Retaining wall displacement calculation device, retaining wall displacement calculation method, and program

Abstract

To provide an earth-retaining wall displacement calculation device, an earth-retaining wall displacement calculation method, and a program which can accurately calculate displacement of an earth-retaining wall.SOLUTION: An earth-retaining wall displacement calculation device includes: a detection part for detecting vibration in a triaxial direction of an earth-retaining wall provided on an excavated wall surface; and a calculation part for generating a plurality of data units at a predetermined time interval on the basis of detection data, performing first filter processing of excluding data exceeding a threshold of an outlier in normal distribution of each of the data units, and performing second filter processing of calculating an average value of each of the data units subjected to the first filter processing and rearranging the data units in an ascending order, and excluding the data units of at least the maximum value and the minimum value of the average value, calculating the average values of the plurality of data units after the second filter processing as acceleration of the earth-retaining wall, and calculating displacement of the earth-retaining wall on the basis of the acceleration.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an earth retaining wall displacement calculation device, an earth retaining wall displacement calculation method, and a program for managing excavation of ground. [Background technology]

[0002] Retaining walls are constructed on the vertical excavation surface of the ground to prevent collapse. For example, a measurement system described in Patent Document 1 is known for managing the retaining walls in real time. This measurement system converts the inclination angle data acquired from an inclinometer installed on the retaining wall by multiplying it by the distance between measurement points to convert it into a horizontal displacement amount, and accumulates it successively upward from the bottom end of the retaining wall to obtain the horizontal displacement distribution of the retaining wall. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-197082 A Summary of the Invention [Problem to be solved by the invention]

[0004] According to the technology described in Patent Document 1, a three-axis MEMS (Micro Electro Mechanical Systems) acceleration sensor (hereinafter, acceleration sensor) is used to calculate the inclination angle of an earth retaining wall. The acceleration sensor is attached to, for example, the core material of the earth retaining wall and detects vibrations of the earth retaining wall. The detection values ​​of the acceleration sensor always include not only constant micro-movements of the ground but also other external factors (traffic vibrations, construction vibrations, etc.) regardless of the measurement time period (see Figures 5 and 9). When calculating the displacement of the earth retaining wall using the detection values ​​of the acceleration sensor, it is ideal to use true values ​​that exclude the effects of vibrations due to external factors.

[0005] However, according to the technology described in Patent Document 1, when detecting acceleration data is extracted for use in calculating the displacement of an earth retaining wall, there is a possibility that the displacement will be calculated in a situation where the earth retaining wall has not actually been displaced due to the time span of the extracted data.

[0006] An object of the present invention is to provide an earth retaining wall displacement calculation device, an earth retaining wall displacement calculation method, and a program that can accurately calculate the displacement of an earth retaining wall. [Means for solving the problem]

[0007] One aspect of the present invention is a retaining wall displacement calculation device that includes a detection unit that detects vibrations in three axial directions of an earth retaining wall installed on an excavated wall surface, and a calculation unit that generates a plurality of data units at predetermined time intervals based on the detected data, performs a first filtering process to exclude data that exceed an outlier threshold in a normal distribution of each of the data units, calculates an average value of each of the data units after the first filtering process and sorts them in ascending order, performs a second filtering process to exclude the data units with at least the maximum and minimum values ​​of the average values, calculates the average value of the plurality of data units after the second filtering process as the acceleration of the earth retaining wall, and calculates the displacement of the earth retaining wall based on the acceleration.

[0008] According to the present invention, in calculating the displacement of the retaining wall, the detection data is subjected to the first filter processing and the second filter processing, thereby removing noise from the detection data of the detection unit and improving the accuracy of the calculation results.

[0009] Furthermore, the threshold value of the present invention may be plus or minus 1.3σ with respect to the standard deviation σ of the normal distribution.

[0010] According to the present invention, by removing data exceeding a threshold in the first filtering process, noise can be removed from the detection data.

[0011] Furthermore, the second filtering process of the present invention may exclude the data units of the maximum value and the minimum value.

[0012] According to the present invention, the accuracy of the calculation result can be improved by removing data units that are significantly affected by noise in the second filtering process.

[0013] Furthermore, the second filtering process of the present invention may exclude two of the data units on the maximum value side and two of the data units on the minimum value side.

[0014] According to the present invention, by increasing the number of data units that are significantly affected by noise in the second filtering process, it is possible to improve the accuracy of the calculation result.

[0015] One aspect of the present invention is a retaining wall displacement calculation method comprising the steps of: detecting vibrations in three axial directions of an earth retaining wall provided on an excavated wall surface; generating a plurality of data units at predetermined time intervals based on the detected data; performing a first filtering process to exclude data that exceed an outlier threshold in a normal distribution of each of the data units; calculating an average value of each of the data units after the first filtering process, sorting them in ascending order, and eliminating the data units with at least the maximum and minimum values ​​of the average values; calculating the average value of the plurality of data units after the second filtering process as the acceleration of the earth retaining wall; and calculating the displacement of the earth retaining wall based on the acceleration.

[0016] According to the present invention, in calculating the displacement of the retaining wall, the detection data is subjected to the first filter process and the second filter process, thereby removing noise from the detection data and improving the accuracy of the calculation result.

[0017] One aspect of the present invention is a program that causes a computer to calculate the displacement of a retaining wall installed on an excavated wall surface, and generates a plurality of data units at a predetermined time interval based on detection data of vibration in three axial directions of the retaining wall, performs a first filter process to exclude data that exceed an outlier threshold in a normal distribution of each of the data units, calculates an average value of each of the data units after the first filter process and sorts them in ascending order, and performs a second filter process to exclude the data units with at least the maximum and minimum values ​​of the average value, calculates the average value of the plurality of data units after the second filter process as the acceleration of the retaining wall, and calculates the displacement of the retaining wall based on the acceleration.

[0018] According to the present invention, a program for calculating the displacement of an earth retaining wall can improve the accuracy of the calculation results. Effect of the Invention

[0019] According to the present invention, the displacement of the retaining wall can be accurately calculated. [Brief description of the drawings]

[0020] [Figure 1] 1 is a block diagram showing a configuration of an earth retaining wall displacement calculation device according to an embodiment of the present invention. FIG. [Diagram 2] FIG. 13 is a diagram showing the state of a detection unit provided on a retaining wall. [Diagram 3] 4 is a diagram showing the relationship between the detection direction of an acceleration sensor and the acting direction of gravity; [Figure 4] FIG. 13 is a diagram showing a method for calculating the displacement of an earth retaining wall. [Diagram 5] FIG. 13 is a diagram showing acceleration waveforms during construction operation hours. [Figure 6] FIG. 13 is a diagram showing acceleration waveforms during times other than construction operation hours. [Figure 7] FIG. 6 is an enlarged view of a portion of the acceleration waveform in FIG. 5. [Figure 8] FIG. 6 is an enlarged view of a portion of the acceleration waveform in FIG. 5. [Figure 9]FIG. 6 is an enlarged view of a portion of the acceleration waveform in FIG. 5. [Figure 10] FIG. 6 is an enlarged view of a portion of the acceleration waveform in FIG. 5. [Figure 11] FIG. 13 is a diagram showing the results of normal QQ plotting of detection data. [Figure 12] FIG. 13 is a diagram showing the results of normal QQ plotting of detection data. [Figure 13] 1 is a flowchart showing each step of a retaining wall displacement calculation method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of an earth retaining wall displacement calculation device according to the present invention will be described with reference to the drawings.

[0022] As shown in Fig. 1 and Fig. 2, in an earth retaining wall displacement calculation device 1, a terminal device 10 calculates the displacement of an earth retaining wall 2. The earth retaining wall 2 is, for example, a wall surface provided to prevent collapse or spring water from forming on an excavation surface obtained by excavating a ground E in a vertical direction. On the earth retaining wall 2, for example, a plurality of detection units 3 are attached at predetermined intervals (for example, 1) along the vertical direction. The detection units 3 detect, for example, vibrations in three axial directions of the earth retaining wall 2 provided on the excavated wall surface. For example, a three-axis MEMS acceleration sensor (hereinafter, appropriately referred to as an acceleration sensor) is used as the detection unit 3. The acceleration sensor detects acceleration in three axial directions. Detection data detected by the plurality of detection units 3 is output to the terminal device 10.

[0023] The terminal device 10 acquires sensor value data output from a detection unit 3 attached to the retaining wall 2, analyzes the data, and calculates the displacement of the retaining wall 2. The terminal device 10 is an information processing terminal such as a personal computer, a tablet terminal, or a smartphone. The terminal device 10 acquires the data output from the detection unit 3 directly or via a network (not shown).

[0024] In the terminal device 10, for example, detection data output from the detection unit 3 is stored in the storage unit 12. The storage unit 12 is configured with a storage medium such as a hard disk drive (HDD) or a flash memory. The storage unit 12 may be provided separately from the terminal device 10. The detection data stored in the storage unit 12 is read out to the calculation unit 11.

[0025] The calculation unit 11 performs various calculation processes based on the detection data. In the calculation process, the calculation unit 11 reads out the detection data from the storage unit 12, and also reads out other data and programs necessary for the calculation process, and executes the calculation process. The calculation results of the calculation unit 11 are displayed on the display unit 13. The display unit 13 is configured with a display device such as a liquid crystal display or an organic EL display. The display unit 13 may be provided separately from the terminal device 10. The display unit 13 may be configured with a smartphone or a tablet terminal.

[0026] 3, the calculation unit 11 calculates the tilt angle of the current position of the detection unit 3 by detecting the direction of gravity and the horizontal acceleration based on the detection data of the detection unit 3. In the illustrated three-dimensional orthogonal coordinate system, the acceleration value detected by the acceleration sensor when the acceleration sensor rotates around the y axis is a x Then, the inclination angle around the y-axis is θ y is calculated using the following equation (1). θ y =sin -1 (α x / 1G) (1)

[0027] This inclination angle θ y The horizontal displacement of the sensor position δ is calculated by multiplying the distance l from the base point (the bottom end of the retaining wall 2) by the horizontal displacement δ x is calculated using the following formula: "1G" is the gravitational acceleration acting on the Earth. δ x = l sinθ y (2)

[0028] Therefore, the detected acceleration α x , the distance l between the detectors 3, and the horizontal displacement δ of the measurement pointx The correlation between the above can be expressed by the following equation (3) using equations (1) and (2), assuming that θ is a sufficiently small approximation of sin θ=θ. l=δ x ·(1G / α x ) (3)

[0029] As shown in Figure 4, the measurement point P 1 The horizontal displacement of the second detector 3, which is located at a distance of l from the 1 Measurement point P 1 The measurement point P of the (n+1)th detector 3, which is installed at a distance of l×n from n+1 In this case, the horizontal displacement is δ n Then, at measurement point P n+1 Horizontal displacement δ n is expressed by the following equation (4). δ n =l(θ 1 +θ 2 +…+θ n-1 +θ n ) (4) However, the reference line: P 1 A vertical line passing through θ n : Inclination angle with respect to the reference line, δ n : displacement relative to the reference line, l: distance between measurement points.

[0030] The acceleration sensor detects acceleration values ​​that are constantly fluctuating due to various external factors. Therefore, the above calculation includes acceleration other than the acceleration based on the actual displacement of the detection unit 3, resulting in errors. In order to determine the direction of gravity in the above calculation, ideally, the effect of vibration should not be included. z It is desirable to obtain a measured value (hereinafter, true value) of the acceleration value in the direction.

[0031] The acceleration waveform during construction work hours is shown in Fig. 5. The acceleration waveform during times other than construction work hours is shown in Fig. 6. As shown in the figure, during construction work hours, the detection data from detection unit 3 always detects vibrations due to constant ground tremors and other external factors (traffic vibrations, construction vibrations, etc.) regardless of the measurement time period.

[0032] Figure 7 shows a waveform for 0.625 seconds (7.8125 ms x 80 plots) extracted from the acceleration waveform starting at 211 seconds during the construction operation time period in Figure 5. Figure 8 shows a waveform for 0.625 seconds (7.8125 ms x 80 plots) extracted from the acceleration waveform starting at 230 seconds during the construction operation time period in Figure 5. Compared to time period A sampled in Figure 7, time period B sampled in Figure 8 contains a lot of spike noise due to external factors.

[0033] If a simple average of the acceleration waveforms is taken as a representative value of the acceleration to use in calculating the displacement of the retaining wall 2, the average value for time period A in Figure 7 is μ1 = 0.004725, and the average value for time period B in Figure 8 is μ2 = 0.004395. As mentioned above, depending on the time period extracted for calculating the acceleration, even if the retaining wall 2 has not actually been displaced, a displacement may appear in the calculation.

[0034] Figure 9 shows the results of extracting a waveform for 60 seconds (7.8125 ms x 7680 plots) starting at 0 seconds from the acceleration waveform during the construction operation time in Figure 5. Figure 10 shows the results of extracting a waveform for 60 seconds (7.8125 ms x 7680 plots) starting at 170 seconds from the acceleration waveform during the construction operation time in Figure 5.

[0035] Figures 11 and 12 show the results of normal QQ plots of the normality of the data. A normal QQ plot shows the expected value for the observed values ​​when the observed values ​​follow a normal distribution. In a normal QQ plot, when the plots are aligned in a straight line, the observed values ​​tend to follow a normal distribution. As shown in the figures, the normal QQ plots in Figures 11 and 12 show clear inflection points that deviate from the linear distribution.

[0036] Therefore, in the calculation of the displacement, data outside the inflection points that deviate from the normal distribution are set as "outliers", and a first filter is set to exclude the outliers so as not to affect the displacement calculation. The first filter excludes data that deviates from μ±1.3σ with respect to the standard deviation σ (10% above and below the total data, i.e. 20% of the total). When the first filter process is performed, spike noise (see Figures 5, 9, and 10) is removed. Note that even if the normality of the data after the first filter process is guaranteed, if a time period that is greatly influenced by external factors is unintentionally extracted, there is a risk that the average value itself will deviate significantly from the true value. Therefore, the second filter process shown below is performed on the data after the first filter process.

[0037] The calculation unit 11 generates data units at a continuous predetermined time interval, such as 60 seconds, based on the detection data. Since the number of data per data unit is preferably 1000 or more from a statistical standpoint, the sampling interval is set to 0.06 seconds or less. The calculation unit 11 generates a plurality of data units (for example, 10) so as to be continuous in time. The calculation unit 11 performs a first filter process to remove data that exceeds an outlier threshold in the normal distribution of each data unit. The threshold is plus or minus 1.3σ with respect to the standard deviation σ.

[0038] The second filter is processed, for example, through the following steps. The calculation unit 11 calculates the average value of each of the multiple data units that have been subjected to the first filter processing, and rearranges the data units in ascending order based on the average value. The calculation unit 11 excludes at least the maximum and minimum data units from the rearranged multiple data units. The calculation unit 11 excludes, for example, one or two data units from the maximum and minimum sides of the rearranged multiple data units. The calculation unit 11 recalculates the average value based on the average value of eight or six of the remaining multiple data units. The calculation unit 11 calculates the average value of the multiple data units after the second filter processing as the acceleration of the retaining wall.

[0039] The figure shows each step of the retaining wall displacement calculation method. The detection unit 3 detects vibrations in three axial directions of the retaining wall 2 installed on the excavated wall surface (step S100). The calculation unit 11 generates multiple data units at predetermined time intervals based on the detected data (step S102). The calculation unit 11 performs a first filter process to remove data that exceeds an outlier threshold in the normal distribution of each data unit (step S104). The calculation unit 11 performs a second filter process to calculate the average value of each data unit after the first filter process, sort the data units in ascending order, and remove data units with at least the maximum and minimum average values ​​(step S106).

[0040] The calculation unit 11 calculates an average value of the multiple data units after the second filter process as the acceleration of the earth retaining wall 2 (step S108). The calculation unit 11 calculates the displacement of the earth retaining wall 2 based on the acceleration (step S110).

[0041] As described above, according to the retaining wall displacement calculation device 1, in calculating the displacement of the retaining wall 2 using a three-axis MEMS acceleration sensor, the detection data is subjected to the first filter process and the second filter process, thereby removing noise and improving the accuracy of the calculation result. According to the retaining wall displacement calculation device 1, the use of a three-axis MEMS acceleration sensor makes it possible to reduce the cost of measurement.

[0042] The above-mentioned calculation unit 11 is realized by a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit) executing a program (software). Some or all of these functional units may be realized by hardware such as an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), or an FPGA (Field-Programmable Gate Array), or may be realized by a combination of software and hardware. The program may be stored in advance in a storage device such as an HDD (Hard Disk Drive) or a flash memory included in the storage unit 12, or may be stored in a removable storage medium such as a DVD or a CD-ROM, and installed in the storage device by mounting the storage medium in a drive device.

[0043] The program causes a computer such as the terminal device 10 to calculate the displacement of the earth retaining wall 2 provided on the excavated wall surface. The program causes a computer to generate a plurality of data units at a predetermined time interval based on detection data of vibration in three axial directions of the earth retaining wall 2, to perform a first filtering process to remove data exceeding an outlier threshold in a normal distribution of each data unit, to sort each data unit after the first filtering process in ascending order, to perform a second filtering process to remove at least the data units with the maximum and minimum values, to calculate an average value of the plurality of data units after the second filtering process as the acceleration of the earth retaining wall 2, and to calculate the displacement of the earth retaining wall 2 based on the acceleration.

[0044] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be modified as appropriate without departing from the spirit of the present invention. For example, the terminal device 10 may be a server device connected via a network and may provide the calculation results via the network. [Explanation of symbols]

[0045] 1. Earth retaining wall displacement calculation device 2 Retaining wall 3. Detection section 11 Arithmetic section

Claims

1. A detection unit that detects vibrations in three axial directions of an earth retaining wall provided on an excavated wall surface; a calculation unit that generates a plurality of data units at a predetermined time interval based on the detection data, performs a first filtering process to exclude data exceeding an outlier threshold in a normal distribution of each of the data units, calculates an average value of each of the data units after the first filtering process and sorts them in ascending order, performs a second filtering process to exclude the data units having at least a maximum value and a minimum value of the average value, calculates the average value of the plurality of data units after the second filtering process as the acceleration of the retaining wall, and calculates a displacement of the retaining wall based on the acceleration. Retaining wall displacement calculation device.

2. The threshold value is plus or minus 1.3σ with respect to the standard deviation σ of the normal distribution. The retaining wall displacement calculation device according to claim 1.

3. the second filtering process excludes the data units having the maximum and minimum values; The retaining wall displacement calculation device according to claim 1 or 2.

4. the second filtering process excludes the two data units on the maximum value side and the two data units on the minimum value side; The retaining wall displacement calculation device according to claim 1 or 2.

5. A step of detecting vibrations in three axial directions of an earth retaining wall provided on an excavated wall surface; generating a plurality of data units at predetermined time intervals based on the detection data; performing a first filtering process to remove data that exceeds an outlier threshold in a normal distribution of each of the data units; performing a second filtering process for calculating an average value of each of the data units that have been subjected to the first filtering process, sorting the average value in ascending order, and excluding the data units having at least the maximum and minimum average values; calculating an average value of the plurality of data units after the second filtering process as an acceleration of the retaining wall; and calculating a displacement of the retaining wall based on the acceleration. Method for calculating retaining wall displacement.

6. A program for causing a computer to calculate the displacement of a retaining wall installed on an excavated wall, generating a plurality of data units at predetermined time intervals based on the detection data of vibration in the three axial directions of the retaining wall; performing a first filtering process for removing data exceeding an outlier threshold in a normal distribution of each of the data units; calculating an average value of each of the data units subjected to the first filtering process, sorting the average value in ascending order, and performing a second filtering process to exclude the data units having at least a maximum value and a minimum value of the average value; Calculating an average value of the plurality of data units after the second filtering process as the acceleration of the retaining wall; Calculating a displacement of the retaining wall based on the acceleration. program.

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