JP2021080755A - Ground improvement body and buried object measuring device, ground improvement body construction device and ground improvement body construction method - Google Patents

Abstract

To improve the measurement accuracy of the shape of a ground improvement body and detect buried objects.SOLUTION: A measuring device 100 comprises: a rotating rod 30 that is inserted into a ground improvement body 50 before hardening; a transmitter 112 that is provided on the rotating rod 30 and simultaneously emits ultrasonic waves of different frequencies from the same sound source in the same direction; a receiver 114 that receives reflected waves H1 and H2 reflected from the boundary of the ground improvement 50 with a ground G and a buried object 55 buried in the ground G by difference frequency sound waves S generated by the interaction of ultrasonic waves of different frequencies transmitted from the transmitter 112 and installed in the rotating rod 30; and a detection device 120 that detects a boundary position K1 of the ground improvement body 50 with the ground G and a buried position K2 of the buried object 55 by the time difference between the transmission of the ultrasonic wave of the transmitter 112 and the reception of the reflected waves H1 and H2 of the receiver 114.SELECTED DRAWING: Figure 1

Description

The present invention relates to a device for measuring a ground improvement body and a buried object, a device for creating a ground improvement body, and a method for creating a ground improvement body.

Patent Document 1 discloses a method for measuring the shape of an unconsolidated deep layer mixing treatment ground improvement body, an injection rod for a cement-based deep layer mixing treatment method, and a technique relating to a stirring rod. In this prior art, a sound wave oscillator and a vibration receiver are provided on the rod, and the sound wave oscillated from the sound wave oscillator continuously receives the reflected wave reflected at the interface between the ground and the ground improvement body. , The molding shape of the ground improvement body is measured.

Japanese Unexamined Patent Publication No. 2012-172329

When measuring the shape of a ground improvement body using sound waves as in Patent Document 1, high-frequency ultrasonic waves can be used to perform measurements with high directivity and high resolution, but the sound waves are greatly attenuated. It is difficult to measure the reflected wave. Therefore, a low frequency sound wave near 10 kHz with little attenuation is often used.

However, a low frequency sound wave in the vicinity of 10 kHz with little attenuation has low directivity and low resolution, so that the measurement accuracy of the shape of the ground improvement body is low. Further, since a sound wave having a low frequency around 10 kHz has low directivity and low resolution, it is difficult to detect a buried object buried in the ground.

In view of the above facts, it is an object of the present invention to improve the measurement accuracy of the shape of the ground improvement body and to detect the buried object.

The first aspect is a shaft member to be inserted into the ground improvement body before hardening, a transmission unit provided on the shaft member and simultaneously transmitting ultrasonic waves of different frequencies from the same sound source in the same direction, and the shaft member. Then, the sound waves of different frequencies generated by the interaction of the ultrasonic waves of different frequencies transmitted from the transmitting unit are reflected at the boundary with the ground of the ground improvement body and the reflected wave reflected by the buried object buried in the ground. Detection that detects the boundary position between the receiving unit and the ground of the ground improvement body and the buried position of the buried object by the time difference between the transmission of the ultrasonic wave of the transmitting unit and the reception of the reflected wave of the receiving unit. It is a ground improvement body and a measuring device for buried objects provided with a part.

In the ground improvement body and the buried object measuring device of the first aspect, the boundary between the ground improvement body and the ground is used by using the reflected wave of the sound wave of the difference frequency generated by the interaction of the ultrasonic waves of different frequencies transmitted from the transmitting part. Detect the position and the burial position of the buried object. Therefore, even if a high-frequency ultrasonic wave with high directivity and high resolution is transmitted from the transmitting unit, the attenuation becomes small by using the reflected wave of the sound wave with a difference frequency lower than the transmitted ultrasonic wave, and the measurement can be performed. It will be possible. Further, the sound wave having a difference frequency has the same directivity as the ultrasonic wave having a high frequency transmitted from the transmitting unit, and therefore has a high resolution. Therefore, the measurement accuracy of the shape of the ground improvement body is improved, and the buried object can be detected.

The second aspect is the measuring device for the ground improvement body and the buried object according to the first aspect, wherein the frequency of the ultrasonic wave transmitted by the transmitting unit is 85 kHz or more, and the difference frequency is 10 kHz or less.

In the ground improvement body and the buried object measuring device of the second aspect, since the frequency of the ultrasonic wave transmitted by the transmitting unit is 85 kHz or more, the directivity is high and the resolution is high. Further, since the difference frequency is 10 kHz or less, there is little attenuation. Therefore, as compared with the case where the frequency of the ultrasonic wave transmitted by the transmitting unit is less than 85 kHz and the difference frequency is larger than 10 kHz, the measurement accuracy of the molded shape of the ground improvement body is further improved and the detection accuracy of the buried object is further improved. ..

In the third aspect, the detection unit detects the boundary position and the buried position by performing noise removal, amplification processing, time fluctuation gain adjustment, and edge detection on the acoustic signal of the reflected wave. The device for measuring a ground improvement body and a buried object according to the second aspect.

In the ground improvement body and the buried object measuring device of the third aspect, the detection unit detects the boundary position and the buried object by performing noise removal, amplification processing, time fluctuation gain adjustment and edge detection on the acoustic signal of the reflected wave. Therefore, the detection accuracy of the boundary position and the buried position is improved as compared with the case where the acoustic signal of the reflected wave is used as it is for detection.

The fourth aspect is a construction section for creating a ground improvement body by ejecting a hardening material from the tip while pulling up a shaft member inserted into the ground, and the first to third aspects inserted into the ground improvement body being constructed. The amount of the hardened material ejected according to the boundary position and the buried position detected by the measuring device for the ground improvement body and the buried object according to any one aspect of the embodiment and the measuring device for the ground improved body and the buried object. It is a ground improvement body construction device equipped with an adjustment unit for adjusting.

In the device for creating the ground improvement body of the fourth aspect, the amount of the hardened material ejected is adjusted according to the boundary position of the ground improvement body with the ground and the burial position of the buried object detected with high accuracy. It can be created with high precision.

The fifth aspect is a construction step of creating a ground improvement body by ejecting a hardening material from the tip while pulling up a shaft member inserted into the ground, and the first to third aspects inserted into the ground improvement body being constructed. The detection step of detecting the boundary position of the ground improvement body with the ground and the burial position of the buried object buried in the ground by the measuring device for the ground improvement body and the buried object according to any one aspect, and the above-mentioned This is a method for creating a ground improvement body including an adjustment step of adjusting the amount of ejected hardened material according to the boundary position and the buried position detected in the detection step.

In the method for creating the ground improvement body of the fifth aspect, the amount of the hardened material ejected is adjusted according to the boundary position of the ground improvement body with the ground and the burial position of the buried object detected with high accuracy. It can be created with high precision.

According to the present invention, it is possible to improve the measurement accuracy of the shape of the ground improvement body and to detect the buried object.

It is a block diagram of the measuring apparatus and the construction apparatus of one Embodiment of this invention. It is a block diagram which shows the measuring apparatus functionally. This is an example of the monitor screen of the detection device that constitutes the measuring device. (A) is an explanatory diagram for explaining the detection of the buried object by the sound wave of the difference frequency, and (B) is an explanatory diagram for explaining the detection of the buried object by the low frequency sound wave of the comparative example. (A) is a block diagram of the experimental device, (B) is a recorded data diagram, (C) an amplitude value graph, (D) is a processed data diagram, and (E) is an edge processing result graph. is there. It is a block diagram of the measuring apparatus and the construction apparatus of the modification of one Embodiment of this invention.

<Embodiment>
A device for measuring a ground improvement body and a buried object, a device for creating a ground improvement body, and a method for creating a ground improvement body according to an embodiment of the present invention will be described.

[Constitution]
First, the configuration of the measuring device and the construction device provided with the measuring device will be described.

As shown in FIG. 1, while cutting the ground G, the preparation device 10 creates the ground improvement body 50 by stirring and mixing the cut ground G and cement milk M as an example of the hardened material injected under high pressure. This is a device for creating a ground improvement body of the high-pressure injection stirring method. Since FIG. 1 and FIG. 6 described later are shown as a model, the sizes of each device, each device, and each member may differ from the actual ones.

The construction device 10 includes a rotating rod 30 as an example of a shaft member, and a device main body 20. The apparatus main body 20 is installed on the ground G (ground), and while rotating the rotary rod 30 around the axis (see arrow Y1), the cement milk M is ejected laterally from the ejection nozzle 32 at the tip portion and rotates. It has a function of raising and lowering the rod 30 (see arrow Y2). Further, the apparatus main body 20 has an operation unit 22 in which a worker (not shown) operates the rotation speed of the rotary rod 30, the vertical movement of the rotary rod 30, the amount of cement milk M ejected per unit time, and the like. ing.

As shown in FIGS. 1 and 2, the measuring device 100 includes a measuring device 34 and a detecting device 120 as an example of the detecting unit.

As shown in FIG. 1, the measuring instrument 34 is attached to the lower end of the ejection nozzle 32 of the rotating rod 30, and the excavation bit 40 is attached to the lower end of the measuring instrument 34. Therefore, the measuring instrument 34 rotates together with the rotation of the rotating rod 30. The detection device 120 is installed on the ground G (ground). The measuring instrument 34 and the detection device 120 are electrically connected by a cable 102.

As shown in FIG. 2, the measuring instrument 34 is functionally configured to include a transmitting unit 112 and a receiving unit 114. The transmitting unit 112 has a function of simultaneously transmitting ultrasonic waves of different frequencies from the same sound source in the same direction. As shown in FIG. 1, a sound wave S having a difference frequency is generated by the interaction of ultrasonic waves having different frequencies, and the sound wave S having a difference frequency is buried at the boundary between the ground improvement body 50 and the ground G and in the ground G. Reflected by the buried object 55. The receiving unit 114 (see FIG. 2) has a function of receiving the reflected wave H1 reflected at the boundary of the ground improvement body 50 with the ground G and the reflected wave H2 reflected by the buried object 55 buried in the ground G.

As shown in FIG. 1, in the present embodiment, a transmission / reception unit 110 in which the transmission unit 112 and the reception unit 114 are integrally configured is provided on the peripheral surface of the measuring instrument 34 (see also FIG. 2). ).

Further, the measuring instrument 34 having the transmitting / receiving unit 110 in which the transmitting unit 112 and the receiving unit 114 are integrally configured as shown in FIG. 2 is a measuring instrument using parametric acoustic technology. Parametric acoustic technology is a technology that applies the non-linearity of sound wave propagation. Specifically, it is a technique that utilizes the secondary wave of the difference frequency generated by the mutual interference of the two frequencies by simultaneously transmitting the primary waves of two different frequencies.

The frequencies of the two ultrasonic waves transmitted from the transmission / reception unit 110 of the measuring instrument 34 are preferably 85 kHz or higher, and more preferably 100 kHz or higher. The difference frequency is preferably 10 kHz or less, and more preferably 5 kHz or less. In the present embodiment, the ultrasonic waves having different frequencies are 100 kHz and 105 kHz, and the difference frequency is 5 kHz.

As shown in FIG. 1, the measuring instrument 34 converts the reflected waves H1 and H2 received by the transmission / reception unit 110 into acoustic signals and transmits them to the detection device 120 (see also FIG. 2) via the cable 102.

As shown in FIGS. 1 and 2, the detection device 120 includes a control unit 122 (see FIG. 2) and a monitor 124 as an example of a display device. The control unit 122 (see FIG. 2) includes a CPU (Central Processing Unit) (not shown), a ROM (Read Only Memory) that stores programs for realizing each processing routine, and a RAM (RAM) that temporarily stores data. Random Access Memory), memory as a storage means, network interface, etc. are included.

The control unit 122 constituting the detection device 120 shown in FIG. 2 controls the measuring instrument 34. Further, the control unit 122 determines the position of the boundary of the ground improvement body 50 shown in FIG. 1 with the ground G (hereinafter referred to as “boundary position K1”) due to the time difference between the transmission of ultrasonic waves and the reception of the reflected waves H1 and H2. And the distance from the position where the buried object 55 is buried (hereinafter referred to as “buried position K2”) is measured, and the boundary position K1 and the buried position K2 are detected.

The buried object 55 in the present embodiment is an artificial object such as a rock or a clay pipe.

In the present embodiment, the control unit 122 of the detection device 120 performs noise removal, amplification processing, time fluctuation gain adjustment, edge detection, and the like on the acoustic signals of the reflected waves H1 and H2, and determines the boundary position K1 and the buried position K2. Clarify and detect each position.

FIG. 3 is an example of the screen of the monitor 124 of the detection device 120. X [mm] indicates the measured diameter of the ground improvement body 50. Further, Y [mm] indicates the vertical length of the ground improvement body 50.

[Creation method]
Next, an example of a method for creating a ground improvement body will be described.

As shown in FIG. 1, while pulling up the rotary rod 30 inserted into the ground G, cement milk M is ejected from the ejection nozzle 32 at the tip, and the excavated ground G and cement milk M are stirred and mixed to improve the columnar ground. Create body 50.

Further, the measuring instrument 34 integrally provided on the rotating rod 30 detects the boundary position K1 of the ground improvement body 50 under construction with the ground G and the burial position K2 of the buried object 55 buried in the ground G. .. The detection result is displayed on the monitor 124. On the monitor 124, the molding shape of the ground improvement body 50, the buried object 55, and the like are displayed.

A worker (not shown) operates the operation unit 22 based on the boundary position K1 and the buried position K2 displayed on the monitor 124, and operates the rotation speed of the rotary rod 30, the pulling speed of the rotary rod 30, and the cement milk M. The amount of ejection per unit time and the like are adjusted so that the molding shape of the ground improvement body 50 approaches the design value.

Specifically, when the boundary position K1 is outside the design value, the amount of cement milk M ejected is reduced or the pulling speed is increased. On the contrary, when the boundary position K1 is inside the design value, the amount of cement milk M ejected is increased or the pulling speed is decreased.

When the buried object 55 is detected, an increase in the amount of cement milk M ejected, a temporary stop of the construction work, removal of the buried object 55, etc. are examined according to the size and position of the buried object 55.

[Action and effect]
Next, the operation and effect of this embodiment will be described.

The measuring device 100 uses the sound wave S of the difference frequency generated by the interaction of ultrasonic waves of different frequencies transmitted from the measuring instrument 34 to the boundary position K1 of the ground improvement body 50 with the ground G and the buried position K2 of the buried object 55. Is detected. Therefore, a high frequency ultrasonic wave having high directivity and high resolution, a difference frequency having a lower frequency than the transmitted ultrasonic wave even if 100 kHz and 105 kHz are transmitted in the present embodiment, and a 5 kHz sound wave S are used in the present embodiment. As a result, the attenuation becomes small, and the reflected waves H1 and H2 can be measured. Therefore, the measurement accuracy of the molding shape of the ground improvement body 50 is improved, and the buried object 55 can be detected.

If the measurement is performed with a low-frequency sound wave, the directivity is low and the resolution is low, so that the measurement accuracy of the molded shape of the ground improvement body 50 is low. Further, when measured with a low-frequency sound wave having low resolution, the buried object 55 cannot be detected even if the buried object 55 is buried in the ground G.

Specifically, as shown in FIG. 4A, in the sound wave S having a difference frequency having good directivity and high resolution in the present embodiment, the sound wave S is irradiated only to a part of the buried object 55, so that the buried object The reflected wave H2 reflected only on 55 can be detected. However, as shown in FIG. 4B, in the low frequency sound wave SS having low resolution, the sound wave SS is also irradiated to the outside of the buried object 55 on the ground G, so that the reflected wave HH2 reflected on the buried object 55 is weak. , Cannot be detected. Therefore, in the low-frequency sound wave SS having low resolution, the buried object 55 cannot be detected even if the buried object 55 is buried in the ground G.

For the same reason, as shown in FIG. 4A, the sound wave S having a difference frequency with good directivity and high resolution in the present embodiment can accurately detect the molding shape of the ground improvement body 50.

Further, the detection device 120 clearly detects the boundary position K1 and the buried position K2 by performing noise removal, amplification processing, time fluctuation gain adjustment, edge detection, and the like on the acoustic signals of the reflected waves H1 and H2. Detection accuracy is improved.

Further, since the amount of cement milk M ejected is adjusted according to the boundary position K1 of the ground improvement body 50 with the ground G and the burial position K2 of the buried object 55 detected with high accuracy, the ground improvement body 50 is highly accurate. Can be created in.

Further, when a buried object 55 that hinders the construction of the ground improvement body 50 is detected, the size and position of the buried object 55 can be analyzed, and the temporary stop of the construction work can be considered.

(Experiment and experimental results)
Next, an experiment confirming that the ground G and the boundary position K1 of the ground improvement body 50 and the buried position K2 of the buried object 55 can be detected by using the measuring device 100 of the present embodiment and the experimental results thereof will be described.

As shown in FIG. 5 (A), the experimental device 200 is attached to the measuring device 100, the wooden board box 202, the mortar 250 before curing filled in the box 202, and the saturated sand 210 and sand 210 filled in the box 202. It has a buried steel pipe 255. The left side of the box 202 is filled with mortar 250, and the right side of the box 202 is filled with sand 210. The mortar 250 before hardening imitates the ground improvement body 50 (see FIG. 1), the saturated sand 210 imitates the ground G (see FIG. 1), and the steel pipe 255 imitates the buried object 55 (see FIG. 1). 1) is imitated.

Then, the measuring instrument 34 of the measuring apparatus 100 is embedded in the mortar 250 before curing, and the reflected waves H1 and H2 of the sound waves S having different frequencies generated by the interaction of ultrasonic waves of different frequencies are received, and the detecting apparatus 120 (FIG. 1) to detect. The speed of sound was calculated using 1645 m / sec, which is the speed of sound in the mortar 250.

FIG. 5B is a diagram of recorded data in which the acoustic signals of the reflected waves H1 and H2 are visualized. In this figure, the darker the intensity of the reflected waves H1 and H2, the greater the intensity. In reality, the greater the intensity of the reflected waves H1 and H2, the darker the red color, and the smaller the intensity, the darker the blue color. It is displayed in gradation.

FIG. 5C is a graph showing the amplitude values of the reflected waves H1 and H2. In the amplitude value graph of FIG. 5C, the boundary position K1 between the mortar 250 and the sand 210, the buried position K2 of the steel pipe 255, and the position of the wall surface 203 (FIG. 1) of the box 202 are stepped. It has become.

FIG. 5D shows that the recorded data of FIG. 5B is subjected to noise removal processing, amplification processing, time fluctuation gain adjustment processing, and edge processing to clarify the strength of the reflected waves H1 and H2. It is a figure of the processed data. Similar to FIG. 5B, the darker the intensity of the reflected waves H1 and H2, the stronger the intensity of the reflected waves H1 and H2. Is displayed in a gradation that makes the image darker.

FIG. 5 (E) is a graph of the edge detection processing result obtained by performing the edge processing of FIG. 5 (D). From this graph, it can be seen that the positions of the boundary position K1, the buried position K2, and the wall surface 203 are accurately detected.

<Modification example>
Next, a modified example of this embodiment will be described.

In the construction device 10 of the above embodiment shown in FIG. 1, a worker (not shown) operates the operation unit 22 based on the boundary position K1 and the buried position K2 displayed on the monitor 124 of the detection device 120. The amount of cement milk M ejected per unit time was adjusted.

On the other hand, in the modified example creation device 11 shown in FIG. 6, the detection device 120 and the device main body 20 are electrically connected by a cable 103. Further, the control unit 122 (see FIG. 2) as an example of the adjustment unit constituting the detection device 120 can control the device main body 20.

The control unit 122 (see FIG. 2) of the detection device 120 controls the device main body 20 based on the boundary position K1 and the buried position K2 measured by the measuring device 100, and the molding shape of the ground improvement body 50 approaches the design value. As described above, the number of rotations of the rotary rod 30, the pulling speed of the rotary rod 30, the amount of cement milk M ejected per unit time, and the like are adjusted. That is, the pulling speed of the rotating rod 30 and the amount of cement milk M ejected per unit time are automatically adjusted based on the boundary position K1 and the buried position K2 measured by the measuring device 100.

<Others>
The present invention is not limited to the above embodiments and modifications.

For example, in the above-described embodiment and modified example, the boundary position K1 and the buried position K2 are measured by the measuring device 100 while creating the ground improvement body 50, but the present invention is not limited to this. The measuring instrument 34 may be inserted into the ground improvement body 50 after the formation and before the hardening for measurement.

Further, for example, in the above-described embodiment and modification, the measuring instrument 34 is attached to the rotating rod 30, but the present invention is not limited to this. The measuring instrument 34 may be attached to a rod (an example of a shaft member) different from the rotating rod 30 and inserted into the ground improvement body 50 during or after the construction for measurement.

Further, for example, in the above-described embodiment and modified example, the present invention is applied to the ground improvement body created by the high-pressure injection stirring method, but the present invention is not limited thereto. The present invention may be applied to a ground improvement body created by a deep mixing treatment method other than the high-pressure injection stirring method, for example, a mechanical stirring method, or a ground improvement created by using the high-pressure injection stirring method and the mechanical stirring method in combination. The present invention may be applied to the body.

In short, the measuring instrument 34 provided on the shaft member may be inserted into the ground improvement body before hardening for measurement.

Further, in the above embodiment and the modified example, the buried object 55 is buried outside the created area of the ground improvement body 50, but is not limited thereto. The buried object 55 may be buried in the created area of the ground improvement body 50.

Further, in the above-described embodiment and modified example, the frequencies of the ultrasonic waves transmitted by the measuring instrument 34 are 100 kHz and 105 kHz, and the difference frequency is 5 kHz, but the difference is not limited thereto. The frequency and difference frequency of the ultrasonic waves transmitted by the measuring instrument 34 can be appropriately set.

Further, in the above-described embodiment and modification, the measuring instrument 34 having the transmitting / receiving unit 110 in which the transmitting unit 112 and the receiving unit 114 are integrally configured is used, but the present invention is not limited thereto. The transmitting unit and the receiving unit may be provided in separate devices.

Further, it can be carried out in various embodiments without departing from the gist of the present invention. A plurality of embodiments, modifications, and the like can be combined and implemented as appropriate.

10 Construction equipment 11 Creation equipment 30 Rotating rod (an example of shaft member)
32 Ejection nozzle 34 Measuring instrument 50 Ground improvement body 55 Buried object 100 Measuring device 112 Transmitter 114 Receiver 120 Detection device 122 Control unit (example of adjustment unit)
G ground
H1 reflected wave
H2 reflected wave
K1 boundary position
K2 burial position
M Cement milk (an example of hardened material)
S sound wave

Claims (5)

Shaft members to be inserted into the ground improvement body before hardening,
A transmitter provided on the shaft member and simultaneously transmitting ultrasonic waves of different frequencies from the same sound source in the same direction.
A buried object provided on the shaft member and having a difference frequency generated by the interaction of the ultrasonic waves of different frequencies transmitted from the transmitting portion at the boundary with the ground of the ground improvement body and buried in the ground. The receiver that receives the reflected reflected wave and
A detection unit that detects the boundary position of the ground improvement body with the ground and the buried position of the buried object by the time difference between the transmission of the ultrasonic wave of the transmitting unit and the reception of the reflected wave of the receiving unit.
A device for measuring ground improvement bodies and buried objects. The frequency of the ultrasonic wave transmitted by the transmitting unit is 85 kHz or higher.
The difference frequency is 10 kHz or less.
The device for measuring a ground improvement body and a buried object according to claim 1. The detection unit detects the boundary position and the buried position by performing noise removal, amplification processing, time fluctuation gain adjustment, and edge detection on the acoustic signal of the reflected wave.
The measuring device for the improved panel and the buried object according to claim 1 or 2. A construction part that creates a ground improvement body by ejecting a hardening material from the tip while pulling up the shaft member inserted in the ground.
The device for measuring the ground improvement body and the buried object according to any one of claims 1 to 3, which is inserted into the ground improvement body under construction.
An adjusting unit that adjusts the amount of the hardened material ejected according to the boundary position and the buried position detected by the ground improvement body and the measuring device for the buried object.
Equipment for creating a ground improvement body equipped with. A construction process in which a hardening material is ejected from the tip while pulling up the shaft member inserted into the ground to create a ground improvement body.
The device for measuring a ground improvement body and a buried object according to any one of claims 1 to 3, which is inserted into the ground improvement body under construction, at a boundary position with the ground and the ground of the ground improvement body. A detection process that detects the burial position of the buried object, and
An adjustment step of adjusting the ejection amount of the cured material according to the boundary position and the buried position detected in the detection step, and an adjustment step.
How to create a ground improvement body equipped with.

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