JP5249874B2 - Ground evaluation apparatus and ground evaluation method - Google Patents

Description

  The present invention relates to a ground evaluation apparatus and a ground evaluation method.

Excavation to a support layer by an excavator such as an earth auger is generally performed by excavating to a design depth set according to the result of test boring or the like.
Since it was difficult to determine whether excavation by the excavator reached the support layer during excavation, it was confirmed by a penetration test conducted after excavation.

  However, when checking after excavation, if it was found that the predetermined support layer was not reached as a result of the penetration test, the repair work was time-consuming.

For this reason, many investigation methods have been developed that make it possible to investigate the ground under excavation.
For example, Patent Document 1 discloses a method for investigating the strength of the ground based on drilling data such as the number of rod hits of an excavator, rotational pressure, and drilling length.

JP 2004-197429 A

However, although the investigation method described in Patent Document 1 can determine the strength of the ground, it cannot identify the type of the ground.
Therefore, for example, in foundation work, if a rock layer having the same strength as the support layer is present in front of the support layer, it is difficult to determine whether or not the support layer has been reached. there were.
The above problem also applies to the case where it is determined whether or not the TBM or shield machine has approached a predetermined ground (for example, a crush zone).

  This invention solves the said problem, and makes it a subject to propose the ground evaluation apparatus and the ground evaluation method which enabled it to judge whether the excavator reached | attained the predetermined ground. .

  The ground evaluation device of the present invention that solves such a problem analyzes a data acquisition unit that acquires time calendar data of a physical quantity correlated with an operating state of an excavator, and the time calendar data acquired by the data acquisition unit. A data analysis unit, and a notification unit for notifying that the excavator has reached the target ground, wherein the data analysis unit provides a spectrum for the time calendar data acquired by the data acquisition unit. A spectrum analysis means for performing an analysis and calculating a frequency spectrum at the time of excavation as a function of a frequency domain, and a first correction spectrum by subtracting the frequency spectrum at the time of non-excavation acquired when the excavator is not excavated from the frequency spectrum at the time of excavation A first correction means for computing a storage means for storing a teacher spectrum obtained when excavating a ground equivalent to the target ground with the excavator, Correction coefficient calculation means for calculating a correction coefficient by dividing the integral value of the teacher spectrum by the integral value of the first correction spectrum; and a second coefficient for calculating the second correction spectrum by multiplying the first correction spectrum by the correction coefficient. Two correction means, correlation coefficient calculation means for calculating a correlation coefficient between the teacher spectrum and the second correction spectrum, and determination means for determining whether or not the correlation coefficient exceeds a threshold value. And the said alerting | reporting part alert | reports that the said excavator reached the said target ground, when it determines with the said correlation coefficient exceeding the said threshold value.

  Further, the ground evaluation method of the present invention acquires time calendar data of a physical quantity correlated with the operating state of the excavator and analyzes the time calendar data to determine whether or not the excavator has reached a target ground. It is a ground evaluation method, a spectrum analysis step for performing spectrum analysis on the time calendar data and calculating a frequency spectrum at the time of excavation that is a function of a frequency domain, and a frequency at the time of non-excavation acquired when the excavator is not excavated A first correction step of calculating a first correction spectrum by subtracting a spectrum from the excavation frequency spectrum; and an integrated value of a teacher spectrum obtained when excavating a ground equivalent to the target ground with the excavator. A correction coefficient calculation step of calculating a correction coefficient by dividing by an integral value of one correction spectrum, and a second by multiplying the first correction spectrum by the correction coefficient A second correction step of calculating a positive spectrum; a correlation coefficient calculation step of calculating a correlation coefficient between the teacher spectrum and the second correction spectrum; and determining whether the correlation coefficient exceeds a threshold value And a determination step.

  Examples of the “physical quantity correlated with the operating state of the excavator” include sound observed in the vicinity of the excavator (such as operating sound of the driving source and sound generated by contact with the ground), and vibration of the excavator. Included acceleration, current supplied to the electric motor, output of the electric motor (torque), pressure of hydraulic oil supplied to the hydraulic motor, output of the hydraulic motor (torque), strain generated on the rotating shaft (shear strain), etc. .

  According to the ground evaluation device and the ground evaluation method, whether the excavator has reached the target ground by acquiring physical quantities (for example, sound, acceleration, torque, current, pressure, etc.) correlated with the operating state of the excavator. It is possible to detect whether or not with high accuracy.

In addition, when the excavator reaches the target ground, it will be notified by the notification unit (eg, display means such as a monitor, speakers, indicator lights, etc.), so that it will be recognized regardless of the experience value and technical ability of the worker. Is possible.
Further, the determination as to whether or not the target ground has been reached is objective because it is recognized by the correlation coefficient between the spectrum of the ground being excavated and the teacher spectrum of the target ground.

  According to the ground evaluation device and the ground evaluation method of the present invention, it is possible to appropriately determine whether or not the excavator has reached a predetermined ground.

It is a schematic diagram which shows the installation condition of the ground evaluation apparatus which concerns on embodiment of this invention. It is a block diagram which similarly shows the structure of a ground evaluation apparatus. It is a flowchart which shows the ground evaluation method which concerns on this embodiment. It is a graph which shows a measurement waveform. (A) And (b) is a graph which shows a frequency spectrum at the time of excavation. (A) is a graph showing a non-excavation frequency spectrum, (b) is a graph showing an excavation frequency spectrum, and (c) is a graph showing a first correction spectrum. (A) A graph showing a first correction spectrum, (b) a graph showing a teacher spectrum, and (c) a graph showing a second correction spectrum.

Preferred embodiments of the present invention will be described with reference to the drawings.
Ground evaluation device 1 of the present embodiment, as shown in FIG. 1, the support ground (target soil) Ground auger excavator that performs digging up G _R (hereinafter, simply referred to as "excavator") auger M1 of M supporting ground it is to determine whether the host vehicle has reached to G _R.

  The ground evaluation device 1 includes an acoustic receiver (data acquisition unit) 2, a triaxial accelerometer (data acquisition unit) 3, and a computer 4.

The acoustic receiver 2 is a device that receives sound generated when the ground G is excavated by the excavator M (for example, sound generated when the tip of the auger M1 comes into contact with the ground G).
The triaxial accelerometer 3 is a device that measures vibration (acceleration) generated in the rod as the excavator M excavates the ground G. The triaxial accelerometer 3 measures the acceleration in the vertical direction and the acceleration along the two axes orthogonal to each other in the horizontal plane.
In the present embodiment, the acoustic receiver 2 and the three-axis accelerometer 3 are used as the data acquisition unit. However, the torque measuring device that measures the output torque of the drive source of the auger M1 and the shear generated in the rod A strain gauge that measures strain may be used as the data acquisition unit. Further, when the drive source of the excavator M is an electric motor, an ammeter that measures the current supplied to the electric motor can be used as the data acquisition unit. When the drive source is a hydraulic motor, A pressure gauge that measures the hydraulic pressure of the hydraulic oil supplied to the hydraulic motor can be used as the data acquisition unit. Moreover, these measuring devices may use a some measuring device together, and may use only one. Further, instead of the triaxial accelerometer 3, a uniaxial accelerometer or a biaxial accelerometer may be employed.

  In the present embodiment, the acoustic receiver 2 and the three-axis accelerometer 3 are installed above the mounting portion M2 of the auger M1 of the excavator M so as not to hinder the auger M1 attachment / detachment work. And the attachment location of the triaxial accelerometer 3 is not limited. Although illustration is omitted, the acoustic receiver 2 and the triaxial accelerometer 3 may be attached to the lower side of the attachment portion M2 or the tip of the auger M1.

  The computer 4 includes a data analysis unit 5 and a notification unit 6. The data analysis unit 5 obtains the time calendar data of the sound acquired by the acoustic receiver 2 and the time calendar data of the vibration (acceleration) acquired by the triaxial accelerometer 3 via the converter (A / D converter) 7. And analyze it. The notification unit 6 notifies the information output from the data analysis unit 5, and is configured by a monitor 61 and a speaker 62 in this embodiment (see FIG. 2).

  As shown in FIG. 2, the data analysis unit 5 includes an input interface 10, an analysis unit 20, a calculation unit 30, a storage unit 40, and a determination unit 50.

The input interface 10 is means for acquiring time calendar data of physical quantities transmitted from the acoustic receiver 2 and the triaxial accelerometer 3.
The input interface 10 is appropriately set according to the format of data output from the data acquisition unit. For example, in the case where a power meter is provided as the data acquisition unit, an input interface for power data is provided. Shall be provided. The time calendar data captured by the data analysis unit 5 is stored in the storage unit 40.

  The analysis unit 20 is a unit that performs spectrum analysis of various time calendar data acquired via the input interface 10. The analysis unit 20 of the present embodiment includes an excavation time spectrum analysis unit 21, a non-excavation time spectrum analysis unit 22, and a teacher spectrum analysis unit 23. Specific functions of each means will be described later.

  The calculation unit 30 includes a first correction unit 31, an excavation data integration unit 32, a teacher data integration unit 33, a correction coefficient calculation unit 34, a second correction unit 35, and a correlation coefficient calculation unit 36. ing. Specific functions of each means will be described later.

  The storage means 40 includes a writable nonvolatile semiconductor memory (flash memory), a hard disk device, an optical disk device, and the like, and a data storage file 41 for storing data input via the input interface 10. A spectrum storage file 42 that stores data analyzed by the analysis means 20 and an integral value storage file 43 that stores the results calculated by the calculation means 30 are provided.

Determining unit 50, a means for determining whether or not the auger M1 by using the correlation coefficient calculated by the correlation coefficient calculation unit 36 (excavator) has reached the supporting ground G _R.

  In this embodiment, a central processing unit (CPU or MPU) (not shown) functions as the analysis unit 20, the calculation unit 30, and the determination unit 50.

Next, a ground evaluation method using the ground evaluation apparatus 1 will be described.
As shown in FIG. 3, the ground evaluation method according to the present embodiment includes a data acquisition step S1, a spectrum analysis step S2, a ground detection step S3, a first correction step S4, a correction coefficient calculation step S5, There are two correction steps S6, correlation coefficient calculation step S7, and determination step S8.

  The spectrum storage file 42 of the ground evaluation apparatus 1 stores in advance a teacher spectrum (see FIG. 7B) and a non-excavation frequency spectrum (see FIG. 6A), and an integrated value storage file 43. Is preliminarily stored with a teacher integral value.

Here, the teacher spectrum is a frequency spectrum (frequency domain function) obtained by performing spectrum analysis (FFT, MEM, etc.) on the time calendar data acquired by the data acquisition unit during the preceding excavation. That is, the teacher spectra (in the present embodiment, the supporting ground G _R) equivalent to ground the target ground (supporting ground G _R) by performing an excavation by pre excavator M in correlation to the operating state of the excavator M The time calendar data of the physical quantities to be performed (sound and acceleration in the present embodiment) is acquired by the data acquisition unit, and the acquired time calendar data can be obtained by performing spectrum analysis with the teacher spectrum analysis means 23. Incidentally, the teacher spectrum analysis means 23 of this embodiment performs FFT (fast Fourier transform), but may be configured to perform spectrum analysis such as MEM (maximum entropy method).

In the present embodiment, performed prior drilling by the drilling machine M in the vicinity of the support ground G _R point or the test boring depth was confirmed in performing the test boring, the tip of the auger M1 support ground G _R During the excavation, time calendar data (hereinafter referred to as “preceding excavation data”) of physical quantities correlated with the operating state of the excavator M is collected.

  The teacher integral value is calculated by integrating the teacher spectrum (see Equation 1). The teacher integration value is calculated by the teacher data integration means 33.

The non-excavation frequency spectrum is calculated by performing spectrum analysis on the time calendar data acquired by the data acquisition unit during non-excavation.
In this embodiment, the auger M1 is idly rotated (rotated without being lowered) in the excavation hole drilled by the preceding excavation, and the sound, vibration, etc. acquired by the acoustic receiver 2 and the triaxial accelerometer 3 at that time The non-excavation frequency spectrum, which is a function in the frequency domain, is calculated by performing spectrum analysis on the physical quantity time calendar data by the non-excavation spectrum analysis means 22.

In the present embodiment, the case where the non-excavation frequency spectrum is calculated from the sound and vibration time calendar data acquired when the auger M1 is idly rotated in the ground (in the excavation hole) is exemplified. The non-excavation frequency spectrum may be calculated from time calendar data such as sound obtained when the auger M1 is idly rotated (outside the excavation hole). When rotating the auger M1 in the air, the auger M1 (rod) is desirably has a length comparable to the excavation of the supporting ground G _R.

  In the present embodiment, the teacher spectrum and the non-excavation frequency spectrum are calculated by the data analysis unit 5, but the teacher spectrum and the non-excavation frequency spectrum may be directly input data.

  In the main excavation, first, a data acquisition step S1 is executed. In the data acquisition step S1, sound and vibration time calendar data (physical quantity time calendar data correlated with the operating state of the excavator M) during excavation by the excavator M is acquired.

  The acoustic receiver 2 receives the sound emitted along with the excavation destruction of the ground by the excavator M. The time calendar data of the sound received by the acoustic receiver 2 is input to the data analysis unit 5 via the converter 7 and the input interface 10 and stored in the data storage file 41.

  The vibration generated in the auger M1 during ground excavation by the excavator M is measured by the triaxial accelerometer 3. The time calendar data of vibration (acceleration) measured by the triaxial accelerometer 3 is input to the data analysis unit 5 via the converter 7 and the input interface 10 and stored in the data storage means 41.

Sound and vibration time calendar data at the time of excavation is acquired as an analog waveform as shown in FIG. 4, but is converted into a digital waveform by the converter 7 and data as discrete data at each sampling interval (reciprocal of sampling frequency). It is stored in the storage file 41. Incidentally, the vertical axis of the graph of FIG. 4 is the acceleration. The input discrete data or the like may be displayed on the monitor 61.
Note that the sound and vibration sampling time T during main excavation is preferably long, but is set in consideration of the time required for data processing and the amount of data to be stored. In the present embodiment, 10 to 60 seconds are secured as one sampling time, but the sampling time is not limited to this.

  In the spectrum analysis step S2, the excavation time spectrum analysis means 21 performs spectrum analysis on the main excavation time calendar data stored in the data storage file 41, and calculates the excavation frequency spectrum as a function of the frequency domain. .

  The excavation time spectrum analyzing means 21 is activated when the time calendar data is stored in the data storage file 41. The excavation time spectrum analyzing means 21 reads time calendar data (discretized time calendar data) such as sound and vibration from the data storage file 41, and performs spectrum analysis (in this embodiment) on the read time calendar data. The frequency spectrum at the time of excavation is obtained by performing (FFT).

  The excavation frequency spectrum obtained by the excavation spectrum analyzing means 21 can be represented by a graph composed of the relationship between the frequency and the amplitude, as shown in FIG. 5 (a) or (b).

In the ground difference detection step S3, the excavation frequency spectrum calculated in the spectrum analysis step S2 is confirmed on the monitor 61, and a difference from the teacher spectrum stored in advance in the spectrum storage file 42 is detected.
Here, when it is determined that the frequency spectrum during excavation is clearly different from the teacher spectrum, excavation by the excavator M is continued without performing the operations after the first correction step S4.

  In addition, the ground difference detection step S3 may be performed as necessary and may be omitted. Further, the difference between the excavation frequency spectrum and the teacher spectrum may be detected mechanically.

  In the first correction step S4, the first correction means 31 cancels the sound / vibration peculiar to the excavating machine from the frequency spectrum during excavation calculated in the spectrum analysis step S2, thereby obtaining the first correction spectrum.

  That is, the first correcting means 31 reads out the excavation frequency spectrum (see FIG. 6B) and the non-excavation frequency spectrum (see FIG. 6A) from the spectrum storage file 42, and from the excavation frequency spectrum. The first correction spectrum (see FIG. 6C) is calculated by subtracting the non-excavation frequency spectrum. The first corrected spectrum is stored in the spectrum storage file 42.

  In the correction coefficient calculation step S5, the correction coefficient is calculated by dividing the teacher integral value by the integral value of the first correction spectrum. The teacher integral value is an integral value (the area of the hatched portion) of the teacher spectrum shown in (b) of FIG. 7, and one stored in advance in the integral value storage file 43 is used.

  The integrated value of the first correction spectrum is the “area” of the hatched portion in FIG. That is, the excavation data integration means 32 reads the first correction spectrum (see FIG. 7A) from the spectrum storage file 42, integrates it, and integrates it (hereinafter referred to as “first integration value”). Is calculated (see Equation 2). The first integral value is stored in the integral value storage file 43.

  The correction coefficient is calculated by the correction coefficient calculation means 34. That is, when the first integration value SS is calculated by the excavation data integration means 32, the correction coefficient calculation means 34 reads the first integration value SS and the teacher integration value St from the integration value storage file 43, and the teacher integration value St A correction coefficient k is calculated by dividing St by the first integral value SS (Equation 3). The calculated correction coefficient k is stored in the storage means 40.

  In the second correction step S6, the second correction spectrum (see FIG. 7C) is calculated using the correction coefficient k calculated in the correction coefficient calculation step S5.

That is, when the calculation of the correction coefficient k is completed, the second correction unit 35 is activated and the calculation of the second correction spectrum is started.
The second correction means 35 reads the first correction spectrum from the spectrum storage file 42 and multiplies the read first correction spectrum by the correction coefficient k to calculate the second correction spectrum. The amplitude xu _i at each frequency of the second correction spectrum is a value obtained by multiplying the amplitude xs _i at each frequency of the first correction spectrum by the correction coefficient k, and is an integrated value of the second correction spectrum ((c in FIG. 7). ) Is equal to the teacher integral value (the area of the hatched portion in FIG. 7B).

  In a correlation coefficient calculation step S7, a correlation coefficient R between the teacher spectrum and the second correction spectrum is calculated.

The correlation coefficient R is calculated by the correlation coefficient calculation means 36.
The correlation coefficient calculating means 36 calculates the correlation coefficient R using the teacher spectrum and the second correction spectrum as shown in Equation 4.

In the determination step S8, it is determined whether or not the correlation coefficient R exceeds a threshold value _R0 .
That is, the determination means 50 compares the preset threshold value R ₀ with the correlation coefficient R, and if the correlation coefficient R exceeds the threshold value R ₀ (R> R ₀ ), the ground under excavation There is determined that the supporting ground G _R, when the correlation coefficient R is not greater than the threshold R ₀ (R ≦ R ₀₎ is ground while drilling is not supporting ground G _R (reaches the support ground G _R Not).
If the correlation coefficient R is 1, it indicates that the second correction spectrum and the teacher spectrum are exactly the same spectrum.

The decision step S8, when the excavator M (auger M1) is determined to have reached the supporting ground G _R, the signal is sent to the notification unit 6, the notification unit 6 having received the signal, the tip of the auger M1 is to inform the operator or the like that has reached the supporting ground G _R. In the present embodiment, the image indicating the arrival to the supporting ground G _R is displayed on the monitor 61, a sound informing that it has reached the support ground G _R (voice or buzzer) is generated from the speaker 62.
It should be noted that the data acquisition step S1 to the determination step S8 are performed a plurality of times, the determination that the correlation coefficient R exceeds the threshold value _R0 (R> _R0 ) continues a plurality of times, and the number of times reaches the specified number. when it reaches, it may be configured as ground while drilling is determined as a supporting ground G _R.

  As described above, according to the ground evaluation device 1 and the ground evaluation method of the present embodiment, it is numerically determined whether the state of the excavator M at the time of the main excavation is similar to the state when the ground equivalent to the target ground is excavated. Therefore, it is possible to ensure a certain level of accuracy without causing errors due to individual differences among workers.

In addition, not only the strength of the ground but also the ground is evaluated by using sound from excavation destruction and vibration transmitted to the rod, etc., so that the ground with similar strength alone is not recognized as the target ground, and high accuracy Construction can be done.
That is, by utilizing the sound or vibration during excavation which varies depending on the type of soil, such as other rock and boulders layer present above the support ground G _R, prevents the recognition of the supporting ground G _R.

  Moreover, since it determines using the spectrum (1st correction spectrum) which excluded the sound and vibration which are emitted from the excavator M, it is highly accurate.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and it goes without saying that the above-described constituent elements can be appropriately changed without departing from the spirit of the present invention.

For example, in the above-described embodiment, the case where the ground evaluation device and the ground evaluation method of the present invention are employed for the basic excavation by the auger excavator has been described. However, the construction method to which the ground evaluation device and the ground evaluation method of the present invention can be applied is as follows. The present invention is not limited, and can be adopted for a construction method using any rotary excavator.
For example, by adopting in TBM or shield construction method, if the ground existing before and after the crushing zone is used as the target ground, grasping that the crushing zone is approached in advance before starting excavation in the crushing zone Therefore, it is possible to prepare for the auxiliary method in advance.

Moreover, although the case where an acoustic receiver and a triaxial accelerator were used as a data acquisition part was demonstrated, the number of data acquisition parts is not limited and may be set suitably.
Also, the type of data acquisition unit is not limited. For example, an ammeter that measures the motor current, a single-axis accelerometer, a two-axis accelerometer, a speedometer, a shear strain gauge on the rotating shaft, or the like may be used. Good.

  Moreover, it is good also as a structure which measures the drilling depth (deep insertion depth etc.) to a support layer by providing a stroke meter.

1 Ground evaluation device 2 Acoustic receiver (data acquisition unit)
3 3-axis accelerometer (data acquisition unit)
4 Computer 5 Data Analysis Unit 6 Notification Unit 10 Input Interface 20 Analysis Unit 30 Calculation Unit 40 Storage Unit 50 Determination Unit

Claims (2)

A data acquisition unit that acquires time calendar data of physical quantities correlated with the operating state of the excavator;
A data analysis unit for analyzing the time calendar data acquired by the data acquisition unit;
A ground evaluation device comprising a notifying unit for notifying that the excavator has reached the target ground,
The data analysis unit
Spectral analysis for time calendar data acquired by the data acquisition unit, spectrum analysis means for calculating a frequency spectrum at the time of excavation that is a function of the frequency domain,
A first correction means for calculating a first correction spectrum by subtracting a non-excavation frequency spectrum obtained during non-excavation of the excavator from the excavation frequency spectrum;
Storage means for storing a teacher spectrum acquired when excavating the ground equivalent to the target ground with the excavator;
Correction coefficient calculation means for calculating a correction coefficient by dividing the integral value of the teacher spectrum by the integral value of the first correction spectrum;
Second correction means for calculating a second correction spectrum by multiplying the first correction spectrum by the correction coefficient;
Correlation coefficient calculating means for calculating a correlation coefficient between the teacher spectrum and the second correction spectrum;
Determining means for determining whether or not the correlation coefficient exceeds a threshold,
The notifying unit notifies that the excavator has reached the target ground when it is determined that the correlation coefficient exceeds the threshold value. Acquire time calendar data of physical quantities that correlate with the operating state of the excavator,
A ground evaluation method for analyzing the time calendar data and determining whether or not the excavator has reached a target ground,
A spectrum analysis step for performing spectrum analysis on the time calendar data and calculating a frequency spectrum at the time of excavation that is a function of a frequency domain;
A first correction step of calculating a first correction spectrum by subtracting a non-excavation frequency spectrum acquired during non-excavation of the excavator from the excavation frequency spectrum;
A correction coefficient calculating step of calculating a correction coefficient by dividing the integral value of the teacher spectrum obtained when excavating the ground equivalent to the target ground with the excavator;
A second correction step of calculating a second correction spectrum by multiplying the first correction spectrum by the correction coefficient;
A correlation coefficient calculating step of calculating a correlation coefficient between the teacher spectrum and the second correction spectrum;
And a determination step of determining whether or not the correlation coefficient exceeds a threshold value.

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