Ground improvement blade rotation detection device

Abstract

The housing structure houses a sensor that reliably detects the rotation of the rotation prevention blades during ground improvement work, protects it from soil and sand, and also enables wireless communication. [Solution] The Z-axis rotation of the rotation prevention blade is detected during ground improvement work. The rotation detection unit 20 is arranged in the housing of the rotation prevention blade, and is composed of an MCU (Micro Controller Unit) 21, a gyroscope 22, a memory 23, a wireless module 24, a battery 25, etc. The opening of the housing is covered with a spacer 70 made of a material that transmits electromagnetic waves, such as synthetic resin, and the outer circumferential surface of this spacer 70 is exposed to the outside for communication. It is composed of a metal protective plate 71 that protects the front surface of the spacer 70.

Description

[Technical field]

[0001] The present invention relates to a ground improvement impeller co-rotation detection device for ground improvement. More specifically, the present invention relates to a ground improvement impeller co-rotation detection device that can detect co-rotation by calculating the relative rotation between an agitating impeller and a co-rotation prevention impeller in the ground and store the data. [Background technology]

[0002] In ground improvement work, in which the agitator blade is rotated underground, a mixture of cement-based solidification material and water is injected into the ground during excavation, especially in the case of soil with high water content. At this time, centrifugal force causes water and slurry to accumulate on the outer circumference of the excavation diameter, making it easy to slip. Therefore, the excavation blade and the agitator blade, which are attached to the agitator shaft and rotate simultaneously, cause a phenomenon in which the excavated soil is forced to rotate together, which may prevent the excavated soil and the ground improvement material from being mixed uniformly. As a means of preventing this phenomenon, a method is known and widely used in which a co-rotation prevention blade with an outer diameter larger than the excavation blade is placed between the agitator blade and the excavation blade, and this co-rotation prevention blade is rotatably installed via the boss of the agitator shaft, thereby keeping the rotation stopped within the ground improvement hole.

[0003] In ground improvement using ground improvement blades, if the rotation prevention blade rotates together with the agitator blade, the quality of the ground improvement pillar formed in the ground deteriorates. Therefore, it is necessary to accurately detect the depth and the extent of rotation. In order to detect the relative rotation of the rotation prevention blade with the agitator blade, the applicants have proposed a method in which a sensor is placed to detect the relative rotation between the agitator shaft and the rotation prevention blade using the principle of electromagnetic induction, and this data is transmitted by wire via the agitator shaft, which is a conductor (Patent Document 1). Although it is not a direct detection of the relative rotation between the agitator shaft and the rotation prevention blade, a method has also been proposed in which the rotation of the rotation prevention blade is detected by a compass including a gyro sensor placed on the rotation prevention blade to detect the rotation (Patent Document 2). In addition, a soil improvement status monitoring system and a soil improvement status monitoring method have also been proposed in which rotation detection data from a sensor placed on the shear aileron (rotation prevention blade) is transmitted to the ground by wireless (Patent Document 3). Also, although not in the field of ground improvement, a pressure-resistant explosion-proof housing containing electrical equipment such as a microphone and a camera is known in which a pressure-resistant glass plate that transmits radio waves is placed in the opening (Patent Document 4). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-66795 A [Patent Document 2] JP 2017-101498 A [Patent Document 3] Patent No. 7012893 [Patent Document 4] JP 2009-273113 A Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, after construction, the columns are drilled to take samples for quality check, and strength tests are performed using uniaxial compression tests and the like. However, even if the test reveals insufficient strength, it is not possible to determine whether the cause is "the influence of soil quality and the insufficient amount of solidification material added" or "the insufficient number of times the agitator blades are cut due to the phenomenon of co-rotation during excavation and mixing". In addition, in the wired method of sensing the rotation of the anti-rotation blades as in Patent Documents 1 and 2, the sensor is located underground in a harsh environment, which is different for each ground, so it is difficult to collect stable data, and the data cannot be transmitted stably. In addition, the wireless data transmission system described in Patent Document 3 lacks reliability in data acquisition because communication is unstable when the agitator blades are underground and it is not always possible to reliably transmit co-rotation data. The pressure-resistant glass plate provided at the opening of the pressure-resistant explosion-proof housing described in Patent Document 4 is exposed to the ground improvement material containing stones and the excavated soil, so it may wear out and be damaged, and cannot be used for ground improvement equipment.

[0006] In view of the above background, the present invention achieves the following objects. The object of the present invention is to provide a ground improvement blade rotation detection device which has a metal housing which houses a rotation detection unit inside and shields electromagnetic waves, and which has a synthetic resin plate spacer which closes the opening of the housing and allows electromagnetic waves to pass through. Another object of the present invention is to provide a ground improvement blade rotation detection device having a small area of ​​a window through which electromagnetic waves pass. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention comprises the following configuration. The ground improvement blade rotation detection device of the present invention 1 is A stirring shaft that is rotated by a rotary drive device and has a discharge hole for discharging a ground improvement material into the ground to form a ground improvement column; A mixing blade fixed to the mixing shaft for mixing the excavated soil and the ground improvement material in the excavated hole in the ground; A drilling blade provided at an end of the stirring shaft on the ground bottom side and having a plurality of drilling blades for drilling the drilled hole; a rotation prevention blade that is rotatably provided on the stirring shaft between the stirring blade and the excavation blade, and during the excavation, an outer peripheral end portion engages with the peripheral wall of the excavation hole to stop rotation, and rotates relative to the rotation of the stirring blade and the excavation blade to mix and stir the excavated soil together with the ground improvement material; A sensor disposed in a co-rotation detection unit in the co-rotation prevention blade for detecting co-rotation data which is the relative rotation between the stirring shaft and the co-rotation prevention blade; a data recording means disposed on the anti-rotation wing for recording the relative rotation detected by the sensor within the borehole during ground improvement work; In the ground improvement device, a metal housing having an opening on one side, housing the rotation detection unit therein, and shielding against electromagnetic waves; a spacer that closes the opening, is fixed to the housing, and is a plate made of a material that transmits the electromagnetic waves; The spacer has an outer peripheral surface exposed to the outside and a front surface covered with a metal protective plate for protecting the spacer from the excavated soil and the ground improvement material.

[0008] The co-rotation detection device for ground improvement blades of the present invention 2 is the same as that of the present invention 1, wherein the outer shape of the spacer is one or more selected from a circle, a regular polygon, and a rectangle. The ground improvement blade rotation detection device of Invention 3 is characterized in that, in Invention 1 or 2, the spacer has a larger protected area when compared between the exposed area of ​​the outer peripheral surface and the protected area of ​​the protective plate that protects the front surface.

[0009] The ground improvement blade co-rotation detection device of invention 4 according to invention 1 or 2 is characterized in that the material of the spacer is one selected from synthetic resin, glass, ceramics, and rubber. The ground improvement blade co-rotation detection device of the fifth invention is characterized in that, in the first or second invention, an O-ring is disposed between the spacer and the housing. Effect of the Invention

[0010] The ground improvement blade co-rotation detection device of the present invention has a small exposed area on the outer surface of the plate spacer, which serves as a window for wireless communication between the co-rotation detection unit and the outside, so the spacer has high wear resistance and excellent sealing properties. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is an external view showing the appearance of the ground improvement machine. [Diagram 2] Figure 2 is an enlarged view of the ground improvement wing. [Diagram 3] FIG. 3 is a functional block diagram showing an embodiment of the system for detecting the rotation of the soil improvement blades. [Figure 4] Figure 4 is a diagram showing an example of construction data when ground improvement is performed using a ground improvement machine, where Figure 4(a) is a diagram showing the rotation speed of the agitator shaft and the anti-rotation blade, and Figure 4(b) is a diagram showing the rotation angle of the anti-rotation blade in Figure 4(a). [Diagram 5] Figure 5 shows the construction example shown in Figure 4 with numerical values ​​for the amount of ground improvement material added per unit depth, the number of times the mixing shaft is cut in the unit depth, and the circulation rate in the unit depth. [Figure 6] FIG. 6 is a flow chart showing an outline of the control operation of the companion evaluation control device 30. As shown in FIG. [Figure 7] FIG. 7 is a flow diagram 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 feeding detection unit 20. As shown in FIG. [Figure 9] FIG. 9 is a partial exploded view of the housing 60 of FIG. [Figure 10] FIG. 10 shows the external shape of the circular spacer 75, with FIG. 10(a) being a front view and FIG. 10(b) being a side view. [Figure 11] FIG. 11 shows the external shape of the regular polymorphic spacer 76, with FIG. 11(a) being a front view and FIG. 11(b) being a side view. [Figure 12] FIG. 12 shows the external shape of the rectangular spacer 77, with FIG. 12(a) being a front view and FIG. 12(b) being a side view. [Figure 13] FIG. 13 is an explanatory diagram showing an overview of a desktop communication test method for measuring radio wave intensity. [Figure 14] FIG. 14 is a front view and a side view showing the outer shape of the spacer used in the desktop communication test. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the ground improvement blade rotation detection device and the ground improvement blade rotation evaluation method of the present invention will be described with reference to the drawings. FIG. 1 is an external view showing the appearance of a ground improvement machine equipped with a ground improvement blade rotation detection device. FIG. 2 is an enlarged view of the ground improvement blade. This ground improvement machine 1 is equipped with a driver's seat 4 on a self-propelled vehicle body 3 that can travel on caterpillars 2, on which an operator sits and drives the machine. These structures and functions are well known, and are not the gist of the present invention, so detailed descriptions thereof will be omitted. A leader 5 that is erected vertically during operation is arranged at the front position of the ground improvement machine 1, and the leader 5 can be driven to rise and fall at a desired angle, such as vertically or horizontally, by a rise and fall cylinder 6 as required for construction, transportation, etc. A swivel head 7 equipped with a hollow spindle that is driven to rotate is mounted on the leader 5 so as to be freely movable up and down by a chain (not shown) drive. The swivel head 7 includes a hydraulic motor 38 (see FIG. 3) that rotates the agitation shaft 8, a chuck that holds and fixes the agitation shaft 8 and rotates it, and the like.

[0013] At the bottom of the agitator shaft 8, an agitator shaft support base 9 is arranged on the leader 5 to rotatably support the agitator shaft 8 and prevent it from shaking. At the bottom of the agitator shaft 8, an excavation blade 10 is arranged and fixed. The excavation blade 10 has excavation blades 11 arranged in the radial direction to excavate and loosen the ground to be improved. At the top of the excavation blade 10, a rectangular plate-shaped anti-rotation blade 12 is rotatably supported by a bearing 13 on the agitator shaft 8. The anti-rotation blade 12 is made of a plate material and is arranged parallel to a plane including the axis of the rectangular agitator shaft 8. Since the diameter of the anti-rotation blade 12 is larger than the ground improvement hole 16, both ends of the blade are partially inserted into the outer diameter of the ground improvement hole 16 (see FIG. 2). For this reason, when the ground is improved normally, the anti-rotation blade 12 does not rotate even if the agitator shaft 8 is driven to rotate.

[0014] Agitator blades 14 are fixed on the top and bottom of the agitator shaft 8 above the anti-rotation blade 12. The agitator shaft 8 is a hollow tube, and the pressurized ground improvement material is discharged from the ground improvement material discharge hole 17 opened at the bottom through a swivel joint 15 arranged at the top of the agitator shaft 8. When ground improvement is performed normally, the agitator shaft 8, the drilling blade 10, and the agitator blade 14 are rotated in synchronization with the driving speed of the agitator shaft 8, but the anti-rotation blade 12 does not rotate because both ends are embedded in the ground of the ground improvement hole 16. Therefore, when the anti-rotation blade 12 rotates in synchronization with the agitator shaft 8, the drilling blade 10, and the agitator blade 14, they are rotating together. These agitation mechanisms are known technologies.

[0015] The central shaft tube 19 at the center of the rotation prevention blade 12 is tubular and can rotate freely around the outer periphery of the agitation shaft 8. In other words, the agitation shaft 8 and the central shaft tube 19 constitute a sliding bearing. A rotation detection unit 20 is fixedly disposed on the central shaft tube 19 in order to detect the rotation of the rotation prevention blade 12 during ground improvement. As described later, the rotation detection unit 20 detects the rotation of the rotation prevention blade 12 when it is located in the ground improvement hole 16. In the present invention, the structure of the ground improvement blade is not limited to that of this embodiment. As long as it has the rotation prevention blade 12, the agitation shaft 8, the excavation blade 10, and the agitation blade 14 described above, it may have another structure. For example, the agitation shaft 8 shown in FIG. 2 is a single tube rod, but as long as it has a blade similar to the function of the rotation prevention blade 12, it may be a ground improvement blade having a structure called a double tube rod or a triple tube rod.

[0016] [Soil improvement blade rotation detection system 50] FIG. 3 is a functional block diagram showing an embodiment of the ground improvement blade supply rotation detection system 50. In this example, the ground improvement blade supply rotation detection system 50 is composed of a supply rotation evaluation control device 30, a ground improvement machine control device 35, etc. The supply rotation evaluation control device 30 acquires data from the supply 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 stirring shaft 8 from the ground improvement machine control device 35 that controls the ground improvement machine 1, processes the data, and displays the construction results and quality of the ground improvement on a display (not displayed). This makes it possible for an operator or manager operating the ground improvement machine 1 to monitor whether the ground improvement is being performed appropriately. The supply rotation evaluation control device 30 is not a special device but is composed of a general-purpose tablet terminal, a portable personal computer, etc. Similarly, the ground improvement machine control device 35 is a general control device for ground improvement with the ground improvement machine 1.

[0017] [Support detection unit 20] As described above, in the embodiment of the present invention, the rotation detection unit 20 of the rotation evaluation control device 30 detects the rotation of the Z axis (axis parallel to the center line of the stirring shaft 8) of the rotation prevention blade 12 during ground improvement. The rotation evaluation control device 30 is a control device for monitoring and evaluating whether ground improvement is being performed properly, and monitors whether the rotation prevention blade 12 rotates in synchronization with the stirring shaft 8, the excavation blade 10, and the stirring blade 14. As shown in FIG. 3, the rotation detection unit 20 is composed 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 processes 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 the principle and function of the gyroscope 22 are well known technologies, so their explanation will be omitted. In the embodiment of the present invention, rotation data about the Z axis of the anti-rotation wing 12 outputted from the gyroscope 22 is used.

[0018] The memory 23 is a flash memory in this example, and records the data obtained from the gyroscope 22. The wireless module 24 is a wireless communication device, and is used for short-distance data communication such as the "Bluetooth" standard. The wireless module 24 (hereinafter also referred to as the "child unit") is for wirelessly transmitting and receiving the Z-axis data and the like obtained from the gyroscope 22 to the feeding evaluation control device 30. That is, when the excavation blade 10 of the stirring shaft 8 is pulled up to the ground, the wireless module 24 wirelessly transmits the clock data and the Z-axis data obtained from the gyroscope 22 to the outside. Since the obtained data is usually transmitted and received on the ground, data can be exchanged without any trouble. The data from the wireless module 24 is wirelessly transmitted to the feeding evaluation control device 30 via the interface 31, which is composed of a transmitting / receiving unit (parent unit) and the like that is paired with the wireless module 24 described above. The battery 25 is a power source for driving the feeding detection unit 20, which is composed of a rechargeable secondary battery or a primary battery such as a dry cell. The interface 31 is fixedly disposed on the front surface of the vehicle body 3 (see FIG. 1). Therefore, when the excavation blade 10 of the agitation shaft 8 is raised above ground, necessary data can be transmitted and received, clocks can be synchronized, and so on, between the feeding detection unit 20 and the feeding evaluation control device 30 by wireless.

[0019] [Ground improvement machine control device 35] The ground improvement machine control device 35 of the ground improvement blade rotation detection system 50 shown in FIG. 3 is a control device for controlling the ground improvement of the ground improvement machine 1. The rotation evaluation control device 30 acquires necessary data from the 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 below. The ground improvement machine control device 35 acquires the rotation speed of the hydraulic motor 38 mounted on the swivel head 7 and driving the stirring shaft 8 via the I / F 36. This data is acquired by detecting the rotation 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 stirring shaft 8 that is mechanically connected to the output shaft of the hydraulic motor 38 via a reducer.

[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 to detect the position of the swivel head 7, i.e., the excavation blade 10. In this example, it detects the vertical movement of the swivel head 7, which is driven by a chain. The pulse encoder 40 detects the rotation speed of the sprocket 39, which is driven by the chain. The ground improvement material flow meter 41 is a flow meter for detecting the discharge flow rate of the ground improvement material 45. When performing ground improvement, the ground improvement machine 1 sucks the ground improvement material 45 in the ground improvement material tank 44 with the pressure pump 43 driven by the motor 42, pressurizes it, and sends it to the top of the agitation shaft 8. The ground improvement material flow meter 41 is an electromagnetic flow meter for detecting the flow rate per unit time when the ground improvement material 45 is sent by the pump 43. The start switch 49 is a start switch when the operator of the cab 4 of the ground improvement machine 1 starts ground improvement work, and the start switch 49 is pressed for each ground improvement pillar to start work. When the operator presses the start switch 49, the pressurized ground improvement material 45 enters the agitation shaft 8 from the swivel joint 15 at the top of the agitation shaft 8 and is discharged from the ground improvement hole 16 at the bottom.

[0021] The above-described ground improvement blade rotation detection system 50 acquires Z-axis rotation data of the rotation prevention blade 12 offline and monitors the quality of the ground improvement column, roughly according to the procedure shown in Table 1 below. That is, when transmitting the Z-axis rotation data detected by the rotation detection unit 20 arranged on the rotation prevention blade 12 to the rotation evaluation control device 30, communication is unstable or impossible when the rotation detection unit 20 of the rotation prevention blade 12 is underground, so the data is stored in the memory 23 of the rotation detection unit 20. Then, when the rotation prevention blade 12 comes above ground and stable communication is possible, the Z-axis rotation data from the time when the rotation prevention blade 12 was underground is wirelessly transmitted to the rotation evaluation control device 30.

[0022] [Table 1]

[0023] [Outline of control operation of the companion evaluation control device 30] FIG. 6 is a flow diagram showing an outline of the control operation of the feed-rotation evaluation control device 30. The feed-rotation evaluation control device 30 mainly acquires data required to obtain diagrams and data tables as exemplified in FIG. 4 and FIG. 5 described later, and performs calculation processing to analyze the quality of the constructed ground improvement column 59 (see FIG. 5). When the excavation blade 10 is located at the start depth position 56 and the start switch 49 of the ground improvement machine control device 35 shown in FIG. 3 is pressed by the operator (S1), the clock of the feed-rotation evaluation control device 30, the ground improvement machine control device 35, and the clock of the feed-rotation detection unit 20 are synchronized or time-adjusted (S2). At the same time, the feed-rotation evaluation control device 30 issues a command to the MCU 21 of the feed-rotation detection unit 20 to record data on the Z-axis rotation of the feed-rotation prevention blade 12 in the memory 23 (S3). The depth at which the start switch 49 is pressed by the operator is the start depth position 56 at which ground improvement is started (see FIG. 5).

[0024] When the excavation wing 10 reaches the deepest position 58 according to the data from the soil improvement machine control device 35, the excavation axis 8 is reversed and raised in the Z-axis direction, and when it reaches the end point (start depth position 56) 56 (FIG. 5) which is the end position of the soil improvement (S4), the supply evaluation control device 30 receives the data in the memory 23, which is the data of the gyroscope 22, via the wireless module 24 (S5). Furthermore, necessary information such as the rotation speed of the stirring axis 8, the movement amount of the Z-axis, and the input amount of the soil improvement material are obtained from the soil improvement machine control device 35 at any time or all at once (S6). Calculations are performed from the obtained data, and figures and tables such as those in FIG. 4 and FIG. 5 described later are displayed on the display and presented to the operator, construction manager, etc. In addition, if necessary, a time stamp is transmitted.

[0025] [Example of ground improvement construction] FIG. 4 is a diagram of an example of construction data when ground improvement is performed using a ground improvement machine. In FIG. 4(a), the vertical axis indicates the rotation speed (rpm) of the stirring shaft 8 and the anti-rotation blade 12, and the horizontal axis indicates time (min). In the diagram of FIG. 4(b), the vertical axis indicates the rotation angle (°) of the anti-rotation blade 12, and the horizontal axis indicates time (min). In the example diagram of FIG. 4, it is shown that the anti-rotation blade 12 rotates for a certain period of time during the forward and reverse rotation of the stirring shaft 8. The operator positions the excavation blade 10 when performing ground improvement using a GNSS (Global Navigation Satellite System) mounted on the ground improvement machine 1, determines the start position for ground improvement, and starts ground improvement from this position. This start position for ground improvement may be started at a position marked on the ground surface toward the operator using a total station or the like.

[0026] When the position on the ground surface is determined, the agitation shaft 8 is set vertically (Z-axis). When the excavation blade 10 reaches the start depth position 56, which is a preset ground improvement start depth slightly lower than the ground surface, the start switch 49 is pressed to start the ground improvement. When the start switch 49 is pressed, the solenoid valve (not shown) opens, and the ground improvement material 45 pressurized by the pump 43 is sent, and the ground improvement material 45 passes through the hollow agitation 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 numerical values ​​of the construction example shown in Figure 4. As shown in Figure 5, in the improvement column 59 of this ground improvement example, when the improvement column 59 reaches the deepest position 58, which is the maximum set depth, the operator rotates the agitation shaft 8 in the reverse direction to agitate and pulls it up to the start depth position (end point) 56.

[0027] In the display example shown in FIG. 5, the section flow rate (L), section cut number (Rev), and supply rate (%) of the ground improvement material per unit depth section of the ground improvement column 59 are shown as numerical values. That is, the "section flow rate (L)" indicates the flow rate of the ground improvement material per unit depth section of the ground improvement column 59, the "section cut number (Rev)" indicates the number of agitation of the agitator blade 14 per unit depth section of the ground improvement column 59, and the "supply rate (%)" indicates the supply rate between the agitator shaft 8 and the supply rate prevention blade 12. The diagrams and tables shown in FIG. 4 and FIG. 5 can be viewed by the operator or supervisor during construction. Therefore, when the section flow rate (L), the section cut number (Rev), and the supply rate (%) do not reach the preset allowable range, re-construction can be performed immediately at a stage when the ground improvement material has not hardened.

[0028] [Wireless module communication example] FIG. 7 is a flow diagram showing an overview of data transmission and reception when "Bluetooth" is used for the wireless module. The reader 5 of the ground improvement machine 1 is set vertically, and the center of the stirring shaft 8 is aligned with the center of the ground improvement hole 16 to be improved. After this positioning is completed, the operator presses the start switch 49 to start ground improvement. By pressing this start switch 49, the ground improvement machine control device 35 is started, and the ground improvement machine 1 is in a state where it can operate. That is, the stirring shaft 8 rotates, the ground improvement material 45 is discharged, and the ground improvement can be started. In this state, the operator performs various recording settings for recording the rotation data of the rotation prevention blade 12 with the rotation detection unit 20 of the rotation prevention blade 12 from the rotation evaluation control device 30 (S1). As can be understood from this explanation, the operator issues a command before starting improvement for each ground improvement hole 16 unit.

[0029] Next, the operator selects the child device to be connected and performs the settings required for pairing (S2). That is, the operator sets items such as data and conditions required for pairing between the wireless module 24, which is the child device in the supply detection unit 20, and the wireless module (not shown, hereinafter also referred to as the "parent device") in the I / F 31 of the supply evaluation control device 30 (S2). This pairing refers to the registration of the parent device and the child device in the Bluetooth device and having them recognize each other, and the purpose of this is to ensure the safety of communication between the devices, and in principle, communication by Bluetooth devices cannot be used unless pairing is performed.

[0030] Then, on the screen (not shown) of the ground improvement machine control device 35, a record start switch for recording ground improvement data is pressed by the operator (S3). Next, the record start switch is commanded to the supply evaluation control device 30 to command the supply detection unit 20 to start recording supply data (S4). After this command from the supply evaluation control device 30, the supply evaluation control device 30 judges whether the above-mentioned pairing between the wireless module 24, which is the child device, and the wireless module of the parent device has been successful (S5). If the pairing has not been successful, the supply evaluation control device 30 notifies the operator by displaying the result on a display or the like or by issuing an alarm (S6). If the pairing has been successful, the supply evaluation control device 30 commands the time data of the parent device and the child device to be synchronized by time stamps (S7). The rotation evaluation control device 30 acquires various ground improvement data from the ground improvement machine control device 35, and the rotation detection unit 20 starts recording the rotation data of the rotation prevention blade 12 (S8 to S9).

[0031] The operator judges whether or not recording of various ground improvement data has been completed based on the construction status of the ground improvement machine 1 (S10). If various data of the ground improvement machine 1 and the supply data from the detection unit 20 have not been obtained, the process returns to S8, and the ground improvement data and the supply data are acquired. If recording of these data has been completed, the ground improvement machine control device 35 executes data storage (S11). Note that, after pairing and synchronizing the parent machine and the child machine, if communication cannot be ensured, the supply data is automatically stored in the local memory 23. Communication between the parent machine and the child machine is not necessarily performed when they are on the ground. If communication is possible, communication may continue even when the child machine is underground. In this way, in this embodiment, the supply data can be safely recorded and stored even if communication between the parent machine and the child machine is interrupted when the stirring shaft 8 is underground.

[0032] When the storage of the necessary data for various ground improvement is completed (S11), the supply evaluation control device 30 commands the downloading of the supply data of the supply prevention blade 12 measured by the supply detection unit 20 (S12). Next, when the excavation blade 10 is underground, communication is usually cut off, and when the excavation blade 10 comes up close to the ground, it is determined whether or not the child machine paired in S2 has been reconnected (S13). If the connection has not been reconnected, the download is performed manually (S14). If the download cannot be performed manually or is not performed, it is determined again whether or not the child machine has been reconnected (S15). If the connection has not been reconnected, it waits for reconnection, and if reconnection is possible, the next supply data is downloaded (S16). After that, the ground improvement machine control device 35 downloads the supply data from the child machine to the parent machine, and creates a combination processing table of the data of the ground improvement machine 1 and the supply data (for example, see FIG. 5).

[0033] [Housing 60 of the feeding detection unit 20] FIG. 8 is an external view showing a housing in which the accompaniment detection unit 20 is stored. FIG. 9 is a partial exploded view of the housing 60 in FIG. 8. The accompaniment detection unit 20 (see FIG. 3) is stored in the housing 60. The accompaniment detection unit 20 mounted on the accompaniment prevention wing 12 is an electronic circuit, so it needs to be completely protected by the housing 60 when it is underground so as not to be exposed to excavated soil, ground improvement material 45, etc. For this reason, the housing 60 is made of a strong, highly wear-resistant metal material. The material of the housing 60 in this example is steel material such as carbon steel for mechanical construction. The housing 60 made of a metal material physically protects the electronic devices inside and acts as an electromagnetic shield to block electromagnetic waves. On the other hand, the wireless module 24 (child unit) including an antenna (not shown) in the accompaniment detection unit 20 in the housing 60 performs wireless communication with the parent unit (31), so it is necessary to perform the communication smoothly, but the wireless module 24 also needs to have a function for smooth wireless communication with the parent unit.

[0034] In this example, the main body 61 of the housing 60 has a box-like shape with an empty rectangular parallelepiped inside, and the rotation detection unit 20 is stored inside. A fixing flange 62, which is the base of the main body 61, is fixed to a front surface 66 of a fixing jig 65 with bolts and nuts 68. The fixing jig 65 is fixed to a bracket (not shown) that forms a pair with the fixing jig 65 on the outer periphery of the central axial tube 19 of the rotation prevention blade 12 with bolts and nuts 67. The main body 61 opens in the radial direction of the central axial tube 19, and a flange 63 having an outer shape larger than the opening is formed on the outer periphery of this opening. An O-ring groove is formed on the front surface of the flange 63 on the outer periphery of the opening, and an O-ring 64 is inserted into the O-ring groove. A spacer 70 made of a plate material made of engineering plastic is disposed on the front surface 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 above-mentioned wireless communication.

[0035] A metal protective plate 71 made of steel or the like and having the same outer shape as the spacer 70 is fixed to the flange 63 of the main house 61 together with the spacer 70 by bolts 72 on the front surface 73 of the spacer 70. The protective plate 71 can also be said to be a cover for preventing the spacer 70 from being exposed to excavated soil, ground improvement material 45, etc. Since the protective plate 71 is on the front surface 73 of the spacer 70, only the outer peripheral surface 74 is exposed to the excavated soil, ground improvement material 45, etc. As can be understood from the above explanation, since the synthetic resin spacer 70 has the metal protective material 71 fixed to its front surface 73, only the outer peripheral surface 74 is exposed to the excavated soil and ground improvement material even when it is underground.

[0036] [Spacer 70 area and outer periphery area] As described above, the spacer 70 of this embodiment is made of synthetic resin, even though it is an engineering plastic, and is vulnerable to wear and tear when exposed to excavated soil, ground improvement material 45, and the like. On the other hand, it is necessary to function as a window for radio waves. In order to minimize the exposed area of ​​the outer peripheral surface 74 of the spacer 70, the area of ​​the outer peripheral surface 74 must be made as small as possible, although there is no problem since the front surface 73 of the spacer 70 is protected by the protective plate 71. However, if the area of ​​the outer peripheral surface 74 is made too small, it will not function as a window for radio waves. Below, we will explore the general relationship between the area of ​​the front surface 73 and the area of ​​the outer peripheral surface 74 of the spacer 70 for each outer shape. (1) Spacer 70 is circular When the spacer 70 for the radio wave window closing the opening of the housing 60 is a circular spacer 75 shown in FIG. 10, the difference in area between the front surface and the outer circumferential surface is as follows. S = (1 / 4) πD 2 where S is the area of ​​the front surface of the circular spacer 75, and D is the diameter of the circular spacer 75. The area S' of the outer circumferential surface of the circular spacer is given by: S'=π D t where t is the thickness of the circular spacer 71 The area of ​​a non-metallic radio wave window, i.e., the exposed area exposed to the ground, should be small. 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 of the radio wave window closing the opening of the housing 60 is a 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 of the radio wave window closing the opening of the housing 60 is a 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, in order 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 the protective material 71, which is a metal material, a desk test was conducted to see whether communication between the wireless communication device in the main body 61 and the external wireless communication device is possible. For example, when using Bluetooth, the frequency band is 2.4 GHz, so if an opening of 63 mm or more, which is half the wavelength of the same frequency, can be secured as a radio wave window, sufficient radio wave strength can be obtained. Although the thickness of the spacer 70 is thin, the outer peripheral surface is long, so it functions as a radio wave window. FIG. 13 is an explanatory diagram showing an outline of a desk communication test method for measuring radio wave strength. The communication standard was Bluetooth, and communication was performed with the distance between the parent unit installed on the ground and the housing 60 (with the child unit built in) of the companion detection unit 20 set to about 2 m, and the power of the radio wave was measured. The results are shown in Table 2 below. The resin window is a radio wave window, and does not have a protective plate 71, but is a resin plate made of MC nylon, with a cover 80 covering the front opening of the housing 61. [Table 2] In the results of this desk experiment, the power was measured for (1) one without 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 to 4, MC Nylon (registered trademark, thicknesses 5 and 10 mm), and Duracon (registered trademark, thicknesses 5 and 10 mm)). Fig. 14 is a front view and a side view showing the outer shape and dimensions of spacer 70 used in the experiment. The MC nylon used was "MC901" (manufactured by Mitsubishi Chemical Advanced Materials Corporation (headquarters: Tokyo)), and the Duracon used was "TF-10LV" (manufactured by Polyplastics Co., Ltd. (headquarters: 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 is no clear difference in the strength of the radio wave between Comparative Examples 1 and 2 and Experimental Examples 1 to 4. In other words, there is almost no difference in the radio wave strength of transmission and reception between the above (1) which does not have the protective plate 71 and spacer 70 that would be an obstacle to wireless communication, the above (2) which does not have the protective plate 71 and only has a resin lid, and the above experimental example (3), and the thickness of the spacer 70 does not have an effect either. Therefore, this desk experiment revealed that even the plate-shaped spacer 70 which is covered with the protective material 71 that serves as a window for radio wave communication and has only the outer periphery exposed to the outside can function as a window for radio waves.

[0040] [Other embodiments] In the above-described embodiment, the outer shape of the spacer 70 is described as a circle, 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 a circle, a regular polygon, or a rectangle, and may be an irregular shape that is a combination of these. In the above-described embodiment, the material of the spacer 70 is a synthetic resin that transmits radio waves, but it is not limited to a material reinforced by metal fibers or the like, and may be glass, ceramics, rubber, or the like that is airtight and wear-resistant as long as it transmits radio waves. [Explanation of symbols]

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

Claims

1. A stirring shaft that is rotated by a rotary drive device and has a discharge hole for discharging a ground improvement material into the ground to form a ground improvement column; A mixing blade fixed to the mixing shaft for mixing the excavated soil and the ground improvement material in the excavated hole in the ground; A drilling blade provided at an end of the stirring shaft on the ground bottom side and having a plurality of drilling blades for drilling the drilled hole; a rotation prevention blade that is rotatably provided on the stirring shaft between the stirring blade and the excavation blade, and during the excavation, an outer peripheral end portion engages with the peripheral wall of the excavation hole to stop rotation, and rotates relative to the rotation of the stirring blade and the excavation blade to mix and stir the excavated soil together with the ground improvement material; A sensor disposed in a co-rotation detection unit in the co-rotation prevention blade for detecting co-rotation data which is the relative rotation between the stirring shaft and the co-rotation prevention blade; a data recording means disposed on the anti-rotation wing for recording the relative rotation detected by the sensor within the borehole during ground improvement work; In the ground improvement device, a metal housing having an opening on one side, housing the rotation detection unit therein, and shielding against electromagnetic waves; a spacer that closes the opening, is fixed to the housing, and is a plate made of a material that transmits the electromagnetic waves; a metal protective plate that exposes an outer peripheral surface of the spacer to the outside and covers a front surface of the spacer to protect the spacer from the excavated soil and the ground improvement material; A ground improvement blade co-rotation detection device comprising:

2. In the ground improvement blade rotation detection device according to claim 1, The outer shape of the spacer is at least one selected from a circle, a regular polygon, and a rectangle. A ground improvement blade co-rotation detection device characterized by the above.

3. The ground improvement blade rotation detection device according to claim 1 or 2, The spacer has an exposed area of ​​the outer circumferential surface that is larger than a protected area of ​​a protection plate that protects the front surface. A ground improvement blade co-rotation detection device characterized by the above.

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

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

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