JP2728633B2 - Construction method and construction device for soil cement pile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for excavating a ground, injecting cement milk into the excavated soil and stirring the excavated soil to form a soil cement pile in the ground.

[0002]

2. Description of the Related Art Conventionally, this kind of soil cement pile forming method comprises an inner pipe and an outer pipe fitted on the inner pipe. The inner pipe has a cutting edge at its tip and a lateral direction in front of it. A stirrer protruding from the inner tube is used, and the outer tube is provided with a stirrer protruding in the lateral direction at the end separated from the stirrer blade on the inner tube side. One excavation hole provided at the excavation blade portion at the tip of the inner pipe while excavating the ground to a predetermined depth while excavating the ground with the excavation blade, and then reversing the inner pipe and the outer pipe to raise both pipes. More cement milk is spouted to create soil cement piles.

[0003]

According to the above-mentioned conventional method, when excavating clay soil, in particular, the excavated clay has an inner pipe-side stirring blade, an outer pipe-side stirring blade, and both of these stirring blades. Soil cement adheres to the outer peripheral part of the inner tube between, and together with the adhesion of the clay, the soil cement,
It grows in the shape of a snowman while rotating together with the rotation of the inner and outer tubes, hindering the stirring action of the stirring blade, and significantly reducing the stirring efficiency. In addition, since the cement milk is ejected from only one cement milk ejection hole provided at the excavation blade portion at the tip of the inner pipe, the cement milk is applied to the excavated soil particularly when the inner and outer pipes are pulled up. Not supplied properly. In other words, the cement milk spouted from the spouting hole at the tip of the inner tube tends to rise along the outer peripheral surface region of the tube, which has relatively little pressure resistance, and is supplied to the rotating action area of the essential stirring blade. Insufficient agitation results in insufficient agitation of cement milk and excavated soil.

SUMMARY OF THE INVENTION The present invention provides a soil cement capable of sufficiently and efficiently stirring excavated soil and cement milk by a stirring blade and accurately supplying cement milk to the excavated soil. An object of the present invention is to provide a method and an apparatus for forming a pile.

[0005]

In order to achieve the above object, a soil cement pile forming method according to the present invention comprises an inner pipe 5 and an outer pipe 6, and a drilling blade 7 is provided at the tip of the inner pipe 5. An upward stirring blade 11 and 12 provided on the inner pipe 5 side; and a downward stirring blade 17 provided on the outer pipe 6 and axially wrapped around the upward stirring blades 11 and 12 but not circumferentially. A stirrer 8, and a portion of the digging blade 7 and the stirrer 8
In the excavation, the excavation of the portion of the excavation blade 7 is performed while excavating the ground by the excavation blade 7 at the tip thereof while rotating at least the inner pipe 5 by using a forming apparatus having a cement milk ejection hole on the upper side of the excavation blade. When the cement milk is ejected from the hole and excavated, and reaches a predetermined depth, the inner tube 5 is reversed and the inner tube 5 and the outer tube 6 are pulled up, and the cement milk is ejected from the ejection hole on the upper side of the stirring section 8. To create soil cement piles.

In this construction method, it is desirable to rotate the inner pipe 5 and the outer pipe 6 in directions opposite to each other during excavation and lifting.

Further, the soil cement pile forming apparatus of the present invention has an inner pipe 5 having a drilling blade 7 at its tip and capable of being driven forward and reverse.
And an outer tube 6 which is fitted to the inner tube 5 and can be driven forward and reverse.
And an agitator 8 provided over the inner and outer pipes 5 and 6. The agitator 8 comprises a plurality of upward stirring blades 11 and 12 provided on the inner pipe 5 side, and the upward stirring blades 11 and 12. , 12 and the outer tube 6 so as not to wrap in the circumferential direction
It comprises a plurality of downward stirring blades 17 provided on the side, and a cement milk ejection hole is provided on the portion of the excavating blade 7 and on the upper side of the stirring section 8 respectively.

In this soil cement pile forming apparatus,
Preferably, each of the stirring blades 12 and 17 is provided so as to be tiltable around a base end thereof within a certain angle range.

Further, in this soil cement pile forming apparatus, a plurality of stirring frames 29 can be provided on the inner pipe 5 side or the outer pipe 6 side on the upper side of the stirring section 8.

Further, in the soil cement pile forming apparatus, a cement milk supply passage 9 is provided inside the inner pipe 5 and the cement milk supply passage 9 is provided at a portion of the drilling blade 7. And a supply path switching mechanism 36 for selectively communicating with a cement milk ejection hole provided on the upper side of the stirring section 8. Alternatively, the supply pipe switching mechanism 36 may be provided inside the inner pipe 5. A cement milk supply passage 9 for supplying cement milk is provided to a cement milk ejection hole provided in the portion of the excavating blade 7, and an inner pipe 5 is provided.
Another cement milk supply passage 43 for supplying cement milk to the cement milk ejection hole provided on the upper side of the stirring section 8 may be provided between the cement milk and the outer pipe 6.

Further, in this soil cement pile forming apparatus, the cement milk ejection hole at the portion of the excavating blade 7 is connected to the cement milk supply passage 9 inside the inner pipe 5 and the cement milk distribution pipe is disposed laterally. 34, and a cement milk ejection hole on the upper side of the stirring section 8 is similarly arranged in the lateral direction in communication with the cement milk supply passage 9 inside the inner pipe 5. It is preferable to use a plurality of jet nozzles 33 provided in the cement milk distribution path 32 provided.

[0012]

First, in excavation, while at least the inner pipe 5 is rotated in a predetermined direction, the ground is excavated by the excavating blade 7 at the tip thereof, and cement milk is spouted from the cement milk spouting hole on the excavating blade 7 side. Digging in. At this time, in a state where the upward stirring blades 11 and 12 and the downward stirring blade 17 of the stirring unit 8 are wrapped with each other in the axial direction, at least the upward stirring blades 11 and 12 rotate around the inner pipe 5 so that the excavated soil is removed. Mix and stir with cement milk.

In this case, since the upward stirring blades 11 and 12 and the downward stirring blade 17 relatively rotate around the inner pipe 5 while being wrapped in the axial direction, the upward stirring blades 11 and 12 and the downward stirring blade The blade 17 exerts a sufficient and strong shearing action on the soil or cement milk or a mixture thereof interposed therebetween, whereby the soil and the cement milk are sufficiently stirred and mixed, and the soil and the soil cement Never make.

When the excavation reaches a predetermined depth, while the inner pipe 5 is reversed and the inner pipe 5 and the outer pipe 6 are lifted, cement milk is spouted out of the cement milk spouting hole on the upper side of the stirring section 8 to remove soil. Create cement piles. Also at this time, the upward stirring blades 11 and 12 rotate around the inner pipe 5 in a state where the upward stirring blades 11 and 12 and the downward stirring blade 17 are axially wrapped with each other in the stirring section 8, and are previously mixed at the time of excavation. The exfoliated soil cement is further stirred, and the unmixed excavated soil and cement milk are mixed and stirred.

In this case, since the upward stirring blades 11 and 12 and the downward stirring blade 17 are relatively rotated while being wrapped in the axial direction, the upward stirring blades 11 and 12 and the downward stirring blade 17 which are wrapped with each other cause the rotation. Sufficient and strong shearing action is exerted on the soil and cement milk interposed therebetween and also on the soil cement as a mixture thereof, whereby the soil and the cement milk or the soil cement can be further finely stirred and mixed. Moreover, in this case, the cement milk is spouted from the cement milk spouting hole on the upper side of the stirring section 8 into the soil excavated at the time of excavation, and
Thus, the excavated soil and the cement milk can be efficiently stirred and mixed. Also, even if the clay is slightly adhered to the stirring blades 11, 12, 17 and the inner tube 5 when the soil is clayey, the adhered material does not expand any more, Cement is stirring blade 11,
Even if it adheres to the parts 12, 17 and the inner pipe 5, the upward stirring blade 1
The shearing action of 1, 12 and the downward stirring blade 17 works,
Therefore, the soil cement does not rotate or rotate together with the stirring blades 11, 12, 17 and the inner tube 5,
The stirring and mixing of soil and cement milk or soil cement can be performed sufficiently efficiently.

[0016]

Embodiments will be described with reference to the drawings.
FIG. 1 is an overall schematic side view of a soil cement pile forming apparatus for carrying out the present invention, and FIGS. 2 to 6 are detailed views of main parts of the forming apparatus including a stirring section, respectively. First, in FIG. 1, reference numeral 1 denotes a leader vertically supported by a crawler crane 2 and reference numeral 3 denotes an elevator frame equipped with a rotary driving device (not shown). And suspended by a lifting operation wire 4. Reference numeral 5 denotes an inner tube (shown by a broken line), and 6 denotes an outer tube which is fitted to the inner tube 5 so as to be rotatable relative to each other. It is connected and hangs from the lower part of the elevator frame 3. Inner tube 5
An excavating blade 7 is provided at the tip of, and a stirring section 8 is provided at the tip of the inner pipe 5 and the outer pipe 6.

Referring to FIGS. 2 to 6, the inner tube 5 has a cement milk supply passage 9 formed along the central axis over substantially the entire length thereof, and the supply passage 9 is not shown. However, cement milk is introduced from the upper end side of the inner pipe 5 by a well-known cement milk supply means provided in the elevator frame 3. The distal end of the inner tube 5 forms a detachable tube portion 5a that can be attached and detached by a pin 10. The detachable tube portion 5a is provided with the excavating blade 7, and the excavating blade 7 includes a blade base 7a,
The blade base 7a and bits 7b and 7c attached to the distal end of the detachable pipe section 5a are provided. FIG. 2 shows the blade rest 7a.
As shown in FIG. 5, for example, four upward stirring blades 11 and 12 are vertically disposed at symmetrical positions on both sides of the inner pipe 5 (detachable pipe section 5 a).

The lower end of the outer tube 6 is slightly shown in the upper part of each of FIGS. 2, 3 and 6, but from the lower end of the outer tube 6, a pair of vertically elongated frames 13 and 13 is
The inner tube 5 protruding from the lower end of the outer tube 6 is continuously provided so as to sandwich it from both sides. The upper end of each frame 13 is fixed to the outer tube 6 via the mounting piece 14, and the lower end is fixed to the mounting plate 15. The mounting plate 15 is fitted to the inner tube 5 so as to be relatively rotatable. It is fixed to the shape 16. Accordingly, the pair of vertically elongated frames 13 on both sides can be integrally rotated with the rotation of the outer tube 6.

As shown in FIGS. 2 to 6, a plurality of, for example, eight downward stirring blades 17 are provided on the lower surface of the mounting plate 15 to which the lower end of the vertically long frame 13 is fixed. The inner pipe 5 (removable pipe section 5a) is sandwiched between the stirring blades 11 and 12 in the axial direction (see FIGS. 2 and 6) but not in the circumferential direction (see FIGS. 4 and 5). At the both sides symmetrical position, it is installed downward. The stirring section 8 is constituted by the upward stirring blades 11 and 12 and the downward stirring blade 17. In addition, upward stirring blade 1
Each of the blades 1 and 12 and the downward stirring blade 17 is formed to be considerably long, and is disposed so as to be sufficiently wrapped in the axial direction as shown in FIGS.

The upward stirring blade 12 and the downward stirring blade 1
7 are mounted on the blade base 7a and the mounting plate 15 so that they can be tilted within a certain angle range around the base end. FIG.
(A) and (B) show the mounting state of the upward stirring blade 12 and the downward stirring blade 17. For example, the upward stirring blade 12 will be described. And the mounting pedestal 18
Is fitted to a receiving seat 20 formed integrally with the tapered shaft 19 and is connected thereto by bolts 21. In mounting, a cylindrical mounting frame 23 is fitted into the opening 22 of the mounting plate 15 from below, and a taper shaft 19 integrally connected to the upward stirring blade 12 is fitted in the cylindrical mounting frame 23. , A rubber cushion member 25 between the receiving seat 20 and the cylindrical mounting frame 23.
, A nut 26 is screwed to the tip of the tapered shaft 19, and a cover 27 is attached to the lower end of the cylindrical mounting frame 23. The same applies to the downward stirring blade 17.

As described above, the upward stirring blade 12 and the downward stirring blade 17 have the tapered shaft 19 integrally connected to the base end thereof formed by the rubber bearing member 24, and the receiving seat 20 formed by the ring-shaped cushion rubber 25. Respectively, so that when a certain lateral load is applied, the rubber bearing member 24 and the cushion rubber 25 are elastically deformed,
It can be tilted around the tapered shaft 19 within a certain angle range. Upward stirring blade 12 and downward stirring blade 17
Has a constant width over the entire length as shown in FIG. 7A when viewed from the side, but has a tapered shape as shown in FIG. 7B when viewed from the front. These stirring blades 12 and 17 are provided on the blade rest 7.
Since it is detachably attached to a and the mounting plate 15, it can be used by replacing it with a desired shape according to the soil properties of the ground. In addition, a projection (blade) that is orthogonal to the blade length direction can be provided on the stirring blades 12 and 17.

As shown in FIGS. 2, 3 and 6,
At the portion of the inner tube 5 located on the upper side of the stirring section 8, a tube 28 for switching the cement milk supply path is fitted around the inner tube 5 so as to be rotatable relative to the inner tube 5 within a certain angle range. 2
8, a pair of vertically stirring frames 29 are provided on the mounting base plate 3 respectively.
The pipe 28 is mounted at a symmetrical position on both sides of the tubular body 28 via the “0”. Each mounting base plate 30 is mounted so as to protrude laterally from the tube body 28 and to be inclined at a predetermined angle as shown in the drawing. The pipe 2 is provided inside the mounting base plate 30.
8 is provided with a cement milk distribution passage 32 communicating with a communication passage 31 penetrating through 8, and a plurality of ejection nozzles 33 as cement milk ejection holes are provided in the distribution passage 32. Each of the ejection nozzles 33 is opened obliquely downward corresponding to the inclination angle of the mounting base plate 30, as shown in FIGS. On the other hand, a pair of cement milk distributing pipes extending in the lateral direction in communication with the cement milk supply passage 9 are provided at the tip of the inner pipe 5 provided with the excavating blade 7, that is, the detachable pipe section 5a, on the lower surface side of the blade base 7a. Numerals 34 are disposed at symmetrical positions on both sides of the detachable pipe portion 5a, and a plurality of jet nozzles 35 as cement milk jet holes are provided in each distribution pipe 34.

The cement milk supply passage 9 inside the inner pipe 5
Is supplied by a supply path switching mechanism 36 provided on the upper side of the stirring unit 8, by a cement milk ejection hole (ejection nozzle 35) on the excavating blade 7 side, and by a cement milk ejection hole (ejection nozzle 33) on the stirring unit 8 upper side. Are switched so that they are alternatively connected to each other. Hereinafter, the supply path switching mechanism 36 will be described with reference to FIGS. 6 and 8 to 10.

The supply path switching mechanism 36 includes the cement milk supply path switching pipe 28 rotatably fitted to the inner pipe 5 as shown in FIG.
As shown in FIGS. 8A and 10A, an annular guide groove 37 is provided on the inner peripheral surface of the tube 28,
A guide piece 38 slidable along 7 is provided on the outer peripheral portion of the inner tube 5, and the guide piece 38 is within a 90-degree angle range between a pair of stopper pieces 39 a and 39 b provided in the guide groove 37. Can slide back and forth. And tube 2
A pair of upper and lower communication passages 40 and 41 communicating with the cement milk supply passage 9 are provided in a portion of the inner pipe 5 in which the cement milk 8 is externally fitted. In addition to the communication passage 31 communicating with the ejection hole, a pair of bypass passages 42 on both sides for interconnecting the upper and lower communication passages 40 and 41 on the inner pipe 5 side are provided.

Since the tube 28 is rotatable with respect to the inner tube 5 within a 90-degree angle range between the stopper pieces 39a and 39b, the inner tube 5 is rotated by a rotation driving device, for example, as shown in FIG.
When the clockwise rotation indicated by the arrow (A) is performed, the guide piece 38 comes into contact with one of the stopper pieces 39a, whereby the tube 28 rotates integrally with the inner tube 5 and the inner tube 5 rotates.
10A is rotated counterclockwise as shown by the arrow in FIG. 10A, the guide piece 38 is rotated 90 degrees counterclockwise from the position where it abuts the one stopper piece 39a, and the other is rotated. The abutment against the stopper piece 39b causes the tube 28 to rotate integrally with the inner tube 5 in a counterclockwise direction.

When the guide piece 38 comes into contact with one of the stopper pieces 39a and the tube 28 rotates clockwise (forward rotation) together with the inner tube 5, as shown in FIGS. Cement milk supply passage 9 and communication passage 4 of inner pipe 5
The cement milk 0, 41 and the bypass passage 42 of the pipe 28 are connected to each other and the communication passage 31 is closed. And the guide piece 38 is connected to the other stopper piece 3 as shown in FIG.
When the pipe 28 rotates counterclockwise together with the inner pipe 5 (reverse rotation) in contact with the inner pipe 5, the cement milk supply path 9 of the inner pipe 5 and the upper communication path 40 and the communication path 31 of the pipe 28 are connected. And the bypass passage 42 is closed,
Thereby, the cement milk from the upstream of the cement milk supply passage 9 is supplied to the cement milk ejection hole (ejection nozzle 33) on the upper side of the stirring section 8.

A method of forming a soil cement pile by using the soil cement pile forming apparatus having the above-described configuration will be described. First, in excavation, the inner pipe 5 is rotated forward by a rotary drive (FIG. 8 ( A), while excavating the ground with the excavating blade 7 on the tip side of the inner pipe 5 while making the outer pipe 6 in the opposite direction to the inner pipe 5, cement milk inside the inner pipe 5 is removed. The cement milk supplied to the supply path 9 is ejected from a cement milk ejection hole (ejection nozzle 35) on the side of the excavation blade 7 and excavates.

At this time, the supply path switching mechanism 36 of the cement milk supply path 9 is, as shown in FIGS.
Since the inner pipe 5 rotates forward and the supply path switching pipe 28 comes into contact with one of the stopper pieces 39a with this,
The communication passage 31 is closed, and the cement milk supply passage 9 is connected to and communicates with the cement milk ejection hole on the side of the cutting blade 7. Therefore, the cement milk from the cement milk supply passage 9 is spouted only from the plurality of spouting nozzles 35 on the excavating blade 7 side, and is not spouted out from the spouting nozzle 33 on the upper side of the stirring unit 8.

As described above, while the inner pipe 5 and the outer pipe 6 are being rotated in the forward and reverse directions, the soil milk is excavated by the excavating blade 7 while the cement milk is discharged from the jet nozzle 35 on the excavating blade 7 side. When excavating and excavating, the stirrer 8
The upper stirring blades 11 and 12 and the lower stirring blades 17 rotate in the forward and reverse directions around the inner pipe 5 in a state of being wrapped in the axial direction and mix and stir excavated soil and cement milk. I do. At this time, the cement milk is dispersed by the plurality of ejection nozzles 35 and is uniformly ejected on the excavated soil.

In this case, the upward stirring blades 11 and 12 and the downward stirring blade 17 are wrapped with each other because they rotate in opposite directions around the inner tube 5 while being wrapped in the axial direction as shown in FIGS. Upward stirring blades 11 and 12 and downward stirring blade 17
With this, a sufficient and powerful shearing action acts on the soil or cement milk or a mixture thereof intervening therebetween, so that the soil and cement milk can be finely and sufficiently stirred and mixed, and the soil and soil cement can be mixed. It does not form lumps, and when the clay is clayey, even if the clay slightly adheres to the stirring blades 11, 12, 17 and the inner tube 5, the attached matter can grow further. Absent.

When the excavation reaches a predetermined depth, the rotation directions of the inner pipe 5 and the outer pipe 6 by the rotary driving device are reversed, and the inner pipe 5 is reversed (counterclockwise direction as shown in FIG. 10A). Then, while rotating the outer pipe 6 forward, the cement milk supplied to the cement milk supply passage 9 inside the inner pipe 5 is supplied to the cement milk ejection hole (ejection nozzle 33) on the upper side of the stirring unit 8.
Initially, the inner and outer pipes 5 and 6 are raised and lowered several times from the lowermost part to a predetermined height to form a solidified part,
Then, after the formation of the root consolidation portion, the above operation is continued, and the soil cement pile is formed while pulling up the inner and outer pipes 5, 6.

At this time, as shown in FIG. 6 and FIG. 10, the supply path switching mechanism 36 of the cement milk supply path 9 causes the inner pipe 5 to reverse and the supply path switching pipe 2 to move.
8 rotates in the opposite direction by 90 degrees, and the other stopper piece 39
b, the bypass passage 42 is closed, and the cement milk supply passage 9 is connected to the cement milk ejection hole on the upper side of the stirring unit 8. Therefore, the cement milk from the cement milk supply passage 9 is spouted only from the spout nozzle 33 on the upper side of the stirring unit 8 and not spouted from the spout nozzle 35 on the excavating blade 7 side. In addition, since this cement milk is jetted from the plural jet nozzles 33,
It spreads evenly on excavated soil.

As described above, the inner pipe 5 is reversed and the outer pipe 6
When the cement milk is spouted from the spout nozzle 33 on the upper side of the stirring section 8 to rotate the pipes 5 forward and upward, the upward stirring blades 11 and 1 of the stirring section 8 are also pulled up.
2 and the respective downward stirring blades 17 are rotated in the forward and reverse directions around the inner tube 5 in a state of being wrapped in the axial direction to further agitate the premixed soil cement at the time of excavation, while still mixing. Mix and stir unexcavated soil and cement milk.

In this case, since the upward stirring blades 11 and 12 and the downward stirring blade 17 are rotated around the inner tube 5 in a state where they are wrapped in the axial direction, the upward stirring blades 1 wrapped with each other.
1, 12 and the downward stirring blade 17, a sufficient and strong shearing action is exerted on the soil and cement milk interposed therebetween and also on the soil cement as a mixture thereof, whereby the soil and the cement milk or the soil cement Can be further finely and densely stirred and mixed,
In addition, since the cement milk is accurately spouted from the spout nozzle 33 on the upper side of the stirring section 8 into the excavated soil during excavation, the excavated soil and the cement milk can be efficiently and sufficiently stirred and mixed. Further, even if the clay is slightly adhered to the portions of the stirring blades 11, 12, 17 and the inner tube 5 when the soil is clay-like, the adhered substance does not expand further. Further, in this case, even if the soil cement adheres to the stirring blades 11, 12, 17 and the inner pipe 5, the upward stirring blades 11, 12 and the downward stirring blade 17 wrapped with respect to the adhered soil cement. Since the shearing action works, the soil cement is used for stirring blades 11,1.
No co-rotation or co-rotation with 2, 17 or the inner pipe 5 can be performed, and the stirring and mixing of the soil and the cement milk or the soil cement can be performed sufficiently efficiently. Piles can be created.

Further, since a pair of vertically long stirring frames 29 are provided in the pipe 28 for switching the cement milk supply path at symmetrical positions on both sides, the stirring frames 29 rotate with the rotation of the inner pipe 5. In addition, at the time of excavation and lifting, the excavated soil, the cement milk, and the soil cement can be subjected to a shearing and stirring action, and the stirring and stirring action of the stirring section 8 can further improve the stirring efficiency. Furthermore, a pair of vertically elongated frames 1 is provided at the lower end of the outer tube 6.
3 is continuously provided so as to sandwich the inner tube 5 from both sides, so that the vertically elongated frame 13 rotates around the inner tube 5 by the rotation of the outer tube 6, similarly to the stirring frame 29. ,
Excavated soil, cement milk,
A shear stirring action can be exerted on the soil cement.

Further, the upward stirring blade 12 and the downward stirring blade 17 of the stirring unit 8 can be tilted around a base end thereof within a certain angle range, so that soil, cement milk or soil is stirred during stirring. If excessive lateral load is applied by the cement, these stirring blades 12 and 17
Can be tilted to absorb the lateral load to prevent breakage.

In the above embodiment, both the inner pipe 5 and the outer pipe 6 are rotated during excavation and lifting, but the outer pipe 6 is stopped and only the inner pipe 5 is rotated. You may make it rotate so that it may become reverse at the time of excavation and at the time of raising.

In the above-described embodiment, the cement milk supply passage 9 is provided inside the inner pipe 5, and the cement milk supply passage 9 is connected to the excavating blade 7 by the supply passage switching mechanism 36.
Cement milk spout holes (spout nozzle 3)
5) and the cement milk ejection hole (ejection nozzle 33) on the upper side of the stirring unit 8 are selectively connected to each other. However, as in the embodiment shown in FIG. The provided cement milk supply passage 9 is configured to always communicate only with the cement milk ejection hole on the side of the excavating blade 7, and a path completely different from the cement milk supply passage 9 between the inner tube 5 and the outer tube. The cement milk supply passage 43 is provided, and the supply passage 43 is always communicated with the cement milk ejection hole (ejection nozzle 33) on the upper side of the stirring unit 8 via the communication passage 44, and the cement milk Cement milk is supplied to the milk ejection hole only through the cement milk supply passage 9 inside the inner tube 5, and the cement milk supply passage between the inner tube 5 and the outer tube 6 is supplied to the cement milk ejection hole above the stirring section 8. 4
3 may be provided. In this case, the cement milk is separately supplied to the cement milk supply path 9 inside the inner pipe 5 and the cement milk supply path 43 between the inner and outer pipes 5, 6 at the upper end portions of the inner and outer pipes 5, 6. .

When the cement milk supply path 9 inside the inner pipe 5 and the cement milk supply path 43 between the inner and outer pipes 5 and 6 are provided as described above, a complicated supply path switching mechanism 36 is not required. The structure on the inner tube 5 side is simplified. In addition, only the cement milk supply passage 9 inside the inner pipe 5 is provided, and the supply passage switching mechanism 36 controls the supply of the cement milk to the cement milk ejection hole on the excavating blade 7 side and the cement milk ejection hole on the upper part of the stirring unit 8. When switching, the switching operation can be performed automatically.

As shown in FIG. 11, the inner pipe 5 and the outer pipe 6
In the cement milk supply passage 43 between the inner tube 5 and the inner tube 5, guide protrusions 45 protruding from the outer surface of the inner tube 5 and rotatably provided on the inner surface of the outer tube 6 are provided at a plurality of positions in the circumferential direction and the inner tube. 5. It is provided at a plurality of locations in the longitudinal direction. Further, the downward stirring blade 17 of the stirring section 8 is attached to the mounting plate 15 directly fixed to the lower end of the outer tube 6.
And a stirring frame 29 provided with an ejection nozzle 33 as a cement milk ejection hole on the upper side of the stirring section 8.
Is attached to the inner tube 5 in the previous embodiment, but is directly attached to the outer tube 6 in this embodiment. Other configurations are the same as those of the previous embodiment, and therefore, the same components are denoted by the same reference numerals and description thereof will be omitted.

[0041]

According to the construction method according to the first aspect of the present invention, when excavating the ground, the upward stirring blade and the downward stirring blade of the stirring section rotate relative to each other in a state where they are wrapped in the axial direction, and are mutually rotated. The wrapped upward stirring blade and downward stirring blade can exert a sufficient and powerful shearing action on the soil or cement milk or a mixture thereof interposed therebetween, so that the excavated soil and cement milk can be sufficiently separated. Can be stirred and mixed, and does not form soil or soil cement lumps.

Also, at the time of lifting, the upward stirring blade and the downward stirring blade are relatively rotated in a state of being wrapped in the axial direction,
The upward stirring blade and the downward stirring blade wrapped with each other can exert a sufficient and strong shearing action on the soil and cement milk interposed therebetween and also on the soil cement as a mixture thereof, so that the soil and cement milk can be used. Alternatively, the soil cement can be further finely stirred and mixed. In particular, at the time of lifting, the cement milk can be spouted accurately into the excavated soil from the cement milk spouting hole on the upper side of the stirring section, whereby the excavated soil and the cement milk can be efficiently stirred and mixed. Also, when the soil is clayey, if the clay adheres slightly to the stirring blade or the inner tube, the attached matter does not expand any further, and the soil cement is not With the pipe, the co-rotation and the co-rotation do not occur, and the stirring and mixing of the soil and the cement milk or the soil cement can be performed extremely efficiently.

According to the second aspect, the stirring efficiency can be further improved by rotating the inner tube and the outer tube in directions opposite to each other.

According to the third aspect of the present invention, the above-mentioned method can be easily implemented, and the agitating section includes a plurality of upward stirring blades and downward stirring blades. The stirring action can be performed well, and sufficient stirring and mixing can be performed.

According to the fourth aspect, even if the upward stirring blade and the downward stirring blade of the stirring section may receive an excessive lateral load due to soil, cement milk or soil cement during stirring, the stirring blade may be used. By tilting so as to absorb the lateral load, breakage can be prevented.

According to the fifth aspect, by providing the stirring frame on the upper side of the stirring section, the stirring efficiency can be further improved.

According to the sixth aspect, the cement milk supply passage inside the inner pipe is selected by the supply passage switching mechanism between the cement milk ejection hole on the excavating blade side and the cement milk ejection hole on the upper side of the stirring section. By performing the communication connection, the operation of switching the supply of the cement milk to both the cement milk ejection holes can be easily performed.

According to the present invention, another cement milk supply passage for supplying cement milk to the cement milk ejection hole on the upper side of the stirring section is provided between the inner pipe and the outer pipe. , No supply path switching mechanism is required,
The structure of the inner tube is simplified.

According to the eighth aspect, since the cement milk ejection hole on the excavation blade side includes a plurality of ejection nozzles, the cement milk can be ejected sufficiently to the excavated soil.

According to the ninth aspect, since the cement milk ejection hole on the upper side of the stirring section includes a plurality of ejection nozzles, the cement milk can be ejected sufficiently to the excavated soil.

[Brief description of the drawings]

FIG. 1 is an overall schematic side view showing a soil cement pile forming apparatus according to the present invention.

FIG. 2 is an enlarged detailed side view of a device portion including a stirring section.

FIG. 3 is a front view of the device portion shown in FIG. 2;

FIG. 4 is a sectional view taken along line VV of FIG. 2;

FIG. 5 is a sectional view taken along line WW of FIG. 2;

FIG. 6 is a partial cross-sectional front view of the device shown in FIG. 2;

FIG. 7A is an explanatory view showing an attached state of an upward stirring blade or a downward stirring blade of a stirring unit, and FIG.
FIG. 4 is a sectional view taken along line -O.

8A is a cross-sectional view taken along line XX of FIG. 6, and FIG.
FIG. 7 is a cross-sectional view taken along line YY of FIG. 6, and shows a state in which cement milk is supplied to a cement milk ejection hole on the side of an excavation blade.

FIG. 9 is a sectional view taken along line ZZ of FIG. 8 (B).

10A is a cross-sectional view taken along line XX of FIG. 6, FIG.
FIG. 7 is a sectional view taken along line YY of FIG.
The state where cement milk is supplied to the cement milk ejection hole on the upper side is shown.

FIG. 11 is a partial cross-sectional front view showing another embodiment of the soil cement pile forming apparatus according to the present invention.

[Explanation of symbols]

 Reference Signs List 5 inner pipe 6 outer pipe 7 excavating blade 8 stirring section 9 cement milk supply path 11 upward stirring blade 12 upward stirring blade 17 downward stirring blade 28 pipe body 29 stirring frame 30 mounting base plate 31 communication path 32 cement milk distribution path 33 ejection nozzle 34 minute pipe 35 ejection nozzle 36 supply path switching mechanism 38 guide piece 39a stopper piece 39b stopper piece 40 communication path 41 communication path 42 bypass path 43 cement milk supply path 44 communication path

Claims (9)

(57) [Claims] 1. An inner pipe and an outer pipe, wherein a cutting edge is provided at a tip of the inner pipe, an upward stirring blade provided on an inner pipe side, and an upward stirring blade provided on an outer pipe, and an axial direction. A stirrer comprising a downward stirring blade which is wrapped in the circumferential direction and not wrapped in the circumferential direction, and excavation is performed using a forming device having a cement milk ejection hole in each of the excavating blade portion and the upper side of the stirring portion. Sometimes, while digging the ground with the drilling blade at the tip while rotating at least the inner pipe, digging out by digging out cement milk from the discharge hole of the digging blade part, when reaching a predetermined depth, the inner pipe is reversed A method for forming a soil cement pile, wherein cement milk is formed by blowing cement milk from a discharge hole on an upper side of the agitating section while pulling up an inner pipe and an outer pipe. 2. The soil cement pile forming method according to claim 1, wherein the inner pipe and the outer pipe are rotated in directions opposite to each other when excavating and lifting. 3. A forward / reversely rotatable inner pipe having a cutting edge at an end thereof, a forward / reversely rotatable outer pipe externally fitted to the inner pipe, and an agitator provided over both the inner and outer pipes. Comprising, a plurality of upward stirring blades provided on the inner tube side,
This upward stirring blade and a plurality of downward stirring blades provided on the outer tube side so as to wrap in the axial direction but not in the circumferential direction are provided. Soil cement pile forming device with vent holes. 4. A soil cement pile forming apparatus according to claim 3, wherein each of the stirring blades is provided so as to be tiltable around a base end thereof within a predetermined angle range. 5. The soil cement pile forming apparatus according to claim 3, wherein a stirring frame is provided on an inner pipe side or an outer pipe side on an upper side of the stirring section. 6. A cement milk supply path is provided inside the inner pipe, and the cement milk supply path inside the inner pipe is connected to a cement milk ejection hole provided at the portion of the excavating blade and an upper side of the stirring section. 6. The soil cement pile forming apparatus according to claim 3, further comprising a supply path switching mechanism for selectively communicating with the provided cement milk ejection hole. 7. A cement milk supply passage for supplying cement milk to a cement milk ejection hole provided in the portion of the excavating blade is provided inside the inner pipe, and the stirring section of the stirring section is provided between the inner pipe and the outer pipe. 6. The soil cement pile forming apparatus according to claim 3, wherein another cement milk supply passage for supplying cement milk is provided to a cement milk ejection hole provided on an upper side. 8. The cement milk ejection hole in the part of the drilling blade,
The soil cement pile according to claim 3, 4, 5, 6, 6 or 7, comprising a plurality of jet nozzles provided in a cement milk distribution pipe arranged in a lateral direction in communication with a cement milk supply passage inside the inner pipe. Creation device. 9. The cement milk ejection hole on the upper side of the stirring section comprises a plurality of ejection nozzles provided in a cement milk distribution passage arranged in a lateral direction in communication with the cement milk supply passage. 9. The soil cement pile forming apparatus according to claim 5, 6, 7, or 8.