Ground improvement wing rotation detection device

Abstract

The enclosure houses a sensor that reliably detects the rotation of the anti-rotation wing during ground improvement work, protects it from soil and other debris, and also has a wireless communication capability. [Solution] The rotation of the Z-axis of the anti-rotation wing is detected during ground improvement. The anti-rotation detection unit 20 is located in the housing of the anti-rotation wing and consists of an MCU (Micro Controller Unit) 21, a gyroscope 22, memory 23, a wireless module 24, a battery 25, etc. The opening in the housing is made of a material that allows electromagnetic waves to pass through, such as synthetic resin, and is covered with a plate spacer 70, with the outer surface of this spacer 70 exposed to the outside for communication. It consists of a metal protective plate 71 that protects the front of the spacer 70.

Description

Technical Field

[0001] The present invention relates to a device for detecting the rotation of ground improvement blades in ground improvement. More specifically, the present invention relates to a device for detecting the rotation of ground improvement blades that can detect rotation by calculating the relative rotation between the stirring blades and the anti-rotation blades in the ground through calculation and store the data.

Background Art

[0002] In ground improvement where excavation is carried out while rotating stirring blades in the ground, in the case of soil with high water content, etc., a ground improvement material mixed with a cement-based solidifying agent and water is injected during excavation. At this time, due to centrifugal force, water and slurry accumulate on the outer periphery of the excavation diameter and become slippery. Therefore, there may be a phenomenon in which the excavated soil is forced to rotate integrally in the same manner by the excavation blades and the stirring blades attached to the stirring shaft and rotating at the same time, resulting in uneven stirring and mixing of the excavated soil and the ground improvement material. As a means to prevent such a phenomenon, an anti-rotation blade having an outer diameter larger than that of the excavation blade is arranged between the stirring blade and the excavation blade, and this anti-rotation blade is provided rotatably via the boss of the stirring shaft, so that a method of preventing the rotation phenomenon by maintaining a rotation stop state in the ground improvement hole is known and widely used.

[0003] In ground improvement using ground improvement blades, if the anti-co-rotation blade rotates together with the mixing blade, the quality of the ground improvement column formed underground deteriorates. Therefore, it is necessary to accurately detect at what depth and to what extent the co-rotation occurs. The applicants have proposed a system in which a sensor is placed to detect the relative rotation of the anti-co-rotation blade with respect to the mixing blade, using the principle of electromagnetic induction, and this data is transmitted via a wire through the mixing shaft, which is a conductor (Patent Document 1). Although it is not a direct detection of the relative rotation of the mixing shaft and the anti-co-rotation blade, a method has also been proposed in which the rotation of the anti-co-rotation blade is detected by a compass including a gyro sensor placed on the anti-co-rotation blade, thereby detecting co-rotation (Patent Document 2). Furthermore, a soil improvement status monitoring system and soil improvement status monitoring method have also been proposed in which rotation detection data from a sensor placed on the shearing auxiliary blade (anti-co-rotation blade) is transmitted wirelessly to the ground (Patent Document 3). Furthermore, although not in the field of ground improvement, there is a known type of pressure-resistant explosion-proof enclosure that incorporates electrical equipment such as microphones and cameras, in which a pressure-resistant glass plate that transmits radio waves is placed at the opening (Patent Document 4). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2017-66795 [Patent Document 2] Japanese Patent Publication No. 2017-101498 [Patent Document 3] Patent No. 7012893 [Patent Document 4] Japanese Patent Publication No. 2009-273113 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Generally, improved columns that have undergone ground improvement are subjected to strength tests such as uniaxial compression tests after boring is performed to confirm their quality. However, even if insufficient strength is found in this test, it is difficult to determine whether it is due to "the influence of soil type and insufficient amount of solidifying agent added" or "insufficient number of blade cutting cycles of the mixing blade due to the co-rotation phenomenon during excavation and mixing." Furthermore, the wired method of sensing the rotation of the co-rotation prevention blade, as described in Patent Documents 1 and 2, is difficult to obtain stable data from because the sensor is located underground in a harsh environment, and the environment differs from ground to ground, and the transmission of that data is also not stable. In addition, the wireless data transmission system described in Patent Document 3 is unreliable for data acquisition because communication is unstable when the mixing blade is underground, and it is not guaranteed that co-rotation data can be reliably transmitted. The pressure-resistant glass plate installed in the opening of the pressure-resistant explosion-proof housing described in Patent Document 4 is exposed to ground improvement materials containing stones and excavated soil, so it may wear down or break and cannot be used in ground improvement devices.

[0006] Based on the above background, the present invention aims to achieve the following objectives. The object of the present invention is to provide a ground improvement wing rotation detection device that includes a metal housing for housing a rotation detection unit and shielding it from electromagnetic waves, and which has a spacer made of synthetic resin that allows electromagnetic waves to pass through and closes the opening of the housing. Another object of the present invention is to provide a ground improvement wing rotation detection device that has a small area of ​​electromagnetic wave-transmitting window. [Means for solving the problem]

[0007] To solve the above problems, the present invention has the following configuration. The ground improvement blade rotation detection device of the present invention 1 is A stirring shaft, which is rotationally driven by a rotary drive device and has discharge holes for discharging ground improvement material into the ground to form ground improvement columns, A stirring blade fixed to the stirring shaft mixes the excavated soil in the excavated hole in the ground with the ground improvement material, A drilling blade is provided at the ground-bottom end of the stirring shaft and has multiple drilling blades for drilling the borehole, A rotation-preventing blade is rotatably mounted on the stirring shaft between the stirring blade and the drilling blade, the outer peripheral end of which engages with the peripheral wall of the drilled hole to stop its rotation during drilling, and which rotates relative to the rotation of the stirring blade and the drilling blade to mix and stir the excavated soil together with the ground improvement material. In order to detect the co-rotation data, which is the relative rotation of the stirring shaft and the co-rotation prevention blade, a sensor is placed in the co-rotation detection unit within the co-rotation prevention blade, The aforementioned anti-rotation wing is provided with data recording means for recording the relative rotation detected by the sensor in the excavation hole during ground improvement. In a ground improvement device consisting of the following, A metal housing with one side open, housing the aforementioned rotation detection unit and shielding it from electromagnetic waves, The opening is closed, and a spacer made of a plate material that is fixed to the housing and allows electromagnetic waves to pass through is provided. The invention is characterized by comprising a metal protective plate that exposes the outer circumferential surface of the spacer to the outside and covers the front surface of the spacer, thereby protecting the spacer from the excavated soil and the ground improvement material.

[0008] The ground improvement wing rotation detection device of the present invention 2 is characterized in that, in the present invention 1, the outer shape of the spacer is one or more selected from a circle, a regular polygon, and a rectangle. The ground improvement wing rotation detection device of the present invention 3 is characterized in that, in the present invention 1 or 2, the spacer has a larger protective area when the exposed area of ​​the outer surface is compared with the protective area of ​​the protective plate protecting the front surface.

[0009] The ground improvement wing rotation detection device of the present invention 4 is characterized in that, in the present invention 1 or 2, the material of the spacer is selected from synthetic resin, glass, ceramics, and rubber. The ground improvement blade rotation detection device of the present invention 5 is characterized in that, in the present invention 1 or 2, an O-ring is arranged between the spacer and the housing.

Advantages of the Invention

[0010] For the rotation detection device of the ground improvement wing of the present invention, since the exposed area of the outer peripheral surface of the spacer of the plate material, which is the window for wireless communication between the rotation detection unit and the outside, is small, the wear resistance of the spacer is high and the sealing property is also high.

Brief Description of the Drawings

[0011] [Figure 1] FIG. 1 is an external view showing the appearance of a ground improvement machine. [Figure 2] FIG. 2 is an enlarged view of the ground improvement wing. [Figure 3] FIG. 3 is a functional block diagram showing an embodiment of the rotation detection system of the ground improvement wing. [Figure 4] FIG. 4 is a diagram of an example of construction data when the ground is improved by a ground improvement machine. FIG. 4(a) is a diagram showing the rotation speeds of the stirring shaft and the rotation prevention wing, and FIG. 4(b) is a diagram showing the rotation angle of the rotation prevention wing in FIG. 4(a). [Figure 5] FIG. 5 is an example showing the input amount of the ground improvement material per unit depth interval, the number of intervals of the stirring shaft per unit depth interval, and the rotation rate per unit depth interval of the construction example shown in FIG. 4 in numerical values. [Figure 6] FIG. 6 is a flowchart showing an outline of the control operation of the rotation evaluation control device 30. [Figure 7] FIG. 7 is a flowchart showing an example of data transmission and reception when "Bluetooth (registered trademark)" is used for the wireless module. [Figure 8] FIG. 8 is an external view showing the housing 30 of the rotation detection unit 20. [Figure 9] FIG. 9 is a partially exploded parts diagram of the housing 60 in FIG. 8. [Figure 10] FIG. 10 shows the outer shape of the circular spacer 75. FIG. 10(a) is a front view, and FIG. 10(b) is a side view. [Figure 11] FIG. 11 shows the outer shape of the regular polygon spacer 76. FIG. 11(a) is a front view, and FIG. 11(b) is a side view. [Figure 12] Figure 12 shows the external shape of the rectangular spacer 77, with Figure 11(a) being a front view and Figure 12(b) being a side view. [Figure 13] Figure 13 is an explanatory diagram illustrating an overview of a desktop communication test method for measuring radio wave intensity. [Figure 14] Figure 14 shows the external dimensions of the spacer used in the desktop communication test, and includes a front view and a side view. [Modes for carrying out the invention]

[0012] The following describes embodiments of the ground improvement blade rotation detection device and the ground improvement blade rotation evaluation method of the present invention based on the drawings. Figure 1 is an external view showing the appearance of a ground improvement machine equipped with the ground improvement blade rotation detection device. Figure 2 is an enlarged view of the ground improvement blade. This ground improvement machine 1 is equipped with a driver's cab 4 on a self-propelled vehicle body 3 that can travel on caterpillar tracks 2, from which an operator sits and drives. These structures and functions are publicly known and are not the essence of the present invention, so a detailed explanation will be omitted. A leader 5 is positioned in front of the ground improvement machine 1, which is erected vertically when in operation. The leader 5 can be luffed vertically, horizontally, or to any desired angle by a luffing cylinder 6 as needed for construction, transportation, etc. A swivel head 7 equipped with a rotationally driven hollow spindle is mounted on the leader 5 so as to be able to move up and down by a chain (not shown). The swivel head 7 is equipped with a hydraulic motor 38 (see Figure 3) that rotates the stirring shaft 8, a chuck that grips and fixes the stirring shaft 8 and rotates it, and other components.

[0013] At the lower part of the stirring shaft 8, a stirring shaft support base 9 is positioned on the leader 5 to rotatably support it and prevent vibration. At the very bottom of the stirring shaft 8, an excavation blade 10 is positioned and fixed. The excavation blade 10 has excavation blades 11 arranged radially to excavate and loosen the ground to be improved. Above the excavation blade 10, a rectangular, plate-shaped anti-rotation blade 12 is positioned and rotatably supported on the stirring shaft 8 by a bearing 13. The anti-rotation blade 12 is a plate material and is positioned parallel to the plane containing the axis of the rectangular stirring shaft 8. Since the diameter of the anti-rotation blade 12 is larger than the ground improvement hole 16, a portion of both ends of the blade bites into the outer diameter of the ground improvement hole 16 (see Figure 2). For this reason, when the ground improvement is being performed normally, the anti-rotation blade 12 will not rotate even if the stirring shaft 8 is rotated.

[0014] The stirring shaft 8, located above the anti-co-rotation blade 12, has stirring blades 14 fixed to it, one above the other. The stirring shaft 8 is a hollow tube, and pressurized ground improvement material is discharged through a ground improvement material discharge hole 17 opening at the bottom of the stirring shaft 8 via a swivel joint 15 located at the top of the stirring shaft 8. When ground improvement is being carried out normally, the stirring shaft 8, drilling blade 10, and stirring blade 14 rotate in sync with the driving speed of the stirring shaft 8, but the anti-co-rotation blade 12 does not rotate because both ends are embedded in the ground of the ground improvement hole 16. Therefore, when the anti-co-rotation blade 12 rotates in sync with the stirring shaft 8, drilling blade 10, and stirring blade 14, all of them are rotating together. These stirring mechanisms are based on known technology.

[0015] The central shaft tube 19 at the center of the anti-rotation blade 12 is tubular and rotatable around the outer circumference of the stirring shaft 8. In other words, the stirring shaft 8 and the central shaft tube 19 constitute a sliding bearing. A rotation detection unit 20 is fixedly positioned on the central shaft tube 19 to detect the rotation of the anti-rotation blade 12 during ground improvement. As will be described later, the rotation detection unit 20 detects the rotation of the anti-rotation blade 12 when it is located in the ground improvement hole 16. In this invention, the structure of the ground improvement blade is not limited to that of this embodiment. Any other structure is acceptable as long as it has the anti-rotation blade 12, stirring shaft 8, drilling blade 10, and stirring blade 14 described above. For example, the stirring shaft 8 shown in Figure 2 is a single-tube rod, but any ground improvement blade having a structure called a double-tube rod or triple-tube rod is also acceptable as long as it has blades similar in function to the anti-rotation blade 12.

[0016] [Ground Improvement Wing Rotation Detection System 50] Figure 3 is a functional block diagram showing an embodiment of the ground improvement blade co-rotation detection system 50. In this example, the ground improvement blade co-rotation detection system 50 consists of a co-rotation evaluation control device 30, a ground improvement machine control device 35, etc. The co-rotation evaluation control device 30 acquires data from the co-rotation detection unit 20 (described later) and data such as the discharge flow rate of the ground improvement material and the rotation speed of the mixing shaft 8 from the ground improvement machine control device 35 that controls the ground improvement machine 1, processes this data, and displays the ground improvement construction results, quality, etc. on a display (not shown). This makes it possible for operators and managers operating the ground improvement machine 1 to monitor whether the ground improvement is being carried out appropriately. The co-rotation evaluation control device 30 is not special and consists of a general-purpose tablet terminal, portable PC, etc. Similarly, the ground improvement machine control device 35 is a general control device for ground improvement with the ground improvement machine 1.

[0017] [Rotation detection unit 20] As described above, the co-rotation detection unit 20 of the co-rotation evaluation control device 30 detects the rotation of the Z-axis (the axis parallel to the center line of the stirring shaft 8) of the co-rotation prevention blade 12 during ground improvement in this embodiment of the present invention. The co-rotation evaluation control device 30 is a control device for monitoring and evaluating whether or not ground improvement is being carried out properly, and it monitors whether or not the co-rotation prevention blade 12 is rotating in synchronization with the stirring shaft 8, the excavation blade 10, and the stirring blade 14. As shown in Figure 3, the co-rotation detection unit 20 consists of an MCU (Micro Controller Unit) 21, a gyroscope 22, a memory 23, a wireless module 24, a battery, etc. The MCU 21 is a microprocessor equipped with a clock, RAM, etc., and it processes the data obtained from the gyroscope 22 into a usable data format and records it in the memory 23. The gyroscope 22 detects rotation around the X, Y, and Z axes using the Coriolis force, but its principle and function are well known technology, so an explanation will be omitted. In this embodiment of the present invention, rotation data of the anti-rotation wing 12 around the Z-axis, output from the gyroscope 22, is used.

[0018] In this example, memory 23 consists of flash memory and records data obtained from the gyroscope 22. The wireless module 24 is a wireless communication device used for short-range data communication, such as the "Bluetooth" standard. The wireless module 24 (hereinafter also referred to as the "slave unit") is used to wirelessly transmit and receive Z-axis data obtained from the gyroscope 22 to the co-rotation evaluation control device 30. Specifically, when the drilling blade 10 of the stirring shaft 8 is pulled up to the ground, the wireless module 24 wirelessly transmits clock data and Z-axis data obtained from the gyroscope 22 to the outside. Normally, the obtained data is transmitted and received on the ground, so data can be exchanged without any problems. The data from the wireless module 24 is sent wirelessly to the co-rotation evaluation control device 30 via an interface 31 consisting of a transmitting and receiving unit (master unit) that is paired with the wireless module 24 as described above. The battery 25 is a power source that drives the co-rotation detection unit 20, consisting of a rechargeable secondary battery or a primary battery such as a dry cell battery. Interface 31 is fixedly positioned on the front of the vehicle body 3 (see Figure 1). Therefore, when the drilling blades 10 of the stirring shaft 8 are lifted to the ground, necessary data can be transmitted and received wirelessly between the co-rotation detection unit 20 and the co-rotation evaluation control device 30, and the clock can be synchronized.

[0019] [Ground Improvement Machine Control Device 35] The ground improvement machine control device 35 of the ground improvement blade co-rotation detection system 50 shown in Figure 3 is a control device for controlling the ground improvement of the ground improvement machine 1. The co-rotation evaluation control device 30 acquires necessary data from the co-rotation detection unit 20 and the ground improvement machine control device 35 that controls the ground improvement machine 1, and monitors the quality of the ground improvement column as described later. The ground improvement machine control device 35 acquires the rotational speed of the hydraulic motor 38 mounted on the swivel head 7 and driving the mixing shaft 8 via the I / F 36. This data is acquired by detecting the rotational speed of the output shaft of the hydraulic motor 38 with a pulse encoder 37. The rotation detected by this pulse encoder 37 is the rotation of the mixing shaft 8, which is mechanically connected to the output shaft of the hydraulic motor 38 via a reduction gear.

[0020] The Z-axis pulse encoder 40 acquires data on the vertical movement of the swivel head 7. The Z-axis pulse encoder 40 detects the vertical movement of the swivel head 7 on the leader 5 and detects the position of the swivel head 7, i.e., the drilling blade 10. In this example, it detects the vertical movement of the chain-driven swivel head 7. The pulse encoder 40 is for detecting the rotational speed of the chain-driven sprocket 39. The ground improvement material flow meter 41 is a flow meter for detecting the discharge flow rate of the ground improvement material 45. When the ground improvement machine 1 improves the ground, it sucks the ground improvement material 45 from the ground improvement material tank 44 with a pressure pump 43 driven by a motor 42, pressurizes it, and sends it to the top of the mixing shaft 8. The ground improvement material flow meter 41 is an electromagnetic flow meter that detects the flow rate per unit time when the ground improvement material 45 is sent by the pump 43. The start switch 49 is the start switch used by the operator in the control panel 4 of the ground improvement machine 1 to begin ground improvement work. The start switch 49 is pressed for each ground improvement column to start the work. When the operator presses the start switch 49, the pressurized ground improvement material 45 enters the mixing shaft 8 through the swivel joint 15 at the top of the mixing shaft 8 and is discharged from the ground improvement hole 16 at the bottom.

[0021] The ground improvement wing rotation detection system 50 described above monitors the quality of the ground improvement column by acquiring Z-axis rotation data of the anti-rotation wing 12 offline, following the procedure outlined in Table 1 below. Specifically, when the anti-rotation detection unit 20 located on the anti-rotation wing 12 transmits the Z-axis rotation data it detects to the anti-rotation evaluation control device 30, communication becomes unstable or impossible when the anti-rotation detection unit 20 on the anti-rotation wing 12 is underground, so this data is stored in the memory 23 of the anti-rotation detection unit 20. Then, when the anti-rotation wing 12 emerges above ground and stable communication becomes possible, the Z-axis rotation data of the anti-rotation wing 12 while it was underground is transmitted wirelessly to the anti-rotation evaluation control device 30.

[0022] [Table 1]

[0023] [Overview of the control operation of the co-rotation evaluation control device 30] Figure 6 is a flowchart showing an overview of the control operation of the co-rotation evaluation control device 30. The main functions of the co-rotation evaluation control device 30 are to acquire data necessary to obtain diagrams and data tables as exemplified in Figures 4 and 5, which will be described later, and to perform calculations for the analysis of the quality of the constructed ground improvement column 59 (see Figure 5). When the excavation blade 10 is positioned at the starting depth position 56 and the start switch 49 of the ground improvement machine control device 35 shown in Figure 3 is pressed by the operator (S1), the clock of the co-rotation evaluation control device 30, the clock of the ground improvement machine control device 35, and the clock of the co-rotation detection unit 20 are synchronized or time-set (S2). At the same time, the co-rotation evaluation control device 30 issues a command to the MCU 21 of the co-rotation detection unit 20 to record the data of the Z-axis rotation of the co-rotation prevention blade 12 in the memory 23 (S3). The depth at which the start switch 49 is pressed by the operator is the starting depth position 56 at which ground improvement begins (see Figure 5).

[0024] Based on data from the ground improvement machine control device 35, when the drilling blade 10 reaches the deepest position 58, the drilling shaft 8 is reversed and raised in the Z-axis direction. When it reaches the end point (starting depth position 56) 56 (Figure 5), which is the end position of ground improvement (S4), the co-rotation evaluation control device 30 receives data from the memory 23, which is data from the gyroscope 22, via the wireless module 24 (S5). Furthermore, necessary information such as the rotation speed of the mixing shaft 8, the amount of movement in the Z-axis, and the amount of ground improvement material to be put in are acquired from the ground improvement machine control device 35 either as needed or in batches (S6). Calculations are performed using the obtained data, and diagrams and tables like those shown in Figures 4 and 5 (described later) are displayed on the screen for the operator, construction manager, etc. If necessary, a timestamp is also transmitted.

[0025] [Example of ground improvement construction] Figure 4 is a diagram of example construction data when ground improvement is performed using a ground improvement machine. In Figure 4(a), the vertical axis shows the rotation speed (rpm) of the mixing shaft 8 and the anti-rotation blade 12, and the horizontal axis shows time (minutes). In the diagram of Figure 4(b), the vertical axis shows the rotation angle (°) of the anti-rotation blade 12, and the horizontal axis shows time (minutes). In the example diagram of Figure 4, it is shown that the anti-rotation blade 12 rotates together with the mixing shaft 8 for a certain period of time while the mixing shaft 8 is rotating in the forward and reverse directions. The operator positions the excavation blade 10 when performing ground improvement using GNSS (Global Navigation Satellite System) mounted on the ground improvement machine 1, determines the starting position for ground improvement, and starts ground improvement from this position. This ground improvement starting position may also be determined by marking a position on the ground surface towards the operator using a total station or the like.

[0026] Once the position on the ground surface is determined, the mixing shaft 8 is set vertically (Z-axis). When the drilling blade 10 reaches the starting depth position 56, which is a preset ground improvement starting depth slightly below the ground surface, the start switch 49 for starting ground improvement is pressed. When the start switch 49 is pressed, a solenoid valve (not shown) opens, and the ground improvement material 45 pressurized by the pump 43 is sent out. The ground improvement material 45 passes through the hollow mixing shaft 8 via the swivel joint 15 and is discharged from the ground improvement material discharge hole 17. Figure 5 is a diagram showing the construction example shown in Figure 4 in numerical terms. As shown in Figure 5, in the improved column 59 of this ground improvement example, when it reaches the maximum set depth position 58, the operator mixes the material by rotating the mixing shaft 8 in the reverse direction and pulls it up to the starting depth position (end point) 56.

[0027] The example shown in Figure 5 numerically displays the section flow rate (L), section cutting count (Rev), and co-rotation rate (%) of the ground improvement material per unit depth section of the ground improvement column 59. Specifically, "section flow rate (L)" indicates the flow rate of the ground improvement material per unit depth section of the ground improvement column 59, "section cutting count (Rev)" indicates the number of times the mixing blades 14 are used per unit depth section of the ground improvement column 59, and "co-rotation rate (%)" indicates the rate of co-rotation between the mixing shaft 8 and the co-rotation prevention blade 12. The diagrams and tables illustrated in Figures 4 and 5 can be viewed by the operator or supervisor during construction. Therefore, if the section flow rate (L), section cutting count (Rev), and co-rotation rate (%) do not reach the preset allowable range, re-construction can be immediately carried out at a stage when the ground improvement material has not yet hardened.

[0028] [Examples of wireless module communication] Figure 7 is a flowchart showing an overview of data transmission and reception when using "Bluetooth" as the wireless module. The leader 5 of the ground improvement machine 1 is positioned vertically, and the center of the mixing shaft 8 is aligned with the center of the ground improvement hole 16 to be improved. After this positioning is complete, the operator presses the start switch 49 to start the ground improvement. Pressing the start switch 49 activates the ground improvement machine control device 35 and makes the ground improvement machine 1 operational. That is, the mixing shaft 8 rotates, the ground improvement material 45 is discharged, and the ground improvement is ready to begin. In this state, the operator makes various recording settings from the co-rotation evaluation control device 30 to record the rotation data of the co-rotation prevention blade 12 using the co-rotation detection unit 20 of the co-rotation prevention blade 12 (S1). As can be understood from this explanation, the operator will issue commands before the start of improvement for each unit of ground improvement holes 16.

[0029] Next, the operator selects the slave unit to connect and performs the necessary settings for pairing (S2). Specifically, the operator sets the data, conditions, and other items necessary for pairing the wireless module 24, which is a slave unit located in the co-rotation detection unit 20, with the wireless module (not shown, hereinafter also referred to as the "master unit") located in the I / F 31 of the co-rotation evaluation control device 30 (S2). In the case of Bluetooth devices, this pairing process involves registering the master unit and the slave unit and allowing them to recognize each other. The purpose of this is to ensure the security of communication between devices, and in principle, communication using Bluetooth devices cannot be used without pairing.

[0030] Then, on the screen of the ground improvement machine control device 35 (not shown), the operator presses the record start switch to record the ground improvement data (S3). Next, based on the command from the record start switch, the co-rotation evaluation control device 30 commands the co-rotation detection unit 20 to start recording the co-rotation data (S4). After this command from the co-rotation evaluation control device 30, the co-rotation evaluation control device 30 determines whether the pairing between the slave unit wireless module 24 and the master unit wireless module has been successful (S5). If pairing is unsuccessful, the co-rotation evaluation control device 30 notifies the operator by displaying an error on its screen or by emitting a warning sound (S6). If pairing is successful, the co-rotation evaluation control device 30 commands the master unit and slave unit to synchronize their time data using timestamps (S7). The co-rotation evaluation control device 30 acquires various ground improvement data from the ground improvement machine control device 35, and the co-rotation detection unit 20 starts recording co-rotation data of the co-rotation prevention wing 12 (S8-S9).

[0031] The operator determines whether the recording of various ground improvement data has been completed based on the ground improvement work status of the ground improvement machine 1 (S10). If various data from the ground improvement machine 1 and co-rotation data from the detection unit 20 have not been obtained, the process returns to S8 to acquire the ground improvement data and co-rotation data. If the recording of these data has been completed, the ground improvement machine control device 35 performs data saving (S11). If communication cannot be secured after the master unit and slave unit have been paired and synchronized, the co-rotation data is automatically stored in the local memory 23. Communication between the master unit and slave unit does not necessarily occur when they are above ground. If communication is possible, communication may continue even when the slave unit is underground. Thus, in this embodiment, even if communication between the master unit and slave unit is interrupted when the mixing shaft 8 is underground, the co-rotation data can be safely recorded and saved.

[0032] Once the necessary data for various ground improvement procedures has been saved (S11), the co-rotation evaluation control device 30 commands the download of the co-rotation data of the co-rotation prevention wing 12 measured by the co-rotation detection unit 20 (S12). Next, when the excavation wing 10 is underground, communication is normally interrupted. When the excavation wing 10 comes close to the surface, it is determined whether or not it has reconnected with the slave unit paired in S2 (S13). If it has not reconnected, a manual download is performed (S14). If a manual download cannot be performed or is not performed, it is determined again whether or not it has reconnected (S15). If it has not reconnected, it waits for reconnection, and once reconnected, the next co-rotation data is downloaded (S16). After that, the ground improvement machine control device 35 downloads the co-rotation data from the slave unit to the master unit and creates a combined processing table of the ground improvement machine 1 data and the co-rotation data (see, for example, Figure 5).

[0033] [Housing 60 of the rotation detection unit 20] Figure 8 is an external view showing the housing containing the co-rotation detection unit 20. Figure 9 is a partially exploded parts view of the housing 60 of Figure 8. The co-rotation detection unit 20 (see Figure 3) is housed inside the housing 60. Since the co-rotation detection unit 20 mounted on the co-rotation prevention wing 12 is an electronic circuit, it needs to be completely protected by the housing 60 when it is underground from exposure to excavated soil, ground improvement materials 45, etc. For this reason, the housing 60 is made of a strong and wear-resistant metal material. In this example, the housing 60 is made of steel such as carbon steel for machine structures. The housing 60 made of metal material physically protects the internal electronic equipment and also provides electromagnetic shielding to block electromagnetic waves. On the other hand, the wireless module 24 (slave unit), including the antenna (not shown) inside the co-rotation detection unit 20 inside the housing 60, communicates wirelessly with the master unit (31), so it is necessary to communicate smoothly, and the wireless module 24 also needs the function to communicate smoothly wirelessly with the master unit.

[0034] In this example, the main body 61 of the housing 60 has a box-like shape with a rectangular parallelepiped interior, and the co-rotation detection unit 20 is housed inside. The fixing flange 62, which is the base of the main body 61, is fixed to the front surface 66 of the fixing jig 65 with bolts and nuts 68. The fixing jig 65 is fixed to a bracket (not shown) that is paired with the fixing jig 65 with bolts and nuts 67 on the outer circumference of the central shaft tube 19 of the co-rotation prevention wing 12. The main body 61 opens radially in the direction of the central shaft tube 19, and a flange 63 with a larger outer diameter than the opening is formed on the outer circumference of this opening. An O-ring groove is formed on the front surface of the flange 63 on the outer circumference of the opening, and an O-ring 64 is inserted into the O-ring groove. A spacer 70 made of engineering plastic is placed in front of the O-ring 64. The material of the spacer 70 is not limited to synthetic resin, as long as it has a predetermined thickness and transmits radio waves for the aforementioned wireless communication.

[0035] On the front surface 73 of the spacer 70, a protective plate 71 made of steel or other metal, which has the same outer shape as the spacer 70, is fixed to the flange 63 together with the spacer 70 and the main structure 61 by bolts 72. The protective plate 71 can be said to be a cover to prevent the spacer 70 from being exposed to excavated soil, ground improvement material 45, etc. Because the protective plate 71 is on the front surface 73 of the spacer 70, only the outer surface 74 is exposed to excavated soil, ground improvement material 45, etc. As can be understood from the above explanation, since the protective material 71 made of metal is fixed to the front surface 73 of the synthetic resin spacer 70, even when underground, only the outer surface 74 is exposed to excavated soil and ground improvement material.

[0036] [Area and perimeter area of ​​spacer 70] As mentioned above, although the spacer 70 in this embodiment is made of engineering plastic, it is made of synthetic resin and is susceptible to wear and tear when exposed to excavated soil, ground improvement materials 45, etc. On the other hand, it needs to function as a window for radio waves. In order to minimize the exposed area of ​​the outer surface 74 of the spacer 70, the front surface 73 of the spacer 70 is protected by the protective plate 71, so there is no problem there, but the area of ​​the outer surface 74 also needs to be made as small as possible. However, if the area of ​​the outer surface 74 is made too small, it will not be able to function as a window for radio waves. Below, we will explore the general relationship between the area of ​​the front surface 73 and the outer surface 74 of the spacer 70 for each external shape. (1) Spacer 70 is circular If the spacer 70 that blocks the opening of the housing 60 is a circular spacer 75 as shown in Figure 10, the difference in area between the front surface and the outer surface is as follows. S = (1 / 4)·πD 2 However, S: Front surface area of ​​the circular spacer 75, D: Diameter of the circular spacer 75 The area S' of the outer surface of the circular spacer is as follows: S'=π·D·t However, t: thickness of the circular spacer 71 The area of ​​the non-metallic radio wave window, that is, the exposed area to the ground, should be as small as possible. S' 2 ) → 4t <D ​When 4t < D, that is, when the thickness t of the circular spacer 71 is within 1 / 4 of D, radio waves can pass through, but the area exposed to earth and sand etc. is smaller than that of the window type opening to the front surface.

[0037] (2) The spacer 70 is a regular polygon When the spacer 70 that closes the opening of the housing 60 is the regular polygon 76 shown in FIG. 11, it is as follows. The area S of the regular polygon is the following formula. S=(n·a 2 ) / (4tan(π / n)) However, S: area (maximum) of the regular polygon spacer 76, a: side length, n: number of angles of the regular polygon The area S' of the outer peripheral surface of the regular polygon spacer 76 is as follows. S'=n·a·t However, t: thickness of the regular polygon spacer 76 S'<S → (n·a·t)<[(n·a 2 ) / (4tan(π / n))] → t<[a / (4tan(π / n))]

[0038] (3) The spacer 70 is a rectangle Similarly, when the spacer 70 that closes the opening of the housing 60 is the rectangular spacer 77 as shown in FIG. 12, it is as follows. S=a·b However, S: opening area (maximum) of the rectangular spacer 77, a: length of the short side, b: length of the long side The area S' of the outer peripheral surface of the rectangular spacer 77 is as follows. S'=2(a+b)·t However, t: thickness of the rectangular spacer 70 S'<S → 2(a+b)·t<a·b As described above, for the spacer 70 of the present invention to make the area of the outer peripheral surface smaller than the area of the front surface, it is necessary to satisfy the above condition of S'<S.

[0039] [Radio wave intensity communication test (experimental example)] Since the spacer 70 is electromagnetically shielded by a protective material 71 made of metal, a test was conducted on a desk to determine whether communication was possible between the wireless communication device inside the main unit 61 and an external wireless communication device. For example, when using Bluetooth, the frequency band is the 2.4GHz band, so sufficient radio wave strength can be obtained if an opening of 63mm or more (half a wavelength) of the same frequency can be secured as a window for radio waves. Even though the thickness of the spacer 70 is thin, its outer surface is long, so it functions as a window for radio waves. Figure 13 is an explanatory diagram showing an overview of the desk communication test method for measuring radio wave strength. The communication standard used was Bluetooth, and communication was performed with a distance of approximately 2m between the base unit installed on the ground and the housing 60 (with the slave unit built in) of the co-location detection unit 20, and the power of the radio waves was measured. The results are shown in Table 2. The resin window is a window for radio waves, and there is no protective plate 71. It is a resin plate made of MC nylon that covers the opening at the front of the housing 61 with a lid 80. [Table 2] In this tabletop experiment, the power was measured for (1) a setup without the protective plate 71 and spacer 70 (Comparative Example 1), (2) a resin window cover (Comparative Example 2), and (3) each spacer covered with a protective plate (Experimental Examples 1-4, MC Nylon (registered trademark, wall thickness 5, 10 mm), Duracon (registered trademark, wall thickness 5, 10 mm)). Figure 14 shows the front and side views of the external shape and dimensions of the spacer 70 used in the experiment. The MC nylon used was "MC901" (manufactured by Mitsubishi Chemical Advanced Materials Corporation, head office: Tokyo), and the Duracon used was "TF-10LV" (manufactured by Polyplastics Co., Ltd., head office: Tokyo). The resin plate in Comparative Example 2 was "MC901" with a thickness of 10 mm. As shown in the results in Table 2, there was no clear difference in the strength of the radio waves between Comparative Examples 1 and 2, and each of the experimental examples 1 to 4. In other words, there was almost no difference in the transmitted and received radio wave strength between (1) above, which lacks the protective plate 71 and spacer 70 that would interfere with wireless communication, (2) above, which lacks the protective plate 71 and only has a resin cover, and (3) above, which is an experimental example, and the thickness of the spacer 70 did not have any effect. Therefore, this bench experiment revealed that even a plate-shaped spacer 70 covered with a protective material 71 that acts as a window for radio wave communication, with only its outer surface exposed to the outside, can function as a window for radio waves.

[0040] [Other embodiments] In the embodiments described above, the outer shape of the spacer 70 was described as circular, a regular polygon, or a rectangle. However, since the outer shape of the spacer 70 varies depending on the outer shape of the housing 60, the shape of the opening, etc., the outer shape of the spacer 70 is not limited to circular, a regular polygon, or a rectangle, but may also be a combination of these shapes. In the embodiments described above, the material of the spacer 70 was a synthetic resin that transmits radio waves, but it does not have to be reinforced with metal fibers or the like. Any material that transmits radio waves and has airtightness and wear resistance, such as glass, ceramics, or rubber, may also be used. [Explanation of symbols]

[0041] 1…Soil improvement machine 2… Caterpillar 3... Vehicle body 4…Driver's cab 5... Leader 6…Relief cylinder 7... Swivel head 8...Stirring shaft 9...Stirring shaft support stand 10…Drilling blades 11…Drilling blade 12… Anti-rotation wing 13…Bearings 14...Agitation blade 17…Soil improvement material discharge hole 20...Rotation detection unit 21…MCU 22... Gyroscope 23…Memory 24… Wireless module 25…Battery 30...Rotation evaluation control device 31…I / F 35... Ground improvement machine control device 36…I / F 37…Agitation shaft rotation detection pulse encoder 38… Hydraulic motor 39... Sprocket Wheel 40...Z-axis pulse encoder 41…Soil improvement material discharge flow meter 42... Ground improvement material drive pump 43…Ground improvement material drive pump motor 44...Ground improvement material tank 45…Soil improvement material 49... Start switch 50… Ground improvement wing rotation detection system 56…Starting depth position 58…Deepest position 59…Soil improvement pillar 60…Cabinet 61...Main unit 65… Fixing jig 70... Spacer 71...Protection plate 75…Circular spacer 76... Regular polygon spacer 77…Rectangular Spacer 80… Resin window cover

Claims

1. A stirring shaft, which is rotationally driven by a rotary drive device and has discharge holes for discharging ground improvement material into the ground to form ground improvement columns, A stirring blade fixed to the stirring shaft mixes the excavated soil in the excavated hole in the ground with the ground improvement material, A drilling blade is provided at the ground-bottom end of the stirring shaft and has multiple drilling blades for drilling the borehole, A rotation-preventing blade is rotatably mounted on the stirring shaft between the stirring blade and the drilling blade, the outer peripheral end of which engages with the peripheral wall of the drilled hole to stop its rotation during drilling, and which rotates relative to the rotation of the stirring blade and the drilling blade to mix and stir the excavated soil together with the ground improvement material. In order to detect the co-rotation data, which is the relative rotation of the stirring shaft and the co-rotation prevention blade, a sensor is placed in the co-rotation detection unit within the co-rotation prevention blade, The aforementioned anti-rotation wing is provided with data recording means for recording the relative rotation detected by the sensor in the excavation hole during ground improvement. In a ground improvement device consisting of the following, A metal housing with one side open, housing the aforementioned rotation detection unit and shielding it from electromagnetic waves, The opening is closed, and a spacer made of a plate material that is fixed to the housing and allows electromagnetic waves to pass through is provided. A metal protective plate is provided to expose the outer surface of the spacer to the outside and to cover the front surface of the spacer, thereby protecting the spacer from the excavated soil and the ground improvement material. A ground improvement blade rotation detection device characterized by comprising the above.

2. In the ground improvement blade rotation detection device described in claim 1, The outer shape of the spacer is one or more selected from a circle, a regular polygon, and a rectangle. A ground improvement blade rotation detection device characterized by the above.

3. In the ground improvement blade rotation detection device according to claim 1 or 2, When comparing the exposed area of ​​the outer circumferential surface of the spacer with the protected area of ​​the protective plate protecting the front surface, the protected area is larger. A ground improvement blade rotation detection device characterized by the above.

4. In the ground improvement blade rotation detection device according to claim 1 or 2, The material of the spacer is selected from synthetic resin, glass, ceramics, and rubber. A ground improvement blade rotation detection device characterized by the above.

5. In the ground improvement blade rotation detection device according to claim 1 or 2, An O-ring is positioned between the spacer and the housing. A ground improvement blade rotation detection device characterized by the above.

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