JPH01219210A - Apparatus for improving soft and weak ground - Google Patents

Abstract

PURPOSE: To extremely simplify a structure, to reduce a manufacturing cost, and to remarkably improve creating work of the ground by connecting at least two auger shafts to a single driving device via a branch transmission device. CONSTITUTION: A weak ground improvement device 1 is composed of a driving device 2, a branch transmission device 4, a rotary main shaft 3 for connecting both devices, plural distribution boxes 14, 15, 16 into which the rotary main shaft and left/right auger shafts 21, 22 are respectively inserted, agitating blades 23 arranged on the left/right auger shafts 21, 22, excavating heads 24 and the like. A motor of the driving device 2 is driven, and the rotary main shaft 3 is normally rotated via a speed reducer. Thus, while the left auger shaft 21 rotates rightward, since the right auger shaft 22 rotates leftward, the left/right excavating heads 24, 24 excavate the weak ground while mutually rotating in the inverse direction.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is a method for improving soft ground by excavating soft ground such as the estuary area of a river, and injecting a soil stabilizer into the excavated ground. Regarding improved equipment.

(Prior Art) As a soft ground improvement device, conventionally, a drive device is fixed to a frame, and the upper end of a chemical injection pipe for injecting a chemical solution such as a soil stabilizer is connected to this drive device, and the chemical solution is injected. A soft ground improvement device is generally known in which a pipe is inserted through the frame and hangs down. This device has an injection port at the top end of the chemical injection tube, a spout port at the bottom end, a plurality of stirring blades at the bottom, and an auger head at the bottom end to remove soft soil. It enables drilling, stirring, and chemical injection.

However, this type of soft ground improvement equipment stirs and mixes the chemical solution and excavated soil simply by rotating the stirring blade installed in one chemical injection pipe, so the area is limited according to the size of one stirring blade. When improving the ground over a vast area, the number of times the chemical injection pipe must be raised and lowered increases significantly, and the construction work requires a great deal of time and expense.

Therefore, at least two drive devices and reducers are installed on the mounting frame, and the upper end is fixed to the mounting frame, while an auger rotation shaft with a plurality of stirring blades is provided at the lower part, and A soft ground improvement device has been proposed that is attached to the pipe and is equipped with a chemical injection pipe that hangs down and has a chemical injection port at its upper end and a chemical injection nozzle at its lower end.

(Problems to be Solved by the Invention) However, this type of soft ground improvement device is equipped with two auger rotating shafts equipped with stirring blades, so it is possible to improve the work efficiency of soil improvement. However, since a drive device, a speed reducer, etc. are required for each auger rotating shaft, and a chemical injection tube is provided separately, the entire device becomes complicated and the manufacturing cost becomes high. Furthermore, since there are multiple drive devices, the amount of energy used during excavation work cannot be ignored. Moreover, the drive device, auger rotation shaft, chemical injection tube, etc. are firmly fixed to the mounting frame, so
It was difficult to disassemble or assemble each part for repair work or maintenance at the work site.

The present invention was made in view of the above-mentioned problems, and an object of the present invention is to provide a soft ground improvement device that efficiently stirs and mixes soil and chemical solution, has a simple structure, and is easy to disassemble and assemble at a work site. It is said that

(Means for Solving the Problems) In order to solve the above problems, the present invention has an upper end of a rotating main shaft rotatably connected to a drive device, and a lower end of the rotating main shaft is connected to a drive device for branch transmission via a coupling. Extended to the equipment,
The branch transmission device includes a box with a lid attached to a main body case, and a rotation transmission mechanism housed in the box that transmits the rotational force of the rotating main shaft to at least two auger shafts. A distribution box for feeding a chemical solution is fixed to the lower surface of the transmission device via bolts, and the lower end of the rotating main shaft and the upper ends of the auger shafts are inserted into the distribution box, and each of the auger shafts It hangs down from the branch transmission device via a coupling, has a hollow hole in its center, and forms an inlet communicating with the distribution box at its upper end,
It is characterized by having a jet orifice formed at the lower end, and equipped with stirring blades and a drilling head.

(Operation) The soft ground improvement device is positioned at a predetermined excavation position, the drive device is driven to rotate, and the left and right auger shafts are rotated in opposite directions via the rotating main shaft to penetrate into the soft ground to a predetermined depth. do. Next, a chemical solution such as cement milk is pumped through the distribution box into the hollow holes of the left and right auger shafts, and is injected into the soil from the spout. Next, while stirring and mixing the injected chemical solution and the soil using a stirring blade, the left and right auger shafts are gradually pulled out, thereby forming a columnar region solidified by the chemical solution in the soft ground.

(Example) Embodiments of the present invention will be described below based on the drawings.

The soft ground improvement device l is shown in FIGS. 1 to 6, and is suspended from a cap 30 fixed to a leader 28 of a crawler crane 27, and is moved up and down along a guide rail 29 of the leader 28. A drive device 2 and a branch transmission device 4 that are freely installed, a rotating main shaft 3 that connects the two devices,
It is equipped with a plurality of distribution boxes 14, 15, 16 into which the rotating main shaft and the left and right auger shafts 21, 22 are inserted, respectively, and a stirring blade 23, a drilling head 24, etc. arranged on the left and right auger shafts 21, 22. It is composed of

The drive device 2 includes a casing 2 shown in FIGS. 1 and 2.
The motor with a speed reducer is housed in a and is installed coaxially with the rotating main shaft 3, and is configured to rotate left and right auger shafts 21 and 22 via a rotation transmission mechanism 6, which will be described later, when driven. The casing 2a is divided into upper and lower parts,
A closed chamber 2b is formed in the upper part, while a motor and a speed reducer are integrally incorporated in the lower part, although not shown. A hook 2C is provided protruding from the top surface, and an end portion of a wire 31 stretched through a pulley of a capacitor 30 is fixed to this hook. Also, casing 2
A guide plate 2d that slides on the guide rail 29 of the leader 28 is provided on the back surface of the wire 28, and the drive device 2 can be moved up and down by winding or feeding out the wire 310. The sealed chamber 2b is a chemical liquid unit for feeding a chemical liquid such as cement milk, and the upper end side of the rotating main shaft 3 having an inlet 3b extends into the sealed chamber. A flexible hose 33 is connected to this sealed chamber 2b through an inlet provided on the back side of the casing 2a, and the cement milk fed under pressure from a chemical liquid feeding device (not shown) is transferred to the rotating main shaft 33. It is possible to feed it to the inlet port 3b side.

The rotating main shaft 3 has a hollow hole 3a at its center, and an inlet 3b communicating with the hollow hole is formed at the upper end, and an outlet 3C is formed at the lower end.

The intermediate portions are connected by an upper coupling 3d with bolts and nuts, allowing for disassembly and assembly.

As shown in FIG. 3, the branch transmission device 4 includes a gear box 59 and a rotation transmission mechanism 6. The gear box 5 includes a substantially rectangular main body case 5a and a flat cover body 5.
A cover body 5b is fixed to the upper surface of the main body case 5a via a pin 5c, and has an internally sealed waterproof structure. A guide plate 5d that slides on the guide rail 29 is provided on the back side of the gear box 5 (see FIG. 1), and the branch transmission device 4 can move up and down in conjunction with the drive device 2. . In addition, a plurality of shaft holes are formed in the upper and lower surfaces of the gear box 5, and the rotation main shaft 3. The left and right auger shafts 21, 22 and the intermediate shaft 6a are inserted at a predetermined interval. In other words, the distance between the rotating main shaft 3 and the left and right auger shafts 21 and 22 is the same! ! ,,! ! , are kept equal and arranged parallel to the axial direction, and the rotation main shaft 3
An intermediate shaft 6a is disposed between the left auger shaft 21 and the left auger shaft 21.

The rotation transmission mechanism 6, as shown in FIGS. 3 and 4,
It is comprised of a gear train 7 housed in the gear box 5, left and right thrust bearings 8 and 9 disposed on the upper and lower surfaces of the gear box 5, a plurality of radial bearings 13, and the like. In the gear train 7, a first gear 7a is fixed to the upper part of the rotating main shaft 3, meshes with a second gear 7b, and rotates clockwise as shown in the schematic diagram of FIG. The second gear 7b has the same diameter and the same number of teeth as the first gear 7a, and is fixed to the right auger shaft 22.
The right auger shaft 22 is rotated to the left by rotating in the opposite direction. The third gear 7C is fixed to the lower side of the first gear 7a,
It meshes with the fourth gear 7d.

This fourth gear 7d is fixed to the intermediate shaft 6a and is a fifth gear.
It meshes with gear 7e and rotates counterclockwise in conjunction with third gear 7C. The fifth gear 7e has the same diameter and the same number of teeth as the third gear 7C, is fixed to the left auger shaft 21, and rotates clockwise in conjunction with the fourth gear 7d.

With the above configuration, when the rotating main shaft 3 rotates clockwise, the first to fifth gears 7a to 7e are driven, and the left and right auger shafts 21.
22 in opposite directions.

The left and right thrust bearings 8, 9 are mounted in a bearing box 10. as shown in FIG. It is comprised of a thrust bearing 11 and a figure nut 12. The bearing box 10 has an elongated hole in its periphery, and is firmly fixed to the lid 5b by a port 10e and a nut inserted into the elongated hole. A recessed fitting portion 10 of a different diameter is provided on the inner circumferential wall of the shaft hole 10a.
b, and a thrust bearing 11 is interposed between this recessed fitting portion and the different diameter stepped portion 21e of each auger shaft 21,22. This thrust bearing is conventionally known, and the lower surface 11b
is in sliding contact with the slip ring loc fitted on the inner circumferential wall of the recessed fitting part 10b, while the upper surface 11a is in sliding contact with the shaped nut 12.
is in contact with. This figure-shaped nut prevents the thrust bearing 11 from coming off, and is provided with an internal thread, and has a pin-shaped engagement claw 12a protruding from its upper surface, while its lower surface is formed into a tapered shape. . And this figure nut 12 is
The different diameter portions 21f and 22f of the left and right auger shafts 21 and 22 are screwed together. To explain the left auger shaft 21 in detail according to FIG. 5, the left auger shaft has a different diameter portion 21f formed at the top, a male thread 21g, and a concave cross section along the axial direction. An engagement groove 21h is provided.

Thus, the cut nut 12 is attached to the outer thread 2 of the different diameter portion 21f.
1g, and at the position where the lower surface touches the thrust bearing 11,
The engaging claw 12a is bent and engaged in the engaging groove 21h. As a result, the cut nut 12 is prevented from rotating.
Dislodgement of the thrust bearing 11 and vertical movement of the left auger shaft 21 are suppressed. A dust seal 10d is fitted into the upper part of the shaft hole 10a of the bearing box 10, and the left and right thrust bearings 8, 9 have an internally sealed waterproof structure. With the above configuration, the left thrust bearing 8 pivotally supports the left auger shaft 21, while the right thrust bearing 9 rotatably supports the right auger shaft 22.

The radial bearing 13 is a conventionally well-known bearing,
Gear box 5 and distribution box 1 as shown in FIG.
4.15.16, it is firmly fixed through bolts 13i. That is, the first
The rotating main shaft 3 is pivotally supported by a radial bearing 13a, a second radial bearing 13b fixed to the center of the lower surface of the main body case 5a, and a third radial bearing 13C fixed to the lower surface of the central distribution box 14. Also, a fourth radial bearing 13d fixed near the first radial bearing 13a, and a bearing 6b fixed near the second radial bearing 13b.
and supports the intermediate shaft 6a.

A fifth radial bearing 13e fixed to the left side of the main body case 5a, a sixth radial bearing 13f fixed to the lower surface of the left distribution box 15, and the left thrust bearing 8
The left auger shaft 21 is pivotally supported by this. Further, the right auger shaft 22 is rotatably supported by a seventh radial bearing 13g fixed to the right side of the main body case 5a, an eighth radial bearing 13h fixed to the lower surface of the right distribution box 16, and the right thrust bearing 9. It is supposed to be done.

Note that the rotation transmission mechanism 6 is not limited to this embodiment in which a gear train 7 consisting of a plurality of gears is arranged, but sprockets are fixed to the rotation main shaft 3 and the left and right auger shafts 21, 22, and the rotation main shaft 3 and the A toothed belt is stretched between each sprocket of the left auger shaft 21, and the rotating main shaft 3 and the right auger shaft 2
A configuration may also be adopted in which a toothed belt is stretched across each of the two sprockets, and the left and right auger shafts 21 and 22 are rotated in opposite directions. This simplifies the configuration and makes it possible to reduce the weight of the entire device.

The distribution box distributes cement milk to the left and right auger shafts 21.
．． As shown in FIG. 3, the central distribution box 14. It has a structure separated into a left distribution box 15 and a right distribution box 16.

The central distribution box 14 has a substantially cylindrical shape and has a sealed chamber 14a, and a shaft hole 14b through which the rotating main shaft 3 is inserted is formed in the upper and lower surfaces of the sealed chamber. As shown in FIG. 6, flow passages 14c, 14c are formed in the left and right inner walls of the sealed chamber 14a, passing through the inside and outside of each side wall.
Cement milk ejected from the outlet 3C is forced to be fed from the closed chamber 14a to the chemical liquid pressure feeding hose 17, which will be described later, via left and right flow passages 14C, 14c.

Further, a recess 14d is formed in the left and right outer walls, and a tapered internal thread 14e is carved in the inner wall of this recess. The central distribution box 14 is fixed to the center of the lower surface of the main body case 5a via a pin. Further, the upper opening 14f has the second
The radial bearing 13b is arranged to be placed inside.

The left and right distribution boxes 15, 16 are formed interspanically in structure with the central distribution box 14. That is, the left auger shaft 21 is inserted into the shaft hole 15b of the left distribution box 15, and the right auger shaft 22 is inserted into the shaft hole 16b of the right distribution box 16, respectively.

A left distribution box 15 is placed on the left side of the lower surface of the main body case 5a, and a right distribution box 16 is placed on the right side of the lower surface.
g and 16g, respectively. In addition, a flow path 15C and a recess 1 are provided on the right side wall of the left distribution box 15.
5d, a flow path 16G and a recess 16d are also formed in the left side wall of the right distribution box 16. A nipple 18 of a chemical liquid pressure feeding hose 17.17 is threaded into the female thread 15e, 16e of each recess 15d, 16d, thereby forming a sealed chamber 15a of each distribution box 15.16.

16a to the inlet 21 of the left and right auger shafts 21.22
Cement milk can be press-fitted into b and 22b.

Furthermore, the fifth radial bearing 13e is installed in the opening 15f of the left distribution box 15, and the fifth radial bearing 13e is installed in the opening 16f of the right distribution box 16.
A seventh radial bearing 13g is installed inside each of the radial bearings.

In addition, the above-mentioned distribution box is separated into three pieces in this example 1; not limited to, the distribution box is a rectangular box with a waterproof and airtight structure provided with a partition.
A configuration in which cement milk can be distributed by forming sealed chambers divided into two, inserting the rotating main shaft 3 and left and right auger shafts 21 and 22 into each sealed chamber, and forming a flow path that communicates between the sealed chambers. You can also use it as

As shown in FIGS. 3 and 6, the chemical solution pressure feeding hose 17 is connected to a nipple 18. Adapter 19 and hose 20
It is equipped with The nipple 18 has a shaft hole 18a in the center, is tapered at the tip end, and has a male thread 18 on its outer periphery.
b is engraved.

The collar part 18C is in the center, and the nut-shaped part 18 is in the rear end side.
d, and the rotation of this nut-like part causes the internal threads 14e, 15 of each said distribution box 14.15.16 to open.
The external thread 18b of the nipple 18 is screwed and connected to e and 16e. Further, a tapered internal thread 18e is formed at the rear end of the nipple 18. Further, a locking groove 18f is provided deep inside the female thread, and a neck portion 18g is formed that extends toward the rear end of the nipple 18 with the locking groove side as a base end.

The adapter 19 has a shaft hole 19a in the center having a diameter substantially larger than that of the neck 18g, is tapered at the distal end, and has a male thread 19b carved on its outer periphery.

A nut-shaped portion 19C is provided on the rear end side,
By rotating this nut-shaped portion, the male thread 19b of the adapter 19 is threadedly connected to the female thread 18e of the nipple 18.

Note that, as the hose 20, it is preferable to use a reinforced rubber or synthetic resin hose that is flexible and has excellent pressure resistance.

The chemical solution pressure feeding hose 17 with the above configuration is connected to the central distribution box 14. The left and right distribution boxes 15°16 are interconnected. To explain the central distribution box 14, first, the adapter 19 is loosely inserted into the hose 20. Then, the hose 20 is fitted into the neck 18g of the nipple 18, and the end 20a of the hose 20 is fitted into the locking groove 18f.

Next, the nut-shaped portion 19C of the adapter 19 is rotated and tightened, and the hose 20 is tightened and held by the contact force between the neck portion 18g of the nipple 18 and the adapter 19. Subsequently, the male thread 18b of the nipple 18 is screwed into the female thread 14e of the central distribution box 14, and the central distribution box 14 is closed.
The chemical liquid pressure feeding hose 17 is connected to. Note that the same applies to other distribution boxes.

The left and right auger shafts 21 and 22 are two shafts in this example, as shown in FIGS. The structure is as follows.

Each auger shaft 21, 22 has a hollow hole 21a in the center.
, 22a are formed, and inlet ports 21b and 22b are provided at the upper end side to communicate with the hollow holes 21a and 22a, and ejection ports 21C and 22 are provided at the lower end to communicate with the hollow holes 21a and 22a.
C is formed.

As a result, the cement milk pumped from the left and right distribution boxes 15 and 16 is transferred to the inlet 21b.

22b and the spout 2I through the hollow holes 21a and 22a.
It is injected from C and 22C and injected into the soil. Further, the auger shafts 21 and 22 are connected by lower couplings 21d and 22d whose upper parts are connected by bolts, and can be disassembled and assembled freely. The intermediate portion is held by a steady rest 25 to prevent twisting during rotational movement. A holder 25a is protrudingly provided on the steady rest, and the tip of the holder is slidably in contact with the guide rail 29 to hold the steady rest 25 in a cantilevered manner.

Also, at the lower end, connecting bearings 26.2 are provided at predetermined intervals.
Two auger shafts 21 and 22 are provided so that the distance between the auger shafts 21 and 22 is maintained at all times.

The stirring blades 23 include blades and reinforcing ribs, and four sets of three stirring blades are arranged below the left and right auger shafts 21 and 22. The stirring blades 23 have different angles in the vertical direction, and are maintained at a distance that does not interfere with each other. The excavation head 24 includes a wing section and a plurality of claw sections, and is fixed to the shaft ends of left and right auger shafts 21 and 22.

Note that the stirring blades 23 and excavating blades 24 are not limited to the shape or the number of attachments in this embodiment, but can of course be changed depending on the soil quality.

Next, we will explain the improvement work for soft ground.

First, the soft ground improvement device 1 is attached to the leader 28 of the crane 27.
It is attached so that it can be raised and lowered and placed upright at the excavation position in soft ground. Then, the ladder 24 is grounded to the excavation, and excavation is started by the weight of the soft ground improvement device 1. That is, the motor of the drive device 2 is driven to rotate the rotating main shaft 3 in the forward direction via the reducer. As a result, the left auger shaft 21 rotates to the right, while the right auger shaft 22 rotates to the left.
゜24 excavates soft ground while rotating in opposite directions.

Next, when the left and right auger shafts 21 and 22 are penetrated to excavate to a predetermined depth, cement milk is fed under pressure from the chemical supply device and press-fitted into the sealed chamber 2b of the casing 2a through the flexible hose 33. .

The cement milk is pumped into the central distribution box 14 via the rotating main shaft 3, and the left and right chemical liquid pumping hoses 17.17
to the left and right distribution boxes 15.16. Then, the distributed cement milk flows down through the hollow holes 21a and 22a of the left and right auger shafts 21 and 22, and reaches the spout 21c at the end of the shaft.

It is ejected into the soil from 22c.

Subsequently, the left and right auger shafts 21.22 are gradually pulled out while stirring and mixing the cement milk and soil using the stirring blades 23.23, thereby forming columnar regions solidified by the cement milk in the soft ground. This columnar area is
Stirring blades 23 arranged on two auger shafts 21° 22...
Since the area is comparable to that of , the area that can be improved by one vertical movement is large, and even if the area is vast, the work can be done quickly.

By the way, if hardened strata or solid objects such as rocks are present in the soft ground during excavation, a reaction force is generated on the excavation head 24, 24 due to an increase in excavation resistance, and the left and right auger shafts 21, 22
However, since both auger shafts are held by the connecting bearing 26 and the steady rest 25, twisting is prevented. In addition, in a conventional device in which two auger rotation shafts are rotated in the same direction, the reaction force is applied to the steady rest 25.
and its holder 25a, and this holder may be damaged, but in this example, the left and right auger shafts 25a
1.22 are rotated in opposite directions, the reaction forces cancel each other out and are extinguished, thereby avoiding concentration on the holder 25a side and preventing damage. Furthermore, even if vertical vibrations or horizontal vibrations occur during excavation, the left and right auger shafts 21 and 22 have thrust bearings 8 at their base ends and upper shafts.
, 9 and radial bearings 13a..., vertical movement is suppressed and lateral vibration is reduced.

Therefore, shaking, damage, etc. of each component can be prevented.

Next, the disassembly and assembly work of the soft ground improvement device of the present invention will be explained.

First, the soft ground improvement device 1 suspended from the leader 28 is laid down on the ground by loosening the wire 32 and letting it out. When disassembling and transporting each part, remove the bolts of the upper coupling 3d that connects the drive device 2 and the branch transmission device 4 to release the connection, and also
5. Remove the bolts of the lower couplings 21d and 22d that connect the left and right auger shafts 21 and 22 to release the connection. As a result, the drive device 29, the branch transmission device 4, and the two left and right auger shafts 21, 22 each become a single unit, making it easy to transport by truck or the like.

Next, the repair and maintenance of the main parts will be explained. First, regarding the branch transmission device 4, remove the bolts 5C fixed to the gear box 5, and remove the lid 5b from the main body case 5a. Thereby, the gear train 7 and the like of the rotation transmission mechanism 6 housed in the branch transmission device 4 can be easily inspected, oiled, and the like. Next, regarding the distribution box, the nipple 18 of the liquid medicine pressure feeding hose 17.17 connected between the central distribution box 14 and the left and right distribution boxes 15.16 is loosened and removed.

Then, the lower couplings 21d and 22d are removed from the left and right auger shafts 21.22, and the third couplings 21d and 22d fixed to the lower surface of each distribution box 14.15.16 are removed. Remove the sixth and eighth radial bearings 13C913f and 13h. Then, each distribution box 14, 15, 16 fixed to the lower surface of the gear box 5 is removed, and the rotating main shaft 3. From left and right auger shafts 21.22 to distribution boxes 14.15 and 1
6 and remove it from the gear box 5.

As a result, each distribution box 14, 15, 16 becomes hollow, so water jets and high pressure air are sent from the shaft holes 14b, 15b, 16b or the flow passages 14c, 15c, 16c on the side walls, and the closed chambers 14a, 15a, 16a It is possible to remove foreign matter such as solidified cement milk that adheres to the inner wall of the pipe or causes clogging of the flow path. In addition, since the rotating main shaft 3 and the left and right auger shafts 21 and 22 can be easily disassembled, each inlet hole 3b, 21b, 22b and outlet port 3c can be easily disassembled.
, the spout ports 21C, 22C, and the hollow hole 3a.

21a, 22a, etc. can be cleaned, and cement milk clogging and pumping failure can be prevented.

When assembling the soft ground improvement device 1 of this embodiment, most of the main parts can be assembled with bolts, so the assembly work can be done easily and quickly.

FIG. 7 is a side view of a soft ground improvement device showing another embodiment of the present invention.

In this embodiment, the rotating main shaft 3 side is formed long, while the left and right auger shafts 21 and 22 sides are shortened, and the branch transmission device 4 is mounted on the lower side of the crawler crane 27 so as to be vertically movable. The other parts are the same as those in the above embodiment, and the first part in the figure is
The same reference numerals as in the figure are the same. The above configuration further facilitates repair and maintenance work on the ground.

(Effects of the Invention) As explained above, according to the present invention, at least two auger shafts are connected to one drive device via a branch transmission device, so a drive device is provided for each auger shaft. Since there is no need to do this, the structure is extremely simple and the manufacturing cost is low. Additionally, since there is only one drive unit, there is an energy saving effect during excavation work. Furthermore, since a plurality of auger shafts are provided and a distribution box for distributing chemical liquid to each auger shaft is provided, the excavated area in one excavation operation is increased. Therefore, since the amount of stirring and mixing of the soil and the chemical solution increases, the efficiency of the ground preparation work is dramatically improved. And 2
Since the auger shafts of the book rotate in opposite directions to each other, the agitation efficiency of the excavated soil is improved, and the reaction force caused by the excavation head contacting obstacles during excavation work can be energized, so the auger shafts can be rotated in opposite directions. This prevents damage to the holder, etc. Furthermore, the main components such as the drive unit 1 branch transmission device 9 distribution box and auger shaft are easy to assemble, making it easy to disassemble at the work site, and can be separated into multiple pieces for easy transportation. . In addition, since it can be disassembled into small parts, it becomes possible to clean the chemical passages, etc., which was difficult in the past, and it also makes repair and maintenance work extremely easy.

[Brief Description of the Drawings] Figures 1 to 7 show embodiments of the present invention, with Figure 1 being a side view of a soft ground improvement device suspended from a crawler crane, and Figure 2 showing the same device. 3 is a longitudinal sectional view partially showing the branch transmission device and the distribution box, FIG. 4 is a schematic plan view of the rotation transmission mechanism, FIG. 5 is a sectional view of the thrust bearing, and FIG. FIG. 6 is a longitudinal sectional view showing the attached state of the chemical liquid pressure feeding hose, and FIG. 7 is a side view showing another embodiment of the soft ground improvement device. 1... Soft ground improvement device, 2... Drive device, 3...
・Rotation main shaft, 4... Branch transmission device, 5... Gear box, 6... Rotation transmission mechanism, 14.15.16...
Distribution box, 21.22...Auger shaft, 23...
Stirring blade, 24...Drilling head

Claims (2)

[Claims] (1) The upper end of the rotating main shaft is rotatably connected to the drive device, and the lower end of the rotating main shaft is extended to the branch transmission device via a coupling, and the branch transmission device has a lid attached to the main body case. The branch transmission device includes a box attached thereto, and a rotation transmission mechanism housed in the box to transmit the rotational force of the rotating main shaft to at least two auger shafts. A distribution box is fixed via bolts, and the lower end of the rotating main shaft and the upper ends of the auger shafts are inserted into the distribution box, and each auger shaft is suspended from the branch transmission device via a coupling. Soft ground improvement characterized by having a hollow hole in the center, forming an inlet communicating with the distribution box at the upper end, forming a spout at the lower end, and equipped with stirring blades and a drilling head. Device. (2) The soft ground improvement device according to claim 1, wherein the auger shaft consists of two left and right auger shafts, and the left auger shaft and the right auger shaft rotate in opposite directions.