JP6969212B2 - Support layer arrival judgment method and judgment support system - Google Patents

Description

The present invention relates to a support layer arrival determination method and a determination support system for determining the arrival of a support layer in a pile hole in which a pile is installed.

When constructing a structure, there is a construction method in which a plurality of piles are driven into a support layer and the load of the structure is supported in the support layer through the piles. Therefore, the pile hole into which the pile is inserted must reach the support layer. However, due to the restrictions of the excavation method, confirmation of arrival at the support layer often depends on subjective judgment based on experience, and objective judgment is difficult.

Usually, before constructing a structure, a ground survey is conducted to identify the depth (position) of the support layer. Then, the N value of the index indicating the hardness of the ground is obtained by the standard penetration test in the ground survey.

However, the geological structure is not always the same at the entire site where the structure is constructed. In addition, it is difficult to conduct a ground survey at all pile hole positions because the ground survey is costly and time-consuming. Further, even if the acquired N values are the same, the geology may be different. Therefore, even if the columnar chart and N value based on the ground survey are grasped, it is difficult to determine the arrival of the pile hole of each pile to the support layer.

Therefore, conventionally, the resistance value (current value for outputting the drilling torque) according to the hardness of the ground at the time of excavation is integrated for each drilling depth to reach the support layer of the pile hole. A technique for determining is being studied (see, for example, Patent Document 1). In Patent Document 1, the current value at the time of excavation of the auger drive motor that drives the auger of the excavator that drills the ground is detected, and the vertical movement distance of the auger is detected. Then, at the same time as the start of excavation by the excavator, the current data of the auger and the measurement of the excavation depth are started, and these and the N value obtained by the boring survey in advance are displayed on the same screen.

Japanese Unexamined Patent Publication No. 5-287721

Even in Patent Document 1 described above, it is difficult to determine the arrival of the support layer depending on the geological structure. For example, a fine sand layer with a high N value may be laminated on a mudstone with a high N value. Here, even when the mudstone is used as the support layer, the N value and the stacking current value are detected high in the fine sand layer of the upper layer, and there is a possibility that the drilling to the support layer is erroneously determined.

The applicant has invented a method for determining the excavation speed at the time of excavation of a pile hole by using a speed index value and a frequency analysis of vibration at the time of excavation. I have applied.

-The support layer arrival determination method for solving the above problems is a support layer arrival determination method for determining the arrival of a pile at a pile hole in a pile hole, and is a value relating to the hardness of the ground at the time of excavation of the pile hole. Is obtained, and the value related to the hardness is associated with the depth of the pile hole at the time of excavation, and in the value related to the hardness, the first statistical value in the first section of the calculation target depth and the first section The second statistical value in the second section that includes the adjacent or the first section and is different from the first section and is longer than the length of the first section is calculated, and the first statistical value and the second statistical value are calculated. The judgment index value is calculated based on the comparison of the above, and the arrival at the support layer is determined based on the judgment index value.

According to the present invention, the arrival of the support layer of the pile hole can be efficiently determined.

It is explanatory drawing of the excavation apparatus for excavating a pile hole in 1st Embodiment, (a) is the schematic front view of the excavation apparatus, (b) is the block diagram which shows the structure of the drilling management system. It is explanatory drawing explaining the structure of the data stored in each storage part of 1st Embodiment, (a) is a judgment standard information storage part, (b) is excavation situation information storage part. The flow chart explaining the processing procedure of the processing process of 1st Embodiment. It is explanatory drawing explaining the evaluation process of the measured value in 1st Embodiment, (a) is the measured value graph, (b) is the graph which extracted the drilling time zone, (c) is the drilling time zone. A graph concatenating the measured values, (d) is a flow chart of the processing procedure. It is explanatory drawing explaining the judgment index value calculation processing in 1st Embodiment, (a) is the explanatory diagram of the judgment index value calculation method, (b) is the flow diagram of the processing procedure. It is explanatory drawing of the graph in 1st Embodiment, (a) is a columnar figure and N value corresponding to a depth, (b) is a depth-integral current value graph, (c) is a depth-drilling speed graph, ( d) shows a judgment index value graph of a drilling speed. It is explanatory drawing of the graph in 1st Embodiment, (a) is a columnar figure and N value corresponding to a depth, (b) is a depth-integral current value graph, (c) is a depth-vibration analysis graph, (d). ) Indicates a vibration judgment index value graph. It is explanatory drawing explaining the setting of the 2nd section in 1st Embodiment, (a) is the judgment index value when the length of the 2nd section is 1m, (b) is the length of the 2nd section. Is 2 m, and (c) is a judgment index value when the length of the second section is 5 m. It is explanatory drawing explaining the judgment index value calculation process in 2nd Embodiment, (a) is the probability of t-test, (b) is the logarithm of the probability of t-test, (c) is the probability of t-test. Inverse value, (d) is the logarithmic value of the inverse number of the t-test, and (e) is the logarithmic value of the inverse number of the t-test with positive and negative signs according to the magnitude relationship between the first statistical value and the second statistical value. .. The flow chart of the processing procedure of the judgment index value calculation processing in the 2nd Embodiment. It is explanatory drawing of the graph in 2nd Embodiment, (a) is a columnar figure and N value corresponding to the depth, (b) is a depth-drilling speed graph, (c) is the judgment of the drilling speed by t-test. The index value graph, (d) shows the judgment index value graph of the drilling speed in the division of the first embodiment. It is explanatory drawing of the graph in 2nd Embodiment, (a) is a column chart and N value corresponding to a depth, (b) is a depth-vibration analysis graph, (c) is a judgment index value graph of vibration by t-test. , (D) show the judgment index value graph of the vibration by the division of the 1st Embodiment. It is a figure explaining the judgment index value according to the set length of the 2nd section in the modification, (a) is the case where the 2nd section is made small, (b) is the case where the 2nd section is made large, (c). Shows the case where the second section is the range from the ground to the calculation target depth.

<First Embodiment>
Hereinafter, the first embodiment in which the support layer arrival determination method and the determination support system are embodied will be described with reference to FIGS. 1 to 8. In this embodiment, the velocity index value for the drilling speed and the frequency analysis value for vibration are used as the value (stiffness information) regarding the hardness of the ground at the time of excavation of the pile hole. Further, as a speed index value for the drilling speed, the drilling speed (average drilling depth for 1 minute) according to the elapsed time is used. In this embodiment, excavation is performed using the judgment index values of drilling speed and vibration acquired from the measuring instrument during excavation and the judgment index values (judgment standard values) acquired in the preceding excavation for creating the judgment criteria. It is determined that the drilling inside reaches the support layer.

FIG. 1A shows an excavator 10 as an excavator for excavating a pile hole h0 in which a pile of a building is installed. The excavator 10 includes a base machine 11, a mast 14, and an auger machine 16. The base machine 11 includes a lower traveling body including a crawler 12 and an upper turning body including an operation chamber 13.

The mast 14 is erected on the base machine 11. A wire for measuring the depth / velocity meter is provided in the mast 14. An auger machine 16 is attached to the mast 14 so as to be able to move up and down. The auger machine 16 includes a drive motor housed in a box and an excavation rod 17 that is rotationally driven by the drive motor. An excavation head 18 is attached to the tip (lower end) of the excavation rod 17. The excavation head 18 has an excavation blade formed at the tip of a pair (two) of excavating arms that swing. The raising and lowering of the excavation head 18 is controlled by the operator of the operation room 13.

Further, an excavator water supply device (not shown) for supplying excavation water to the excavation head 18 is connected to the excavator 10. The amount of this excavated water is adjusted by the operator of the operation room 13 according to the excavation situation.

As shown in FIG. 1 (b), the excavator 10 includes a drilling management system 20. The drilling management system 20 includes a computer terminal 30, a drilling depth measuring instrument 21, a flow rate measuring instrument 22, a current measuring instrument 23, a vibration measuring instrument 24, an input unit 25, and a display unit 26. Each measuring instrument (21 to 24) constantly performs measurement and transmits the measured value to the computer terminal 30. Here, the drilling depth measuring instrument 21 functions as a measuring unit for measuring the velocity index value.

The drilling depth measuring instrument 21 measures the amount of wire drawn out in the mast 14, and measures the drilling depth (depth) according to the position of the excavation head 18.
The flow rate measuring instrument 22 measures the injection flow rate of the excavated water supplied from the excavated water supply device.
The current measuring instrument 23 measures the load current of the drive motor of the auger machine 16.
The vibration measuring instrument 24 functions as a vibration measuring unit and measures vibration at the mounting location. In the present embodiment, the vibration measuring instrument 24 is attached to the operation room 13, the roof of the operation room 13, or the operation lever in the operation room 13. The vibration measuring instrument 24 measures vertical vibration and horizontal vibration.

The input unit 25 includes a keyboard, a pointing device, and the like arranged in the operation room 13, and is used for inputting various data to the computer terminal 30.
The display unit 26 includes a display or the like arranged in the operation room 13 and displays various data.

The computer terminal 30 acquires each measured value data from each measuring instrument (21 to 24). The computer terminal 30 includes a control unit 31, a determination standard information storage unit 35, and an excavation status information storage unit 36 as a measurement information storage unit.

The control unit 31 includes control means (CPU, RAM, ROM, etc.) and performs processes described later (each process such as a reference registration stage, a measured value management stage, a vibration analysis stage, a judgment index value calculation stage, and an output management stage). Do it. Therefore, by executing the drilling management program stored in the memory, the control unit 31 has the reference registration unit 311, the measured value management unit 312, the vibration analysis unit 313, the judgment index value calculation unit 314, and the output management unit 315. Functions as.

The reference registration unit 311 executes a process of registering the determination reference information in the determination reference information storage unit 35.
The measured value management unit 312 functions as a recording unit, stores the measured values acquired from each measuring instrument (21 to 24) in a memory, evaluates the measured value at predetermined time intervals, and specifies the evaluation result. Specifically, the measured value management unit 312 specifies the velocity index value, the current value, and the vibration characteristic value in the time zone (drilling time zone) actually dug. The excavation head 18 may be temporarily withdrawn immediately before digging in a hard stratum or the like. Therefore, as shown in FIG. 4A, the actual drilling depth of the excavation head 18 does not always increase monotonically with the elapsed time. Therefore, the measured value management unit 312 removes the period of lifting and stopping of the excavation head 18 (the shaded time zone of FIG. 4B) from the total working time, and is substantially used for drilling. Specify the measured value of the drilling time zone. The measured value management unit 312 concatenates the measured values in the specified drilling time zone to generate the graph shown in FIG. 4 (c).

The vibration analysis unit 313 executes the analysis process of the vibration characteristics by performing the frequency analysis of the vibration measured by the vibration measuring instrument 24. In the present embodiment, the vibration analysis unit 313 specifies the magnitude of vibration (for example, maximum amplitude, maximum acceleration, etc.) for each of the measured horizontal and vertical vibration frequency bands. Then, the vibration analysis unit 313 calculates the average of the magnitudes of the vibrations of all the frequencies in the horizontal direction and the vertical direction. Further, the vibration analysis unit 313 stores a concentration specifying table in order to display the magnitude of vibration as a density in a graph.

The judgment index value calculation unit 314 executes a process of calculating the judgment index values of the drilling speed and vibration. In the present embodiment, the first statistical value (STA: short-time average) of the drilling speed (or the magnitude of vibration) is used as the judgment index value, and the second statistical value (or the magnitude of vibration) of the drilling speed (or the magnitude of vibration) is used. LTA: Long-term average) divided by the value is used. Here, as shown in FIG. 5A, the short-term average and the long-term average are average values in the first section Δd and the second section ΔD. The first section Δd and the second section ΔD are sections of the pile hole having predetermined distances, respectively. The second section ΔD is made longer (larger) than the first section Δd. Then, the first section Δd and the second section ΔD are set adjacent to each other. In the present embodiment, the direction in which the depth becomes deep is positive, and the first section Δd is the range of the calculation target depth d or more (the calculation target depth d is the minimum value of the first section Δd) and the second section ΔD. , The calculation target depth d or less (the calculation target depth d is the maximum value of the second section ΔD) is set. Here, the first section Δd uses the range from the calculation target depth d to “d + 0.5 m”, and the second section ΔD uses the range from the calculation target depth d to “d-2 m”. Further, the calculation target depth d is the depth (position) of the target for which the judgment index value is calculated, and is set to a width (pitch) of 10 cm in the present embodiment. The method of determining the range (length) of the second section ΔD will be described later.
In this embodiment, the magnitude of vibration at all frequencies in the first section Δd and the second section ΔD is used as the vibration judgment index value.
The output management unit 315 functions as an output unit, and displays on the display unit 26 a graph or the like that describes each measured value at the time of excavation and the measured value according to the calculated depth.

As shown in FIG. 2A, the determination standard information storage unit 35 stores the determination standard information 350 used for determining the arrival at the support layer. In the present embodiment, the determination criterion information 350 includes a histogram 351 and a depth-N value graph 352 and a determination criterion graph 355 associated with the site identifier.

The histogram 351 is created based on the soil sample obtained in the boring survey at the construction site where the pile hole is excavated. The depth-N value graph 352 is created based on the standard penetration test data acquired in this boring survey.
Here, the histogram 351 and the depth-N value graph 352 shown in FIGS. 6 (a) and 7 (a) are recorded.

The determination reference graph 355 is a graph showing the reference value of the measured value used when determining whether or not the pile hole has reached the support layer, in correspondence with the depth. The determination criterion graph 355 is generated and registered in a preceding excavation process (eg, the first pile hole excavation process) performed in the vicinity of the boring survey at the site specified by the site identifier. The judgment reference graph 355 includes a depth-elapsed time reference graph R1, a depth-drilling speed reference graph R2, a depth-integrated current value reference graph R5, a depth-vibration analysis reference graph R6, and a drilling speed judgment index reference graph R12. , Vibration determination index reference graph R16 is included. Each reference graph (R1, R2, R5, R6, R12, R16) is used as a reference for change of the corresponding graph (361, 362, 365, 366, 372, 376) described later.

As shown in FIG. 2B, the excavation status information storage unit 36 stores excavation status information 360 regarding the excavation status of the pile hole. The excavation status information 360 includes a depth-elapsed time graph 361, a depth-drilling speed graph 362, a depth-integrated current value graph 365, a depth-vibration analysis graph 366, and a drilling speed in association with the site identifier and the pile number. The judgment index value graph 372 of the above and the judgment index value graph 376 of the vibration are included. Each measured value of these graphs (361, 362, 365, 366, 372, 376) is additionally recorded each time it is acquired during excavation in the measured value management process described later.

As shown in FIG. 4C, the depth-elapsed time graph 361 is a graph in which the excavation depth (drilling depth) is on the vertical axis and the elapsed time (drilling time) is on the horizontal axis.
As shown in FIG. 6 (c), the depth-drilling speed graph 362 is a graph in which the drilling depth is on the vertical axis and the drilling speed is on the horizontal axis. The depth-drilling velocity graph 362 is calculated by dividing a constant drilling range (eg, every 30 cm in depth) by the time required for drilling in this constant drilling range.

As shown in FIGS. 6 (b) and 7 (b), the depth-integrated current value graph 365 is a graph in which the drilling depth is on the vertical axis and the integrated current value is on the horizontal axis.
As shown in FIG. 7 (c), the depth-vibration analysis graph 366 is a graph relating to vibration characteristic values according to the drilling depth. In this depth-vibration analysis graph 366, the drilling depth is used on the vertical axis and the frequency is used on the horizontal axis, and the graph is represented by a concentration corresponding to the magnitude of vibration at each frequency. In the present embodiment, the average value of the magnitude of the vibration in the horizontal direction and the magnitude of the vibration in the vertical direction is shown by the concentration.

As shown in FIG. 6D, the drilling speed judgment index value graph 372 is a graph in which the drilling depth (depth) is on the vertical axis and the drilling speed judgment index value is on the horizontal axis.
As shown in FIG. 7D, the vibration judgment index value graph 376 is a graph in which the drilling depth (depth) is on the vertical axis and the vibration judgment index value is on the horizontal axis.

[Method of determining the length of the second section ΔD]
Next, a method of determining the length of the second section ΔD will be described with reference to FIG. Here, the second section is such that the judgment index value used for determining whether or not the support layer or the boundary of the stratum has been reached is a value that is more apparent than the other parts at the depth corresponding to the support layer or the boundary of the stratum. Determine the length of ΔD.

FIG. 8 shows a judgment index value graph when the second section ΔD is changed. 8 (a), 8 (b) and 8 (c) show the second section ΔD as “d-1 m”, “d-2 m” and “d-5 m” from the calculation target depth d, respectively. The judgment index value when the range is up to is shown. In this judgment index value, the first section Δd is set as a range from the calculation target depth d to “d + 0.5 m”.
In the figure, the depth indicated by the white triangle is the depth (position) determined to be the boundary of the stratum corresponding to the columnar chart 351 and the depth-N value graph 352, and the depth indicated by the black triangle is It is a depth (position) determined to have reached the support layer corresponding to the columnar chart 351 and the depth −N value graph 352.

As for the judgment index value in FIG. 8A, the judgment index value gradually increases from the portion shallower than the depth of the stratum boundary as compared with FIG. 8B. The judgment index value in FIG. 8 (c) is generally changed so that the judgment index value becomes smaller as the depth becomes deeper than in FIG. 8 (b). Therefore, in FIG. 8 (b) of FIGS. 8 (a) to 8 (c), the judgment index values at the positions of the stratum boundary and the support layer are clearer than the judgment index values at other positions. .. Therefore, in the present embodiment, the second section ΔD is set as a range from the calculation target depth d to “d-2m”.

<Excavation>
Next, a process of excavating a pile hole will be described with reference to FIGS. 3 to 7 using the excavator 10 configured as described above. Here, it is assumed that a plurality of pile holes are excavated on the site of the construction site.

(Boring survey process)
First, as shown in FIG. 3, a boring survey step is performed before excavation. In this boring survey process, as is known, a geological survey is conducted on the site of the construction site. Columnar charts are generated according to the type of soil sample according to the depth obtained during this geological survey. In addition, the N value for each predetermined depth is acquired, and a depth-N value graph is generated.

Then, the control unit 31 of the computer terminal 30 is used to execute the registration process of the columnar chart and the depth −N value (step S1-1). Specifically, the reference registration unit 311 of the control unit 31 outputs the reference value registration screen to the display unit 26. This reference value registration screen includes an input field for registering data related to the histogram and graph data of N values according to the depth. The manager of the construction site inputs the site identifier, the histogram, and the graph of the N value according to the depth on the reference value registration screen. The control unit 31 of the computer terminal 30 generates the determination reference information 350 in which the input site identifier, the column chart 351 and the depth −N value graph 352 are recorded, and registers the determination reference information 350 in the determination reference information storage unit 35.

(Excavation process)
After that, the excavation process of each pile hole is performed. In this case, there is a preceding excavation step for generating the determination criterion graph 355 and a subsequent excavation step for determining the arrival of the support layer using the generated determination criterion graph 355. In the preliminary excavation process, a pile hole near the point where the boring survey was conducted is excavated. In the following, the preceding excavation process will be described first, and then the subsequent excavation process will be described.

<Advance excavation process>
In this preliminary excavation process, the computer terminal 30 of the drilling management system 20 starts the rotation of the drive motor of the auger machine 16 and inserts the drilling head 18 into the ground to start drilling.

In this case, first, the control unit 31 of the computer terminal 30 executes the output processing of the determination reference information (step S2-1). Specifically, the output management unit 315 of the control unit 31 displays an output screen including a display area for displaying each graph (361, 362, 365, 366, 372, 376) on the display of the display unit 26.

Further, the output management unit 315 outputs a column chart 351 and a depth −N value graph 352 of the determination reference information 350 corresponding to the depth of each graph (361-376) on this output screen.

Next, the control unit 31 of the computer terminal 30 executes the measurement value acquisition process (step S2-2). Specifically, the measured value management unit 312 of the control unit 31 acquires the measured values measured by each measuring instrument (21 to 24) at predetermined time intervals. Each time the measurement value acquisition process (step S2-2) is executed, the processes of steps S2-3 to S2-5 are executed.

Next, the evaluation process of the measured value is executed by using the control unit 31 of the computer terminal 30 (step S2-3). Specifically, the control unit 31 calculates a velocity index value, a vibration characteristic value, an integrated current value, and a judgment index value in the drilling time zone from each measured value acquired from each measuring instrument (21, 23, 24). do. The details of this process will be described later.

Next, the control unit 31 of the computer terminal 30 executes the output processing of the evaluation result (step S2-4). Specifically, the output management unit 315 of the control unit 31 adds the drilling depth in the drilling time zone specified in step S2-3 to the depth-elapsed time graph 361. Further, the output management unit 315 adds the drilling speed, the integrated current value, and the determination index value associated with the drilling depth stored in the memory in step S2-3 to each graph (361-376), respectively.

Then, the control unit 31 of the computer terminal 30 is used to execute the arrival determination process to the support layer (step S2-5). Specifically, the change in each measured value displayed on the display of the display unit 26 is compared with the columnar diagram 351 of the determination reference information 350 and output. Then, the operator determines the judgment index value when the support layer is reached by using the judgment index value corresponding to the columnar diagram 351.

Then, when it is determined that the support layer has been reached, the excavation head 18 is pulled out from the pile hole.
Here, when the rise corresponding to the withdrawal of the excavation head 18 is detected, the control unit 31 of the computer terminal 30 executes the registration process of the determination reference graph (step S2-6). Specifically, the reference registration unit 311 of the control unit 31 uses each graph (361 to 376) registered in the excavation status information storage unit 36 as each graph (R1 to R16) of the determination reference graph 355 as the determination reference information. Record in the storage unit 35.

<Subsequent excavation process>
Next, the subsequent excavation process for determining the arrival of the support layer will be described using the determination criterion graph 355.

In this subsequent excavation process, the computer terminal 30 of the drilling management system 20 starts rotating the drive motor of the auger machine 16 and inserts the drilling head 18 into the ground to start drilling.

In this case, first, the control unit 31 of the computer terminal 30 executes the output processing of the determination reference information (step S3-1). Specifically, the output management unit 315 of the control unit 31 has a display area for displaying each graph (361-376) on the display of the display unit 26 and each graph (361-376), as in step S2-1. ) Is displayed, and the output screen including the columnar diagram 351 corresponding to the depth and the depth −N value graph 352 is displayed.

Further, the output management unit 315 displays each graph (R1 to R16) of the determination reference graph 355 of the determination reference information 350 so as to correspond to each graph (361-376) on this output screen.

Next, the control unit 31 of the computer terminal 30 performs the measurement value acquisition process (step S3-2), the measurement value evaluation process (step S3-3), and the evaluation result, as in steps S2-2 to S2-5. Output processing (step S3-4) and arrival determination processing to the support layer (step S3-5) are executed. In the arrival determination process for the support layer (step S3-5), the operator compares the determination standard graph 355 corresponding to the histogram 351 with the newly acquired determination index value graphs 372 and 376. , Determine if the support layer has been reached. The processes of steps S3-3 to S3-5 are executed each time the measured value acquisition process (step S3-2) is executed. Then, when it is determined that the support layer has been reached, the excavation head 18 is pulled out from the pile hole.

[Measured value evaluation process]
Next, the details of the above-mentioned measurement value evaluation process (step S2-3) will be described with reference to FIG. 4 (d).

First, the control unit 31 of the computer terminal 30 executes the process of acquiring the drilling depth of the excavation head (step S4-1). Specifically, the measured value management unit 312 of the control unit 31 acquires the drilling depth measured from the drilling depth measuring instrument 21, and temporarily stores it in the memory together with the acquired measurement time.

Then, the control unit 31 of the computer terminal 30 executes the extraction process of the drilling time zone (step S4-2). Specifically, the measured value management unit 312 of the control unit 31 has a depth of more than the maximum value among the past drilling depths recorded in the excavation status information storage unit 36 in the drilling depth temporarily stored in the memory. To identify the drilling time zone where the depth is monotonically increasing. When the excavation head 18 is pulled up, it is added again to the drilling time zone from the time when the excavation head 18 reaches the hole bottom.

Next, the control unit 31 of the computer terminal 30 executes the process of specifying the measured value in the drilling time zone (step S4-3). Specifically, the measured value management unit 312 of the control unit 31 connects the drilling depths in the drilling time zone and calculates the elapsed time according to the drilling depth. Then, the measured value management unit 312 calculates the drilling speed in the drilling time zone. Then, the measured value management unit 312 specifies the instantaneous current value in the drilling time zone, adds it to the integrated current value at the measurement time before that, and calculates the integrated current value.

Next, the control unit 31 of the computer terminal 30 executes the frequency analysis process (step S4-4). Specifically, the vibration analysis unit 313 of the control unit 31 performs frequency analysis on the vibration in the drilling time zone, and specifies the magnitude (vibration characteristic value) of the vibration for each frequency band. Then, the measured value management unit 312 specifies the concentration according to the magnitude of the specified vibration in the concentration specifying table.

Next, the control unit 31 of the computer terminal 30 executes the judgment index value calculation process (step S4-5). In the present embodiment, the judgment index value of the drilling speed and the judgment index value of the vibration are calculated. This process will be described later.

Next, the control unit 31 of the computer terminal 30 executes an association process between the determination index value and the like and the depth (step S4-6). Specifically, the measured value management unit 312 of the control unit 31 determines the drilling speed, the integrated current value, the vibration characteristic value (concentration according to the magnitude of vibration in each frequency band), and the drilling through the measurement time. It is stored in the memory in association with the hole depth. Further, the measured value management unit 312 associates the drilling speed determination index value and the vibration determination index value with the drilling depth and stores them in the memory via the measurement time.

[Judgment index value calculation process]
Next, the judgment index value calculation process will be described with reference to FIG. 5 (b).
First, the control unit 31 of the computer terminal 30 executes a long-term average calculation process (step S5-1). Specifically, the judgment index value calculation unit 314 of the control unit 31 calculates the drilling speed in the second section ΔD of the calculation target depth d.

Next, the control unit 31 of the computer terminal 30 executes a short-time average calculation process (step S5-2). Specifically, the judgment index value calculation unit 314 of the control unit 31 calculates the drilling speed in the first section Δd of the calculation target depth d.

Then, the control unit 31 of the computer terminal 30 executes the division process of the short-time average by the long-term average (step S5-3). Specifically, the judgment index value calculation unit 314 of the control unit 31 divides the short-time average calculated in step S5-2 by the long-term average calculated in step S5-1 to calculate the judgment index value.

<Relationship between the judgment index value and the N value according to the histogram and depth>
6 (a) and 7 (a) are the same figures, showing a histogram and N values according to the depth. 6 (b) and 7 (b) are the same figures, showing a depth-integrated current value graph. FIG. 6C shows a depth-drilling speed graph, and FIG. 6D shows a judgment index value graph of the drilling speed. FIG. 7 (c) shows a depth-vibration analysis graph, and FIG. 7 (d) shows a vibration judgment index value graph.

Based on the histograms and N values of FIGS. 6 (a) and 7 (a), about 5.5 m to about 9.5 m is a "fine sand" layer, and about 9.5 m to about 10.5 m is "fine". The "sand / hard silt" layer, deeper than about 10.5 m, is the "mudstone" layer.

Based on the integrated current values in the depth-integrated current value graphs of FIGS. 6 (b) and 7 (b), it can be determined that the "mudstone" layer, which is the support layer, has been reached at about 11.5 m.
As shown in FIG. 6 (c), the drilling speed is low at a depth of about 11 m. When excavating a hard layer support layer, the drilling speed may be low. Therefore, it is possible to determine that the hard layer has been reached around this depth.

Furthermore, based on the judgment index value of the drilling speed in FIG. 6 (d), the inflection point at a value considerably smaller than "1" is found at a depth of about 11 m (the depth indicated by the black triangle in the figure). be. This inflection corresponds to the histogram 351. That is, it can be determined that the drilling speed suddenly decreases due to the change of the layer to be excavated (drilling conditions), and the soft layer reaches the hard "mudstone" layer to be the support layer. Therefore, the depth indicated by the black triangle in the figure is the position where the support layer has reached the support layer.
By using the judgment index value of the drilling speed, the change of the stratum around about 9.5 m (the depth indicated by the white triangle in the figure) can also be judged corresponding to the columnar diagram 351. .. Therefore, the depth indicated by the white triangle in the figure is the position of the stratum boundary.

On the other hand, in the depth-vibration analysis graph of FIG. 7 (c), the magnitude of vibration becomes small after the depth of about 11 m. When excavating hard mudstone with an excavation blade, the water used for excavation may turn the mudstone into mudstone, causing the excavation blade to slip and the vibration to suddenly decrease. Therefore, it is possible to determine that the hard layer has been reached around this depth.

Furthermore, based on the vibration judgment index value in FIG. 7 (d), an inflection point is shown at a value considerably smaller than "1" at a depth of about 11 m (the position indicated by the black triangle in the figure). There is. This inflection corresponds to the histogram 351. That is, it can be determined that the vibration changes abruptly due to the change of the layer to be excavated (drilling conditions), and the soft layer reaches the hard "mudstone" layer to be the support layer. By using this vibration judgment index value, the change in the stratum around about 9.5 m (the position indicated by the white triangle in the figure) can also be judged corresponding to the columnar chart 351.

According to this embodiment, the following effects can be obtained.
(1-1) In the present embodiment, the control unit 31 of the computer terminal 30 includes the calculated drilling speed judgment index value in the drilling speed judgment index value graph 372 and displays it. As a result, the change in the drilling speed can be efficiently grasped by using the judgment index value of the drilling speed. Therefore, it is possible to accurately determine the arrival of the support layer.

(1-2) In the present embodiment, the control unit 31 of the computer terminal 30 includes the calculated vibration judgment index value in the vibration judgment index value graph 376 and displays it. As a result, it is possible to efficiently grasp the change in vibration generated during excavation by using the vibration judgment index value. Therefore, it is possible to accurately determine the arrival of the support layer.

(1-3) In the present embodiment, the control unit 31 of the computer terminal 30 specifies a value obtained by dividing the short-time average by the long-term average as a judgment index value. Thereby, the fluctuation of the first section Δd can be grasped in consideration of the fluctuation of the value in the second section ΔD longer than the first section Δd. Therefore, the change in the layer to be excavated can be efficiently determined.

(1-4) In the present embodiment, the first section Δd is in the range of the calculation target depth d or more, and the second section ΔD is in the range of the calculation target depth d or less. As a result, the drilling speed and vibration of the drilling holes drilled to the calculation target depth d and the drilling speed and vibration of the drilling drilled deeper than the calculation target depth d are compared. In, it is possible to efficiently determine that the hardness of the layer to be excavated has changed.

(1-5) In the present embodiment, the control unit 31 of the drilling management system 20 uses the determination reference value (372,376) specified in the preceding excavation process as the drilling speed determination index reference graph R12 and vibration determination. It is included in the judgment standard graph 355 as the index standard graph R16. Then, in the subsequent excavation process, the judgment index reference graph R12 for the drilling speed and the judgment index reference graph R16 for the vibration are displayed. As a result, it is possible to determine the arrival of the drilled hole in the support layer by using the value and depth of the inflection point of the judgment index value actually already acquired at the same construction site.

(1-6) In the present embodiment, the control unit 31 of the drilling management system 20 displays an output screen including the columnar chart 351 and the depth −N value graph 352, and the determination of the determination reference information 350 is determined on this output screen. Each graph (R1 to R16) of the reference graph 355 is displayed. As a result, the arrival of the drilled hole in the support layer can be determined more reliably from a plurality of changes in the measured values having different properties and the judgment index value.

<Second embodiment>
Next, a second embodiment in which the support layer arrival determination method and the determination support system are embodied will be described with reference to FIGS. 1 to 4 and 9 to 12. In the first embodiment, the judgment index value is calculated by dividing the first statistical value by the second statistical value, but in the present embodiment, it is calculated by using the probability of the t-test. Therefore, in the present embodiment, the same parts as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

In the present embodiment, the judgment index value calculation unit 314 of the control unit 31 of the computer terminal 30 in FIG. 1 uses the t-test to obtain the first statistical value (STA: short) of the drilling speed (or the magnitude of vibration). Calculate the probability (%) that the time average) and the second statistic (LTA: long-term average) of the drilling speed (or the magnitude of vibration) are the same, and determine the logarithmic value of the reciprocal of this probability. Used as an index value. In the present embodiment, it is determined that the portion where the properties of the layer to be excavated changes and the excavation speed or vibration suddenly changes reaches the support layer. Therefore, the probability of assuming that the first statistic and the second statistic are equal specifies an extremely low depth (depth), and it is determined that the drilling has reached the support layer at this depth.

FIG. 9A shows the probabilities calculated using the t-test. FIG. 9B shows the logarithmic value of this probability. FIG. 9 (c) shows the reciprocal of the probability. FIG. 9D shows the reciprocal logarithmic value of the probability. FIG. 9 (e) shows a value obtained by adding a sign to the logarithmic value of the reciprocal of the probability. In FIG. 9 (e), the case where the first statistic is larger than the second statistic (when the drilling speed or vibration becomes large) is regarded as “positive”, and the first statistic is smaller than the second statistic. The case (when the drilling speed or vibration becomes small) is marked as "negative".
In FIGS. 9 (b), 9 (c) and 9 (d), there is an inflection point at a large value after a depth of 11 m. Then, in the present embodiment, the value shown in FIG. 9 (e) (the logarithm value of the reciprocal of the t-test with positive and negative values according to the magnitude relationship between the first statistic and the second statistic) is used as a judgment index value. Used as.

FIG. 10 shows a processing procedure of the judgment index value calculation processing of the present embodiment.
In this process, first, the control unit 31 of the computer terminal 30 performs a long-term average calculation process (step S6-1) and a short-time average calculation process (step S6-), as in steps S5-1 and S5-2. 2) is executed.

Then, the control unit 31 of the computer terminal 30 executes the calculation process of the probability of the t-test (step S6-3). Specifically, the judgment index value calculation unit 314 of the control unit 31 uses a known t-test to determine the probability p (%) that the short-time average calculated in step S6-2 can be determined to be the same as step S6-1. Calculate using.

Next, the control unit 31 of the computer terminal 30 executes a process of calculating the logarithm of the reciprocal of the signed probability p (step S6-4). Specifically, the judgment index value calculation unit 314 of the control unit 31 uses the reciprocal (1 / p) of the probability p calculated in step S6-3 as a logarithm, and the magnitude relationship between the first statistic and the second statistic. A value with a positive or negative sign corresponding to the above is specified as a judgment index value.

<Relationship between the judgment index value and the N value according to the histogram and depth>
11 (a) and 12 (a) are the same views as in FIG. 6 (a), and show a histogram and N values according to the depth. FIG. 11B shows a depth-drilling velocity graph, which is the same as FIG. 6C. FIG. 11C shows a judgment index value graph of the drilling speed in the present embodiment. For comparison, FIG. 11 (d) shows a graph of judgment index values of the drilling speed calculated in the first embodiment (FIG. 6 (d)).

Further, FIG. 12 (b) shows a depth-vibration analysis graph, which is the same as FIG. 7 (c). FIG. 12C shows a vibration judgment index value graph in the present embodiment. For comparison, FIG. 12 (d) shows a vibration judgment index value graph (FIG. 7 (d)) calculated in the first embodiment.

Even in the judgment index value of the present embodiment shown in FIG. 11 (c), there is a large inflection point on the minus side at a depth of about 11 m (position indicated by a black triangle in the figure). This inflection corresponds to the histogram 351. Therefore, it can be determined from this inflection that the "mudstone" layer, which is the support layer, has been reached. By using the judgment index value of the drilling speed, the change of the stratum around about 9.5 m (the position indicated by the white triangle in the figure) can also be judged corresponding to the columnar diagram 351. The depths shown by the black triangle and the white triangle shown in FIG. 11 (c) and the respective depths shown in FIG. 11 (d) are almost the same.

Further, also in the vibration judgment index value of FIG. 12 (c), there is an inflection point at a negative value at a depth of about 11 m (position indicated by a black triangle in the figure). This inflection corresponds to the histogram 351. Therefore, it can be determined that the "mudstone" layer, which is the support layer, has been reached around this point. By using this vibration judgment index value, it is possible to judge the change of the stratum around about 9.5 m (the position indicated by the white triangle in the figure). The depths shown by the black triangle and the white triangle shown in FIG. 12 (c) and the respective depths shown in FIG. 12 (d) are almost the same.

According to the present embodiment, in addition to the same effects as the above (1-1), (1-2), (1-4) to (1-6), the following effects can be obtained.
(2-1) In the present embodiment, the control unit 31 of the computer terminal 30 uses a value using the probability p that the short-time average and the long-term average calculated by using the t-test are the same as the judgment index value. Use. When this probability p is low, it can be determined that the drilling speed or vibration has suddenly changed because the short-time average is different from the long-time average. Therefore, it is possible to efficiently grasp that the properties of the layer to be excavated have changed.

(2-2) In the present embodiment, the control unit 31 of the computer terminal 30 has the reciprocal of the probability (%) that the short-term average (STA) calculated by using the t-test is the same as the long-term average (LTA). A value obtained by adding a positive or negative value to the logarithmic value according to the magnitude relationship between the first statistical value and the second statistical value is used as the judgment index value. As a result, the difference can be emphasized when the probability is low by the reciprocal, a large value can be limited by the logarithm, and the magnitude relationship can be grasped by the sign of positive or negative.

Further, each of the above embodiments may be changed as follows.
-In each of the above embodiments, the judgment index value calculation unit 314 of the control unit 31 has calculated the judgment index value of the drilling speed. The judgment index value regarding the speed index value regarding the drilling speed is not limited to this. For example, the judgment index value may be calculated and displayed in the same manner for the change in the amount of water. Further, in the above embodiment, the average drilling depth for 1 minute is used as the drilling speed, but the drilling speed is not limited to this, and the average drilling depth for several minutes may be used, or the average drilling depth for several tens of seconds. The excavation depth may be used.

-In each of the above embodiments, the judgment index value calculation unit 314 of the control unit 31 calculates the average value of the magnitudes of vibrations of all frequencies as the judgment index value of vibration. As the vibration determination index value, instead of using such vibrations of all frequencies, vibrations only in the vertical direction or vibrations in the horizontal direction may be used, or vibrations in a specific frequency band may be used.
Further, as long as it is a value related to the hardness of the ground at the time of excavation of a pile hole (hardness information), it is not limited to a speed index value such as a drilling speed or a frequency analysis value of vibration, and other values may be used. ..

In each of the above embodiments, the judgment index value calculation unit 314 of the control unit 31 includes the average value in the first section Δd including the calculation target depth d as the minimum value, and the second calculation target depth d as the maximum value. The judgment index value was calculated using the average value in the interval ΔD. Here, the first interval Δd is not limited to the case where the calculation target depth d is included as the minimum value, and may be a value related to the calculation target depth d. For example, the first section Δd may be the first section Δd included in the second section ΔD having the calculation target depth d as the minimum value, or the first section Δd having the calculation target depth d as the median value. It may be Δd. Further, the second section ΔD may have a length equal to or longer than the length of the first section Δd different from the first section Δd, and may be in a shallow range. In this case, the second statistic may be calculated as a range from the ground to the calculation target depth d without setting the second section ΔD as a fixed range.

-In each of the above embodiments, the first section Δd is set as a range of +0.5 m from the calculation target depth d, and the second section ΔD is set as a range of the calculation target depth d to -2 m. The sizes of the first section Δd and the second section ΔD may be appropriately changed according to the situation at the site. In FIGS. 13 (a) and 13 (b), when the support layer is at a depth of about 50 m, the second section ΔD is shortened to a range of -3 m from the calculation target depth d, and the calculation target depth is shown. The range of -10 m from d and the case of lengthening are shown. At this site, it is easier to grasp the inflection point of the judgment index value indicating the support layer when the second section ΔD is made smaller. Further, FIG. 13C shows a judgment index value when the second section ΔD is set from 0 m (ground) to the calculation target depth d.

-In each of the above embodiments, the judgment index value calculation unit 314 of the control unit 31 uses the average value in the first section Δd and the second section ΔD. The first statistical value and the second statistical value used by the judgment index value calculation unit 314 for the judgment index value are not limited to the average value, and may be statistical values in each section such as the median value.
-In the above embodiment, since the support layer is hard mudstone, the depth (position) where the vibration suddenly becomes small, that is, the depth corresponding to the inflection at the negative value where the judgment index value is large is determined as the support layer. bottom. Judgment as to whether or not the support layer is reached using the judgment index value is not limited to the negative value. For example, when the support layer is a layer containing sand or gravel, the vibration is considered to increase rapidly. Therefore, in the case of such a support layer, it is determined that the vibration determination index value has reached the support layer at a depth corresponding to the inflection point at a large positive value.

In the first embodiment, the judgment index value calculation unit 314 of the control unit 31 uses a value obtained by dividing the short-time average by the long-term average as the judgment index value. Further, in the second embodiment, the judgment index value calculation unit 314 uses a value obtained by adding a sign to the logarithm of the reciprocal of the probability calculated by the t-test as the judgment index value. The judgment index value is not limited to the above-mentioned value as long as it is a value based on the comparison between the first statistic of the calculation target depth d and the second statistic in the section having a length longer than the first statistic. .. For example, the difference between the long-term average and the short-term average may be used, or the logarithm of the probability using the t-test may be used. Further, the judgment index value calculation unit 314 calculates as the judgment index value a value using the probability that the assumption that the first statistic and the second statistic are the same is established by using a method other than the t-test. May be good.

In the above embodiment, the control unit 31 of the drilling management system 20 outputs the drilling speed determination index value graph 372 and the vibration determination index value graph 376 to the display of the display unit 26. Here, instead of displaying the graph and causing the determination, the control unit 31 of the computer terminal 30 determines the support layer for drilling based on the judgment index value graph (372,376) and the judgment index reference graph (R12, R16). You may determine the arrival at. Specifically, the control unit 31 determines the value of the inflection point in the judgment index value graph 372 of the drilling speed during excavation, the depth at that time (calculation target depth d), and the judgment index reference graph of the excavation speed. The value and depth of the inflection point determined to have reached the support layer by R12 are compared. Further, the control unit 31 determines that the inflection point value and the calculation target depth d in the vibration judgment index value graph 376 during excavation and the inflection point determined to have reached the support layer in the vibration judgment index reference graph R16. Compare the value and depth of. Then, as a result of comparison, when the inflection points during excavation match within a predetermined range, the control unit 31 determines that the support layer has been reached.
-In the above embodiment, the judgment index value is calculated and displayed during the excavation of the hole, and it is determined whether or not the hole has reached the support layer. The judgment index value may be calculated not during excavation but after excavation is completed. In this case, it can be further confirmed that the drilled hole has reached the support layer by another velocity index value or the like.

-In each of the above embodiments, the vibration measuring instrument 24 is attached to the operation room 13, the roof of the operation room 13, or the operation lever in the operation room 13. The mounting position of the vibration measuring instrument 24 is not limited as long as it can detect vibration corresponding to excavation, and may be, for example, an excavation rod 17.

Next, the technical ideas that can be grasped from the above embodiment and other examples will be added below together with their effects.
(A) A support layer arrival determination method for determining the arrival of a pile at a support layer in a pile hole.
Obtain the speed index value for the excavation speed at the time of excavation of the pile hole, and
The velocity index value is associated with the depth of the pile hole at the time of excavation,
In the velocity index value, the first statistical value in the first section of the calculation target depth and the length of the first section that is adjacent to the first section or includes the first section and is different from the first section or more. Calculated with the second statistic in the second section of
The judgment index value is calculated based on the comparison between the first statistic and the second statistic.
A support layer arrival determination method, characterized in that the arrival at the support layer is determined based on the determination index value.
Therefore, according to the invention described in (a), it is possible to efficiently determine the arrival of the support layer of the pile hole.

(B) A support layer arrival determination method for determining the arrival of a pile at a support layer in a pile hole.
With a vibration measuring instrument attached to the excavator of the pile hole, the vibration during excavation is measured and
The frequency analysis result obtained by performing the frequency analysis of the vibration is associated with the depth of the pile hole at the time of excavation.
In the frequency analysis result, the first statistical value in the first section of the calculation target depth and the length of the first section that is adjacent to the first section or includes the first section and is different from the first section or more. Calculated with the second statistical value in the second section of
The judgment index value is calculated based on the comparison between the first statistic and the second statistic.
A support layer arrival determination method, characterized in that the arrival at the support layer is determined based on the determination index value.
Therefore, according to the invention described in (b), it is possible to efficiently determine the arrival of the support layer of the pile hole.

d ... Calculation target depth, p ... Probability, Δd ... 1st section, ΔD ... 2nd section, h0 ... Pile hole, R1 ... Depth-elapsed time reference graph, R2 ... Depth-Drilling speed reference graph, R5 ... Depth -Integrated current value reference graph, R6 ... Depth-Vibration analysis reference graph, R12 ... Judgment index reference graph, R16 ... Judgment index reference graph, 10 ... Excavator, 11 ... Base machine, 12 ... Crawler, 13 ... Operation room, 14 ... Mast, 16 ... Auger machine, 17 ... Drilling rod, 18 ... Drilling head, 20 ... Drilling management system, 21 ... Drilling depth measuring instrument, 22 ... Flow measuring instrument, 23 ... Current measuring instrument, 24 ... Vibration measuring instrument , 25 ... Input unit, 26 ... Display unit, 30 ... Computer terminal, 31 ... Control unit, 35 ... Judgment standard information storage unit, 36 ... Excavation status information storage unit, 311 ... Standard registration unit, 312 ... Measurement value management unit, 313 ... Vibration analysis unit, 314 ... Judgment index value calculation unit, 315 ... Output management unit, 350 ... Judgment standard information, 355 ... Judgment standard graph, 360 ... Excavation status information, 361 ... Depth-elapsed time graph, 362 ... Depth- Drilling speed graph, 365 ... Depth-integrated current value graph, 366 ... Depth-vibration analysis graph, 372 ... Judgment index value graph, 376 ... Judgment index value graph.

Claims (4)

It is a support layer arrival determination method for determining the arrival of a pile at a pile hole in a pile hole.
Obtain the value related to the hardness of the ground at the time of excavation of the pile hole,
The value related to the hardness is associated with the depth of the pile hole at the time of excavation,
Regarding the values related to the hardness, the first statistical value in the first section in the range deep from the calculation target depth, the second section adjacent to the first section, shallower than the calculation target depth, and longer than the first section, or the above. The second statistical value in the second section adjacent to the first section and including the shallow section below the calculation target depth and the first section is calculated.
A determination index value corresponding to the calculated target depth rather based on a comparison between the second statistical value and the first statistical value sequentially calculated,
A support layer arrival determination method, characterized in that the arrival at the support layer is determined based on the sequentially calculated changes in the determination index value. Wherein a value obtained by dividing the second statistic a first statistic, a support layer arrival determination method according to claim 1, characterized in that calculated as the determining index value. The value of using a first statistical value and the second statistics the probability that the assumption holds the same, the support layer arrival determination method according to claim 1, characterized in that calculated as the determining index value. It is a judgment support system to support the judgment of the arrival of the pile at the support layer of the pile hole.
A measuring unit that measures the value related to the hardness of the ground when excavating the pile hole,
A recording unit that records the value related to the hardness in the measurement information storage unit in association with the depth of the pile hole at the time of excavation.
Regarding the values related to the hardness, the first statistical value in the first section in the range deep from the calculation target depth, the second section adjacent to the first section, shallower than the calculation target depth, and longer than the first section, or the above. The second statistical value in the second section adjacent to the first section and including the shallow section below the calculation target depth and the first section is calculated, and the first statistical value and the second statistical value are calculated. comparing sequentially the determination index value corresponding to the calculated target depth rather based, and a control unit that calculates,
A determination support system, characterized in that the control unit includes an output unit that outputs changes in the determined determination index values sequentially calculated.

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