JP2001220736A - Method of driving pile directly below structure and bag- equipped pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of driving a pile directly below a structure such that the support force, bearing strength and deformation performance of a foundation can be easily and surely enhanced by injection of a small amount of self-hardening fluid, and a bag-equipped pile for use therein. SOLUTION: The method of driving the pile directly below an existing structure includes the steps of digging a hole 7a in the foundation 7 of the structure; driving the pile 1 into the hole 7a; pouring the self-hardening fluid into a bag 3 mounted to the periphery of the pile 1; and inflating the bag 3 upwardly for bringing it into intimate contact with the lower surface 7b of the foundation 7. The method involves the use of the bag-equipped pile 1 comprising a pile 2, the bag 3 mounted to the outer periphery of the pile 2, and an injection means 6 for pouring the self-hardening fluid into the bag 3, with the bag 3 mounted in such a manner that it has an extra length 3a at one end of the pile 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pile driving method directly below a structure for improving the strength of the foundation of an existing structure and the deformation performance during an earthquake, and a pile with a bag used in the method.

[0002]

2. Description of the Related Art To cope with an increase in the load on an upper structure, loosening of the upper ground due to the installation of a new underground structure immediately below an existing structure, or seismic reinforcement including measures for liquefaction. Occasionally, the existing foundation lacks the proof stress and the deformation performance during an earthquake.

As a method of reinforcing the existing structure in such a case, there is a method of increasing the pile outside the existing pile to improve the bearing capacity, the proof strength and the deformation performance in the event of an earthquake. Also,
In the method of increasing piles and the like, there is a method of improving the ground of the entire lower and surrounding grounds in any of the pile foundation and the direct foundation to increase the ground strength immediately below the existing structure or directly below the existing pile.
However, in the reinforcement by such a ground improvement method, the predetermined performance cannot be satisfied unless the entire area immediately below the existing structure or other wide areas is ground improved, resulting in an increase in cost. Therefore, without increasing the area for ground improvement and without removing the existing foundation, it is possible to easily and reliably improve the bearing capacity, bearing capacity and deformation performance of the foundation, and if there is an existing pile, make effective use of it. The following method has been proposed as a cast-in-place pile construction method directly under the existing structure.

In this method, a vertical through-hole is formed in an existing structure having an existing pile, and the ground is cut using the through-hole to make the hole larger in diameter than the through-hole. Then, the pile is inserted from the through hole, and the hole passing through the pile is filled with a self-hardening fluid such as cement milk, mortar or concrete to form a cast-in-place pile.

[0005]

However, in the above-mentioned method of filling a hole through a pile with a self-hardening fluid to form a cast-in-place pile, the self-hardening fluid permeates the ground, so that the lower surface of the existing foundation and the self-hardening There may be a gap between the fluid and the fluid.
When this gap occurs, there is a problem that the strength for supporting the existing structure is insufficient. Further, if the self-hardening fluid is further injected to eliminate the gap, there is a problem that the usage amount of the self-hardening fluid increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to simply and surely improve the foundation's supporting force, proof stress and deformation performance with a small amount of self-hardening fluid. To provide a pile driving method directly below a structure and a pile with a bag used in this method.

[0007]

According to the first aspect of the present invention, there is provided a first step of forming a hole in a foundation of a structure, a second step of driving a pile into the hole, and a step surrounding the pile. A third step of pouring a self-hardening fluid into the bag attached to the base, inflating the bag upward, and bringing the bag into close contact with the lower surface of the foundation. According to the above configuration, a hole is formed in the foundation of the structure, and after the pile is driven into the hole, the bag attached to the pile is used to connect the upper end side of the pile to the foundation. When the self-hardening fluid is poured, the bag swells upward, so that the bag comes into close contact with the lower surface of the foundation. When the self-hardening fluid in the bag is solidified, the pile and the lower surface of the foundation are connected via the self-hardening fluid in the bag. For this reason, the structure can be supported by the piles that are punched into the existing structure by making holes.

According to a second aspect of the present invention, in the third step, the bag has an extra portion at an upper portion, and the bag is inflated from below while leaving the extra portion, whereby the bag is inflated. The pile driving method immediately below a structure according to claim 1, wherein the bag body is inflated upward and adheres to a lower surface of the foundation.
According to the above configuration, when the self-hardening fluid is injected, the lower portion of the bag body expands and presses the ground, so that the bag has an extra portion at the top. Therefore, when the bag body expands in order from below and reaches the extra length, the bag body expands upward with the already expanded portion as a support, and comes into close contact with the lower surface of the foundation of the existing structure.

According to a third aspect of the present invention, in the third step, the bag comprises an upper bag and a lower bag, and the upper bag is expanded after the lower bag is expanded. The pile driving method immediately below a structure according to claim 1, wherein the bag body is inflated upward and adheres to a lower surface of the foundation.
According to the above configuration, the self-hardening fluid is injected into the lower bag body, expanded, and solidified to a certain extent. Next, when the self-hardening fluid is injected into the upper bag body and inflated, the already expanded lower bag body becomes a support, the upper bag body swells upward, and comes into close contact with the lower surface of the foundation of the existing structure. become.

According to a fourth aspect of the present invention, the upper portion of the bag body expands toward the lower surface of the foundation and also extends under the periphery of the hole. It is a pile driving method just below the structure. According to the above configuration, since the bag body expands not only on the lower surface of the foundation but also around the hole provided in the foundation, after the self-hardening fluid in the bag body is hardened, the vertical support of the foundation is achieved. Not only does it provide horizontal support for the foundation.

According to a fifth aspect of the present invention, there is provided a pile with a bag, comprising: a pile; a bag attached to an outer periphery of the pile; and an injection means for flowing a self-hardening fluid into the bag. The bag body is a pile with a bag body attached to one end side of the pile so as to have an extra length. According to the above configuration, when the pile to which the bag is attached is driven into the hole of the existing structure and the self-hardening fluid is poured into the bag by the injection means, the pile expands in order from below while leaving the upper extra portion.

According to a sixth aspect of the present invention, there is provided the pile with a bag according to the fifth aspect, wherein the bag is provided with a restricting means for restricting the bag so as to sequentially inflate toward the extra length portion. .
According to the above configuration, the upper extra portion does not disappear due to the weight of the self-hardening fluid injected below the bag.

According to a seventh aspect of the present invention, there is provided a pile with a bag, comprising: a pile; a bag attached to an outer periphery of the pile; and an injection means for pouring a self-hardening fluid into the bag. The bag includes a first bag and a second bag attached to the pile in series, and the injecting unit includes a first injecting unit for the first bag and a second injecting unit for the second bag. It is a pile with a bag that is composed of an injection means. According to the above configuration, the self-hardening fluid is injected into the second bag from the second injection means to be inflated and solidified to support it. Then, when the first bag is inflated, the first bag is moved upward. Swell.

The invention according to an eighth aspect is the pile with a bag according to the seventh aspect, wherein the first bag located at one end of the pile is attached so as to have an extra length at the one end. .
According to the above configuration, when the first bag body is inflated with the second bag body as a support, the first bag body is easily inflated upward if there is an extra length portion.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partial cross-sectional view showing a structure of a bag-equipped pile according to the first embodiment of the present invention and a step of a pile driving method immediately below the structure according to the first embodiment of the present invention. It is an expanded sectional view of the A section of FIG.

Referring to FIGS. 1 and 2, the structure of the pile with a bag according to the first embodiment will be described. The pile 1 with a bag is a pile body 2
A bag 3, a fixing means 4 at both ends of the bag, an extra portion 3a of the bag 3, a restricting means 5 for the extra portion 3a, and an injecting means 6. When a self-hardening fluid is poured into the body 3, the bag body 3 expands toward the extra length portion 3a.

The pile body 2 is formed in a hollow structure.
An injection port 2a for injecting the self-hardening fluid into the bag body 3 is provided in the hollow interior. In addition, in the hollow interior of the pile main body 2, an injection means 6 is arranged from the injection port 2a in parallel with the axial direction of the pile main body 2. The pile main body 2 is inserted into the ground (underground) 8 through a hole 7 a formed in the foundation 7 of the existing structure, and a reinforcing portion 9 formed at the lower end 2 b of the pile main body 2.
To the ground 8a. This reinforcement 9
For example, it is formed by injecting a chemical solution. The pile main body 2 is configured to have a predetermined length by connecting a number of short piles in series. In the illustrated example, the upper end of the pile main body 2 is a short pile to which the bag body 3 is attached.

The bag body 3 is a densely woven cylindrical woven fabric made of nylon, is covered so as to cover the outer peripheral surface of the upper part 2 c of the pile main body 2, and is attached by the fixing means 4. The bag body 3 is made of nylon, but is not limited to nylon. The bag body 3 is formed of a fiber having a dehydrating effect of permeating water of the injected self-hardening fluid and a strength sufficient to hold the injected self-hardening fluid. It should just be. Therefore, for example, it may be formed of synthetic fibers such as polyethylene and vinylon. Instead of densely weaving, a tubular woven fabric coated with a resin may be used. In this case, perfect watertightness is not required.

The fixing means 4 at both ends of the bag body fixes the bag body 3 to the outer peripheral surface of the pile main body 2 at two places, that is, the upper part (see FIG. 2) and the lower part of the cylindrical bag body 3. Further, fixing means 4 at both ends of the bag body
Is designed so that even if a self-hardening fluid is injected between the outer peripheral surface of the pile body 2 and the cylindrical bag body 3, the self-hardening fluid does not leak from the upper and lower parts of the bag body 3. . The fixing means 4 is, for example, a steel restraint, but is not limited thereto.
What is necessary is just to be able to fix the bag body 3 to the pile main body 2 so that the self-hardening fluid does not leak.

The extra length portion 3a of the bag is, as shown in FIG.
The upper end of the bag body 3 is formed by mountain-folding toward the inside of the cylindrical bag body 3, and the upper end of the bag body 3 is further formed by valley folding. The extra length portion 3a of the bag body 3 is inflated by injecting a self-hardening fluid and then folded with a sufficient margin L so as to press the lower surface 7b of the foundation 7 of the structure (see FIG. 5). ing.

The restricting means 5 for the extra length portion includes the extra length portion 3a
Is provided on the outer peripheral surface of the extra length portion 3a so as to maintain the folded state. When the self-hardening fluid is injected between the bag body 3 and the outer peripheral surface of the pile body 2, the extra length portion 3a is left. The bag body is restricted so that the lower part and the center part of the bag body 3 swell as it is. Thereafter, the bag body 3 expands in order toward the extra length portion 3a, and when the self-hardening fluid starts to enter the extra length portion 3a, the restricting means 5 is broken and dissociated. In other words, the restricting means 5 is formed to have such strength that the self-hardening fluid enters the extra length portion 3a after the lower portion and the central portion of the bag body 3 expands and the extra length portion 3a starts to expand, and is dissociated. ing.
As the restricting means 5, for example, a tape or a string is used.
Wrap a tape or string around the outer circumference of the extra length 3a
The folded state is maintained. In addition, the limiting means 5
It is not limited to a tape or a string, but may be sewn so as to maintain the folded state of the extra length portion 3a, or may be kept in a folded state with an adhesive.

The injection means 6 includes an injection pipe 6 through which the self-hardening fluid passes.
And is fixed to the injection port 2a through the hollow interior of the pile main body 2. The upper part of the injection pipe 6 protrudes from the upper end 2d of the pile main body 2 and is connected to a self-hardening fluid supply means (not shown). This injection tube 6 is, for example,
It is formed of a steel tube, a tubular tube, or a rubber tube. still,
The injection means 6 extends through the hollow interior of the pile body 2 and
However, the present invention is not limited to the one fixed to the vehicle. For example, when the injection port for the self-hardening fluid is provided in the bag 3, the injection means 6 is directly connected to the injection port provided in the bag 3. As described above, the injection means 6 may be any as long as the self-hardening fluid is supplied between the bag body 3 and the outer peripheral surface of the pile main body 2 when the self-hardening fluid is supplied from the supply means.

Next, the shape of the bag 3 will be described with reference to FIG. As shown in FIG. 12A, the bag body 3 is formed in a different diameter cylindrical shape having an enlarged diameter portion 3b and a reduced diameter portion 3c. When the self-hardening fluid is injected between the outer peripheral surface of the pile main body 2 and the bag body 3, the enlarged diameter part 3 b is formed at the central part of the bag body 3.
It is formed larger than the outer diameter of the pile body 2 so that b expands. Further, the reduced diameter portion 3c is provided so that the self-hardening fluid does not leak out from both ends of the bag body 3 when the self-hardening fluid is injected, and the pile main body 2 is sufficiently maintained in close contact with the outer peripheral surface of the pile main body 2. Is formed to be substantially the same as the outer diameter of. in this way,
When the formed bag body 3 is folded, an extra length portion 3a is formed as shown by a two-dot chain line.

Next, different shapes of the bag 3 will be described. The enlarged diameter portion 3b may be formed in a rectangular shape as shown in FIG. 12B, or both ends of the enlarged diameter portion 3b may be formed in an arc shape as shown in FIG. 12C.

Next, a structure for attaching the bag body 3 to the pile body 2 will be described with reference to FIGS. The pile body 2 is inserted from the reduced diameter portions 3 c at both ends of the bag body 3, and the bag body 3 is positioned at a predetermined position above the pile body 2. The positioning at the predetermined position on the upper portion of the pile main body 2 is because the pouch with the bag according to the present invention presses the foundation 7 of the structure by the inflated bag 3. Bag 3 positioned at predetermined position
The reduced diameter portions 3c at the upper and lower ends of the bag body 3 are fixed by the fixing means 4 so that the self-hardening fluid does not leak from both ends of the bag body 3 when the self-hardening fluid is poured. Next, the enlarged diameter portion 3b on the upper side of the bag body 3 (the foundation 7 side of the structure) is folded inward toward the inside, and
Furthermore, it is folded outward to form an extra length portion 3 a outside the fixing means 4. When the extra portion 3a is formed, the restricting means 5 keeps the folded state so that the extra portion 3a is not dissociated.

A pile driving method according to a first embodiment using the pile 1 with a bag will be described with reference to FIGS. 1 and 3 to 5.

First Step A hole 7a having a diameter capable of inserting the peg 1 with a bag is formed in the foundation 7 of the structure. The holes 7a are opened by the number of the pegs 1 with the bag inserted.

Second Step The pile 1 with a bag is driven into the ground 8 from the hole 7a, and the lower end of the pile body 2 is brought into contact with the ground 8a. At this time, it is preferable to form a reinforcing portion 9 at the lower end 2b of the pile main body 2 and firmly fix the reinforcing member 9 to the ground 8a. The reinforcing portion 9 is formed by injecting a chemical solution into the ground 8a. . In addition, the pile 1 with a bag is formed by connecting short piles of an appropriate length, and finally connecting short piles with a bag.

Third Step First Stage Self-hardening between the bag body 3 attached around the upper end side of the pile main body 2 and the outer peripheral surface of the pile main body 2 through the injection pipe 6 and the injection port 2a from supply means (not shown). Pour fluid. When the self-hardening fluid is poured, as shown in FIG. 3, the enlarged diameter portion of the bag body 3 starts to expand uniformly toward the drilled surface 8 b of the ground 8 while leaving the extra length portion 3 a, and the enlarged diameter portion 3 b Is the drilled surface 8 of the ground 8
Contact with b.

Second stage Further, when a self-hardening fluid is poured, as shown in FIG.
Pressure is applied to the inside of the bag 3, and the enlarged diameter portion of the bag 3
Widen while pressing b. Also, the self-hardening fluid flows into the extra length portion 3a, and the extra length portion 3a gradually starts to expand,
The restriction means 5 is broken and dissociated.

Third Step Further, when a self-hardening fluid is poured, as shown in FIG.
The self-hardening fluid spreads over the extra length portion 3a with the expanded diameter portion 3b already expanded, and the bag body 3 expands upward so as to be in close contact with the lower surface 7b of the foundation 7 of the structure. As described above, when the injected self-hardening fluid solidifies, the lower surface 7 of the foundation 7 of the structure is
b and the upper part of the pile main body 2 are connected via the self-hardening fluid in the bag body 3. For this reason, the structure can be supported by the pile main body 2.

As described above, the bag body 3 expands sequentially from below while expanding the drilled surface 8b of the ground 8, and when the extra length portion 3a finally expands, the extra length portion 3a It comes into close contact with the lower surface 7b. It is applied when the ground 8 is soft and the ground 8 is expanded by the expansion of the bag body 3. The ground 8 is hard, and the ground 8
Is hardly spread, the drilling surface 8b of the ground 8 is made larger than the hole 7a of the foundation 7 in advance. However, the size of the drilling surface 8b is set to such a size that the bag body 3 can be sequentially expanded from below.

Further, as shown in FIG.
Is installed above the lower surface 7b of the foundation 7 of the structure, and the gap between the outer periphery of the pile body 2 and the hole 7a of the foundation 7 is increased. It expands toward the lower surface 7b of the foundation 7
It expands by penetrating into the area around a. Due to the expansion of the bag body 3, the foundation 7 and the pile main body 2 are pressed not only in the vertical direction but also in the horizontal direction.

Next, another example of the pile with bag 1 according to the first embodiment and the restricting means 5 applied to the pile driving method will be described. As shown in FIG. 1 and FIG.
a, a plurality of belts 1 are provided on the bag body 3 at predetermined intervals, as shown in FIG.
Limiting means 11 may be configured by providing 1a to 11f.
In this case, when the self-hardening fluid is injected, the belts 11c-1
1f in order from the lower side of the bag 3 (belt 11c-
11f). Then, belt 1
1b and 11a are dissociated in this order, and the extra length part 3a expands last, and presses the lower surface 7b of the foundation 7 of the structure.

As shown in FIGS. 1, 2 and 7, instead of the limiting means 5 and 11 of the type wound around the outer peripheral surface of the bag body 3, the limiting means 12 comprises: As shown in FIG. 8, the extra length portion 3a is lifted by the belt 12 provided on the bag body 3, and the extra length portion 3a is pulled upward so as to maintain the folded state of the extra length portion 3a. May be. In this case, the lower end of the belt 12 is
a, the upper end of the belt 12 is fixed inside the upper end of the pile main body 2, and the extra length portion 3a is pulled. In the belt 12, the self-hardening fluid enters the extra length portion 3a,
When the extra length portion 3a starts to expand, the extra length portion 3a is formed to have such strength that it is broken and dissociated.

Further, instead of the limiting means 5 and 11 of the type wound around the outer peripheral surface of the bag body 3 as in the piles 1 and 10 with a bag body shown in FIGS. As shown in FIG. 9, the extra length portion 3a may be pulled up by a belt 13 provided inside the bag body 3.

Next, the structure of the pile 21 with a bag according to the second embodiment will be described with reference to FIG. FIG. 10 is a partial cross-sectional view illustrating a structure of a pile with a bag according to the second embodiment of the present invention and a step of a pile driving method immediately below the structure according to the second embodiment of the present invention.

The pile 21 with a bag includes a pile main body 22, a first bag 23a, a second bag 23b, fixing means 25 to 27,
The first bag 23 includes an extra portion 23 c, a restricting means 28 for the extra portion 23 c, and injection means 29 and 30.
The fixing means 25 and 27 and the restricting means 28 are the same as the fixing means 4 and the restricting means 5 of the first embodiment shown in FIG.

The pile body 22 has a first inlet 22a and a second inlet 22a.
The point that the inlet 22b is provided is different from the pile main body 2 of the first embodiment, but the other points are the same.

The first bag 23a and the second bag 23b are connected to each other in FIG.
As shown in FIG. 3 (a), it is a tubular woven fabric formed integrally, and the joint between the first bag body 23a and the second bag body 23b is reduced in diameter. Further, the first bag body 23a and the second bag body 23b each have an enlarged diameter portion in which the self-hardening fluid injected therein is stored. The material of the first bag 23a and the second bag 23b is the same as that of the bag 3 of the first embodiment. The first bag body 23a and the second bag body 23b are not limited to those having the shapes shown in FIG. 13A, but may have the shapes shown in FIGS. 13B and 13C. In addition, the first bag 23a and the second bag 23
b may be a separately formed tubular woven fabric.

The fixing means 26 is provided at a reduced diameter portion 23d which is a joint portion between the upper first bag 23a and the lower second bag 23b, and is injected from the second injection means 30 into the second bag 23b. The self-hardening fluid is fixed so as not to advance toward the first bag 23a. The fixing means 26 is the same as the fixing means 4 of the first embodiment.

The extra portion 23c of the bag is formed on the upper portion of the first bag 23a, and the other points are the same as the extra portion 3a of the first embodiment. The first bag 23a of the second embodiment supports the second bag 23b to support the foundation 7 of the structure.
Since it swells toward the lower surface 7b, the extra length portion 23c need not be provided.

The first injection means 29 is fixed to the first injection port 22a through the hollow inside of the pile main body 22. Also,
The second injection means 30 is fixed to the second injection port 22b through the hollow inside of the pile main body 22. First injection means 29,
The material of the second injection means 30 is the same as that of the injection means 6 of the first embodiment.
Is the same as In addition, the first injection means 29 and the second injection means 30 pass through the hollow interior of the
a, it is not limited to the one fixed to the second inlet 22b. For example, the injection port of the self-hardening fluid is connected to the first bag 23 and the second bag 23.
When provided in the bag 24, the first injection means 29 and the second injection means 30 are directly connected to the injection ports provided in the first bag 23 and the second bag 24.

Next, the steps of the pile driving method of the second embodiment using the pile 21 with a bag will be described with reference to FIG.
Note that the first step and the second step are the same as the steps of the pile driving method of the first embodiment, and a description thereof will be omitted.

Third Step First Step The second bag 24 attached to the periphery of the pile main body 22 and the outer peripheral surface of the pile main body 22 are connected by a second supply means (not shown) from the supply means (not shown).
The self-hardening fluid flows through the injection pipe 30 and the second injection port 22b. When the self-hardening fluid is poured, the enlarged diameter portion of the second bag 23b starts to expand evenly toward the drilling surface 8b of the ground 8, and the enlarged diameter portion of the second bag 23b comes into contact with the drilled surface 8b of the ground 8. Abut Further, when the self-hardening fluid is poured, the second bag 2
Pressure is applied to the inside of 3b, and the enlarged diameter portion of the second bag body 23b widens while pressing against the drilled surface 8b.

Second stage When the self-hardening fluid in the second bag 23b solidifies to some extent,
Self-hardening fluid is poured from a supply means (not shown) between the first bag 23a attached around the pile body 22 and the outer peripheral surface of the pile body 22 through the first injection pipe 29 and the first injection port 22a. When the self-hardening fluid is poured, the enlarged portion of the first bag 23a starts to swell evenly toward the drilled surface 8b of the ground 8 with the second bag 23b supported on the second bag 23b,
The enlarged diameter portion of the first bag body 23 a contacts the drilled surface 8 b of the ground 8.

Third Step Further, when a self-hardening fluid is poured into the first bag 23a,
The first bag 2 is supported by the already inflated second bag 23b.
The self-hardening fluid spreads over the extra portion 23c of 3a, and the first bag body 23a expands upward so as to be in close contact with the lower surface 7b of the foundation 7 of the structure. As described above, when the injected self-hardening fluid is solidified, the lower surface 7b of the foundation 7 of the structure and the upper part of the pile body 22 are connected via the self-hardening fluid in the first bag 23a.
Therefore, the structure can be supported by the pile main body 22.

As described above, the first bag 23a expands upward with the second bag 23b already expanded and solidified as a support. That is, the first bag body 23a can expand upward regardless of the state of the ground 8. Therefore, the method of the second embodiment can be applied when the drilling surface 8b provided on the ground 8 is too large or when the ground 8 is too weak.

[0049]

FIG. 14 shows a practical example of the pile driving method according to the first embodiment.
It will be described based on.

An example will be described in which the pile driving method of the first embodiment is used to improve the strength and deformation performance of an existing underground structure.

A foundation 7 of the structure is provided below the floor 33 of the structure. The foundation 7 is supported by an existing pile 34. A new hole 7a is opened in the lower portion of the foundation 7, and the pile 1 with a bag according to the first embodiment is driven. Next, in order to reinforce the lower end of the pile body 2, for example,
Strengthen 5. Next, a self-hardening fluid is injected into the bag 3,
The upper portion of the bag body 3 and the lower surface 7b of
And the pile main body 2 are connected to improve the strength of the structure.

[0052]

According to the first aspect of the present invention, the lower surface of the foundation of the existing structure and the pile are filled without gaps by the hardening of the self-hardening fluid in the bag body that expands upward.
The existing foundation can be supported stably. In addition, by providing a hole larger than the hole of the foundation of the existing structure in the upper ground and increasing the capacity of the bag attached to the pile, the contact area between the lower surface of the foundation of the existing structure and the bag is increased. The connection between the newly driven pile and the existing foundation can be ensured. Further, the bag attached to the pile is formed so as to expand upward, so that the amount of self-hardening fluid injected into the bag can be reduced.

According to the second aspect of the present invention, by appropriately setting the gap between the size of the upper ground located below the foundation and the outer shape of the pile, the bag body can push the ground outward and move the upper body upward. Since the balloon expands upward while leaving the extra length, the lower surface of the foundation can be brought into close contact with the bag without increasing the amount of self-hardening fluid injected into the bag.

According to the third aspect of the present invention, the upper bag body can be expanded upward regardless of the size and strength of the upper ground below the foundation. Without worrying about the size of the hole
The lower surface of the foundation and the bag can be closely attached.

According to the fourth aspect of the present invention, after the self-hardening fluid in the bag is hardened, the lower surface and the periphery of the hole of the existing structure are supported, so that the strength of the existing structure is only in the vertical direction. It is also reinforced in the horizontal direction and is suitable for seismic reinforcement.

According to the fifth aspect of the present invention, by using a pile to which a bag body having an upper extra portion is attached, the lower surface of the foundation is formed by a pile driven into the ground from a hole in the existing structure. It can be reliably supported using a self-hardening fluid.

According to the sixth aspect of the present invention, when the bag body is inflated from below by the self-hardening fluid injected into the bag body, the regulating member supports the weight of the self-hardening fluid. Since the remaining extra length is inflated last, the bag body can be reliably brought into close contact with the lower surface of the foundation.

According to the seventh aspect of the present invention, by using the pile to which the first bag body and the second bag body are attached, the lower surface of the foundation is formed by the pile driven into the ground from the hole of the existing structure. It can be reliably supported using a self-hardening fluid.

According to the invention described in claim 8, when the second bag body is inflated with the first bag body as a support, the extra length part is finally inflated, so that the second bag body is securely placed on the lower surface of the foundation. Can be in close contact.

[Brief description of the drawings]

FIG. 1 shows a structure of a pile with a bag according to a first embodiment of the present invention,
It is a fragmentary sectional view showing a process of a pile driving method under a structure concerning a 1st embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a portion A in FIG.

FIG. 3 is a partial cross-sectional view showing an inflation process of a bag body of the pile with a bag body according to the first embodiment of the present invention and a step of a pile driving method immediately below a structure according to the first embodiment of the present invention.

FIG. 4 is a partial cross-sectional view showing an inflation process of a bag of the pile with a bag according to the first embodiment of the present invention and a step of a pile driving method immediately below a structure according to the first embodiment of the present invention.

FIG. 5 is a partial cross-sectional view showing an inflation process of a bag body of the pile with a bag body according to the first embodiment of the present invention and a step of a pile driving method immediately below a structure according to the first embodiment of the present invention.

FIG. 6 is a partial cross-sectional view showing preferred steps of a pile driving method immediately below the structure according to the first embodiment of the present invention.

FIG. 7 is a partial cross-sectional view showing an example of another restricting means of the pile with a bag according to the first embodiment of the present invention.

FIG. 8 is a partial sectional view showing an example of another restricting means of the pile with a bag according to the first embodiment of the present invention.

FIG. 9 is a partial sectional view showing an example of another restricting means of the pile with a bag according to the first embodiment of the present invention.

FIG. 10 is a partial cross-sectional view of a pile with a bag according to a second embodiment of the present invention.

FIG. 11 is a view showing a process of expanding a pile with a bag body according to a second embodiment of the present invention and a step of a pile driving method immediately below a structure according to a second embodiment of the present invention.

FIG. 12 is a view showing various forms of the bag according to the first embodiment.

FIG. 13 is a view showing various forms of a bag according to a second embodiment.

FIG. 14 is a diagram showing a cross section of a structure reinforced by a step of a pile driving method immediately below the structure of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pile with bag body 2 Pile body 3 Bag body 3a Extra length 4 Fixing means 5 Limiting means 6 Injection means 7 Foundation of structure 8 Ground 10 Pile with bag body 11-13 Limiting means 21 Pile with bag body 22 Pile body 23a First bag 23b Second bag 25-27 Fixing means 28 Limiting means 29 First injecting means 30 Second injecting means

Claims (8)

[Claims] A first step of drilling a hole in the foundation of the structure;
A second step of driving a pile into the hole, and a third step of flowing a self-hardening fluid into a bag attached to the periphery of the pile, inflating the bag upward, and bringing the bag into close contact with the lower surface of the foundation. Pile driving method just below the structure comprising. 2. In the third step, the bag has an extra portion at an upper portion, and the bag is inflated from below while the extra portion is left, so that the bag is inflated upward. The pile driving method immediately below a structure according to claim 1, wherein the pile is brought into close contact with the lower surface of the foundation. 3. In the third step, the bag body includes an upper bag body and a lower bag body, and the upper bag body is inflated after the lower bag body is inflated. The pile driving method immediately below a structure according to claim 1, wherein the pile is inflated and brought into close contact with a lower surface of the foundation. 4. The pile driver directly under the structure according to claim 1, wherein the upper portion of the bag body expands toward the lower surface of the foundation and also extends under the periphery of the hole. Method. 5. A bag-equipped pile comprising: a stake, a sac attached to an outer periphery of the stake, and an injecting means for pouring a self-hardening fluid into the sac. A pile with a bag attached so as to have an extra length at one end of the pile. 6. The pile with a bag according to claim 5, wherein the bag is provided with restricting means for restricting the bag so as to inflate in order toward the extra length portion. 7. A bag-equipped pile comprising a stake, a sack attached to an outer periphery of the stake, and an injection means for pouring a self-hardening fluid into the sac, wherein the sac is The bag comprises a first bag and a second bag attached in series to a stake, and the injecting means comprises a first injecting means for the first bag and a second injecting means for the second bag. Pile with body. 8. The pile with a bag according to claim 7, wherein the first bag located at one end of the pile is attached so as to have an extra length at the one end.