FIG. 9, when a large frictional force F2 acts on a position away from the ground surface G of the caisson 1 (near the bottom wall 6), the magnitude of the reaction force F3 is the magnitude of the reaction force F3 in the steady state. Is about the same as. In this case, the optical fiber 11 detects the compressive force and the tensile force with respect to the caisson 1. Specifically, the optical fiber 11 detects a peak P in which the compressive force with respect to the caisson 1 increases as the depth from the ground surface G increases, and the tensile force with respect to the caisson 1 increases at the location where the large frictional force F2 is concentrated.

As shown in FIG. 10, when a large frictional force F2 acts near the ground surface G of the caisson 1, the reaction force F3 becomes small and the optical fiber 11 detects the compressive force and the tensile force with respect to the caisson 1. In this case, the optical fiber 11 detects a tensile force that becomes a large peak P in the vicinity of the ground surface G, and detects a tensile force that becomes smaller from the peak P as the depth increases.

As shown in FIGS. 9 and 10 above, the structure management device 10 (control device 13) detects the tensile force and the compressive force with respect to the caisson 1 by the optical fiber 11 installed on the inner peripheral surface 3d of the caisson 1. .. Then, by detecting the peak P of the tensile force by the structure management device 10, it becomes possible to specify the concentration point of the frictional force F2 on the outer peripheral surface 3c. That is, since the structure management device 10 can specify the concentration point of the large frictional force F2 by specifying the peak P, the above-mentioned injection of the lubricant can be performed pinpointly with respect to the concentration point of the frictional force F2. It will be possible.

Next, an example of the process of the structure management method according to the present embodiment will be described. 11 (a), 11 (b) and 11 (c) are vertical cross-sectional views of the caisson 1 and the optical fiber 11 schematically showing the process. FIG. 12 is a flow chart showing an example of the process. First, the optical fiber 11 is prepared (step S1 of preparing the optical fiber).

In step S1, for example, four optical fibers 11 and a temperature-correcting optical fiber 12 having a length at least twice the maximum height in the vertical direction of the cason 1 are prepared, and the optical fiber 11 and the temperature-correcting optical fiber are prepared. Each end of 12 is connected to the control device 13. Then, the first lot of the caisson 1 is constructed (step of constructing the block, step S2, step S3).

Specifically, the block 5 including the bottom wall 6 is constructed as the block of the first lot, and for example, the formwork is installed, the reinforcing bars are arranged, and the concrete is placed. Then, after constructing the block 5 of the first lot, the formwork is removed (step S4), and the optical fiber 11 is installed (laid) in the block 5 of the first lot (step S5 of installing the optical fiber). ..

In step S5, as shown in FIG. 11A, the optical fiber 11 is fixed to the inner peripheral surface 3d of the block 5 while leaving an extra length of 11 g. The optical fiber 11 is fixed to the inner peripheral surface 3d by, for example, an adhesive. As an example, a flat optical fiber 11 as shown in FIG. 5A is attached to the inner peripheral surface 3d with an adhesive. Then, the temperature compensation optical fiber 12 is also attached to the inner peripheral surface 3d while leaving an extra length of 12 g, like the optical fiber 11.

After installing the optical fiber 11 and the temperature-correcting optical fiber 12 on the inner peripheral surface 3d of the block 5, the initial values of the optical fiber 11 and the temperature-correcting optical fiber 12 are set (step S6). Then, as shown in FIG. 11B, the subsidence of the block 5 in the ground B and the measurement of the strain of the block 5 by the optical fiber 11 are started (the step of detecting the strain of the block by the optical fiber, step S7). ).

In the measurement of the strain of the block 5, for example, the graph shown on the right side of FIGS. 7 to 10 is displayed on the display of the control device 13, which makes it possible to identify the presence or absence of the concentration point of the frictional force F2. (Step to identify the location where frictional force is generated). For example, when a concentrated portion of the frictional force F2 is specified as the peak P, the lubricant is injected from the lubricant injection device 15 into the concentrated portion (step of injecting the lubricant). As a result, the frictional force F2 at the concentrated portion can be pinpointly reduced before the peak P at the concentrated portion of the frictional force F2 becomes large.

By performing the measurement as described above, it is determined whether or not the construction of the block 5 of the Nth lot (N is a natural number of 2 or more, N = 7 in the example of FIG. 1) is completed (step S8, step S9). ). Then, when the construction of the Nth lot is completed, a series of steps is completed. On the other hand, if the construction of the Nth lot is not completed, step S3 is executed again, and for example, the construction of the block 5 of the second lot is started (step of constructing the block).

Specifically, the block 5 located above the block 5 of the first lot is constructed as the block of the second lot, and the formwork is installed, the reinforcing bars are arranged, and the concrete is placed in the same manner as described above. Then, after the block 5 of the second lot is constructed, the mold is removed (step S4), and the optical fiber 11 is installed in the block 5 of the second lot (step of installing the optical fiber, step S5).

Then, as shown in FIG. 11 (c), the optical fiber 11 is fixed to the inner peripheral surface 3d of the block 5 in the same manner as described above, while leaving an extra length of 11 g. Then, like the optical fiber 11, the temperature compensation optical fiber 12 is also attached to the inner peripheral surface 3d while leaving an extra length of 12 g. After that, the initial values of the optical fiber 11 and the temperature compensation optical fiber 12 are set (step S6).

As described above, the initial values of the optical fiber 11 and the temperature compensation optical fiber 12 are set for each lot (construction of the block 5). For example, the m-th lot (m is a natural number) block 5 and the m + 1-th lot block 5 have different material ages, and when a new block 5 is constructed, the caisson skeleton 2 is constructed. Therefore, in order to measure the strain distribution of the block 5 using one optical fiber 11 straddling the plurality of blocks 5, it is necessary to set the initial value according to the progress of the construction of the block 5. Specifically, it may be necessary to set the initial values of the optical fiber 11 and the temperature compensation optical fiber 12 for each construction of one block 5.

After that, in the same manner as described above, the subsidence of the block 5 in the second lot on the ground B and the measurement of the strain of the block 5 by the optical fiber 11 are started (step of detecting the strain of the block by the optical fiber, step S7), N. It is determined whether or not the construction of the block 5 of the lot is completed (step S8, step S9). Then, when the construction of the block 5 of the Nth lot is not completed, the process proceeds to step S3 again, and for example, the construction of the blocks 5 of the third and subsequent lots is repeated, and the construction of the block 5 of the Nth lot is completed. If finished, the series of steps is completed.

Next, the operation and effect obtained from the structure management device 10 and the structure management method according to the present embodiment will be described in detail. In the structure management device 10 and the structure management method according to the present embodiment, the optical fiber 11 is installed in each of the plurality of blocks 5, and the distortion of the plurality of blocks 5 is detected by the installed optical fiber 11.

Therefore, by installing the linear optical fiber 11 over the plurality of blocks 5, it is possible to detect distortion in a wider area with a small number of optical fibers 11. Therefore, since it is possible to measure the strain by installing the optical fiber 11 in each of the plurality of blocks 5 while constructing each of the plurality of blocks 5, the behavior of a wide portion of the plurality of blocks 5 can be reduced in number. It can be grasped by the optical fiber 11.

Further, in the structure management device 10 and the structure management method according to the present embodiment, the optical fiber 11 is installed while leaving an extra length of 11 g in the constructed block 5, the block 5 is constructed, and the optical fiber 11 is attached to the block 5. The structure is constructed by repeating the installation of the block 5 and the detection of the distortion of the block 5 by the optical fiber 11.

Therefore, it is possible to install the optical fiber 11 in the block 5 while leaving an extra length of 11 g for each construction of the block 5, and to construct the structure while repeating the construction of the block 5 and the installation of the optical fiber 11. It will be possible. The optical fiber 11 can be easily installed because one optical fiber 11 may be fixed to the block 5 while leaving an extra length of 11 g. Therefore, since a small number of optical fibers 11 can be performed together with the construction of the block 5, the installation work can be easily performed and distortion in a wide range can be efficiently detected.

In the step of detecting the distortion of the block 5 by the optical fiber 11, the distortion of the block 5 may be detected by Rayleigh measurement. In the Rayleigh measurement, the distortion of the block 5 is measured by detecting the Rayleigh backscattered light in the light propagating through the optical fiber 11. The light intensity of Rayleigh backscattered light is weaker than the light intensity of the input measured light. Therefore, by detecting this change in light intensity, the magnitude of the strain generated in the optical fiber 11 can be obtained. Therefore, Rayleigh measurement using Rayleigh backscattered light has the advantages of high accuracy and resistance to light loss.

The block 5 may be a reinforced concrete block, and the structure may be a reinforced concrete structure. In this case, the strain can be easily measured in a wide range of the reinforced concrete structure gradually constructed for each block 5.

The structure may be a caisson 1 containing a reinforced concrete block. In this case, for example, it is possible to install the optical fiber 11 for each of the constructed blocks 5 with respect to the blocks 5 that are gradually constructed for each of the blocks 5 by the pneumatic caisson method. Therefore, the strain generated in each of the plurality of blocks 5 of the caisson 1 can be measured by the optical fiber 11. Therefore, the strain can be easily measured over a wide range of the caisson 1 by using a small number of optical fibers 11.

As illustrated in FIG. 10, the structure management method according to the present embodiment includes a step of identifying a location where a frictional force F2 is generated on the outer peripheral surface 3c of the caisson 1 from the detected strain, and a frictional force F2. It may be provided with a step of injecting a lubricant into the generated portion. In this case, it is possible to measure the frictional force F2 on the inner peripheral surface 3d of the caisson 1 from the strain and identify the location where the frictional force F2 is generated (for example, as a peak P).

By specifying the concentrated points of the frictional force F2, it is possible to take necessary measures before the quality of the caisson 1 deteriorates. That is, since the lubricant is injected into the place where the frictional force F2 is generated, it is possible to inject as much lubricant as necessary into the required place. This makes it possible to prevent the caisson skeleton 2 from hanging from the position where the frictional force is generated. Therefore, it is possible to efficiently and quickly inject the lubricant pinpointly and promptly to prevent the occurrence of a problematic phenomenon, so that a high-quality caisson 1 can be efficiently constructed.

Next, the process of the structure management method according to the modified example will be described with reference to FIGS. 13 and 14. In the modified example, a case where the optical fiber is arranged inside the skeleton will be described. Since a part of the structure management method and the structure management device according to the modified example overlaps with a part of the structure management method and the structure management device described above, the description of the overlapping part will be omitted as appropriate.

First, the optical fiber 11 is prepared (step of preparing the optical fiber, step S11). Then, as shown in FIG. 13A, the first lot of the caisson 1 is constructed, and the optical fiber 11 is laid on the block 5 of the first lot. Specifically, for example, the formwork is installed and the reinforcing bars are arranged, and the optical fiber 11 and the temperature compensation optical fiber 12 are arranged along the reinforcing bars. That is, the arrangement of the optical fiber 11 and the temperature compensation optical fiber 12 is performed at the same time as the assembly of the reinforcing bar or between the assembly of the reinforcing bar and the placement of the concrete. Then, concrete is placed and the optical fiber 11 and the optical fiber 12 for temperature compensation are embedded inside the block 5 (step of constructing the block, step of installing the optical fiber, step S12, step S13).

After that, the mold is removed (step S14), and the initial values of the optical fiber 11 and the temperature compensation optical fiber 12 are set (step S15). Then, as shown in FIG. 13B, the subsidence of the block 5 in the ground B and the measurement of the strain of the block 5 by the optical fiber 11 are started (the step of detecting the strain of the block by the optical fiber, step S16). ).

The measurement of the block 5 is started, and it is determined whether or not the construction of the block 5 of the Nth lot is completed (step S17, step S18). If the construction of the Nth lot is not completed, the process proceeds to step S13, and the blocks 5 of the second and subsequent lots are constructed as shown in FIG. 13C, and the same process as described above is performed. repeat. On the other hand, when the construction of the Nth lot is completed, a series of steps is completed.

As described above, in the structure management method according to the modified example, the optical fiber 11 is installed in each of the plurality of blocks 5, and the distortion of the plurality of blocks 5 is detected by the installed optical fiber 11. Therefore, by installing the linear optical fiber 11 over the plurality of blocks 5, it is possible to detect distortion in a wider area with a small number of optical fibers 11. Therefore, the same effect as the above-mentioned structure management method and structure management device 10 can be obtained.

Further, in the structure management method according to the modified example, since the optical fiber 11 is embedded in the block 5, the strain measurement can be started before the concrete constituting the block 5 is hardened, and the data can be acquired from an earlier stage. Is possible. Further, the optical fiber 11 can be hidden from the surface of the caisson 1 and the possibility that the optical fiber 11 comes off from the caisson 1 can be eliminated.

The embodiment of the structure management device and the structure management method according to the present disclosure has been described above. However, the present invention is not limited to the above-described embodiments or modifications. That is, it is easily recognized by those skilled in the art that the present invention can be modified and modified in various ways without changing the gist described in the claims. For example, the configuration, shape, size, number, material and arrangement mode of each part of the structure management device, and the content and order of the steps of the structure management method are not limited to the above-mentioned contents and can be appropriately changed.

For example, in the above-described embodiment, an example of detecting the distortion of the caisson 1 by Rayleigh measurement using the optical fiber 11 has been described. However, the distortion may be detected by a method other than Rayleigh measurement, such as Brillouen measurement.

Further, in the above-described embodiment, an example in which the optical fiber 11 is installed on the inner peripheral surface 3d of the caisson 1 has been described. However, the installation position of the optical fiber 11 is not limited to the inner peripheral surface 3d of the caisson 1, and can be appropriately changed. For example, as shown in FIGS. 15 (a) and 15 (b), the optical fiber 11 may be installed on the outer peripheral surface 3c of the caisson 1.

15 (a) and 15 (b) show an example in which four optical fibers 11 are arranged so as to be arranged along the circumferential direction of the block 5. In this way, when the optical fiber 11 is installed on the outer peripheral surface 3c of the caisson skeleton 2, it is possible to estimate the axial deformation of the entire caisson skeleton 2 and monitor the caisson 1 so that excessive deformation does not occur. While doing so, the block 5 can be sunk.

Further, as shown in FIGS. 16A and 16B, the optical fiber 11 may be installed so as to be annular in a plan view along the circumferential direction D of the caisson 1. 16 (a) and 16 (b) show an example in which the optical fiber 11 is installed on the inner peripheral surface 3d of the caisson 1 along the circumferential direction D.

As shown in FIGS. 16A and 16B, by arranging the optical fiber 11 so as to extend along the circumferential direction D, it is possible to estimate the out-of-plane deformation of the wall constituting the caisson 1. can. Then, the block 5 can be sunk while monitoring so that the caisson 1 is not excessively deformed.

Further, in the above-described embodiments and modifications, an example in which the structure is a caisson has been described. However, the structure may be a reinforced concrete block other than a caisson, or a block other than a reinforced concrete block. For example, the structure may be a steel structure. Also in this case, the same action and effect as those of the above-described embodiments and modifications (the effect of avoiding cracks and / or the effect of avoiding impact) can be obtained.

That is, as schematically shown in FIG. 17, the present invention can be applied to any site where the block 55 is constructed step by step. In this case, as shown in FIGS. 17 (a) and 17 (b), an optical fiber 51 for detecting strain is prepared and a block 55 is constructed. Then, the optical fiber 51 is installed in the constructed block 55 while leaving the extra length 52, and the distortion of the block 55 is detected by the optical fiber 51.

As shown in FIGS. 17 (c) and 17 (d), the construction of the block 55, the installation of the optical fiber 51 while leaving the extra length 52, and the detection of the distortion of the block 55 by the optical fiber 51 are repeated. Build the structure. The structure may be, for example, a road including a box culvert or an arch culvert, a railroad, an embankment or a tunnel, or a bridge. For example, in the case of a bridge, creep strain of the block 55 during construction can be detected by sequentially installing optical fibers 51 above and below the block 55 constituting the bridge. As described above, the structure targeted by the present invention is not particularly limited.

1 ... caisson (structure), 2 ... caisson skeleton, 3 ... side wall, 3b ... cutting edge, 3c ... outer peripheral surface, 3d ... inner peripheral surface, 4 ... working room, 5,55 ... block, 6 ... bottom wall, 7 ... Steel sheet pile, 10 ... Structure management device, 11, 11A, 51 ... Optical fiber, 11b ... Optical fiber core wire, 11c ... Tension member, 11d ... Sheath, 11f ... Core wire, 11g, 52 ... Extra length, 12 ... Temperature correction Optical fiber for use, 12b ... Optical fiber core wire, 12c ... Tubular member, 12g ... Extra length, 13 ... Control device, 15 ... Lubricant injection device, B ... Ground, D ... Circumferential direction, F1 ... Load, F2 ... Friction force, F3 ... reaction force, G ... ground surface, P ... peak, T ... tunnel, X ... crack.

Claims (6)

It is a structure management method used when constructing a structure containing a plurality of the above blocks by constructing blocks step by step.
The process of preparing an optical fiber to detect distortion, and
The process of constructing the block and
The process of installing the optical fiber in the constructed block while leaving an extra length, and
The process of detecting the strain of the constructed block by the optical fiber and
Equipped with
The structure is constructed by repeating the steps of constructing the block, installing the optical fiber while leaving an extra length, and detecting the strain of the block by the optical fiber.
Structure management method. In the step of detecting the strain of the block by the optical fiber, the strain of the block is detected by Rayleigh measurement.
The structure management method according to claim 1. The block is a reinforced concrete block, and the structure is a reinforced concrete structure.
The structure management method according to claim 1 or 2. The structure is a caisson containing the reinforced concrete block.
The structure management method according to claim 3. A step of identifying a location where a frictional force is generated on the outer peripheral surface of the caisson from the detected strain, and
The step of injecting the lubricant into the place where the frictional force is generated, and
The structure management method according to claim 4. A structure management device used when constructing a structure including a plurality of the blocks by constructing blocks step by step.
Equipped with an optical fiber that detects distortion
The optical fiber is installed in the block constructed each time the block is constructed, leaving an extra length.
The optical fiber installed in each of the plurality of blocks detects distortion.
Structure management device.

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