JP2003301449A - Foundation pile and cement milk injecting head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foundation pile and a cement milk injecting head, which can enhance efficiency of injection work by using a hose in place of piping for injection so as to inject cement milk for reinforcement and the like into ground from a lower end of the foundation pile made of a steel pipe. <P>SOLUTION: The foundation pile is equipped with a constitution in which a check valve for preventing a reverse inflow of sediment, the cement milk and the like into the steel pipe is attached to an opening which is provided in an end surface plate for closing a lower opened end thereof, and in which a joint cylinder is mounted on the side of a top surface of the end surface plate so as to be concentric with the opening. The cement milk injecting head is equipped with a constitution in which an intermediate pipe long enough to protrude both upper and lower ends thereof is fitted into an inside hollow part of a thick-walled cylindrical body with a prescribed length via a bearing, in which a cement milk feeding hose is coupled to the upper end of the intermediate pipe, and in which a discharge valve for the cement milk is attached to the lower end thereof. A lower end surface of the thick-walled cylindrical body, which is supported on the hose in a suspended state, is brought into pressure contact with an upper end surface of the joint cylinder so as to be connected to the joint cylinder. <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 steel pipe which is provided with a screw bit on the outer peripheral surface of the lower end and has a tip bit projecting from an end plate for closing the lower end opening. The present invention relates to a foundation pile provided with an opening having a check valve for injecting a ground strengthening agent such as milk or a curable resin liquid, or water, and a cement milk injection head used in combination with the foundation pile.

[0002]

2. Description of the Related Art As a method of injecting cement milk into the ground in order to reinforce the ground in the vicinity of the lower end of a buried steel pipe foundation pile, conventionally, a pipe for feeding cement milk is provided at the upper end opening of the steel pipe. It was inserted until it reached the lower end opening, and the cement milk was discharged toward the ground.
The above-mentioned piping is also used to inject water for softening the ground in order to reduce the excavation resistance of the foundation pile.

[0003]

As described above, according to the method of inserting the pipe for feeding cement milk into the inner space of the foundation pile, the long pipe is inserted and the used pipe is pulled out. In addition, it requires a certain amount of equipment, and too much time and labor is required to insert and remove the pipes, which increases the construction cost and prolongs the construction time.

Therefore, an object of the present invention is to replace the conventional piping for injecting cement milk with a hose for injecting cement milk so that the above-mentioned inconvenience can be largely eliminated. And to provide a cement milk injection head for this foundation pile.

[0005]

In order to achieve the above object, a foundation pile according to the present invention has a steel pipe of a predetermined length, to which a screw bit is attached to the outer peripheral surface of the lower end portion, and a tip end is attached to an end face plate closing the lower end opening. In the projecting bit, an opening is provided in the center of the end plate for injecting a ground strengthening agent such as cement milk or a curable resin liquid into the ground. It is characterized by mounting a check valve to prevent the reverse inflow of ground strengthening agents. Further, the present invention is also characterized in that a frusto-conical joint tube that spreads upward is attached to the upper surface of the end plate so as to be concentric with the opening. Then, the plate-shaped tip bit is provided with a hollow at a position facing the opening,
Alternatively, the tip bit may be omitted at this point.

Then, the cement milk injection head according to the present invention is dropped from the upper end opening of the steel pipe foundation pile according to any one of claims 1 to 3 and is connected to the joint cylinder so that the cement milk or the ground is added to the ground. A device for injecting a ground strengthening agent such as a curable resin liquid, in which a thick-walled tubular body of a predetermined length is used as a main body, and the upper and lower ends of the thick-walled tubular body are hollowed out. The intermediate pipe of a length that can be projected from the section is fitted coaxially through the bearing and the seal ring, the cement milk supply hose is connected to the upper end of the intermediate pipe, and the cement milk supply is interrupted at the lower end. A discharge valve is attached to the cement milk supply hose, and the lower end surface of the thick-walled tubular member suspended from the cement milk supply hose is liquid-tightly pressed against the upper end surface of the joint cylinder by its own weight. To do. The bearing and seal ring can be omitted if desired.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION First, a foundation pile according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 3 and 10 to 12. For example, the structural feature of the foundation pile A1 of this embodiment, which is buried through the procedure shown in FIGS. 10 to 12, is the lower end portion thereof as shown in FIGS.

That is, a screw bit 2 is attached to the outer peripheral surface of the lower end of a steel pipe 1 (see FIG. 10) having a predetermined length, which constitutes the main body of the foundation pile A1, and an end face plate 3 for closing the lower end opening of the steel pipe 1. In this case, a thick plate-shaped tip bit 4 is provided so as to project downward.

The end face plate 3 is provided with a circular opening 5 in the center thereof for injecting a ground strengthening agent such as cement milk or a curable resin liquid or water toward the ground. As mentioned above, the injected water softens the ground,
This is to play a role of reducing the excavation resistance of the ground to the foundation pile A1.

On the lower surface side of the end face plate 3, a check valve 6 is installed so as to block backflow of the ground strengthening agent such as earth and sand, cement milk or the like or water or the like into the steel pipe 1 so as to close the opening 5. There is. The check valve 6 of this embodiment is made of a rubber plate, and its fixed side end is fixed to the end face plate 3 by a stopper 7 as shown in FIG.

As can be seen from FIG. 1, the check valve 6 interferes with the tip bit 4 as it opens and closes.
Therefore, in the tip bit 4, at a position facing the opening 5,
A through hole a is provided.

Further, on the upper surface side of the end face plate 3, a short cylindrical joint cylinder 10 is provided so as to project upward concentrically with the opening 5. The joint cylinder 10 of this embodiment is formed in a frustoconical shape that expands upward.

Next, the foundation pile A of the second embodiment according to the present invention.
2 is limited to the lower end which is the characteristic part of FIG.
It was shown to. The only difference from the foundation pile A1 of the first embodiment is the form of the tip bit 4. That is, the tip bit 4 formed in a rectangular plate shape and provided with the cutting blade 4a at the lower end edge thereof is
Interference with the check valve 6 that opens and closes is avoided by omitting the middle portion in the lateral direction and providing the gap b.

Next, an embodiment of the cement milk injection head according to the present invention will be described with reference to FIGS. 7 and 8. The cement milk injection head B1 of this embodiment, the longitudinal section of which is shown in FIG. 7 and the appearance of which is shown in FIG. 8, is connected to the joint cylinder 10 of the foundation pile A1 described above, and then cemented to the ground through the opening 5. It is a device for injecting milk and the like.

As shown in FIG. 7, the cement milk injecting head B1 has, as a main body, a thick-walled tubular body 21 having a predetermined length and an outer shape that allows it to be loosely fitted in the steel pipe 1. In the inner space c of the thick-walled tubular body 21, an intermediate pipe 22 serving as a cement milk injection path is housed. The upper and lower ends of the intermediate pipe 22 are respectively projected from the inner space c.

The intermediate pipe 22 is fitted in a bearing 23 and a seal ring 24, which are respectively attached to upper and lower ends of the thick-walled tubular body 21. As a result, even if the foundation pile A1 rotates during the burying operation, the intermediate pipe 22 can be kept stationary. Further, it is possible to cut off the communication between the inner space portion c and the outer world around the inner portion.

At the upper end of the intermediate pipe 22, a joint portion (not shown) for connecting the cement milk supply hose 25 is provided. On the other hand, a discharge valve 30 for interrupting the supply of cement milk to the ground is attached to the lower end of the intermediate pipe 22.

An example of the structure of the discharge valve 30 is shown in FIG. Reference numeral 31 denotes a tubular casing, the upper end of which is connected to the lower end of the intermediate pipe 22, and the conical diameter-reduced lower end is provided with a valve port 32. A cylinder 33 whose upper end is closed is placed above the valve opening 32. The piston-shaped valve element 34 housed in the cylinder 33 is urged downward by a spring 35, and its tip rod 34a normally closes the valve opening 32 as shown in FIG. There is.

To explain the operation of the discharge valve 30, pressurized cement milk from a cement milk supply source (not shown) passes through the cement milk supply hose 25 and the intermediate pipe 2.
When it is supplied to 2, the pressurized cement milk that has spilled around to the lower side of the cylinder 33 pushes up the valve element 34 against the pressing force of the spring 35, and as shown in FIG. Let go.

Next, using the above-mentioned foundation pile A1 and the cement milk injection head B1, a method of burying the foundation pile in the construction ground, an example of which will be described with reference to FIGS. explain. D in this figure is a self-propelled pile burying machine, and a column 41 is attached to the front part of the pile burying machine so as to be vertically movable.

A rotation drive device 42 for holding and rotating the upper end of the foundation pile A1 is attached to the support column 41 so as to be vertically movable. Further, a cement milk supply hose 25 is hung at the top end of the support column 41 so as to be freely drawn and pulled up.
A hose reel 43 is attached. 44 is a foundation pile A1
It is a cylindrical holding member for holding and moves up and down along the support column 41. 45 is a wire for lifting the foundation pile A1.

After moving the pile burying machine D to the burying position on the construction site, as shown in FIG. 10, the foundation pile A1 is erected at a predetermined position by using the lifting wire 45 and
As shown in FIG. 1, its upper end is connected to the rotary drive device 42. After that, if the rotary drive device 42 is activated, the foundation pile A1 is pushed into the ground by the action of the screw bit 2 and the tip bit 4 while turning, as shown in FIG. go.

If necessary, while successively adding a plurality of foundation piles A1, when the tip reaches a predetermined depth,
The cement milk supply hose 25, which is suspended on the hose reel 43 at the top end of the support column 41 and has the cement milk injection head B connected to the tip thereof, is lowered. Of course, as illustrated, the cement milk supply hose 25 may be lowered together with the foundation pile A1.

Then, as shown in FIG. 7, the tip portion of the discharge valve 30 at the lower end of the cement milk injection head B is guided by the inner peripheral surface of the upwardly conical joint cylinder 10 to open the opening 5. Go through. Then, the flat lower end surface of the thick-walled tubular body 21 is liquid-tightly pressed against the upper end surface of the joint cylinder 10 by the weight of the cement milk injecting head B1 and the weight of the cement milk supply hose 25, and the cement milk injecting head. B1 is in a state of being connected to the joint cylinder 10. 26 is an annular packing.

Then, the supply source of the cement milk is activated to supply the pressurized cement milk to the discharge valve 30 via the cement milk supply hose 25 and the intermediate pipe 22, and the foundation pile A1 is also rotated. Along with this, the discharge valve 30 is opened as described above, and the cement milk ejected from the valve port 32 is injected into the ground loosened by the screw bit 2 and the tip bit 4.

During this period, the foundation pile A1 which continues to rotate is
Since it moves forward for some more distance, the ground at the lower end of the foundation pile A1 that has been buried, over a relatively wide area,
It can be strongly reinforced with infused cement milk.

The cement milk injecting head B1 which has finished the role of injecting the cement milk is pulled out of the steel pipe 1 by pulling up the cement milk supply hose 25 with a winding device (not shown) mounted on the pile burying machine D. Easy to take out.
And you can continue to use it repeatedly.

Next, FIG. 13 shows another embodiment of the cement milk injection head. The cement milk injection head B2 of this embodiment is for replacing the cement milk supply hose 25 with a pipe (not shown) as in the prior art.

Compared with the cement milk injection head B1,
The difference of the cement milk injection head B2 of this embodiment is basically that the intermediate pipe 2 is rotated even if the foundation pile A is rotated.
The bearing 2 and the seal ring 24 for keeping the stationary state 2 are omitted in FIG.

The cement milk supply pipe (not shown) is connected to a pipe joint provided at the upper end of the intermediate pipe 22. Further, in the thick-walled tubular body 21 of this embodiment, only the upper and lower end portions are thickened, and the middle portion is thinned. An annular packing 26 for maintaining liquid tightness is attached to the lower end surface of the thick-walled tubular body 21.

[0031]

As is apparent from the above description, the foundation pile and the cement milk injection head according to the present invention are configured so that the cement milk supply hose is used in place of the conventional cement milk supply pipe. For example, compared to the prior art, the practically excellent effects listed below can be obtained. (A) The work of dropping the cement milk supply hose toward the tip of the steel pipe foundation pile is much quicker and easier than the work of inserting the pipe. (B) The hose can be used much more efficiently than the piping for the withdrawal / washing work after the injection. (C) The check valve provided in the foundation pile and the discharge valve provided in the injection head reliably prevent the reverse inflow of earth and sand and cement milk into the inner space of the foundation pile. (D) Even if the foundation pile pivots, the intermediate pipe is kept stationary, so that the problem of twisting the cement milk supply hose does not occur. (E) In general, the work of reinforcing the ground by injecting the ground strengthening agent such as cement milk can be performed extremely efficiently and economically.

[Brief description of drawings]

FIG. 1 shows a first embodiment of a foundation pile according to the present invention, and is a vertical cross-sectional front view of a lower end portion forming a main part thereof.

FIG. 2 is a vertical sectional side view of the same.

FIG. 3 is a bottom view of FIG.

FIG. 4 shows a second embodiment of the foundation pile according to the present invention, and is a vertical sectional front view of a lower end portion which constitutes a main part thereof.

FIG. 5 is a vertical side view of the same.

FIG. 6 is a bottom view of FIG.

FIG. 7 is a longitudinal sectional view showing an embodiment of the cement milk injection bed according to the present invention, showing a state where the cement milk injection bed is accommodated in the lower end portion of the inner space of the foundation pile.

8 is an external view corresponding to FIG. 7, same as above.

FIG. 9 is a vertical cross-sectional view showing a portion of the discharge valve in a closed valve state and an opened valve state.

FIG. 10 is a schematic view of a state at the start of construction, showing a construction state using the foundation pile and the cement milk injection bed according to the present invention.

FIG. 11 is a sketch of the same as above, when the foundation pile is buried.

FIG. 12 is a sketch diagram showing a state at a stage where the burying is almost completed.

13 is a view corresponding to FIG. 7, showing another embodiment of the cement milk injection bed according to the present invention.

[Explanation of symbols]

A1, A2 foundation pile B1, B2 Cement milk injection bed D pile burying machine 1 steel pipe 2 screw bits 3 End plate 4 Tip Bit 5 openings 6 Check valve 7 stopper 10 Joint tube a hole b gap c inner space 21 Thick-walled tubular body 22 Intermediate pipe 23 Bearing 24 seal ring 25 Cement milk supply hose 26 Annular packing 30 discharge valve 31 casing 32 valve 33 cylinders 34 Disc 35 spring 41 prop 42 rotary drive 43 hose reel 44 Guide member 45 Lifting wire

Continued front page    F-term (reference) 2D040 AB01 AB14 CA01 CB03 DA01                       DA05 DA07 DA08 DA11 DB05                 2D041 AA02 BA35 BA52 CA05 CB06                       DB02 FA14

Claims (5)

[Claims] 1. A steel pipe having a predetermined length, a screw bit being attached to the outer peripheral surface of the lower end portion, and an end bit projecting from the end face plate closing the lower end opening, wherein cement milk is added to the ground in the center of the end face plate. And an opening for injecting a ground reinforcement such as curable resin liquid,
A foundation pile characterized in that a check valve is attached to this opening to prevent the reverse flow of earth and sand and ground reinforcement into the steel pipe. 2. The foundation pile according to claim 1, further comprising a frusto-conical joint tube, which extends upward, mounted on the upper surface of the end plate so as to be concentric with the opening. 3. The plate-shaped tip bit is provided with a hollow at a location facing the opening, or the tip bit is absent at this location.
Foundation pile described. 4. A ground strengthening agent, such as cement milk or a hardening resin liquid, which is dropped from the upper end opening of the steel pipe foundation pile according to any one of claims 1 to 3 and connected to a joint cylinder. A device for injecting, which has a thick-walled tubular body of a predetermined length as a main body, and an inner space of the thick-walled tubular body has an intermediate length that allows its upper and lower ends to project from the inner space. A pipe is fitted coaxially through a bearing and a seal ring, a cement milk supply hose is connected to the upper end of the intermediate pipe, and a discharge valve for interrupting the supply of cement milk is attached to the lower end. Cement milk injecting head for foundation piles, characterized in that the lower end surface of a thick-walled tubular member suspended from a cement milk supply hose is liquid-tightly pressed against the upper end surface of a joint cylinder by its own weight. . 5. The cement milk injection head for a foundation pile according to claim 4, wherein the bearing and the seal ring are omitted.