JP2022029525A - Evaluation device and evaluation method - Google Patents

Abstract

To provide an evaluation device and an evaluation method capable of easily and efficiently evaluating the soundness of a waterfront structure.SOLUTION: An evaluation device 1 evaluates the soundness of a steel sheet pile revetment 2. The evaluation device 1 includes a vibration meter 20 and an information generation device 21 as an information generation unit. The vibration meter 20 measures a microtremor of the steel sheet pile revetment 2. The information generation device 21 generates information indicating the soundness of the steel sheet pile revetment 2 based on the microtremor of the steel sheet pile revetment 2 measured by the vibration meter 20. Since the information indicating the soundness of the steel sheet pile revetment 2 is generated based on the microtremor applied to the steel sheet pile revetment 2 from the natural world, etc., the evaluation device can evaluate the soundness of the steel sheet pile revetment 2 without requiring equipment to vibrate the steel sheet pile revetment 2.SELECTED DRAWING: Figure 1

Description

The present invention relates to an evaluation device and an evaluation method.

Most of the seawalls and breakwaters, which are waterfront structures installed in contact with the sea as port facilities, are below the surface of the sea. Therefore, when evaluating the soundness of the waterside structure, an inspection by a diver is required. In addition, in a port facility where a wave-dissipating block is installed, the water-side structure may be hidden by the wave-dissipating block and sufficient inspection may not be possible. Due to the difficulty of such inspections, it is required to establish a simple and efficient evaluation method for border structures.

For example, a soundness diagnostic device for diagnosing the soundness of a structure by applying vibration to the structure is disclosed (see Patent Document 1). In addition, an evaluation method for evaluating the soundness, tension, etc. of structures such as tunnels, steel towers, and anchors has been proposed (see Non-Patent Document 1, Patent Documents 2, and 3).

Ushizu Jiang, 4 outsiders, "Proposal of soundness evaluation method for tunnel lining based on constant tremor measurement", Tunnel Engineering Report Collection / Japan Society of Civil Engineers Tunnel Engineering Committee, Japan Society of Civil Engineers, November 25, 2010 , Volume 20, pp205-209

Japanese Patent Application Laid-Open No. 2003-106931 Japanese Unexamined Patent Publication No. 2013-234945 Japanese Unexamined Patent Publication No. 2018-13361

However, in the soundness diagnosis device disclosed in Patent Document 1, the diagnosis target is limited to the steel tower structure. The method of diagnosing soundness is greatly influenced by the structure of the structure. For this reason, it is difficult to directly apply the diagnostic method performed for a tower structure as performed by this device to a waterfront structure. Therefore, it is desired to construct a mechanism that can evaluate the soundness of the waterfront structure.

The present invention has been made under the above circumstances, and an object of the present invention is to provide an evaluation device and an evaluation method capable of easily and efficiently evaluating the soundness of a waterfront structure.

In order to achieve the above object, the evaluation device according to the first aspect of the present invention is
It is an evaluation device that evaluates the soundness of waterside structures that come into contact with waterside.
A vibrometer that measures the constant tremor of the waterside structure at the first position away from the waterside, and
An information generation unit that generates information indicating the soundness of the waterside structure based on the frequency component of the constant tremor of the waterside structure measured by the vibration meter.
To prepare for.

In this case, the information generation unit is
A Fourier transform unit that obtains a Fourier spectrum by performing a Fourier transform on the constant tremor of the waterside structure measured by the vibration meter.
A spectral density calculation unit for calculating the spectral density of the Fourier spectrum obtained by the Fourier transform unit, and a spectral density calculation unit.
To prepare
It may be that.

In addition, the information generation unit is
It is provided with an extraction unit for extracting the spectral density of the first frequency or higher and lower than the second frequency higher than the first frequency from the spectral density of the constant tremor Fourier spectrum.
It may be that.

The vibrometer
At a second position closer to the water's edge than the first position, constant tremors in the water's edge structure were measured.
The information generation unit
A first determination unit for determining the soundness of the waterfront structure is provided by comparing the spectral density corresponding to the first position with the spectral density corresponding to the second position.
It may be that.

The information generation unit
A second determination unit for determining the soundness of the waterfront structure based on the time change of the spectral density extracted by the extraction unit is provided.
It may be that.

The information generation unit
A display information generation unit that generates display information that displays the spectral density extracted by the extraction unit in different colors according to its size.
A display unit that displays the display information generated by the display information generation unit, and a display unit that displays the display information.
To prepare
It may be that.

The vibrometer measures constant tremors in the vertical direction.
It may be that.

The evaluation method according to the second aspect of the present invention is
It is an evaluation method to evaluate the soundness of waterfront structures.
The vibration meter measures the constant tremor of the waterside structure,
The information processing device generates information indicating the soundness of the waterside structure based on the measured constant tremor of the waterside structure.

According to the present invention, information indicating the soundness of the waterside structure is generated based on the frequency component of the constant tremor of the waterside structure at a position away from the waterside. The frequency component of the constant tremor at a position away from the water's edge changes due to deterioration of the internal structure of the water's edge structure. Therefore, by using such information, it is possible to easily and efficiently evaluate the soundness of the waterfront structure without providing equipment for applying vibration to the waterside structure.

It is a schematic diagram which shows the structure of the evaluation apparatus which concerns on Embodiment 1 of this invention. (A) is a figure which shows the state of consolidation settlement of the filling earth and sand. (B) is a figure which shows how the apron sinks according to the consolidation settlement of the filling earth and sand. (A) is a diagram showing a state in which a steel sheet pile is corroded and a hole is formed. (B) is a figure which shows the state which the filling earth and sand flow out. It is a figure which shows the state that the apron concrete collapsed. It is a schematic diagram which shows the structure of the information processing unit provided in the evaluation apparatus of FIG. It is a graph which shows an example of the spectral density distribution of the Fourier spectrum of the constant vibration measured at three measurement positions when the waterside structure is in three states. It is a graph which shows the distribution of the spectral density of 300Hz or more and 500Hz or less. It is a flowchart which shows the operation of the evaluation apparatus which concerns on Embodiment 1 of this invention. It is a schematic diagram which shows the structure of the information processing unit provided in the evaluation apparatus which concerns on Embodiment 2 of this invention. It is a schematic diagram which shows the structure of the evaluation apparatus which concerns on Embodiment 3 of this invention. It is a schematic diagram which shows the structure of the information processing unit provided in the evaluation apparatus of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all drawings, the same or equivalent parts are designated by the same reference numerals. In the present specification, the "waterfront structure" is a facility such as a seawall or a breakwater installed at the waterside such as the sea or a river, and is also referred to as a harbor structure. Further, "constant tremor" is not a vibration caused by an intentionally applied force, but a minute vibration normally generated in a structure, and is a vibration generated in a structure due to a natural phenomenon or human activity.

Embodiment 1
First, Embodiment 1 of the present invention will be described. As shown in FIG. 1, the evaluation device 1 evaluates the soundness of the waterside structure in contact with the waterside. Here, "soundness" is a measure indicating whether or not the structure of the structure maintains the structure when it is installed, that is, whether or not it has deteriorated, and is also referred to as the degree of deterioration or the degree of soundness. Should be.

First, the waterfront structure to be measured according to the present embodiment will be described. In the present embodiment, the waterfront structure is a steel sheet pile revetment (sheet pile) 2. In the steel sheet pile revetment 2, a steel sheet pile 6 is installed at a portion in contact with the sea 3 or a river, that is, at the water's edge. In the present embodiment, it is assumed that the steel sheet pile 6 is in contact with the sea 3.

The filling earth and sand 5 is filled between the steel sheet pile 6 and the conventional earth and sand 4 that has existed conventionally. A superstructure 7 is provided on the upper part of the steel sheet pile 6. Further, a tie rod 9 is embedded in the conventional earth and sand 4 and the filling earth and sand 5, and a backing plate 10 is embedded in the conventional earth and sand 4. The steel sheet pile revetment 2 has a structure in which the steel sheet pile 6 is fixed to the filling earth and sand 5 by connecting the superstructure 7 to the backing plate 10 via the tie rod 9 and pulling it to the back side. That is, the steel sheet pile revetment 2 is a so-called tie rod type revetment. Apron concrete (hereinafter referred to as "apron") 8 is spread on the upper part of the steel sheet pile revetment 2.

As the steel sheet pile revetment 2 deteriorates over time, the apron 8 may collapse. Hereinafter, the collapse mechanism of the steel sheet pile revetment 2 due to aging deterioration will be described with reference to FIGS. 2 (A), 2 (B), 3 (A), 3 (B) and 4 (B).
(1) As shown in FIG. 2 (A), the filling sediment 5 is consolidated and subsided.
(2) As shown in FIG. 2B, the apron 8 sinks due to its own weight or the repeated load of a load (for example, a vehicle or the like) on the apron 8 with the subsidence of the filling earth and sand 5.
(3) As shown in FIG. 3A, a hole 6a is formed in the steel sheet pile 6 due to the concentrated corrosion of the steel sheet pile 6 generated below the mean low water level (MLWL).
(4) As shown in FIG. 3 (B), the bottom of the apron 8 is further hollowed out by the outflow of the filled sediment 5 into the sea due to the washing out of the filled sediment 5 due to the ebb and flow of the sea 3 or the waves.
(5) As shown in FIG. 4, the load bearing capacity of the apron 8 decreases, and finally it collapses.

In order to prevent such a situation, the evaluation device 1 evaluates the soundness of the steel sheet pile revetment 2. As shown in FIG. 1, the evaluation device 1 includes a vibration meter 20 and an information generation device 21 as an information generation unit.

The vibration meter 20 measures the constant fine movement of the steel sheet pile revetment 2. As the vibration meter 20, it is necessary to use a highly sensitive one for measuring the constant fine movement generated in the steel sheet pile revetment 2. Further, it is desirable to use a vibration meter 20 capable of measuring vibration having a frequency of 500 Hz.

In the present embodiment, the vibration meter 20 is attached to the measurement positions A, B, and C in FIG. 1, respectively, and constantly fine movement of the steel sheet pile revetment 2 is measured at the measurement positions A, B, and C, respectively. That is, in the present embodiment, the vibration meter 20 constantly measures fine movements at the steel sheet pile revetment 2 at a plurality of measurement positions A, B, and C having different distances from the water's edge. The measurement position A is a position on the superstructure 7 and is a position corresponding to the water's edge. Further, the measurement positions B and C are positions away from the water's edge. The measurement position B is on the sea side of the measurement position C. As described above, in the present embodiment, the measurement positions B and C correspond to the first position, and the measurement position A corresponds to the second position closer to the water's edge than the first position. The vibration meter 20 can be said to be a measuring device that constantly measures the fine movement of the steel sheet pile revetment 2 at the first position away from the water's edge.

Here, the direction along the quay is the X-axis direction, the normal direction of the quay is the Y-axis direction, and the vertical direction is the Z-axis direction. The vibration meter 20 measures vibrations in three axial directions in the X-axis direction, the Y-axis direction, and the Z-axis direction. The vibration meter 20 and the information generation device 21 are connected to each other so as to be able to communicate by wire or wirelessly. The vibration waveform data of the constant tremor in the three-axis direction measured by the vibration meter 20 is transmitted to the information generation device 21.

The measurement by the vibration meter 20 is continuously performed by DT (see FIG. 5) for a certain period of time, and information for evaluating the soundness of the steel sheet pile revetment 2 is generated based on the measurement result of the DT for a certain period of time. The fixed time DT is, for example, 10 minutes.

The information generation device 21 generates information indicating the soundness of the steel sheet pile revetment 2 based on the frequency component of the constant tremor of the steel sheet pile revetment 2 measured by the vibration meter 20. The information generation device 21 may be located at a position away from the steel sheet pile revetment 2.

As shown in FIG. 5, the information generation device 21 includes a receiving unit 30, an A / D conversion unit 31, a Fourier transform unit 32, a spectral density calculation unit 33, a filter unit 34 as an extraction unit, and display information. It includes a generation unit 35 and a display unit 36.

The receiving unit 30 receives the vibration waveform data of the constant tremor measured by the vibration meter 20. The receiving unit 30 receives the vibration waveform data of the DT for a certain period of time measured by the vibration meters 20 at the measurement positions A, B, and C from the vibration meters 20, respectively.

The A / D conversion unit 31 converts the vibration waveform data received by the reception unit 30 into digital data at the sampling interval ΔT. As a result, digital data indicating the constant tremor of the steel sheet pile revetment 2 at the measurement positions A, B, and C can be obtained. In this case, the number of samplings per second can be, for example, 1280 times / second. If the vibration waveform data transmitted from the vibration meter 20 is digital data, the A / D conversion unit 31 may not be provided.

The Fourier transform unit 32 performs a Fourier transform on the digital data converted by the A / D conversion unit 31 to obtain the Fourier spectrum thereof. Specifically, the Fourier transform unit 32 obtains the Fourier spectra of the constant tremors of the steel sheet pile revetment 2 at the measurement positions A, B, and C, respectively. In this case, for example, the Fourier transform unit 32 can perform a fast Fourier transform (FFT) on the digital data every time T, for example, every second (1280 pieces) to obtain a Fourier spectrum for each time T.

The spectral density calculation unit 33 calculates the spectral density of the Fourier spectrum. Here, since the Fourier spectrum of the DT for a certain period of time is obtained, as shown in FIG. 5, distribution data of the spectral density in a certain frequency range (0 to Smax) in the DT for a certain period of time can be obtained. The spectral density distribution data can be expressed by the ratio of each frequency component when Smax, for example, an integral value up to 640 (Hz) is taken for the obtained Fourier spectrum and the total of each is set to 1.

The filter unit 34 extracts a frequency component of the first frequency S1 or higher and the second frequency S2 or lower higher than the first frequency S1 from the constant tremor of the steel sheet pile revetment 2 measured by the vibration meter 20. The first frequency is, for example, 300 Hz and the second frequency is, for example, 500 Hz. In FIG. 5, this frequency component is shown by being surrounded by a dotted line.

The display information generation unit 35 generates information indicating the soundness of the steel sheet pile revetment 2 based on the frequency component extracted by the filter unit 34. Specifically, the display information generation unit 35 generates display information in which the spectral density extracted by the filter unit 34 is color-coded according to its size and displayed. The display information generation unit 35 generates information indicating the soundness of the steel sheet pile revetment 2 based on the difference in the constant fine movement measured at each of the plurality of measurement positions A, B, and C.

The display unit 36 displays information indicating the soundness of the steel sheet pile revetment 2 generated by the display information generation unit 35. In the present embodiment, the distribution data of the spectral density color-coded according to the magnitude of the spectral density is displayed on the display unit 36. Here, the distribution data of the spectral densities corresponding to the measurement positions A, B, and C are displayed in a comparable manner.

The relationship between the constant fine movement of the steel sheet pile revetment 2 and deterioration will be described. In FIG. 6, the steel sheet pile guard 2 is in a healthy state (see FIG. 1), the filling sediment 5 is submerged (see FIG. 2 (A)), and the steel sheet pile 6 has a corroded hole (see FIG. 2 (A)). 3 (A) and 3 (B)) show a graph showing an example of the spectral density distribution of the Fourier spectrum of constant vibration measured by the vibration meter 20 at the measurement positions A, B, and C. In this graph, the horizontal axis indicates time (seconds), the vertical axis indicates frequency (Hz), and the colors on the graph indicate the spectral density at the corresponding time and the corresponding frequency. The spectral density is a negative value because the value less than 1 is displayed logarithmically. The spectral density is color-coded so as to change from a warm color system to a cool color system from 0 to -80. For example, in the region where the spectral density is -20 to -40, it is color-coded into yellow, and when the spectral density is -40 to -60, it is color-coded into yellow-green, and the spectral density is -60 to -80. In the color coding, it is color-coded to green.

First, when the steel sheet pile revetment 2 is in a healthy state, the distributions of the spectral densities at the measurement positions A, B, and C are different from each other. Specifically, at the measurement position A, the spectral density is yellow in most frequency regions, at the measurement position B, the spectral density is yellowish green in most frequency regions, and at the measurement position C, most of the spectral density is yellowish green. In the frequency domain, the spectral density is green. That is, in a healthy state, the value of the superstructure 7 is the largest at a frequency of 300 Hz or more and 500 Hz or less, and the spectral density of the Fourier spectrum of constant vibration decreases as the distance from the sea 3 to the measurement position increases. .. From this result, in a healthy situation, the filling earth and sand 5 is filled under the apron 8 and it is in a stable and hard to shake state, so that the energy from the external force such as a ship or waves is transmitted from the superstructure 7 to the apron 8. It is presumed that it is decaying.

Further, in the state where the filling sediment 5 is subsided, the spectral density at the measurement position A has almost the same distribution as in the healthy state. Further, at the measurement positions B and C, the spectral density is slightly larger than that in the sound state. In particular, at the measurement position C, the spectral density changes from green to yellowish green.

Further, in the state where the steel sheet pile 6 is corroded and has holes, the spectral density at the measurement position A is almost the same as that in the sound state, while the spectral densities at the measurement positions B and C are higher than those in the sound state. It is slightly larger and its distribution has changed to yellowish green.

As described above, the spectral density tends to show a large value at the measurement position A of the superstructure 7 regardless of whether the filling sediment 5 is subsided or the steel sheet pile 6 has a hole due to corrosion. On the other hand, no significant difference was confirmed at the measurement positions B and C on the apron 8. It is considered that this is because the reduction and runoff of the filling sediment affect the energy transfer by the external force due to the large deformation of the apron 8.

FIG. 7 shows an example of the distribution of the spectral density of 300 Hz or more and 500 Hz or less at the measurement positions A, B, and C of FIG. As shown in FIG. 7, in a healthy state, the value of the superstructure 7 is the largest, and the spectral density decreases as the distance from the sea 3 to the measurement position increases. On the other hand, in the subsidence state or the state with corroded holes, the spectral densities corresponding to the measurement positions B and C are larger than in the sound state.

As shown in FIGS. 6 and 7, the display information generation unit 35 generates color-coded distribution data of the spectral densities at the measurement positions A, B, and C, and displays the color-coded distribution data on the display unit 36. By looking at this display image, it is possible to grasp how much the steel sheet pile revetment 2 has deteriorated. For example, if the colors indicated by the spectral densities at the measurement positions A, B, and C are different, it can be determined that the steel sheet pile revetment 2 is in a healthy state, and the spectral densities at the measurement positions A, B, and C are different. When the colors indicated by are the same, it can be considered that an abnormality has occurred in the steel sheet pile revetment 2.

The constant tremor shown in FIGS. 6 and 7 is vibration in the vertical direction, that is, in the Z-axis direction. In the vibration meter 20, the constant vibration in the vertical direction is larger than that in the other directions, the X-axis and the Y-axis directions, and if the vibration waveform data of the constant vibration in the vertical direction (Z-axis direction) is used, the vibration This is because the change can be detected with high accuracy.

In the present embodiment, the Fourier conversion unit 32, the spectral density calculation unit 33, the filter unit 34, the display information generation unit 35, and the display unit 36 are a CPU (Central Processing Unit) as a calculation means and a memory as a storage means. A computer equipped with an external storage device, an I / O device as an input / output interface, and a display as a display means is realized by executing a software program stored in a memory.

The software program is stored in a recording medium or a server computer, is downloaded from the storage medium or the server computer, is installed in an external storage device, is read into the memory, and is executed by the CPU. Instead of the CPU, a DSP (digital signal processor) specialized for performing signal processing such as Fourier transform may be used.

Next, the operation of the evaluation device 1 according to the embodiment of the present invention, that is, the evaluation method for evaluating the soundness of the steel sheet pile revetment 2 will be described.

As shown in FIG. 8, first, the constant fine movement of the steel sheet pile revetment 2 is measured by the vibration meter 20 (step S1: measurement step). Here, the vibration at the measurement positions A, B, and C is measured by the vibration meter 20.

Next, the information processing apparatus 11 generates information indicating the soundness of the steel sheet pile revetment 2 based on the measured constant tremor of the steel sheet pile revetment 2 (step S2; information generation step). In this information generation step, reception of vibration data measured by the vibration meter 20 in the receiving unit 30, A / D conversion in the A / D conversion unit 31, Fourier transform in the Fourier transform unit 32, and spectral density in the spectral density calculation unit 33. Is calculated, the spectral density in a predetermined frequency range is extracted by the filter unit 34, the display information is generated by the display information generation unit 35, and the display information is displayed by the display unit 36.

By the above processing, the display image as shown in FIG. 7 is displayed on the display unit 36. Looking at this display image, it is possible to evaluate the soundness of the steel sheet pile revetment 2. When it is determined that the steel sheet pile revetment 2 is deteriorated, the steel sheet pile revetment 2 can be repaired to prevent the apron 8 from collapsing.

Embodiment 2
Next, Embodiment 2 of the present invention will be described. The configuration of the evaluation device 1 according to the present embodiment is the same as the configuration of the evaluation device 1 according to the first embodiment shown in FIG. The evaluation device 1 according to the first embodiment displays information indicating the soundness of the steel sheet pile revetment 2. The evaluation device 1 according to the present embodiment not only displays information indicating the soundness of the steel sheet pile revetment 2, but also determines the soundness of the steel sheet pile revetment 2.

In the evaluation device 1 according to the present embodiment, the configuration of the information generation device 21 is different from the configuration of the evaluation device 1 according to the first embodiment. As shown in FIG. 9, the information generation device 21 includes a determination unit 40 as a first determination unit. The determination unit 40 determines the soundness of the steel sheet pile revetment 2 based on the difference in the spectral densities extracted by the filter unit 34 for the measurement positions B and C and the measurement position A.

For example, the determination unit 40 obtains an average value of the spectral densities of 300 Hz or more and 500 Hz or less at the measurement position A and an average value of the spectral densities of 300 Hz or more and 500 Hz or less at the measurement position C. Then, if the difference between the obtained average values is equal to or greater than the threshold value, it can be determined that the steel sheet pile revetment 2 is in a sound state.

By providing the determination unit 40, it is possible to automatically determine whether or not the steel sheet pile revetment 2 is in a sound state. The determination result of the determination unit 40 can be displayed on the display unit 36 together with the display information generated by the display information generation unit 35.

In general, it is better to use the data at the measurement position C, which is the farthest from the measurement position A, than to use the data at the measurement position B, to determine the deterioration of the steel sheet pile revetment 2 earlier. can do.

Embodiment 3
Next, Embodiment 3 of the present invention will be described. In the evaluation device 1 according to the first and second embodiments, the vibration meter 20 is installed at the measurement positions A, B, and C. As shown in FIG. 10, in the evaluation device 1 according to the present embodiment, the vibration meter 20 is installed at the measurement position C and not at the measurement position B. The vibration meter 20 constantly measures the fine movement of the steel sheet pile revetment 2 at the measurement position C.

As shown in FIG. 11, in the present embodiment, the information generation device 21 includes a determination unit 41 as a second determination unit and a storage unit 50, which is related to the first embodiment. It is different from the configuration of the evaluation device 1.

The storage unit 50 stores the distribution data of the spectral density at the measurement position C in a sound state. The determination unit 41 compares the spectral density distribution data at the measurement position C measured this time with the spectral density distribution data at the measurement position C stored in the storage unit 50, and is based on the time change of the spectral density. , Judge the soundness of the steel sheet pile guard bank 2.

Specifically, the determination unit 40 has the initial average value of the spectral density of 300 Hz or more and 500 Hz or less at the measurement position C and the spectral density of 300 Hz or more and 500 Hz or less at the measurement position C stored in the storage unit 50. Find the average value in this measurement. Then, if the difference between the obtained average values is equal to or greater than the threshold value, it can be determined that the steel sheet pile revetment 2 is in a sound state.

By providing the determination unit 40, it is possible to automatically determine whether or not the steel sheet pile revetment 2 is in a sound state. The determination result of the determination unit 40 can be displayed on the display unit 36 together with the display information generated by the display information generation unit 35.

In general, it is better to use the data at the measurement position C, which is the farthest from the measurement position A, than to use the data at the measurement position B, to determine the deterioration of the steel sheet pile revetment 2 earlier. can do.

As described in detail above, according to the above embodiment, information indicating the soundness of the steel sheet pile revetment 2 is generated based on the frequency component of the constant tremor of the steel sheet pile revetment 2 at a position away from the water's edge. .. The present inventor has found that the frequency component of constant tremor differs depending on the water's edge, that is, the distance from the sea 3, and even at the same position, it changes due to deterioration of the internal structure of the steel sheet pile revetment 2. By using the generated information, the soundness of the steel sheet pile revetment 2 can be easily and efficiently evaluated without providing equipment for applying vibration to the steel sheet pile revetment 2.

Further, in the above embodiment, the soundness of the steel sheet pile revetment 2 was evaluated based on the spectral density of the Fourier spectrum of constant tremor. Since the spectral density is normalized data, it is possible to judge the deterioration of the steel sheet pile revetment 2 on a uniform scale regardless of the change in the magnitude of the tremor at all times. However, the scale for evaluating the soundness of the steel sheet pile revetment 2 is not limited to the spectral density. For example, the Fourier spectrum itself may be used as a measure for evaluating the soundness of the steel sheet pile revetment 2.

Further, in the above embodiment, the vibration waveform data is converted into a Fourier spectrum by a fast Fourier transform (FFT). However, the present invention is not limited to this. Other Fourier transform processes may be used.

Further, in the above embodiment, the soundness of the steel sheet pile revetment 2 was evaluated based on the spectral density of the first frequency S1 or higher and the second frequency S2 or lower higher than the first frequency S1. This makes it possible to evaluate the soundness of the steel sheet pile revetment 2 with high accuracy by using the frequency component from which the noise component having a long period is removed.

In the above embodiment, the first frequency S1 is set to 300 Hz and the second frequency S2 is set to 500 Hz. The reason why the first frequency S1 is set to 300 Hz is that a large noise component is observed below 300 Hz. This noise component is considered to be due to the influence of disturbance such as the ship being moored or a strong wind blowing. However, the values of the first frequency S1 and the second frequency S2 can be appropriately determined. When the steel sheet pile revetment 2 was measured under various measurement conditions, it was confirmed that if the first frequency S1 was set to 300 Hz and the second frequency S2 was set to 550 Hz, fine movements could always be observed satisfactorily during that period. ..

Further, the evaluation device 1 according to the first and second embodiments evaluated the soundness of the steel sheet pile revetment 2 by comparing the frequency components of the steel sheet pile revetment 2 at different measurement positions. By doing so, it is possible to evaluate the soundness of the steel sheet pile revetment 2 without providing a storage unit for storing past frequency components.

In the above-described first and second embodiments, the number of measurement positions is three, but at least two may be sufficient. Further, the soundness of the steel sheet pile revetment 2 may be evaluated by comparing the spectral densities of the measurement position B and the measurement position C. Further, the number of measurement positions may be four or more. If the measurement position is in the form of a matrix, it is possible to make a more detailed judgment of soundness.

Further, the evaluation device 1 according to the third embodiment stores information indicating the frequency component in a sound state of the steel sheet pile revetment 2, and measures the stored frequency component and newly obtains it. The soundness of the steel sheet pile revetment 2 was evaluated by comparison with the frequency component. By doing so, it is possible to directly measure the aged deterioration of the characteristics of the steel sheet pile revetment 2 at the same measurement position C.

Further, in the above-described embodiment, the spectral densities are color-coded according to their magnitudes and displayed. By looking at this display, the spectral densities can be compared by color, so that changes in the characteristics of the steel sheet pile revetment 2 can be easily recognized at a glance. However, the method for displaying the spectral density is not limited to the color-coded display. The pattern may be changed according to the magnitude of the spectral density. Further, the magnitude of the spectral density may be displayed three-dimensionally.

Further, in the above embodiment, the soundness of the steel sheet pile revetment 2 was evaluated based on the Fourier spectrum of the constant tremor in the vertical direction. This is because the vibration in the vertical direction is the largest among the vibrations in the three axial directions that can be measured by the vibration meter 20. However, the present invention is not limited to this. The soundness of the steel sheet pile revetment 2 may be evaluated based on the Fourier spectrum of the constant tremor in the triaxial direction. Further, the soundness of the steel sheet pile revetment 2 may be evaluated based on the Fourier spectrum of the vibration obtained by synthesizing the constant tremors in the three axial directions.

Further, in the above embodiment, the functions of the Fourier transform unit 32, the spectral density calculation unit 33, the filter unit 34, and the display information generation unit 35 are realized by the computer executing the software program. .. However, the present invention is not limited to this. The Fourier transform unit 32, the spectral density calculation unit 33, the filter unit 34, and the display information generation unit 35 may be realized by a hardware processing circuit that performs signal processing.

Further, the evaluation device 1 according to the above embodiment is attached to the target steel sheet pile revetment 2 at the time of evaluation in order to periodically evaluate the soundness of the steel sheet pile revetment 2. The invention is not limited to this. The evaluation device 1 may constantly observe the frequency component of the constant tremor of the steel sheet pile revetment 2 by the vibration meter 20.

In the above embodiment, the target waterside structure is a tie rod type steel sheet pile revetment 2. However, the steel sheet pile revetment 2 includes a self-standing steel sheet pile, an oblique resistance type steel sheet pile, a combined steel sheet pile, a cell type steel sheet pile, and the like. The present invention can be applied to such steel sheet piles. Further, the present invention is not limited to this. For example, the target waterside structure may be a breakwater. In addition, the present invention is applicable as long as it is a waterside structure installed at the waterside.

For example, the breakwater has a different structure from the steel sheet pile revetment 2, but when the internal structure changes due to deterioration, a change in the spectral density of the Fourier spectrum of constant tremor is observed, so that the present invention can be applied. be.

The present invention allows for various embodiments and variations without departing from the broad spirit and scope of the invention. Further, the above-described embodiments are for explaining the present invention, and do not limit the scope of the present invention. That is, the scope of the present invention is shown not by the embodiment but by the claims. And, various modifications made within the scope of the claims and the equivalent meaning of the invention are considered to be within the scope of the present invention.

The present invention can be applied to the evaluation of the soundness of the waterfront structure installed at the waterside.

1 Evaluation device, 2 Steel sheet pile guard (sheet pile), 3 Sea, 4 Conventional earth and sand, 5 Filled earth and sand, 6 Steel sheet pile, 7 Superstructure, 8 Apron concrete (apron), 9 Tie rod, 10 Back plate, 11 Information processing Device, 20 vibrometer, 21 information generator, 30 receiver, 31 A / D converter, 32 Fourier transform, 33 spectral density calculation, 34 filter, 35 display information generator, 36 display, 40, 41 Judgment unit, 50 storage unit

Claims (8)

It is an evaluation device that evaluates the soundness of waterside structures that come into contact with waterside.
A vibrometer that measures the constant tremor of the waterside structure at the first position away from the waterside, and
An information generation unit that generates information indicating the soundness of the waterside structure based on the frequency component of the constant tremor of the waterside structure measured by the vibration meter.
An evaluation device equipped with. The information generation unit
A Fourier transform unit that obtains a Fourier spectrum by performing a Fourier transform on the constant tremor of the waterside structure measured by the vibration meter.
A spectral density calculation unit for calculating the spectral density of the Fourier spectrum obtained by the Fourier transform unit, and a spectral density calculation unit.
To prepare
The evaluation device according to claim 1. The information generation unit
It is provided with an extraction unit for extracting the spectral density of the first frequency or higher and lower than the second frequency higher than the first frequency from the spectral density of the constant tremor Fourier spectrum.
The evaluation device according to claim 2. The vibrometer
At a second position closer to the water's edge than the first position, constant tremors in the water's edge structure were measured.
The information generation unit
A first determination unit for determining the soundness of the waterfront structure is provided by comparing the spectral density corresponding to the first position with the spectral density corresponding to the second position.
The evaluation device according to claim 3. The information generation unit
A second determination unit for determining the soundness of the waterfront structure based on the time change of the spectral density extracted by the extraction unit is provided.
The evaluation device according to claim 3. The information generation unit
A display information generation unit that generates display information that displays the spectral density extracted by the extraction unit in different colors according to its size.
A display unit that displays the display information generated by the display information generation unit, and a display unit that displays the display information.
To prepare
The evaluation device according to claim 3. The vibrometer measures constant tremors in the vertical direction.
The evaluation device according to any one of claims 1 to 6. It is an evaluation method to evaluate the soundness of waterfront structures.
The vibration meter measures the constant tremor of the waterside structure,
An information processing device generates information indicating the soundness of the waterside structure based on the measured constant tremor of the waterside structure.
Evaluation methods.

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