JP2003313858A - Device and method for soil improvement having spreading excavating blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and a method for soil improvement capable of increasing the performance of an expanded improved soil body for agitating and mixing solidifying material liquid with excavated soil even when there is only one stage of a spreading excavating blade when an improved part expanded to the inside is formed by excavating from a surface side with a small diameter. <P>SOLUTION: A tip excavating bit 4 and one stage of spreading excavating blade 5 are fitted to an excavating rotating shaft of double tube structure having an inner tube 2 and an outer tube 3, and the spreading excavating blade 5 of such a type that a base end side on the opposite side of the bit is opened by the slide hole 15 of an expanding and retracting guide member 14 fitted to the tip part of the outer tube. A delivery port 6 is provided in the side face of the outer tube so that the solidifying material liquid 7 strikes the rear face of the tip part of the spreading excavating blade in the spread state of the spreading excavating blade 5. When the excavating rotating shaft is raised and spread, the solidifying material liquid 7 is jetted in an unexcavated soil, the soil and solidifying material liquid are agitated and mixed by the injection pressure of the solidifying material liquid, and the agitated and mixed soil is further excavated by the excavating blade and agitated and mixed on the side face of the excavating blade. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground improvement device having expansion / contraction type excavation blades capable of excavating a small diameter from the surface side and constructing a ground improvement body having an enlarged portion inside, and a surface side having a small diameter inside. The present invention relates to a ground improvement method capable of creating a ground improvement body having an enlarged portion.

[0002]

2. Description of the Related Art A ground improvement device having an excavation blade capable of expanding and contracting by relatively sliding an inner pipe and an outer pipe of a double pipe structure is known. For example, Japanese Patent Laid-Open No. 9-256355
As disclosed in Japanese Laid-Open Patent Publication No. 2001-26923, in a conventional ground improvement device having expandable / contractible excavation blades, expansion / contraction excavation blades are rotatably supported on the outer pipe side.
A structure in which the other end side of the expansion / contraction type excavation blade is inserted into a slide hole provided at the rear side of the drill bit at the tip of the inner pipe protruding from the outer pipe, and the expansion / contraction is performed by relative sliding of the inner pipe and the outer pipe. Has been done.

Further, the apparatus disclosed in the above-mentioned Japanese Patent Laid-Open No. 9-256355 has a structure in which the solidifying material liquid is discharged from the discharge port provided in the drill bit at the tip.

On the other hand, in the apparatus disclosed in Japanese Unexamined Patent Publication No. 2001-26923, expansion / contraction type excavation blades are provided in multiple stages on the outer pipe, and a tip discharge port for the solidifying material liquid is provided at the center of the tip drill bit. , An intermediate discharge port for the solidifying material liquid is provided on the side surface of the outer pipe, the solidifying material liquid is supplied from the tip discharge port, and the intermediate discharging port is located near the shaft supporting portion of the second excavation blade on the base end side away from the excavation bit. It is described that the solidifying material liquid is discharged from the outlet toward the tip side. The solidifying material liquid discharged from this intermediate discharge port is discharged to the unexcavated soil portion when the diameter of the material is lifted and expanded, but the direction of the discharge port is not suitable for the expanded excavation blade, The solidifying material liquid is merely discharged.

[0005]

All of the above-mentioned conventional ground improvement devices having expandable / contractible excavating blades supply the solidifying material liquid into the excavation holes whose diameters have been expanded to the excavating blades. The earth and sand excavated by means of only the rotary motion of the excavation blades, the solidifying material liquid and the excavated soil are only agitated. Therefore, as described in Japanese Patent Application Laid-Open No. 2001-26923, if the excavating blade capable of expanding and contracting is provided in only one stage, stirring and mixing of the solidifying material liquid and the excavated soil become insufficient.

Therefore, in order to solve this problem, Japanese Unexamined Patent Application Publication No.
In Japanese Patent Laid-Open No. 001-26923, expandable / contractible excavation blades are provided in multiple stages, and a solidifying material liquid is discharged from an intermediate discharge port. However, since there is no other way than to expand and contract the multi-stage stirring blades at the same time, if you pull up to near the ground surface and finish the enlarged excavation section and reduce the diameter of the excavation blades, the portion between the two excavation blades will not be stirred and mixed. Moreover, since the solidified material liquid is only discharged from the intermediate discharge port to the unexcavated soil portion, the portion between the two excavating blades becomes insufficient in stirring and mixing the solidified material liquid and the excavated soil. .

According to the present invention, when excavating with a small diameter from the surface side and forming an improved portion enlarged inside, even if there is only one stage of expanding blade type excavation blade, excavation with the solidifying material liquid in the expanded ground improvement body It is an object of the present invention to provide a ground improvement device capable of improving the performance of stirring and mixing with soil. Another object of the present invention is to provide a ground improvement method capable of enhancing the stirring and mixing performance of the solidifying material liquid and the excavated soil in the expanded ground improvement body by using the above ground improvement device. is there.

[0008]

According to a first aspect of the present invention, the excavation rotary shaft of the ground improvement device has a double pipe structure composed of an inner pipe and an outer pipe, and the inner pipe and the outer pipe can rotate integrally. Further, it is provided so as to be relatively slidable in the axial direction, and a drill bit and a blade for expanding blades are provided in order from the tip side to the tip of the inner pipe protruding from the outer pipe, and the drill bit for the blade for expanding blades. Side is pivotally supported on the inner pipe side to allow the expanding blade type excavating blade to rotate, and the other end side or the side near the other end of the expanding blade type excavating blade is inserted into a guide hole provided on the outer pipe side. , The outer pipe is expanded when it is relatively slid in the direction of approaching the drill bit, and the outer pipe is configured to be reduced when it is relatively slid in the direction of moving the drill bit away. Is characterized in that the discharge port is provided on the outer pipe so as to face the tip of the expanded blade A soil improvement apparatus having that 拡翼 drilling blades.

That is, in the ground improvement device according to the first aspect of the present invention, as shown in FIGS. 1 and 2, after a small diameter excavation hole is excavated, a ground improvement body which is enlarged by pulling up the excavation rotary shaft is constructed. In the above, the expanding blade is a type in which the base end side opposite to the tip drilling bit is opened with one stage. The expansion / contraction mechanism of the blade expansion type blade is configured, for example, by providing a slide hole in the expansion / contraction guide member provided at the tip of the outer pipe, and the excavation bit side of the blade expansion type excavation blade is provided with a rotation shaft And insert the other end into the slide hole. By sliding the outer pipe with respect to the inner pipe or sliding the inner pipe with respect to the outer pipe, the expansion blade type excavation blade expands and contracts. Figure 2
As shown in FIG. 4, the discharge port is provided on the side surface of the outer pipe so that the solidified material liquid hits the rear surface of the tip of the expanding blade when the expanding blade is expanded in diameter. Further, the solidifying material liquid is discharged when the diameter of the excavating rotary shaft is lifted and expanded, and the solidifying material liquid is supplied to the unexcavated ground. Therefore, the discharge port is preferably a discharge port capable of spraying the solidified material liquid so as to reach the expanded blade, and more preferably the high pressure discharge port.

According to the first aspect of the present invention, after the small-diameter drilling hole is drilled with the tip-end drilling bit in a state where the expanded-blade-type drilling blade is reduced in diameter, the drilling rotary shaft is pulled up to enlarge the diameter of the expanded blade. When excavating, the solidifying material liquid supplied from the discharge port arranged on the lifting side of the excavation blade is injected toward the back surface of the tip of the expanded excavation blade, and the excavation blade with expanded diameter still excavates. Since it is supplied to the ground that has not been solidified, the ground containing the solidifying material liquid is excavated with the expanded excavation blade, and the excavation action and the stirring and mixing action on the side face of the excavation blade can be achieved at the same time. The excavated soil and the solidifying material liquid can be sufficiently stirred and mixed as compared with the case of the conventional technique in which there is a portion where the solidifying material liquid and the solidifying material liquid are not sufficiently stirred and mixed.

Further, when the solidifying material liquid is jetted from the discharge port, the ground and the solidifying material liquid are agitated and mixed by the injection pressure of the solidifying material liquid supplied from the discharge port, and the agitated and mixed ground is further excavated by an excavation blade. It can be drilled and agitated and mixed at the sides of the drilling blade.

In addition, in order to jet the solidifying material liquid into the unexcavated soil to reach the back surface of the expanded excavation blade, normally,
It is necessary to inject the solidifying material liquid at high pressure, but since the injected solidifying material liquid is blocked by the back surface of the expanded blade,
The solidified material liquid does not reach the outside of the outer diameter of the excavated blade where the diameter of the injected solidified material liquid is expanded, and the ground outside the excavated blade is not excavated or the ground is not loosened. In this way, the improved portion can be surely created up to the outer diameter of the expanded excavation blade.

If the solidified material liquid is not suppressed from being expanded by the excavation blade, the solidified material liquid may be jetted at high pressure to loosen the ground having a diameter larger than the required diameter, which may cause the ground to be displaced. In order to prevent such ground deformation, it is necessary to control the injection pressure extremely accurately according to the ground condition.
In the present invention, since the excavating blade is present, if the injection pressure is set to be applicable to any ground, it is not necessary to adjust the injection pressure according to the ground condition.

As described above, even if there is only one stage of the expanding blade for excavation, it is possible to easily and surely form the ground improvement body in which the excavated soil and the solidifying material liquid are sufficiently agitated and mixed over the entire length.

According to a second aspect of the present invention, the excavation bit at the tip of the inner pipe has an opening at the center thereof. . That is, as shown in FIG. 1, the drill bit is integrally provided on the outer peripheral portion of the tip opening of the inner pipe.

[0016] According to this claim 2, Japanese Patent Laid-Open No. 2001-2
As described in Japanese Patent No. 6923, when the tip drill bit of the inner pipe is opened, a core material having a tip portion capable of closing the opening is previously inserted into the inner pipe, and a drill hole is formed. When the desired depth is reached, the core material can be left in the drill hole, and when the core material is left, the solidified material liquid can be discharged from the central opening of the tip drilling bit and left. It becomes possible to form a layer of the solidifying material liquid having high adhesive strength around the core material.

According to a third aspect of the present invention, the outer surface of the expanded blade type excavating blade in the reduced diameter state is set within the outer diameter of the excavating bit. It is a ground improvement device having a type excavation wing. According to the third aspect, the diameter of the excavation hole excavated by the tip excavation bit can be reduced. That is, the diameter of the excavation hole on the ground surface side can be reduced.

According to a fourth aspect of the present invention, the inner pipe projects from the outer pipe on the side opposite to the drill bit side, and the expanding blade according to the first, second or third aspect. It is a ground improvement device having a type excavation wing. That is, if the inner pipe projects from the outer pipe on the drive portion side opposite to the drill bit, the inner pipe functions as a guide when the outer pipe relatively moves from the ground surface along the inner pipe. It is a preferable structure because it can be achieved.

According to a fifth aspect of the present invention, on the side opposite to the drill bit side, the outer pipe is pressed along the inner pipe toward the drill bit side, and the pressing expands the blade for expanding blade. The ground improvement apparatus having the expanding blade type excavation blade according to claim 1, claim 2, claim 3 or claim 4, wherein That is, when expanding the diameter of the expanding blade, it is preferable to move the outer pipe rather than move the inner pipe.

According to a sixth aspect of the present invention, the excavation rotary shaft of the ground improvement device has a double pipe structure composed of an inner pipe and an outer pipe, and the inner pipe and the outer pipe are integrally rotatable and relatively slidable in the axial direction. It is provided so that the tip of the inner pipe protruding from the outer pipe is provided with a drill bit and a blade-expanding blade in order from the tip side.
The drilling bit side of the blade-expanding blade is rotatably supported on the inner pipe side so that the blade-expanding blade is rotatable, and the other end side or the side near the other end of the blade-expanding blade is the outer pipe side. Diameter is increased when the outer pipe is slid in the direction approaching the excavation bit, and the outer pipe is relatively slid in the direction away from the excavation bit. The expansion-type ground improvement device is installed on the outer pipe to face the tip of the expanded-blade excavation blade whose solidified material liquid outlet has been expanded, and the stopper part is used at the tip. The core material having the above is inserted into the inner pipe in advance from the tip bit side, the ground is excavated to a predetermined depth by the excavating bit in the state where the expanding blade is reduced in diameter, and the outer pipe is placed at the position of the bottom of the excavation hole. Slide the blade to the side of the excavation bit to expand the diameter of the expansion blade and excavate the core material. The solidified material liquid is discharged from the central opening of the drill bit that is left on the bottom and the core material is left, and the solidified material liquid is expanded from the discharge port provided in the outer pipe. It is a ground improvement method characterized by moving an excavation rotary shaft to the ground surface side while discharging it toward an excavation blade to construct a ground improvement body enlarged to a desired position.

According to a sixth aspect of the present invention, the expanding blade type ground improvement device of the present invention is used in which the expanding blade type ground improvement device is of a single stage and the base end side opposite to the tip drilling bit is opened, and the core material is drilled. At the same time as it is left inside, the solidifying material liquid is supplied around the core material, and when the diameter of the excavating rotary shaft is lifted and expanded, the solidifying material liquid is discharged from the discharge port on the side surface of the outer pipe so as to hit the rear surface of the tip of the expanded blade. This is a ground improvement method.

According to the sixth aspect of the present invention, the effects of the above-described ground improvement device of the present invention are exhibited, and the core material is left in the ground improvement body in which the excavated soil and the solidifying material liquid are sufficiently stirred and mixed. In addition, the solidified material layer is formed between the ground improvement body and the core material, and the bonding strength is improved as compared with the case where the ground improvement body and the core material are in direct contact with each other, and the ground improvement body including the core material is provided. The effect that the bending strength of can be improved is exhibited.

According to a seventh aspect of the present invention, after constructing an enlarged ground improvement body, the outer pipe is relatively slid in the direction away from the excavation bit to reduce the diameter of the expanding blade and the excavation hole. The ground improvement method according to claim 6, wherein the ground improvement method is performed outside the ground. In other words, when a ground improvement body is created that is expanded to near the surface by pulling and expanding the diameter, the expansion-type digging blade is reduced in diameter and brought out of the digging hole to reduce the diameter of the digging hole on the surface. This is a preferable ground improvement method. If the diameter of the excavation hole on the surface side can be made small, it is possible to form an enlarged ground improvement body inside even if it is not preferable to provide a large diameter excavation hole on the surface such as a retaining wall.

[0024] A eighth aspect of the present invention is the ground improvement method according to the sixth or seventh aspect, which is characterized by constructing a ground improvement body which is enlarged with respect to a slope or a cut surface. The ground improvement method of the present invention can be applied to a railway track surface, but a particularly effective place is a slope or a cut surface. Therefore, it can also be used for forming a retaining wall.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described based on illustrated embodiments. 1 and 2 show an embodiment of a ground improvement device having an expandable / contractible excavation blade of the present invention,
1 shows a state in which the excavation blade has a reduced diameter, and FIG. 2 shows a state in which the excavation blade has an enlarged diameter.

As shown in the external side view of FIG. 1 (a) and the vertical sectional view of FIG. 1 (b), the excavation rotary shaft 1 of the ground improvement device has a double pipe structure composed of an inner pipe 2 and an outer pipe 3. The inner pipe 2 and the outer pipe 3 can be integrally rotated and axially slidable relative to each other by fitting such as a square cross-section, a key or a spline, and a tip drill bit 4 is provided at the tip of the inner pipe 2. An excavation blade 5 is provided on the side surface of the inner pipe 2 behind the tip excavation bit 4,
A discharge port 6 for the solidifying material liquid is provided on the side surface of the outer tube 3 at the tip portion.

The tip excavation bit 4 is constructed by attaching an excavation blade 11 to the side surface of the excavation portion 10 which is integrally provided at the tip portion of the inner pipe 2 and has a truncated cone shape in a side view. The excavation portion 10 is provided on the outer peripheral portion of the inner pipe 2, and the tip opening 2a is formed at the central portion of the tip excavation bit 4. Drilling blade 1
As shown in the front view of FIG. 1 (c), a plurality of (1 in the illustrated example) 1 are arranged at intervals in the circumferential direction, and the excavating blade 11 excavates the ground.

The excavation blade 5 has its base end attached to the attachment member 12 provided on the side surface of the inner pipe 2 on the rear side of the tip excavation bit 4 by the rotating shaft 13 and rotates in the direction perpendicular to the axis of the excavating rotating shaft 1. It is free. Further, the tip end side of the excavation blade 5 is inserted into a guide hole 15 of an expansion / contraction guide member 14 provided integrally with the tip end portion of the outer tube 3. This excavation wing 5
1 is arranged outside the inner pipe 2 so as not to dig outside the diameter of the digging hole drilled by the tip drill bit 4 in the state where the digging blade 5 is reduced in diameter.

The guide hole 15 of the expansion / contraction guide member 14 is, as shown in the cross-sectional view of FIG. 1 (d), a dovetail groove in which a pair of left and right locking pieces face each other at a distance, and the excavation blade 5 Has a reverse T-shape that can slide in the dovetail-shaped guide hole 15 in a fitted state, and is locked by the collar portions 5a protruding to the left and right thereof so that the excavation blade 5 does not come off to the outside. ing. The outer surface of the digging blade portion 5b is positioned outside the guide hole 15. The side view shape of the collar portion 5a is as shown in FIG.
As shown in (b), the excavation blade 5 has an arcuate shape that is convex toward the inside of the excavation rotary shaft 1 and extends along the axial direction. When the expansion / contraction guide member 14 moves in the axial direction, the excavation blade 5 gradually expands or contracts in diameter. It is supposed to do.

In the illustrated example, the excavation blades 5 are provided at two positions in the circumferential direction of the excavation rotary shaft 1 at intervals of 180 ° (the external side view of FIG. 2 (a), Figure 2 (b)
However, the present invention is not limited to this, and for example, it is also possible to dispose them at four places at intervals of 90 ° (not shown).

As shown in FIGS. 1 (a) and 1 (b), the discharge port 6 is provided with the solidifying material liquid 7 on the tip side of the discharge pipe portion 20 integrally provided on the outer surface of the tip portion of the outer tube 3. It is provided so as to be able to inject toward the outside of the excavation rotary shaft 1 in the direction perpendicular to the axis.
A supply passage 21 for the solidifying material liquid is provided in the discharge pipe portion 20, and the discharge port 6 communicates with the tip end side of the supply passage 21. Further, a supply passage 22 for the solidifying material liquid is provided on the inner surface of the outer pipe 3 at the intermediate portion, and the tip end side of the supply passage 22 communicates with the base end side of the supply passage 21. The solidifying material liquid 7 supplied from the outside to the base end of the excavating rotary shaft 1 is supplied to the supply path 2
2. It passes through the supply path 21 and is ejected from the ejection port 6. It is preferable that the discharge port 6 is located outside the surface of the outer tube 3 so that the solidifying material liquid 7 can be ejected far away.

When the inner tube 2 or the outer tube 3 is moved in the axial direction so that the expansion / contraction guide member 14 approaches the mounting member 12 from the state shown in FIGS. 1 (a) and 1 (b), FIG. As shown in, the diameter of the excavation blade 5 is increased while the collar portion 5a of the excavation blade 5 slides in the guide hole 15. The axial position of the discharge port 6 is determined so that the solidification material liquid 7 ejected from the discharge port 6 in the state of the expansion / contraction guide member 14 contacting the mounting member 12 as shown in FIG. Has been. Therefore, when the injection of the solidifying material liquid 7 from the discharge port 6 is started,
It is preferable to start after the state shown in (a) is reached. Further, the solidified material liquid 7 injected from the discharge port 6 does not excavate the ground outside the excavation blade 5 or loosen the ground because the excavation blade 5 exists.

The discharge port 6 and the discharge pipe portion 20 are shown in FIG.
As shown in FIG. 5, only one location is provided at a position corresponding to the excavation blade 5 on one side, but it may be provided at a total of two locations (not shown) corresponding to the other excavation blade 5. By increasing the number of the discharge ports 6 in this way, the supply amount of the solidifying material liquid per unit excavated soil can be increased. The same applies to the case where the excavation blades 5 are arranged at four positions as described above.

To return the excavation blade 5 shown in FIG. 2 from the expanded diameter state to the reduced diameter state shown in FIG. 1, the expansion / contraction guide member 14 is separated from the mounting member 12 by the inner pipe 2 or the outer pipe. 3 may be moved in the axial direction.

Next, the ground improvement device having the expandable and contractible excavation blade of the present invention having the above-mentioned structure is used by inserting the core material (anchor) of the ground improvement body to be constructed into the inner pipe at the time of use. It The state in which this core material is inserted is illustrated in FIG.

3A is a vertical sectional view of the entire apparatus, FIG. 3B is a front view of the apparatus, and FIG. 3C is a vertical sectional view of the core material.
Has a blade portion 31 at the tip and has a flange-shaped stopper portion 32 at a distance from the blade portion toward the base end side, and is inserted into the inner pipe 2 from the tip end side. The stopper portion 32 serves to prevent the core material 30 from entering the inner pipe 2 during the excavation of the excavating rotary shaft 1 and to rotate together with the inner pipe 2 to close the tip opening 2a of the inner pipe 2. Is.

As shown in FIG. 3 (c), the core material 30 comprises a hollow portion 30a at the tip and a main body portion 30b. A blade portion 31 is provided at the tip of the hollow portion 30a, and a stopper portion 32 is provided at the rear end of the hollow portion 30a. Such a hollow portion 30
The front end portion of the main body portion 30b is inserted into and integrated with the rear end side of a. The stopper portion 32 may be provided on the side of the main body portion 30b.

In the illustrated example, the stopper portion 32
As shown in FIG. 3 (b), the notches 33 are formed at intervals of 180 °. The meaning of the presence of the pair of notch portions 33 is that the pair of excavating blades 11a and the pair of excavating blades 11 among the four excavating blades 11 have different shapes as shown in FIG. 1 (a) and FIG. This is because
That is, the tip end surface of the excavating blade 11b is at the same position as the tip end surface of the inner pipe 2, and the tip end surface of the excavating blade 11a projects from this.

Then, in order to close the tip opening of the inner pipe 2, it is necessary to pass the tip portion of the excavating blade 11a having a protruding tip. For this reason, the notch 33 is provided in the flange-shaped stopper 32. If a pair of drilling blades 1
Similarly to the pair of excavating blades 11a, when the distal end portion of 1b projects from the distal end surface of the inner pipe 2, the notch portion 33 is also provided at a position corresponding to the distal end portion of the excavating blade 11b.

As shown in FIG. 3B, the flange-shaped stopper portion 32 having the cutout portion 33 has the cutout portion 3 as shown in FIG.
A pair of right and left rising portions of 3 hit the side surfaces of the excavating blade 11a and are locked. Therefore, when the excavation rotary shaft 1 is rotated, the core material 30 can rotate together with the inner pipe 2. As a result, the tip blade portion 31 of the core material 30 also rotates, and the tip blade portion 31 can also be excavated. The tip of the excavating blade 11a protruding from the stopper 32 can also be excavated.

When the excavation to the predetermined depth is completed, the flange-shaped stopper portion 32 is in a state of being caught by the tip excavation bit 4, so that the tip blade portion 31 of the core material 30.
By pulling up the excavation rotary shaft 1 from the state in which the pierced into the bottom of the excavation hole, the core material 30 can be left in the excavation hole as shown in FIG. The vertical cross-sectional view of FIG. 4 (a) and the front view of FIG. 4 (b) show a state in which the excavation blade 5 is expanding, but it is in a contracted state when the excavation is completed to a predetermined depth. is there. Next, the operation of the ground improvement device of the present invention will be described.

As shown in the vertical cross-sectional view of FIG. 5, first, the excavating blade 1 of the tip excavating bit 4 is moved by excavating the excavating blade 5 while rotating the excavating rotary shaft 1 in a reduced diameter state.
The excavation hole 40 having a predetermined depth is formed while excavating the ground with the blade portion 31 of 1 or the tip of the core material.

Then, when excavating to a predetermined depth, while excavating rotary shaft 1 with excavating blades 5 having a reduced diameter,
When the outer tube 3 provided with the expansion / contraction guide member 14 is gradually moved to the tip excavation bit 4 side, the excavation blade 5 gradually expands in diameter to expand the excavation hole diameter. When the excavation blade 5 is in a sufficiently opened state, the solidifying material liquid 7 is injected from the discharge port 6 into the ground on the unexcavated side to reach the back side of the tip of the enlarged excavation blade 5. Next, the excavation rotary shaft 1 is slightly lifted up and rotated in this state, whereby the excavated soil and the solidifying material liquid are sufficiently stirred and mixed to the tip of the excavation hole (see FIG. 6).

As another means in such a process, when the earth mass is large at the tip of the excavation hole and the earth mass is large, the solidification material liquid 7 is injected from the discharge port 6 without expanding the diameter of the excavation blade 5, and the injection pressure is increased. There is also a method of expanding the diameter of the stirring blade 5 after stirring and mixing the ground and the solidifying material liquid.

After that, the excavating rotary shaft 1 is gradually lifted and rotated so that the excavated soil and the solidifying material liquid are sufficiently stirred and mixed while enlarging the excavated hole 40 as shown in the vertical sectional view of FIG. In this way, the excavated soil and the solidifying material liquid can be sufficiently stirred and mixed with each other because the ground where the solidifying material liquid is stirred and mixed by the injection pressure of the solidifying material liquid 7 supplied from the discharge port 6 is further expanded. This is because the diameter of the excavating blade 5 can be used for excavation, and the side surfaces of the excavating blade 5 can be stirred and mixed.

Using the ground improvement device having the above-mentioned structure,
An example of forming a ground improvement body / anchor body on the slope will be described. The construction procedure is shown below (see the sectional view of FIG. 7).

(1) As described above with reference to FIG. 3, the excavation rotary shaft 1 is inserted with the core material 30 inserted and the excavation blade 5 reduced in diameter.
The digging hole 40 is formed in the ground by rotating and excavating. This state is shown in FIG. 7 (a).

(2) As shown in FIG. 7 (b), when the depth of the excavation hole 40 reaches a predetermined depth, the excavation blade 5 is expanded in diameter as described with reference to FIG. The solidifying material liquid 7 is jetted from the discharge port 6. This state is shown in FIG. 7 (c).

(3) As shown in FIG. 7 (d), the excavated soil and the solidified material liquid are stirred and mixed by rotating the excavation rotary shaft 1 while pulling the excavation rotary shaft 1 while the excavation blade 5 is expanded. The improvement body 41 is formed in the ground in a state in which it is larger than the drill hole 40.

(4) When it is not preferable to form the expanded ground improvement body 41 up to the slope surface, the stirring blade 5 is reduced in diameter as shown in FIG. When the excavation blade 5 is enlarged, the inside of the enlarged excavation blade 5 is still disturbed by the solidifying material liquid from the discharge port 6, and the ground and the solidifying material liquid are mixed, so that the discharge port 6 After continuing the supply of the solidifying material liquid 7 for a while, the supply of the solidifying material liquid 7 is stopped and the excavating blade 5 is rotated while being gradually contracted, whereby the excavated soil and the solidified liquid are sufficiently stirred and mixed.

(5) After the state shown in FIG. 7 (e) in this manner, the ground improvement device is lifted up to the slope surface with the diameter of the excavation blade 5 reduced, and the construction is completed. From the above, the core material 3
A ground improvement body 41 having a diameter of 0 is formed.

Although not explicitly shown in FIG. 7, FIG.
When the excavation rotary shaft 1 is lifted from the state of (c), the inner pipe 2
When the solidifying material liquid is supplied to the inside of the, the solidifying material liquid is discharged from the tip opening 2a of the tip drilling bit 4 (see FIG. 4 (a)), and a solidifying material layer can be formed around the core material 30. . When the solidifying material layer is formed between the ground improvement body 41 and the core material 30 in this way, the ground improvement body 41 and the core material 30 are formed.
The adhesive strength is improved compared to the case where the
The bending strength of the ground improvement body 41 including the core material 30 is improved.

The solidifying material liquid used in the present invention includes, for example, cement milk. Further, a steel pipe or the like can be used as the core material. Further, in the present invention, in the case of forming an expansion improving body, an expansion improving body including an anchor body on a slope, a cut surface, a retaining wall, a lower portion of a railway line, a lower portion of a road, or a rear surface of another hard surface. Can be applied to.

[0054]

EFFECTS OF THE INVENTION (1) In the ground improvement device having the expanding blade type excavation blade of the present invention, the excavation rotary shaft of the ground improvement device has a double pipe structure including an inner pipe and an outer pipe. Are integrally rotatable so as to be slidable relative to each other in the axial direction, and the tip of the inner pipe protruding from the outer pipe is provided with a drill bit and a blade-expanding blade in order from the tip side. The digging bit side of the expanded wing is rotatably supported on the inner pipe side so that the expanded wing is rotatable, and the other end side or the side near the other end of the expanded wing is provided on the outer pipe side. The outer pipe is inserted into the guide hole, and the diameter is expanded when the outer pipe is relatively slid in the direction approaching the drill bit, and the outer pipe is contracted when the drill bit is relatively slid in the direction away from the drill bit. It is provided on the outer pipe so that the discharge port of the solidifying material liquid faces the tip of the expanded blade with the expanded diameter. Therefore, when excavating a small diameter drill hole with the tip drilling bit in a state where the expanded blade is reduced in diameter, the excavation blade is lifted when the drilling rotary shaft is lifted and the expanded drilling hole is used to drill the expanded hole. The solidifying material liquid supplied from the discharge port arranged on the side is sprayed toward the back surface of the tip of the expanded digging blade and is supplied to the ground that has not been excavated by the expanded digging blade. Therefore, the ground containing the solidified material liquid is excavated by the expanded blade, and the excavation action and the stirring and mixing action on the side surface of the excavation blade can be achieved at the same time. Even in the case of the one-stage expanding blade type excavating blade, the excavated soil and the solidifying material liquid can be sufficiently stirred and mixed as compared with the case of the conventional technique in which there is a portion that is not stirred and mixed. Furthermore, when injecting the solidifying material liquid from the discharge port, the ground and the solidifying material liquid are agitated and mixed by the injection pressure of the solidifying material liquid supplied from the discharge port, and the ground that is agitated and mixed is further excavated by an excavation blade, It is possible to stir and mix on the side of the drilling blade.

In order to jet the solidifying material liquid into the unexcavated soil to reach the back surface of the excavated blade whose diameter has been expanded, it is usually
It is necessary to inject the solidifying material liquid at high pressure, but since the injected solidifying material liquid is blocked by the back surface of the expanded blade,
The solidified material liquid does not reach the outside of the outer diameter of the excavated blade where the diameter of the injected solidified material liquid is expanded, and the ground outside the excavated blade is not excavated or the ground is not loosened. In this way, the improved portion can be surely created up to the outer diameter of the expanded excavation blade.

If the solidified material solution is not suppressed from expanding and jetted by the excavating blade, high pressure jetting of the solidified material liquid may loosen the ground having a diameter larger than a necessary diameter and cause a ground displacement. In order to prevent such ground deformation, it is necessary to control the injection pressure extremely accurately according to the ground condition.
In the present invention, since the excavating blade is present, if the injection pressure is set to be applicable to any ground, it is not necessary to adjust the injection pressure according to the ground condition.

As described above, even when there is only one stage of the expanding blade for excavation, it is possible to easily and surely form the ground improvement body in which the excavated soil and the solidifying material liquid are sufficiently agitated and mixed over the entire length.

(2) In the ground improvement method of the present invention, the excavation rotary shaft of the ground improvement device has a double pipe structure consisting of an inner pipe and an outer pipe, and the inner pipe and the outer pipe are rotatable integrally and in the axial direction. The inner pipe protruding from the outer pipe is provided with an excavating bit and a blade-expanding blade in order from the tip side. The expanding blade type excavating blade is rotatably supported on the pipe side, and the other end side or the side near the other end of the expanding blade type excavating blade is inserted into a guide hole provided on the outer pipe side to form an outer pipe. Is configured to expand when it is slid relatively in the direction approaching the drill bit, and to reduce the diameter when the outer pipe is relatively slid in the direction away from the drill bit. The wing expansion type ground improvement device installed on the outer pipe is used so that it faces the tip of the expanded wing. And insert a core material with a stopper at the tip into the inner tube from the tip bit side beforehand.
With the diameter of the expansion blade excavating blade reduced, the ground is excavated to a predetermined depth by the excavation bit, and the outer pipe is slid relative to the excavation bit side at the position of the bottom of the excavation hole to expand the expansion blade. The diameter of the core material is left at the bottom of the excavation hole, and the core material is left to discharge the solidification material liquid from the central opening of the drilling bit opened and the solidification material from the discharge port provided in the outer pipe. Since the excavation rotary shaft is moved to the ground surface side while discharging the liquid toward the expanded blade type excavation blade, a ground improvement body expanded to a desired position is constructed, and thus the ground of the present invention described above. In addition to the effect of the improvement device, the core material can be left in the ground improvement body in which the excavated soil and the solidification material liquid are sufficiently agitated and mixed, and the solidification material is further provided between the ground improvement body and the core material. When a layer is formed and the ground improvement body and the core material are in direct contact In comparison, the adhesive strength is improved, and an effect that it is possible to improve the bending strength of the soil improvement comprising a core material.

[Brief description of drawings]

FIG. 1 is an embodiment of a ground improvement device having an expandable / contractible excavation blade of the present invention, showing a state in which the excavation blade has a reduced diameter,
(a) is a side view, (b) is a longitudinal sectional view, (c) is a front view of the tip bit, and (d) is a transverse sectional view of the outer tube tip portion.

2 is a side view of the ground improvement apparatus of FIG. 1, showing a diameter expansion state, and FIG. 2 (b) is a front view of a tip bit.

3 shows a state in which a core material is inserted into the ground improvement device of FIG. 1, (a) is a vertical sectional view, (b) is a front view of a tip bit, (c).
[Fig. 3] is a vertical sectional view of a core material.

4 (a) is a longitudinal sectional view and FIG. 4 (b) is a front view of the tip bit, showing a state of the ground improvement device of FIG. 3 at the time of lifting.

FIG. 5 is a side view showing a state of the ground improvement device of FIG. 3 at the end of excavation.

FIG. 6 is a side view showing a state of the ground improvement device of FIG. 3 at the time of lifting.

FIG. 7 is a cross-sectional view showing, in the order of steps, the ground improvement method by the ground improvement device of the present invention.

[Explanation of symbols]

1 ... Excavation rotary axis 2 …… Inner tube 2a ... Tip opening 3 ... Outer tube 4 ... Tip drilling bit 5 ... Expansion-contraction type excavation blade 5a ... collar part 5b ... Drilling blade 6 ... Discharge port 7 ... Solidifying material liquid 10 ... excavation department 11 ... Drilling blade 12 ... Mounting member 13 ... Rotary axis 14 ... Expansion / contraction guide member 15 ... Guide hole 20 ... Discharge pipe section 21 ... Supply path 22 ... Supply path 30: Core material 30a ... Hollow end 30b ... main body 31 ... Tip blade 32 ... Stopper part 33 ... Notch 40 ... Drilling hole 41 ... Ground improvement body

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Amami Kami             6-13-7 Akasaka, Minato-ku, Tokyo Co., Ltd.             In Tenox (72) Inventor Shozo Suzuki             Tokyu, 1-16-14 Shibuya, Shibuya-ku, Tokyo             Inside the corporation F-term (reference) 2D029 EB00                 2D040 AB05 AB14 BA08 BC01 CA01                       CB03 DA17 DB07 EA11 EA17                 2D041 GA01

Claims (8)

[Claims] 1. An excavation rotary shaft of a ground improvement device has a double pipe structure composed of an inner pipe and an outer pipe, and the inner pipe and the outer pipe are integrally rotatable and relatively slidable in an axial direction. ,
The tip of the inner pipe protruding from the outer pipe is provided with an excavating bit and a blade-expanding blade in order from the tip side, and the excavating bit side of the blade-expanding blade is axially supported by the inner pipe to expand the blade. Type excavating blade is rotatable, and the other end side or the side near the other end of the expanding blade type excavating blade is inserted into a guide hole provided on the outer pipe side, and the outer pipe is relatively moved in a direction approaching the excavating bit. Expanded wing type with expanded diameter when slid on the outer pipe and reduced diameter when the outer pipe is relatively slid in a direction away from the drill bit, and with a widened discharge port for solidifying material liquid A ground improvement device having an expanding blade for excavation, which is provided on the outer pipe so as to face the tip of the ground. 2. The ground improvement device having a blade for expanding blades according to claim 1, wherein the excavating bit at the tip of the inner pipe has an opening at the center thereof. 3. The ground having expanded blade type excavating blades according to claim 1, wherein the outer surface of the expanded blade type excavating blades in a reduced diameter state is contained within the outer diameter of the excavating bit. Improved device. 4. The ground having the expanding blade according to claim 1, wherein the inner pipe projects from the outer pipe on the side opposite to the drill bit side. Improved device. 5. On the side opposite to the drill bit side, the outer pipe is configured to be pressed toward the drill bit side along the inner pipe,
The expansion blade excavation blade is expanded in diameter by the pressing, and the ground improvement device having the expansion blade excavation blade according to claim 1, claim 2, claim 3 or claim 4. . 6. The ground improvement device has an excavation rotary shaft having a double pipe structure including an inner pipe and an outer pipe, and the inner pipe and the outer pipe are integrally rotatable and relatively slidable in the axial direction. ,
The tip of the inner pipe protruding from the outer pipe is provided with an excavating bit and a blade-expanding blade in order from the tip side, and the excavating bit side of the blade-expanding blade is axially supported by the inner pipe to expand the blade. Type excavating blade is rotatable, and the other end side or the side near the other end of the expanding blade type excavating blade is inserted into a guide hole provided on the outer pipe side, and the outer pipe is relatively moved in a direction approaching the excavating bit. Expanded wing type with expanded diameter when slid on the outer pipe and reduced diameter when the outer pipe is relatively slid in a direction away from the drill bit, and with a widened discharge port for solidifying material liquid Using a blade expansion type ground improvement device installed on the outer pipe so that it faces the tip of the, the core material having a stopper at the tip is inserted into the inner pipe from the tip bit side beforehand, and the blade is excavated. Excavate the ground to a specified depth with the drill bit while the blades are reduced, and The blade is expanded relatively to the side of the drill bit to expand the diameter of the blade, and the core material is left on the bottom of the drilling hole, and the core material is left behind to solidify the solidified material from the center opening of the drill bit. While discharging the liquid,
The solidification material liquid is discharged from the discharge port provided in the outer pipe toward the expanded blade type expanding blade, and the excavation rotary shaft is moved to the ground surface side to expand the ground to the desired position. A ground improvement method characterized by building a body. 7. After constructing the enlarged ground improvement body, the outer pipe is slid relatively in the direction away from the excavation bit to reduce the diameter of the expanding blade and bring it out of the excavation hole. The ground improvement method according to claim 6, which is characterized. 8. The ground improvement method according to claim 6 or 7, wherein a ground improvement body expanded to a slope or a cut surface is constructed.