Excavation and mixing equipment and ground improvement method

Abstract

To provide an excavation and mixing device and a ground improvement method capable of forming a good columnar structure. [Solution] The drilling and stirring device 110 of the present invention comprises a drilling blade 203 installed symmetrically with respect to a central axis 200, at least one lateral stirring blade 201, 206 positioned above the drilling blade 203, a co-rotation prevention blade 201 positioned symmetrically with respect to the drilling blade 203 and the lateral stirring blades 201, 206, extending radially outward from the drilling blade 203 and the lateral stirring blades 201, 206, and having stoppers 201f, 201g at both ends that abut the inner wall of the drilled hole, and co-rotation detection sensors 300a, 300b for detecting the co-rotation of the co-rotation prevention blade 210 by the stoppers 201f, 201g at both ends.

Description

Technical Field

[0001] The present invention relates to soil improvement technology, and more particularly to an excavation and stirring device and a ground improvement method for creating improved columns in soil.

Background Art

[0002] When the viscosity of the soil is high (clay or silt), the excavated soil and the solidifying material slurry tend to rotate together as the excavation blades rotate. When the co-rotation phenomenon occurs, the stirring of the solidifying material slurry and the soil becomes insufficient, and a non-uniform improved column in which soil lumps are unevenly mixed is formed. To prevent this, an additional blade called an anti-co-rotation blade is formed on the excavation and stirring device, and it is necessary to further mix the soil that tends to rotate together.

[0003] The anti-co-rotation blade is formed longer than the excavation blade and is rotatably attached to the excavation rod. When the stirring and mixing device is in the ground, the anti-co-rotation blade is longer than the excavation blade, so the tip portion thereof cannot rotate due to the resistance of the peripheral ground of the excavation hole and remains stationary. When the anti-co-rotation blade remains stationary, the anti-co-rotation blade acts like a jam plate of a mixer, and shears and stirs the excavated soil lumps. With such an anti-co-rotation blade, the soil and the solidifying material slurry can be well stirred.

[0004] Many anti-co-rotation blades as described above have been proposed so far. For example, in Japanese Patent No. 2905378 (Patent Document 1), when a second stirring blade provided on an excavation shaft for rotating the stirring blade rotates together with the stirring blade, a plurality of vertical blades rotatably provided on the second stirring blade are forcibly rotated by the anti-co-rotation blade and pseudo teeth, and an excavation and stirring device for performing three-dimensional mixing and stirring with the vertical blades of the stirring blade and the second stirring blade is described. In addition, the applicants of the present application have proposed an excavation and stirring device having a configuration for stirring soil in response to the stationary state of the anti-co-rotation blade in Japanese Patent No. 7217900 (Patent Document 2).

[0005] As the soil excavation progresses, the anti-rotation blades descend along the inner wall of the borehole, becoming embedded in the soil. It cannot be said that the anti-rotation blades are securely fixed in the soil, which affects the quality of soil improvement. Furthermore, the inclination of the excavation and mixing device within the soil also affects the quality of soil improvement. Therefore, it is necessary to detect the state of the anti-rotation blades within the soil. Studies have been conducted to detect the state of the excavation and mixing device within the soil. For example, Japanese Patent No. 7606199 describes a detection device equipped with a gyroscope for detecting the state of the anti-rotation blades (Patent Document 3). Also, Japanese Patent No. 7629669 describes a ground improvement device in which a gyroscope is used as a sensor in a co-rotation detection unit to detect the relative rotation of the anti-rotation blades (Patent Document 4).

[0006] Patent documents 3 and 4 both address the issue of detecting the state of anti-rotation blades, but they detect the rotation of the anti-rotation blades using a gyroscope positioned along the rotation axis, and do not detect the position of the tip of the anti-rotation blade in the soil. Furthermore, they do not detect in real time the discrepancy between the position where the soil should be improved and the position of the excavation and mixing device. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Patent No. 2905378 specification [Patent Document 2] Patent No. 7217900 specification [Patent Document 3] Patent No. 7606199 specification [Patent Document 4] Patent No. 7629669 specification [Overview of the project] [Problems that the invention aims to solve]

[0008] The present invention has been made in view of the above-mentioned prior art, and aims to provide an excavation and mixing device and a ground improvement method that enables the formation of a good ground-forming column by detecting and visualizing the state of the co-rotation prevention blade of the excavation and mixing device in real time along with the position of the excavation axis. [Means for solving the problem]

[0009] This invention was made in view of the problems of the prior art described above. According to the present invention, an excavation and stirring apparatus for excavating and stirring the ground, Drilling blades are installed symmetrically with respect to the central axis, At least one transverse stirring blade is positioned above the drilling blade, A co-rotation prevention blade is provided, which is positioned symmetrically between the drilling blade and the lateral stirring blade, extends radially outward from the drilling blade and the lateral stirring blade, and has stoppers at both ends that abut against the inner wall of the drilled hole. The stoppers at both ends are co-rotation detection sensors for detecting the co-rotation of the co-rotation prevention wing. A drilling and stirring device equipped with the following is provided.

[0010] Furthermore, according to the present invention, a ground improvement method is provided, A method of ground improvement, A process of excavating the ground with an excavation and stirring device equipped with anti-rotation blades having stoppers at both ends that contact the excavation hole, The process involves supplying a solidifying agent to the excavated soil excavated by the excavation blades of the excavation and agitation device, The process involves detecting co-rotation using the co-rotation detection sensor described above and adjusting the construction accordingly. The process of withdrawing the drilling and stirring device from the drilled hole to form a column for ground improvement, A ground improvement method is provided, which includes the following. [Effects of the Invention]

[0011] According to the present invention, there are provided an excavation and agitation device and a ground improvement method capable of forming a good formed column by detecting and visualizing in real time the state of the anti-rotation wings of the excavation and agitation device together with the position of the excavation shaft.

Brief Description of the Drawings

[0012] [Figure 1] FIG. 1 shows an embodiment of a ground improvement method 100 using the excavation and agitation device of the present embodiment. [Figure 2] FIG. 2 shows the excavation and agitation device 110 of the present embodiment. [Figure 3] FIG. 3 shows a partial cross-section of the member configuration of the excavation and agitation device 110 of the present embodiment. [Figure 4] FIG. 4 shows a second embodiment of the excavation and agitation device of the present embodiment. [Figure 5] FIG. 5 is a diagram illustrating the internal structure of stoppers 210f and 210g fixed to both ends of the anti-rotation wings 210 in the present embodiment. [Figure 6] FIG. 6 is a diagram showing an exemplary configuration of the anti-rotation detection sensors 300a and 300b of the present embodiment. [Figure 7] FIG. 7 is a diagram showing an embodiment of visualizing the state of the anti-rotation wings 210 in the ground in the excavation and agitation method of the present embodiment. [Figure 8] FIG. 8 shows an exemplary flowchart of the ground improvement method according to the present embodiment.

Modes for Carrying Out the Invention

[0013] Hereinafter, the present invention will be described based on embodiments, but the present invention is not limited to the embodiments described below. FIG. 1 shows an embodiment of a ground improvement method 100 using the excavation and agitation device 110 of the present embodiment. The ground improvement method 100 in the present embodiment excavates the ground GR with an excavation and agitation device while supplying a solidifying material slurry, and forms a column 120 improved with soil and the solidifying material slurry.

[0014] To explain the excavation method shown in Figure 1, first, the excavation rod 111 is fixed to a rotational force supply mechanism 114 located at the tip of a crane 113 or the like fixed to a work vehicle 112. The excavation and mixing device 110 of this embodiment is attached to the tip of the excavation rod 111, and the ground GR is excavated by rotating this excavation and mixing device 110 while pressing it against the ground GR. In parallel with the excavation, a solidifying agent slurry is supplied from a discharge port formed at the tip of the excavation and mixing device 110 and mixed with the excavated soil to form a cylindrical column 120 for ground improvement inside the excavation hole. In addition, a GNSS sensor 111a for acquiring the position of the excavation rod 111 is installed at the ground-side tip of the excavation rod 111. In this embodiment, the center of the excavation rod 111 can be set as the center of the excavation hole.

[0015] The drilling and mixing device 110 excavates through the ground GR according to the rotation direction indicated by arrow A of the drilling rod 111, and is withdrawn from the ground GR by rotation in the opposite direction. As will be described in more detail later, the drilling and mixing device 110 is formed with a lateral mixing blade, an anti-rotation blade, and a drilling blade. The drilling blade drills through the ground GR while rotating laterally, and the anti-rotation blade prevents the mixed soil in the excavation hole from rotating together with the mixing blade. Furthermore, the anti-rotation blade is made slightly longer than the diameter of the drilling blade, and as the drilling progresses, a stopper (not shown) located at the tip of the anti-rotation blade becomes fixed to the outer edge of the excavation hole, and a vertical rotating member is provided that rotates vertically in synchronization with the rotation of the drilling rod 111.

[0016] The vertical rotating member includes a second radial gear, which is mounted vertically and meshes with a first radial gear, which is fixed horizontally to the drilling rod 111. The vertical rotating member rotates vertically in synchronization with the rotation of the first radial gear during the period when the anti-rotation blades are fixed by the ground GR and provide an anti-rotation function. In addition, a plurality of vertical stirring blades are formed on the surface of the vertical rotating member. During the period when the anti-rotation blades provide an anti-rotation function, the vertical rotating member mixes the solidification slurry with the excavated soil by applying a vertical shear force to the mixture of excavated soil and solidification material and stirring and mixing it along the drilling direction.

[0017] Furthermore, the vertical rotating member does not perform vertical rotation because, during periods when the anti-co-rotation wing does not provide the anti-co-rotation function, it rotates in sync with the rotation of the drilling rod 111, i.e., it rotates together with the first radial gear.

[0018] In this embodiment, horizontal rotation refers to rotation in a direction that crosses the excavation direction, and vertical rotation refers to rotation in a direction that is parallel to the excavation direction. Furthermore, in this embodiment, the solidifying agent refers to a material for improving the ground, and means a composition that appropriately contains cement, bentonite, water glass, kaolin, hardening accelerator, water, etc., and is not particularly limited as long as it has the function of improving the ground.

[0019] After drilling to a predetermined depth is completed, the drilling rod 111 is rotated in reverse and withdrawn from the borehole to form a column 120 for ground improvement within the borehole after the solidification material has hardened.

[0020] The anti-rotation blades of the excavation and mixing device 110 have stoppers formed at both ends to contact the inner wall of the column in the soil and allow the vertical rotating blades to function. Inside both stoppers are housed anti-rotation detection sensors 300a and 300b. The anti-rotation detection sensors 300a and 300b detect the rotation and other conditions of the anti-rotation blades in the ground, i.e., the stoppers of the anti-rotation blades. The detected stopper positions are transmitted to the work vehicle 112 on the ground via wireless or wired communication.

[0021] The ground-based work vehicle 112 is equipped with an information processing device 130 such as a personal computer, tablet, or smartphone, which detects the condition of the anti-rotation wing located underground and adjusts the construction work accordingly.

[0022] Figure 2 shows the drilling and stirring device 110 of this embodiment. The drilling and stirring device 110 comprises lateral stirring blades 201 and 206, a co-rotation prevention blade 210, and a drilling blade 203, which extend radially from a central axis 200. The upper end of the central axis 200 has a chuck mechanism 212 formed thereon for holding it on the drilling rod 111, and the rotation of the drilling rod 111 rotates the drilling and stirring device 110, enabling drilling and withdrawal.

[0023] Furthermore, a center bit 204 is positioned at the tip of the center shaft 200 to maintain the center of the drilling shaft. Between the upper end and the tip of the center shaft 200, drilling blades 203, anti-rotation blades 210, lateral stirring blades 206 and lateral stirring blades 201 are formed in order from the tip. Multiple drilling bits 205 are positioned on the bottom of the drilling hole side of the drilling blade 203 to enable drilling into the ground. The anti-rotation blades 210 are composed of multiple members and apply vertical rotation to the excavated soil with vertical rotating blades, enabling good mixing and stirring with the solidification material slurry. The configuration of the anti-rotation blades 210 will be described in detail later.

[0024] Above the anti-rotation blades 210, two-stage lateral stirring blades 201 and 206 are positioned, inclined with respect to the axial direction of the center shaft 200, to apply lateral shear force to the excavated soil and generate thrust for drilling. Also, near the anti-rotation blades 210 of the center shaft 200, a first radial gear 209 is positioned. The first radial gear 209 meshes with the second radial gears 201c and 210d formed on the vertical rotating members 210a and 210b, applying a balanced vertical rotation force to the vertical rotating members 210a and 210b. Furthermore, a discharge port 215 is formed on the center shaft. A solidifying agent supply member, which passes through the inside of the center shaft 200, is connected to the discharge port 215, and discharges the solidifying agent slurry supplied from the top of the drilling rod 111, enabling ground improvement.

[0025] In the embodiment shown in Figure 2, the first radial gear 209 is positioned below the anti-rotation wing 210. However, the first radial gear 209 can also be positioned above the anti-rotation wing 210, or two first radial gears 209 can be positioned in tandem above and below the anti-rotation wing.

[0026] The configuration of the anti-rotation wing 210 of this embodiment will now be described. The anti-rotation wing 210 is rotatably held between hubs 207 fixed to a center shaft 200, and includes a wing central member (not shown) extending radially from the center shaft 200, vertical rotating members 210a and 210b rotatably arranged on the wing central member, and stoppers 210f and 210g positioned on the side of the anti-rotation wing 210 closest to the ground.

[0027] The inside of the stoppers 210f and 210g is partially or entirely hollow, and the co-rotation detection sensors 300a and 300b are placed inside this hollow. The co-rotation detection sensors 300a and 300b consist of a GNSS receiver, an inertial sensor, and a transmitter, and the information detected by the co-rotation detection sensors 300a and 300b is sent to the information processing device 130 on the ground or via appropriate relay equipment.

[0028] The information processing device 130 uses the received position information to obtain the positions and center positions of the stoppers 210f and 210g in the ground, thereby enabling adjustments to subsequent construction work. In addition, a center detection sensor with a configuration similar to that of the co-rotation detection sensors 300a and 300b can be placed at an appropriate location to detect the center position. The structure of the co-rotation detection sensors 300a and 300b will be described in detail later.

[0029] The vertical rotating members 210a and 210b have second radial gears 210c and 210d formed on the center shaft 200 side and are fixed radially so as to be able to rotate vertically by anti-rotation members 210j and 210k positioned opposite to the ground GR side. The second radial gears 210c and 210d mesh with the first radial gear 209, and when the center shaft 200, i.e., the drilling rod 111, rotates, the rotational force converts the lateral rotational force of the center shaft 200 into a vertical rotational force during the period when the anti-rotation wing 210 is held by the ground and provides the anti-rotation function, causing the vertical rotating members 210a and 210b to rotate vertically.

[0030] Multiple vertical stirring blades 210e are formed on the outer surfaces of the vertical rotating members 210a and 210b. The vertical stirring blades 210e apply a vertical rotational shear force to the soil as the vertical rotating members 210a and 210b rotate, making the mixing and stirring of the solidification material slurry with the ground more efficient.

[0031] Furthermore, the first radial gear 209 and the second radial gear in this embodiment each have a generally flat plate shape, and their gear pitches are equal. Therefore, the rotational speeds of the vertical rotating members 210a and 210b are equal to the rotational pitch of the drilling rod 111. That is, while the drilling rod 111 rotates once, the vertical rotating members 210a and 210b each rotate once in the vertical direction.

[0032] Furthermore, in this embodiment, the first radial gear 209 and the second radial gears 210c and 210d of the anti-rotation wing 210 are always meshed symmetrically, generating rotational torque equally on both sides. As a result, no uneven force is applied to the center shaft 200, enabling smooth excavation, and efficient excavation is also possible without applying unnecessary rotational force to the excavation rod 111.

[0033] Here, we will explain the concept of the number of cuts as an indicator of the quality of ground improvement. The number of cuts (cuts / m) is given by the following formula (1), and it gives an indication of how well the soil for ground improvement has been mixed with the solidifying agent.

[0034]

number

[0035] According to the above formula, the calculation formula for the number of blade cutting cycles includes the shaft rotation speed during drilling as a parameter. The vertical rotating members 210a and 210b of this embodiment rotate in sync with the rotation speed of the drilling rod 11 and further provide efficient vertical rotation with multiple vertical stirring blades 201e. For this reason, the number of co-rotation prevention blades 210 and the vertical stirring blades 210e provided by the co-rotation prevention blades 210, which were not conventionally included as blades subject to the number of blade cutting cycles, can be included in the above formula (1) as the number of stirring blades.

[0036] As a result, while conventionally the anti-rotation blades 210 were excluded when calculating the number of blade breakage cycles, the excavation and agitation device 110 of this embodiment can impart an efficient rotational action to the anti-rotation blades 210 as well, enabling better mixing and agitation.

[0037] Furthermore, the vertical rotating members 210a and 210b receive rotational force through the multiple teeth of the radial protrusions of the first radial gear 209 and the second radial gears 210c and 210d, which allows for a stable increase in rotational torque and enables better vertical stirring.

[0038] Figure 3 is a diagram showing a partial cross-section of the component structure of the drilling and mixing device 110 of this embodiment. A chuck mechanism 212 is attached to the upper part of the center shaft 200, and a solidifying material supply member extends from the center of the center shaft 200 to the discharge port. A center bit 204 and drilling blades 203 are fixed to the lower part of the center shaft 200, and a first radial gear 209 is fixed above them. The first radial gear 209 meshes with second radial gears 210c and 210d formed on the center shaft 200 side of the vertical rotating members 210a and 210b.

[0039] Furthermore, the wing center members 210h and 210i of the anti-rotation wing 210 are fixed to a central portion shaped to surround the center axis 200, for example by welding or bolting, and are rotatably held by the hub 207. The wing center members 210h and 210i have their central portions positioned between the hubs 207 and are fixed rotatably to the center axis 200 by bolting from both sides. Thrust bearings or radial bearings can be appropriately placed between the hubs 207 and the wing center members 210h and 210i.

[0040] Furthermore, fixing bolts for securing the stopper members 210j and 201k are indicated on the ground side of the wing central members 210h and 210i, respectively. Further on the ground side, stoppers 210f and 210g are positioned, forming the anti-rotation wing 210. The lower tips of the stoppers 210f and 210g are formed into blades, which are configured to move up and down while rotating slightly within the borehole as the excavation progresses.

[0041] The implementation shown in Figure 3 is an embodiment in which position information acquired by co-rotation sensors 300a and 300b is transmitted to the ground via wireless communication. Communication lines 320a and 320b extend from the co-rotation detection sensors 300a and 300b, which are located inside the stoppers 210f and 210g, through the wing center members 210h and 210i to the upper end of the hub 207. Transmitters 310a and 310b, connected to the communication lines 320a and 320b, are located at the upper end of each of the hubs 207, and the transmitters 310a and 310b send the detected data to the ground information processing device 130 or an appropriate relay device.

[0042] Furthermore, the reason why detection data is sent from stoppers 210f and 210g to the central hub 207 is that, near the center axis 200, a certain gap exists between the soil and the drilling rod 111, allowing for more efficient wireless communication from within the ground than at other locations. In addition, in the embodiment shown in Figure 3, in order to ensure the propagation of radio waves, a sheath 310c can be placed outside the drilling rod 111, extending in the drilling direction beyond the upper end of the hub 207 to cover the transmitters 310a and 310b, and further extending to the ground. The sheath 111b is fixed to the outer surface of the drilling rod 111 by multiple studs, and moves up and down in conjunction with the drilling rod 111, as well as rotating with the rotation of the drilling rod 111. Since there is no room for soil to enter between the outer surface of the drilling rod 111 and the inner surface of the sheath 111b, this space secures the space for wireless communication. Furthermore, in other embodiments, if the drilling depth is such that radio waves, such as WiFi HaLow, can propagate, communication with the ground can be made from the positions of stoppers 210f and 210g without going through communication lines 320a and 320b.

[0043] There are no particular limitations on the wireless transmission method to the ground using transmitters 310a and 310b; for example, protocols such as Wi-Fi, IWLAN, Bluetooth, LoRaWAN, Trusted Wireless, and Wi-Fi HaLow can be used.

[0044] Figure 4 shows a second embodiment of the drilling and mixing device of this embodiment. The embodiment shown in Figure 4 has the same configuration as the embodiment shown in Figure 3, with respect to the drilling and mixing device 110, drilling rod 111, and sheath 111b. In the embodiment of Figure 4, communication between the co-rotation detection sensors 300a, 300b and the ground receiving device is carried out by wired communication. Communication lines 320a, 320b are inserted into the space formed between the drilling rod 111 and the sheath 111b. The communication lines 320a, 320b extend through the space to the ground and transmit to the ground receiving device. The communication protocol for the communication lines 320a, 320b used in Figure 4 is not particularly limited, and any wired communication method known to date, such as USB, can be used.

[0045] In the embodiment shown in Figure 4, since the communication lines 310a and 310b pass through a continuous space down to the ground, communication can be ensured with the ground even in ground environments where wireless communication is not possible. In this embodiment, the communication lines 310a and 310b up to the upper end of the hub 207 can be separated from the communication lines 310a and 310b above that point, and an electrical contact (not shown) can be placed between them.

[0046] In this embodiment, even if the rotation of the drilling rod 111 and the rotation between it and the anti-rotation blade 210 are not synchronized, the communication lines 310a and 310b up to the upper end of the hub 207 and the communication lines 310a and 310b above that point are separated. Therefore, problems such as disconnection of the communication lines 320a and 320b between the anti-rotation sensors 300a and 300b can be avoided.

[0047] In this case, the outputs of the co-rotation detection sensors 300a and 300b communicate alternately, communicating while in contact and interrupting communication when separated. However, by synchronously analyzing the detection signals, the rotation of the co-rotation detection sensors 300a and 300b can be detected. In this embodiment, the communication lines 320a and 320b may be fixed to the surface of the drilling rod 111.

[0048] Furthermore, if the drilling and stirring device 110 does not have an upper lateral stirring blade 201, the communication lines 320a and 320b can simply be passed through the space between the inner surface of the sheath 111b and the outer surface of the drilling rod 111 all the way to the ground.

[0049] Figure 5 illustrates the internal structure of the stoppers 210f and 210g fixed to both ends of the anti-rotation wing 210 in this embodiment. The inside of the stoppers 210f and 210g is partially or entirely hollow, and the anti-rotation sensors 300a and 300b are housed inside. Electromagnetic wave-transmitting windows 210l and 210m are positioned on the upper parts of the stoppers 210f and 210g to allow reception of radio waves from GNSS satellites or GNSS radio waves from terrestrial positioning systems, for example.

[0050] The electromagnetic wave-transmitting window can be made of a low-dielectric-constant polymer or low-dielectric-constant ceramic. Specifically, polymer compounds such as polyethylene, polypropylene, ABS, and PC-ABS can be used. As for ceramic materials, zirconia, alumina, silicon nitride, silicon carbide, and aluminum nitride can be used. Here, the upper part of stoppers 210f and 210g has relatively little friction with the soil and is oriented in the direction of receiving GNSS radio waves, making it an appropriate location for installing the window.

[0051] Figure 6 shows an exemplary configuration of the co-rotation detection sensors 300a and 300b of this embodiment. The co-rotation detection sensors 300a and 300b are composed of multiple modules, including GNSS antennas 360a and 360b, GNSS receivers 350a and 350b, and inertial sensors 340a and 340b. The co-rotation detection sensors 300a and 300b are also equipped with a battery, such as a lithium-ion secondary battery, to supply power to the above modules.

[0052] The GNSS antennas 360a and 360b are positioned to efficiently receive GNSS radio waves as deep underground as possible, and it is preferable to position them directly below the electromagnetically transparent windows 210l and 210m. The GNSS receivers 350a and 350b receive the GNSS radio waves received by the GNSS antennas 360a and 360b, and send the received data to the transmitters 310a and 310b via the communication interfaces 370a and 370b. The data received by the GNSS receivers 350a and 350b is sent from the transmitters 310a and 310b to a ground relay device or information processing device 130 and used as position information.

[0053] Furthermore, the co-rotation detection sensors 300a and 300b of this embodiment are equipped with inertial sensors 340a and 340b. The inertial sensors 340a and 340b are equipped with a gyroscope, an accelerometer, etc., and use data from the gyroscope and accelerometer to acquire the position of the co-rotation detection sensors 300a and 300b in the ground.

[0054] In this embodiment, it is also possible to implement either a set of GNSS antennas 360a, 360b and GNSS receivers 350a, 350b, or either inertial sensors 340a, 340b. However, GNSS receivers are unsuitable for deep construction because reception within the ground becomes unreliable depending on the depth, and using only inertial sensors 340a, 340b results in inaccurate positioning of the co-rotation detection sensors 300a, 300b within the ground, requiring correction using a reference position.

[0055] To solve the above problems, in this embodiment, it is preferable to equip both GNSS receivers 350a and 350b and inertial sensors 340a and 340b. Specifically, after the start of excavation and mixing work, the positions of the co-rotation detection sensors 300a and 300b are determined based on GNSS information up to a depth where GNSS information can be used. After that, when construction progresses and GNSS information can no longer be acquired, the positions of the co-rotation detection sensors 300a and 300b are determined along with the depth using the data from the inertial sensors 340a and 340b as a reference. This determination method can minimize the error of the inertial sensors 340a and 340b.

[0056] Figure 7 shows an embodiment of the excavation and mixing method of this embodiment, in which the state of the anti-rotation blade 210 in the ground is visualized. The illustrated information processing device 400 can be an information processing device 130 located in the driver's seat of the work vehicle 112. In this embodiment, the information processing device 400 may also be connected to the information processing device 130 via a network and installed synchronously via the network in a construction management office or the like. When the information processing device 130 is installed in a construction management office, the construction status can be displayed on an external large-screen display device 410, allowing multiple people to review the construction while visually observing it.

[0057] The information processing device 130 is composed of information processing elements such as a CPU, RAM, ROM, HDD, and SSD, and operates GNSS analysis applications, numerical analysis applications, and graphics applications by CPU execution under an operating system such as Windows®, IOS®, UNIX®, or LINUX® to perform the visualization of this embodiment.

[0058] The drilling and stirring method of this embodiment will be explained using the visualization information shown in Figure 7. As drilling and stirring progresses and a borehole is formed, the positions of the stoppers 210f and 210g are acquired by the co-rotation detection sensors 300a and 300b, and the corresponding borehole region 430 and center position 440 are calculated by the information processing device 130 or 400.

[0059] The calculated borehole area 430, center position 440, and the positions of the stoppers 210f and 210g are displayed superimposed on the borehole area 420 and center position 450 to be drilled according to the design plan. Along with this, the positions of the stoppers 210f and 210g over time are displayed superimposed on the display device 410. In Figure 6, the white circles shown in the calculated borehole area 430, indicated by the dashed line on the display device, indicate the positions of the respective stoppers 210f and 210g that were detected immediately before at a predetermined measurement interval.

[0060] In the embodiment shown in Figure 7, it is shown that the stoppers 210f and 210g have displaced from their previous positions to their current positions by a predetermined measurement interval. This indicates that the anti-rotation vane 210 rotated during the measurement interval, and the anti-rotation function was impaired. If this displacement is observed to exceed, for example, a set threshold amount, the excavation work conditions can be adjusted by instructing the site or the site to proceed with the excavation work.

[0061] Therefore, in this embodiment, it becomes possible to visualize the status of excavation and mixing work in real time, thereby improving construction quality.

[0062] Figure 8 shows an exemplary flowchart of the ground improvement method 100 according to this embodiment. The method in Figure 8 starts at S100, and the drilling and mixing device is started at S110. At this point, the anti-rotation blades 210 begin to rotate in accordance with the rotation of the drilling rod 111. Next, at S120, the positions of the stoppers 210f and 210g at both ends of the anti-rotation blades 210 are monitored by GNSS and data is acquired. At S130, the latest position of the stoppers, the linear stopper position, and the center position are displayed on the display device 410, superimposed on the design position. Note that when the drilling and mixing device is above ground or rotates in the borehole, as described above, the positions of the stoppers 210f and 210g change in a circular motion as they rotate in accordance with the rotation of the drilling rod 111.

[0063] Next, in S140, it is determined whether or not position information has been received from GNSS receivers 350a and 350b. If position information can no longer be received from GNSS receivers 350a and 350b, it indicates that the depth of GNSS receivers 350a and 350b is no longer suitable for GNSS position measurement. Therefore, if position information can be received from GNSS receivers 350a and 350b (S140: yes), the process returns to S120, and GNSS position information is acquired and construction is managed.

[0064] On the other hand, if position information from GNSS receivers 350a and 350b becomes unavailable in S140 (S140: no), the information processing device 130 or 400 calculates the current positions of stoppers 210f and 210g by accumulating the measured values ​​of inertial sensors 340a and 340b from the time of the last acquired GNSS position information up to the present. It is assumed that the center position is measured by a GNSS sensor 111a installed at the center of the uppermost part of the drilling rod 111. However, it is also possible to separately calculate the center position at the drilling location from the positions of stoppers 201g and 201f at both ends.

[0065] Next, in S160, the positions of the previous stoppers 210f and 210g, the current positions of the stoppers 210f and 210g, and the current center position are superimposed and displayed on the display device. If the anti-rotation wing 210f and 210g rotate together, it is possible to visually confirm on the display device at this point whether the current position of the anti-rotation wing 210 has shifted from the position of the previous anti-rotation wing 210, enabling quick correction.

[0066] In this embodiment, the marks indicating the center position and the positions of the stoppers 210f and 210g displayed on the display device 410 can be displayed in a size corresponding to a predetermined threshold. In other words, if the marks do not overlap, it can be visually determined that the movement has exceeded a predetermined threshold. By using a GUI (Graphical User Interface), it is possible to prevent waste from excessively responding to minute movements and further improve construction efficiency.

[0067] If, in S170, the displacement of the center position, the movement of stoppers 210f and 210g, or both cannot be visually confirmed (S170: no), the process returns to S150 and the method is repeated. On the other hand, if, in S170, the displacement of the center position, the movement of stoppers 210f and 210g, or both can be visually confirmed (S170: yes), in S180, while monitoring the center position and stopper positions, the position and rotation speed of the drilling and mixing device are adjusted to correct the center position and prevent the co-rotation prevention blades 210 from moving.

[0068] Subsequently, if it is not confirmed in S190 that the target depth has been reached based on GNSS data or data from inertial sensors (S190: no), the process returns to S160 and continues excavation, mixing, and display on the screen, continuing the ground improvement method 100. If it is confirmed in S190 that the target depth has been reached (S190: yes), the process ends in S200.

[0069] As described above, the present invention makes it possible to provide an excavation and mixing device and a ground improvement method that can form a good ground surface. Furthermore, the excavation and mixing device 110 of this embodiment is particularly suitable for efficiently excavating and mixing clayey ground containing a large amount of clay, such as Kanto loam, and can provide high constructability and construction quality.

[0070] Furthermore, the drilling and stirring apparatus to which the present invention is applied is not limited to the embodiment, and any drilling and stirring apparatus equipped with anti-rotation blades having stoppers at both ends can be applied without limitation.

[0071] Although the present invention has been described above with reference to embodiments, the present invention is not limited to the embodiments shown in the drawings. It can be modified in any way that is conceivable by a person skilled in the art, including other embodiments, additions, changes, and deletions. Any embodiment that achieves the function and effects of the present invention is included within the scope of the present invention. [Explanation of Symbols]

[0072] 100: Ground improvement method 110: Drilling and mixing equipment 111: Drilling Rod 111a: GNSS sensor 111b: Sheath 112: Work vehicle 113: Crane 114: Rotational force supply mechanism 120: Column 130: Information Processing Device 200: Center axis 201: Horizontal stirring blade 201c: Second radial gear 201e: Longitudinal stirring blade 203: Excavation blade 204: Center bit 205: Drilling bit 206: Horizontal stirring blade 207: Hub 209: First radial gear 210: Anti-rotation wing 210a: Vertical rotating member 210b: Vertical rotating member 210c: Second radial gear 210d: Second radial gear 210e: Longitudinal stirring blade 210f: Stopper 210g: Stopper 210h: Wing center member 210i: Wing center member 210j: Wheel stopper 210k: Wheel stopper 210l: Window 210m: Window 212: Chuck mechanism 215:Discharge port 300a: Co-rotation detection sensor 300b: Co-rotation detection sensor 310a: Transmitter 310b: Transmitter 320a: Communication line 320b: Communication line 340a: Inertial sensor 340b: Inertial sensor 350a: Receiver 350b: Receiver 360a: Antenna 360b: Antenna 370a: Communication interface 370b: Communication interface 400: Information Processing Device A: Arrow line GR:Ground

Claims

1. An excavation and mixing device for excavating and mixing the ground, Drilling blades are installed symmetrically with respect to the central axis, At least one transverse stirring blade is positioned above the drilling blade, A co-rotation prevention blade is provided, which is positioned symmetrically between the drilling blade and the lateral stirring blade, extends radially outward from the drilling blade and the lateral stirring blade, and has stoppers at both ends that abut against the inner wall of the drilled hole. The stoppers at both ends are co-rotation detection sensors for detecting the co-rotation of the co-rotation prevention wing. An excavation and stirring device equipped with the following:

2. A first radial gear fixed to the center shaft near the aforementioned anti-rotation wing, A vertical rotating member is held by the aforementioned anti-rotation wing so as to be able to rotate vertically, and comprises a second radial gear that meshes with the first radial gear on the side of the center axis. The drilling and stirring apparatus according to claim 1, comprising:

3. The drilling and stirring apparatus according to claim 1, wherein the co-rotation detection sensor includes at least a GNSS receiver.

4. The excavation and stirring apparatus according to claim 3, wherein the co-rotation detection sensor includes at least an inertial sensor.

5. A method of ground improvement, A process of excavating the ground with an excavation and stirring device equipped with anti-rotation blades having stoppers at both ends that contact the excavation hole, The process involves supplying a solidifying agent to the excavated soil excavated by the excavation blades of the excavation and agitation device, A step of detecting co-rotation using the excavation and stirring device described in any one of claims 1 to 4 and adjusting the construction, The process of withdrawing the drilling and stirring device from the drilled hole to form a column for ground improvement, Ground improvement methods, including those mentioned above.

6. The process includes a step of applying vertical shear force to the mixture of the excavated soil and the solidifying agent by vertical rotation and stirring it, The ground improvement method according to claim 5, wherein the ground is clayey ground.

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