JPH07122263B2 - Ground improvement method and auger device used for construction of the method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a ground having a small bearing capacity for a structure on the ground by mixing and stirring soil and a solidifying material to increase the bearing capacity. The present invention relates to a ground improvement method for building in a foundation ground with an enlarged excavated bottom and an auger device used for construction of the method.

[Prior Art] Conventionally, a solidified material is injected while excavating the ground having weak bearing capacity, and the mixture is mixed with the excavated soil and stirred to form an independent foundation composed of pillar piles having vertical wall surfaces in the ground, or continuous. A ground improvement method has been known in which a continuous foundation consisting of underground walls is formed to enhance the ground bearing capacity.

Further, as the auger device for constructing the ground improvement method, an auger shaft which is inserted into the ground and driven to rotate, and a bit for excavation attached to a lower end of the auger shaft,
A plate-shaped stirring blade mounted laterally (radially) around the lower part of the auger shaft, and a nozzle part provided in the vicinity of the bit for discharging the solidified material pressure-fed to the feeding passage in the auger shaft. Was formed.

With this auger device, while excavating the ground with a bit, the solidifying material is discharged from the nozzle portion, the auger shaft is driven to rotate, and the solidifying material and excavated soil are mixed and stirred by the plate-shaped stirring blades to solidify. By hardening the material, the foundation consisting of column piles or continuous underground walls was formed.

[Problems to be Solved by the Invention] As a desirable foundation, a bottom portion that disperses the weight of the structure on the foundation on a wide bottom surface, is stable in the ground, and can save required materials and work amount Awaiting the realization of the expanded foundation of

However, the foundation constructed by the conventional ground improvement method is a foundation composed of column piles or continuous underground walls each having a vertical wall surface and does not have a wide bottom surface, and therefore the structure on the foundation is There is a problem that the weight of an object cannot be dispersed on a wide bottom surface and is unstable in the ground.

Further, the conventional auger device for constructing the ground improvement method is for excavating only in the axial direction, has a structure mainly corresponding to the auger shaft thrust load, and the radial load and the moment load were also considered. No auger device was present. Furthermore, an auger device equipped with multiple auger shafts can be constructed continuously for the number of auger shafts by one descent, and excavated soil can be transferred between adjacent auger shafts, making it relatively easy. However, there is a problem in that the excavated soil or the agitated soil and the solidified material co-rotate with the auger, so that the mixed soil of the excavated soil and the solidified material cannot be efficiently mixed and stirred.

The present invention has been made for the purpose of solving the above-mentioned conventional problems, and is an auger device having a plurality of auger shafts, and a ground improvement method for building a foundation with an enlarged bottom in the ground, It is intended to provide an auger device used for construction of the construction method.

[Means for Solving the Problems] The present invention uses a plurality of auger shafts each having a bit at the tip and a stirring member in the middle to excavate and propel the soil in the soil at different angles. And the solidified material sprayed from the auger shaft are mixed and stirred to obtain a foundation with an enlarged bottom in a fan-shaped cross-sectional shape, a fan-shaped cross-sectional shape with a key block, or a tree root-shaped cross-sectional shape. A base portion connected to the lower surface of the front arm so as to be swingable in the front-rear direction, a support member provided at the lower end with an auger shaft support rod vertically fixed to the central lower surface of the base portion, and the base. An auger device is formed by four auger shafts that are rotatably supported on the lower surface of the part, and a hydraulic motor is installed on the base part, and a deceleration interlocked with the hydraulic motor is installed in the base part. Gi And the upper ends of the respective auger shafts are connected to the reduction gears, and the supporting member projects the auger shaft supporting rods in both directions of the lower end portion of the supporting rod vertically fixed to the lower center of the base. And an injection port for the solidifying material is provided above the support rod, the injection port communicates with a flow path that penetrates the center of the support rod to the lower end, and a stopper plug is attached to the lower end opening. While being fixed, branch flow paths branched laterally from the flow path above the lower end opening are provided to extend inside the auger shaft support rod, and each tip of the branch flow path is in front of the auger shaft support rod. Each of the rear surfaces is opened to form a solidified material ejection port, while fixed wing pieces are fixed to both ends of the auger shaft support rod, and the lower part of the auger shaft is supported by the auger shaft support rod. Each of the four bearings penetrating therethrough is provided, and each bearing is Each auger shaft is pierced through, and a bit provided with a large number of excavating blades is fixed at the lower end of each auger shaft in the same phase, and each auger shaft between the base and the auger shaft support rod is A stirring member is fixed to the outer periphery in one step or a plurality of steps, and the bits at the lower ends of the two auger shafts of the auger shafts that are close to the supporting rod are a short sloped surface serving as a central cutting blade and an outer peripheral cutting blade. Is formed in a substantially base shape having a long slope, and is configured to rotate the auger shafts in the same direction by fixing the auger shafts by deviating to the short slope side, respectively. Bits at the lower ends of the two auger shafts located at both ends of the auger shaft are formed in a base shape having slopes of equal length to each other, and the auger shafts are fixed to the central portions of the auger shafts. The supporting rod The auger shafts of the two auger shafts, which are arranged so as to rotate in the opposite directions to the two auger shafts that are close to each other, are closer to the support rod than the agitating member of the bit. A small blade with a rake angle,
A push-out blade having a push-out angle and a balance blade made of a flat plate are fixed at substantially equal angular positions on the outer periphery of the auger shaft in one step or a plurality of steps with different phases, Further, among the auger devices, the agitator members of the two auger shafts located outside are fixed to the plate-shaped agitating blades in one stage or in a plurality of stages with different phases. The above problems were solved by adopting and respectively.

[Operation] According to the present invention including the above method and device, the auger device is excavated and propelled in the soil at different angles, and the excavated soil and the solidifying material are mixed and stirred, whereby the mixture forms an auger shaft support rod. It is prevented by the fixed blades from co-rotating with each bit, and the stirring member further mixes and stirs well to obtain a base with an enlarged bottom.

[Embodiment] In the ground improvement method according to the present invention, a plurality of auger shafts each having a bit at the tip and a stirring member in the middle are used to excavate and propel the soil in different angles. The gist of the present invention is to obtain a foundation whose bottom is enlarged into a fan-shaped cross-sectional shape, a fan-shaped cross-sectional shape with a key block, or a root-shaped cross-sectional shape of a tree by mixing and stirring with a solidifying material sprayed from an auger shaft.

Hereinafter, an example of implementation of the ground improvement method according to the present invention and an auger device used for construction of the method will be described in detail with reference to the drawings.

FIG. 1 is a schematic view showing an auger device for constructing a ground improvement method according to the present invention and a construction state thereof, showing a forward arm A ₂ connected to a base arm A ₁ of a backhoe B as a base machine. An auger device M is attached to the tip.

FIG. 2 is a front view of a main part showing the details of the auger device M, but for convenience of description, it is shown by shortening the vertical direction and reducing the stirring blades from the actual length.

The auger device M comprises a base member 1 connected to the front arm A ₂ of the backhoe B and an auger shaft support rod 2 vertically fixed to the lower central surface of the base member 1 at a lower end thereof.
And four auger shafts 4a to 4d rotatably supported on the lower surface of the base 1.

A hydraulic motor 5 is installed on the base 1, and the rotation of the hydraulic motor 5 is transmitted to a reduction gear (not shown) installed in the base 1 to reduce the speed. The generated rotational force is transmitted to the auger shafts 4a-4d.

The floor plate 6 of the backhoe B and the base arm A ₁ are connected by a _first hydraulic cylinder S ₁ , and the base arm A ₁ can be raised and lowered by the expansion and contraction operation of the piston rod R ₁ , and the base arm A ₁ and the tip Arm A ₂ is the second hydraulic cylinder
Linked by S _2, by expansion and contraction operation of the piston rod R _2, being adapted to be moved along the longitudinal direction of the other party arm A _2, 3 provided further to the other party arm A ₂
The tip of the piston rod R ₃ of the hydraulic cylinder S ₃ is fixed to the upper surface of the base 1, and the piston rods R ₃ fixed to the base 1 are sandwiched between the bases on both sides of the piston rod R _3. A support plate 7 is vertically fixed to the upper surface of the portion 1, and a connecting plate 8 is provided above and below the supporting plate 7 and above and below the lower part of the forward arm A _{2 respectively.} Axis 9 to 8 respectively
Is loosely inserted, each shaft 9 is fixed to the support plate 7 and the front arm A ₂ , and the base 1 and the backhoe B are connected.

The support member 3 is formed by projecting auger shaft support rods 2 on both sides of the lower end of a support rod 10 vertically fixed to the lower part of the base 1. An injection port 11 for injecting the solidifying material from a solidifying material pump (not shown) through a hose is provided in the upper part of the supporting rod 10, and the injecting port 11 penetrates the center portion of the supporting rod 10 to the lower end. The passage 12 is communicated with the channel 12, and a stopper 13 is attached and fixed to the lower end opening 12a of the channel 12.

The auger shaft support rod 2 is provided with bearings 14 that support the lower portions of the auger shafts 4a to 4d, respectively, and fixed wing pieces 15 are extended and protruded from both side edges of the auger shaft support rod 2. Further, a branch flow path branched from the flow path 12 of the support rod 10 in the lateral direction at a position slightly above the lower end opening 12a thereof.
Reference numeral 16 is provided so as to extend inside the auger shaft support rod 2, and each tip thereof is opened to the front and rear surface sides of the auger shaft support rod 2 to form jetting ports 17a and 17b of the solidifying material.

Four connecting shafts 18 connected to gears in the base unit 1 for transmitting the rotation of the hydraulic motor 5 are projectingly provided below the base unit 1, and each auger shaft is attached to each connecting shaft 18. The upper ends of the auger shafts 4a to 4d are connected and fixed, and the lower parts of the auger shafts 4a to 4d are pierced by the bearings 14 of the auger shaft support rod 2.

Bits 20a to 20d having a large number of excavating blades 19 for excavating and propelling soil are fixedly installed at the lower ends of the auger shafts 4a to 4d, respectively, and a stirring member 21 is provided above the auger shafts 4a to 4d. Is fixed. Bits 20a to 20d provided on the auger shafts 4a to 4d are mounted in the same phase as shown in FIG. 3, and do not interfere with each other. , Drilling will be done without leaving any residue.

Among these bits 20a to 20d, the bits 20a and 20b fixedly mounted on the two inner auger shafts 4a and 4b have the support rod 10 positioned between the auger shafts 4a and 4b. , It is impossible to provide each bit 20a, 20b close to each other. As a result, it is considered that the lower part of the support rod 10 cannot be sufficiently excavated, so that the two auger shafts 4a, 4b are rotated in the same direction and the bits 20a, 20b are constantly passed. While changing the direction,
In order to prevent the bits 20a and 20b from colliding and interfering with each other, as shown in FIG.
With a long slope 22b and a substantially base shape, and is formed by being offset to the side of the short slope 22a and fixed to the auger shafts 4a, 4b, respectively, and the side of the short slope 22a serves as the center sweeping blade 23a. , The long slope 22b is used as the outer peripheral cutting blade 23b, the outer peripheral cutting blade 23b is brought closer to the lower surface side of the support rod 10, and the bits 20a, 20b are attached in the same phase as shown in FIG. By the rotation of the auger shafts 4a, 4b, below the support rod 10, when the center sweeping blade 23a of one bit 20a passes, the outer circumferential sweeping blade 23b of the other bit 20b passes, and conversely one bit. When the center sweeping blade 23b of 20a passes, the center sweeping blade 23a of the other bit 20b passes and does not collide with or interfere with each other, and adopts a structure that promotes excavation of soil under the supporting rod 10. ing.

Further, the bits 20c, 20d fixed to the lower ends of the auger shafts 4c, 4d located at both ends have a base shape having slopes 24 of equal length to each other, and the center part thereof is auger shafts 4c, 4d. The auger shafts 4c and 4d are fixed in the same phase as the bits 20c and 20d, and the auger shafts 4c and 4d are formed to rotate in opposite directions to the auger shafts 4a and 4b, respectively.

When the solidification material is injected from the injection port 11 through the flow path 12, when the stopper 13 is attached to the lower end opening 12a, the solidification material is injected from the injection ports 17a and 17b via the branch flow path 16, respectively. It When the stopper 13 is appropriately removed according to the nature of the soil, the solidifying material is also sprayed from the lower end opening 12a. The spouts 17a, 17b are located at positions where a negative pressure is generated by the soil in the rotating direction of the bits 20a-20d, respectively.
Since it is opened on the front and rear sides of each,
It is effective for mixing the solidifying material into the soil without being blocked.

While removing the solidified material from the jet outlets 17a, 17b and further the stopper 13 and jetting it from the lower end opening 12a, the auger shafts 4a-4a
When d is rotated to promote soil excavation, each bit 20a
Bits 2 of soil and solidification material that are drilled and stirred by ~ 20d
Although co-rotating with 0a to 20d, since the inner bits 20a, 20b and the outer bits 20c, 20d rotate in opposite directions, respectively, excavation soil is transferred between adjacent bits 20a to 20d, Further, as the auger shafts 4a to 4b descend into the ground, the mixture of soil and solidifying material rises and collides with the auger shaft support rod 2 acting as a fixed wing without rotating and the fixed wing piece 15 on the outside thereof. Then, the rotation of the mixture is stopped, and the mixture is crushed and mixed well, and the soil mixture is further moved up and mixed and stirred by the stirring member 21.

However, the inner auger shafts 4a and 4b and the outer auger shafts 4c and 4d, which are located on the left and right sides of the supporting rod 10 on the structure side, respectively.
And the auger shafts 4a-4d are kneaded in the shape of a figure of 8 by the stirring members 21 provided in one step or in a plurality of steps with different phases. .

The stirring members 21 of the outer auger shafts 4c and 4d are fixed to the outer auger shafts 4c and 4d by fixing plate-shaped stirring blades 25 in one step or in a plurality of steps with different phases.
The vicinity of 4c and 4d is well stirred. However, the supporting rod 1
Between the inner auger shafts 4a, 4b sandwiching 0, the support rod 10 becomes an obstacle, and the stirring member 21 fixed to each auger shaft 4a, 4b is formed in the same shape as the stirring blade 25 of the auger shafts 4c, 4d. Then,
There is a possibility that the transfer of the mixture cannot be carried out easily and therefore the auger shaft support rod 2 in the vicinity of the support rod 10.
There is a possibility that an unstirred portion may remain on the top.

The stirring member composed of the three blades of the scraping blade 26, the pushing blade 27, and the balance blade 28 prevents the possibility that an unstirred portion remains in the vicinity of the auger shafts 4a and 4b.
21. That is, the three blades are formed at positions that divide the auger shafts 4a and 4b into approximately three equal parts in the circumferential direction.

As shown in FIG. 4, the scraping blade 26 has auger shafts 4a, 4b.
At the tip of the arm 29 whose base is fixed to the auger shaft 4a, 4
It is fixed so as to form an obtuse angle with respect to the rotation direction of b, and the push-out blade 27 has an acute angle with respect to the rotation direction of the auger shafts 4a and 4b at the tip of the arm 30 whose base is fixed to the auger shafts 4a and 4b. The balance blade 28 is fixed to the auger shafts 4a and 4b at the vertical end faces of the flat plate, and the stirring member 21 including these three blades is formed. The outer locus of these three wings is smaller than that of bits 20a, 20b,
The hole walls excavated by the bits 20a and 20b are not roughened. In particular, the outer peripheral locus of the scraping blade 26 is further reduced so that the scraping of foreign matter is less likely to occur.

More specifically, as shown in FIG. 4, the scraping blade 26 scrapes the mixed agitated material toward the auger shafts 4a, 4b with respect to the rotation direction of the auger shafts 4a, 4b. ₁ is provided and receives the mixed agitated material extruded from the hole wall and the supporting rod 10 by the extruding blade 27, which will be described later, as well as the periphery thereof by the scraping blade 26, and approaches the supporting rod 10 to support the auger shaft. The mixing and stirring material on the rod 2 has a function of further stirring by mainly stirring.

The push-out blade 27 pushes the agitated mixture outward from the auger shafts 4a, 4b side, and therefore the push-out angle θ _{2 with} respect to the arm 30.
The mixing blades are mainly pushed outward by the pushing blades 27 from the auger shafts 4a, 4b, and the hole walls perforated by the bits 20a, 20b and the supporting rod 1 are provided.
It has a function of further mixing and stirring by pushing the mixed and stirred product through the gap of 0.

The balance blade 28 displaces the auger shafts 4a, 4b to one side by the reaction force of the scraping blade 26 and the push-out blade 27, and at the same time balances the force of bending by the self-stirring resistance force. It has the effect of mixing and stirring in the direction.

By the action of the three blades being combined, the mixture is passed between the auger shafts 4a and 4b sandwiching the support rod 10 and the mixing and stirring are smoothed.

The force balance of each of the three blades will be described in detail with reference to the vector of FIG. For the sake of convenience of explanation, it is assumed that the density and viscosity of the agitated substance that acts by the rotation of these three blades are uniform, and the forces applied to the arms 29.30 of the scraping blade 26 and the pushing blade 27 are ignored.

The scraping blade 26, as a reaction force of the scraping operation of the mixed agitated material due to the rotation, has a rotating circumference whose radius is the length of the arm 29 from the auger shafts 4a and 4b, its blade area, and the scraping angle θ.
₁ , the force F ₁ that pulls the auger shafts 4a and 4b outward is generated at the blade center x. On the other hand, the push-out blade 27 similarly generates a force F ₂ pushing the auger shafts 4a and 4b inward at the blade center y with respect to the rotation circumference, the blade area thereof, and the push-out angle θ ₂ . The resultant force F ₃ of these two forces F ₁ and F ₂ appears on the xy line. This x
A balance blade 28 is provided on a line that is orthogonal to the y-line and passes through the axis O of the auger shafts 4a and 4b, and the radius r ₁ from the axis O to the xy-line.
Each force is balanced by equalizing the product of the product of the total force F ₃ and the radius r ₂ from the center z of the balance wing 28 to the axis O and the resistance force F ₄ generated by the wing area of the balance wing 28. Therefore, there is no fear that the auger shafts 4a and 4b will be displaced to one side or bent.

Further, in order to reduce the resultant force F ₃ of the pulling force F ₁ and the pushing force F ₂ , it becomes the minimum if the mounting narrow angle θ ₃ of the scraping blade 26 and the pushing blade 27 is small, but the narrow angle 0 ° At this time, the resistance to stirring becomes large due to the overlapping, but the stirring efficiency is low, and a narrow angle of at least 30 ° or more is necessary in view of the stirring efficiency. Further, when the narrow angle is 180 °, the resultant force F ₃ is the maximum, so it is desirable that the narrow angle θ is an angle of 20 ° to less than 180 °.
As shown in FIG. 4, it is extremely effective from the viewpoint of agitation and mechanical structure to provide three blades at substantially equal angular positions.

Next, the operation of the embodiment will be described.

The auger device M has its auger shafts 4a to 4d rotatable by a hydraulic motor 5 and is swingably attached to the front and back by operating a _third hydraulic cylinder S3. Operate the second hydraulic cylinders S ₁ and S ₂ to determine the construction position and the construction direction by operating the crawler and turning of the backhoe B that is the base machine, and operate the third hydraulic cylinder S ₃ to operate the ground. Set the angle to the inside,
After that, while adjusting with the second hydraulic cylinder S ₂ , the auger device M is lowered by the first hydraulic cylinder S ₁ , and the hose (not shown) from the solidified material pump is supplied to the inlet 11 of the support rod 10. ) Is connected and the solidifying material is injected into the support rod 10,
The hydraulic motor 5 is rotated while injecting the solidifying material from the jet outlets 17a, 17b and the lower end opening 12a, and the ground G is excavated by the auger shafts 4a to 4d driven by this, and the soil and the solidifying material there are After stirring and mixing, the injection of the solidifying material is stopped in a state where the stirring and mixing in the place is sufficient, and the first hydraulic cylinder S ₁ is operated to pull up the auger device M, and further
By operating the hydraulic cylinder S ₃ of the above, the auger device M is swung back or forth to change the angle, and the operation of excavating and stirring at that position is repeated, and the enlarged base K of the required shape whose bottom is enlarged is repeated. To form.

It is possible to excavate and stir by changing the angle in the ground,
For the moment load applied to each auger shaft 4a-4d,
By supporting the auger shafts 4a to 4d portions near the respective bits 20a to 20d by the bearings 14 of the auger shaft support rod 2, the auger shafts 4a to 4d are integrated with the upper base portion 1 to form the auger shafts 4a to 4d. This is because they are rotatably supported.

As for the cross-sectional shape of the expanded foundation K in which the bottom portion after the construction is expanded, specifically, the expanded foundation having the fan-shaped cross-sectional shape shown in FIG.
There are various types of fan-shaped cross-sectional expanded bases with key blocks shown in Fig. 7 and tree root-shaped expanded bases shown in Fig. 7. For example, fan-shaped expanded bases for light and medium-weight structures built on top of them. When considering the lateral pressure of retaining walls, etc., expand the fan-shaped cross-sectional shape with a key block, and expand the root-shaped cross-sectional shape of trees for larger lateral pressure, weight, high-rise structures, and structures. The foundation is selected and constructed according to the type of cloth foundation and independent foundation.

In order to construct these expanded foundations K reliably and systematically, it is desirable to excavate in the following order and to mix and stir with the solidifying material in relation to the reaction force from the ground to the auger device M and the soil. .

Explaining the fan-shaped cross-sectional expansion foundation shown in FIG. 5, first, while pouring the solidifying material, the auger device M is vertically lowered to the ground as shown by an arrow a to perform excavation stirring, and then to the excavation hole. Overlapping, the piston rod R ₃ of the third hydraulic cylinder S ₃ is extended and angled as indicated by the arrow b, and excavation is propelled and agitated in that direction, and the third hydraulic pressure is indicated by the arrow c. angled by loosening the piston rod R ₃ of the cylinder S _3, agitating drilled promoted in that direction, as indicated by the arrow d while maintaining the depth from the ground surface, the third hydraulic cylinder S ₃ Piston rod
R ₃ is expanded and contracted back and forth to rock the auger device M back and forth to excavate the remaining portion and perform complete agitation, stop the solidifying material injection, and complete the construction of the fan-shaped expanded base K. In this case, if you try to propel at an angle from the beginning, due to the relationship between the auger torque and the reaction force from the ground,
Since the auger device M becomes unstable and the construction position becomes inaccurate, construction is first started from a stable vertical direction. In the case of a larger cross section, the angle is gradually increased so that the target angle can be obtained by a plurality of times of propulsion.

Explaining the fan-shaped cross-section expanded base with a key block shown in FIG. 6, first, the fan-shaped expanded base with a fan-shaped cross-section shown in FIG. 5 is constructed, then deeply excavated and propelled in the direction of arrow a ₁ to stir, Alternatively, the construction of the enlarged foundation K with a fan-shaped cross-section with a key block is completed by first deeply excavating and agitating.

Explaining the expanded foundation of the root-shaped cross-sectional shape of the tree shown in FIG. 7, first, the expansion foundation of the fan-shaped sectional shape shown in FIG. 5 is constructed, and then the arrow a ₂ direction, arrow b ₂ direction, arrow
c and stirred sequentially by deeply digging promoted in _two directions, or at the beginning or middle, arrows a _2, arrow b _2, by stirring by deeply digging propulsion in each direction of the arrow c _2, the tree roots form the cross-sectional shape Complete the construction of the expanded foundation K.

When the construction of the expanded foundation K is completed on the predetermined ground,
By moving the backhoe B to a non-constructed place by crawler running so as to slightly overlap with the already constructed part, and repeating the injection of the solidifying material, excavation, and stirring repeatedly, thus, the cloth foundation is moved from the left to the right in FIG. A certain expansion foundation K is continuously stretched.

When the auger device M is not moved and installed, or when the auger device M is installed by several discontinuous movements,
Each will be an independent foundation construction.

[Advantages of the Invention] Since the present invention is as described above, the auger shaft provided with a bit at the tip promotes excavation while changing the angle in the soil, and at the same time, the solidified material is mixed and stirred in the excavated soil.
A solid foundation with an enlarged excavated bottom is obtained.

Furthermore, excavation and stirring can be performed by changing the angle in the ground because the auger shaft support rod of the support member allows the base above the bit to be excavated on the auger shaft against the moment load applied to each auger shaft. It is an effect that it is rotatably supported as a unit with one part, and the auger shaft supporting rod and the fixed wing piece act as a fixed wing without rotating, thereby preventing the mixture from co-rotating with the bit, Further, it is agitated by the agitating member above, so that the soil and the solidifying material are extremely efficiently mixed.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an auger device of the present invention and a construction state thereof, and FIG. 2 is a front view of a main part of the auger device of the present invention,
FIG. 3 is a bottom view of the bit part, FIG. 4 is an enlarged cross-sectional view showing details of a stirring member composed of a scraping blade, an extruding blade, and a balance blade, and FIG. 5 is a sectional view of an enlarged foundation having a fan-shaped cross-section. FIG. 6 is a construction sectional view of an enlarged foundation having a fan-shaped sectional shape with a key block, and FIG. 7 is a construction sectional view of an enlarged foundation having a root-shaped sectional shape of a tree. In the figure, B is a backhoe, M is an auger device, K is a base,
G is the ground, 1 is the base part, 2 is an auger shaft supporting rod, 3 is a supporting member, 4a, 4b, 4c and 4d are auger shafts, 5 is a hydraulic motor, 10 is a supporting rod, 11 is an injection port, 12 is Flow path, 12a is a lower end opening, 13 is a stopper, 14 is a bearing, 15 is a fixed wing piece, 16 is a branch flow path, 17a, 17b is a jet outlet, 19 is an excavating blade, 20a, 20b, 20c, 20d
Is a bit, 21 is a stirring member, 22a is a short inclined surface, 22b is a long inclined surface, 23a is a central cutting edge, 23b is an outer peripheral cutting edge, 24 is an inclined surface of equal length, 25 is a plate-shaped stirring blade, and 26 is a scraping blade. , 27
Is an extrusion wing and 28 is a balance wing.

Claims (4)

[Claims] 1. A plurality of auger shafts each having a bit at the tip and a stirring member in the middle, excavating and propelling the soil in different angles, and at this time, the soil to be excavated and the solidification injected from the auger shaft. A ground improvement method characterized by obtaining a foundation with an enlarged bottom in a fan-shaped cross section by mixing and stirring the material. 2. A plurality of auger shafts each having a bit at the tip and a stirring member in the middle are used to excavate and propel the soil in different angles, and at this time, the soil to be excavated and the solidification injected from the auger shafts. A ground improvement method characterized by obtaining a foundation with an enlarged bottom in a fan-shaped cross section with a key block by mixing and stirring the material. 3. A plurality of auger shafts each having a bit at the tip and a stirring member in the middle to excavate and propel the soil in different angles, and at this time, the soil to be excavated and the solidification injected from the auger shaft. A ground improvement method characterized by obtaining a foundation with an expanded bottom in a root-shaped cross-sectional shape of a tree by mixing and stirring the material. 4. A base portion connected to the lower surface of the front arm of the backhoe so as to be swingable in the front-rear direction, and an auger shaft support rod vertically fixed to the central lower surface of the base portion at the lower end. An auger device is formed by a support member and four auger shafts that are rotatably supported on the lower surface of the base part. A hydraulic motor is installed on the base part, and the auger device is installed in the base part. A reduction gear that operates in conjunction with the hydraulic motor is provided, and the upper ends of the auger shafts are connected to the reduction gear. The support member is provided on both sides of the lower end of a support rod vertically fixed to the lower center of the base. Is formed by projecting an auger shaft support rod in a direction, and an injection port for the solidifying material is provided above the support rod, and the injection port communicates with the flow path that penetrates the center portion of the support rod to the lower end, and the lower end. Install and fix the stopper on the opening and open the lower end. Branch flow path branching to each lateral direction from said channel in 稍上 side than parts is provided by extending the auger shaft supporting 杆内, before that the tip of each auger shaft supporting rod,
Each of the rear surfaces is opened to form a solidified material ejection port, while fixed wing pieces are fixed to both ends of the auger shaft support rod, and the lower part of the auger shaft is supported by the auger shaft support rod. Each of the four bearings penetrating is provided, and each auger shaft is pierced through each bearing, and a bit having a large number of drilling blades is fixed to the lower end of each auger shaft in the same phase, A stirring member is fixed to the outer periphery of each auger shaft between the base portion and the auger shaft support rod in one or more stages, and the lower ends of the two auger shafts of the auger shaft that are close to the support rods. The bit of is formed in a substantially base shape having a short bevel serving as a central cutting edge and a long bevel serving as an outer peripheral cutting edge, and the auger shafts are fixed by being deviated to the respective short slanting sides to fix the auger shafts. I will rotate the axis in the same direction The bits at the lower ends of the two auger shafts located at both ends of the auger shaft are formed in a base shape having slopes of equal length to each other, and the auger shaft is fixed to the center part thereof. And each auger shaft is configured to rotate in a direction opposite to each of the two auger shafts adjacent to the support rod, and the two auger shafts adjacent to the support rod among the auger shafts are agitated. The member is smaller than the outer peripheral locus of the bit, and the staking blade with a rake angle, the extrusion blade with a squeeze angle, and the balance wing made of a flat plate are the outer periphery of the auger shaft. Of the two auger shafts, which are fixed to one of the auger devices at a substantially equal angular position for one step or a plurality of steps with different phases, and the agitating members of the two auger shafts located outside of each auger device are plate-shaped agitators. One step over the wings Auger apparatus for use in construction of ground improvement method, characterized in that fixed over a plurality of stages out of phase.