JP2003213671A - Foundation pile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a foundation pile conformable to various seismic forces and avoid an increase in cost thereof. <P>SOLUTION: The pile body 4 of this foundation pile 1 is formed by vertically connecting two or more pile components 2. Of the pile components 2, at least two pile components vertically adjacent (a first pile component 2A and a second pile component 2B) are mutually connected through a connecting mechanism 3 for regulating the relative displacement in mutually approaching directions and allowing the relative displacement in mutually separating directions. Accordingly, the foundation pile 1 can be extended, following the floating of the upper structure of a building and reduce a seismic input energy to the upper structure of the building in the event of earthquake. Since the rotating rigidity of the connecting part is minimized, the pile can follow the ground deformation in the earthquake to prevent the damage of the pile body. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foundation pile used for transmitting a load of a superstructure of a building to the ground.

[0002]

2. Description of the Related Art As this type of foundation pile, for example, ready-made piles such as steel pipe piles and PHC piles are known. In such a ready-made pile, the pile body may be composed of a single member, or may be formed by rigidly connecting a plurality of pile constituent bodies made of steel pipes or concrete pipes vertically.

[0003]

Generally, during an earthquake, the horizontal force acting on a building changes the axial force acting on the foundation pile, resulting in a tower ratio (ratio of height to building width). In case of large piles or foundation piles with seismic resistant elements such as walls, the fluctuated axial force may exceed the long-term axial force and pull-out force may act. Therefore, in order to counter such pull-out force, conventionally, a method of increasing a long-term axial force with a counterweight (weight) or preventing a lift by a ground anchor has been adopted. However, these methods are not only costly, but also applicable only within the assumed design seismic force range.

On the other hand, in recent years, a construction method for reducing seismic energy input to a building at the time of an earthquake by using a design that allows the columns and foundations to be lifted has begun to be adopted.
They do not have rigid connections to the column bases and pile heads, but instead use vertically movable joints to enable floating. However, since the joint that allows such uplifting also serves as the joint of dissimilar members such as the column base that attaches to the beam and the pile head that attaches to the foundation, its fitting becomes somewhat complicated, which causes a cost increase. Is concerned.

In view of the above-mentioned circumstances, in the present invention, the foundation pile is provided with a mechanism for permitting lifting.
The challenge is to be able to deal with various seismic forces and to avoid cost increases.

[0006]

In order to solve the above problems, the following means are adopted in the present invention. That is,
The foundation pile according to claim 1 is a foundation pile used for transmitting a load of an upper structure of a building to the ground, and a pile main body having an upper end joined to the upper structure, the pile main body comprising:
It is formed by connecting a plurality of pile structures to each other vertically, and among these pile structures, at least two pile structures vertically adjacent to each other have a relative displacement in a direction in which these two pile structures approach each other. It is characterized in that they are connected via a connection mechanism that regulates and allows relative displacement in the separating direction.

With such a structure, the pile constituents are vertically separated from each other, whereby the length dimension of the pile main body can be extended and it is possible to cope with the floating of the upper structure.

The foundation pile according to claim 2 is the foundation pile according to claim 1, wherein the connecting mechanism has a lower end and a lower end of the first pile structure located above in the vertically adjacent pile structures. And a cylindrical joining ring arranged so as to surround the upper end of the second pile structure located at, and joined to the inner peripheral surface of this joining ring, and the lower end of the first pile structure and the first An axial force transmission member that is interposed between the upper ends of the two pile components and that transmits a compression axial force acting on the pile body between the first pile component and the second pile component; It is characterized by having.

With such a structure, the lower end of the first pile structure and the upper end of the second pile structure are held by the joining ring, while the lower ends of the first pile structure and the second pile structure are held. A compressive axial force can be transmitted to the upper end of the body.

The foundation pile according to claim 3 is the foundation pile according to claim 2, wherein the joining ring has inner diameters that are the lower end of the first pile structure and the upper end of the second pile structure. It is characterized in that it is made larger than at least one of the external dimensions. In such a configuration, the joining ring does not constrain both the first pile structure and the second pile structure, and therefore the axis of the first pile structure is the second pile structure. Relative displacement of the first pile structure and the second pile structure so as to incline with respect to the axis of (the first pile structure is rotationally displaced with respect to the second pile structure) Is not regulated by the joining ring.

The foundation pile according to claim 4 is the foundation pile according to claim 2 or 3, wherein at least a part of the foundation pile is formed by an elastic member. With such a configuration, the axial force transmitting member can favorably follow the relative displacement / rotation angle of the first and second pile components.

The foundation pile according to claim 5 is the one according to claims 2 to 4.
The foundation pile according to any one of claims 1 to 5, wherein the joining ring and the lower end of the first pile structure and the upper end of the second pile structure are joined to each other by the first pile structure and the second pile structure. It is characterized in that they are locked to each other when they are separated from the ring by a predetermined dimension. With such a configuration, it is possible to prevent the first pile structure from coming off the second pile structure.

The foundation pile according to claim 6 is the foundation pile according to claim 5, wherein the lower end of the first pile structure and the upper end of the second pile structure are orthogonal to the axial direction of the pile body. A protrusion protruding outward is provided, and the inner peripheral surface of the joint ring is locked to the protrusion and is formed from the first pile structure and the second pile structure of the joint ring. It is characterized in that a locking portion for preventing separation is provided.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 is a diagram schematically showing an embodiment of the present invention, in which reference numeral 1 indicates a foundation pile. This foundation pile 1 has a structure in which a pile body 4 is formed by vertically connecting a plurality of pile structures 2 made of, for example, steel pipes via a connection mechanism 3. And in this foundation pile 1, the upper end 4a of the pile main body 4 is joined to the footing 5 forming a part of the superstructure of the building, whereby the load of the superstructure of the building is compressed. It is transmitted to the ground as an axial force.

FIG. 1 is a vertical sectional view showing the structure in the vicinity of the connection mechanism 3, and FIG. 2 is a sectional view taken along the line II in FIG. As shown in the figure, the connection mechanism 3 is configured to include a joining ring 6 and an axial force transmitting member 7 joined to an inner peripheral surface 6 a of the joining ring 6.

Of these, the joining ring 6 is formed of a tubular steel material, and the vertically adjacent pile components 2, 2.
2, the lower end 2 of the first pile structure 2A located above
Aa and the upper end 2Ba of the second pile structure 2B located below
It is arranged to surround and.

The axial force transmitting member 7 is arranged horizontally, and its outer peripheral edge 8a is the inner peripheral surface 6 of the joining ring 6.
The rib plate 8 welded to a, the elastomer member (elastic member) 9 arranged so as to sandwich the rib plate 8 from above and below, and the rib plate 8 and the elastomer members 9 above and below the rib plate 8 are sandwiched further from above and below. And a loading plate 10 arranged horizontally. The elastomer member 9 and the loading plate 10 are the rib plates 8
It is configured to be movable relative to.

In addition, in the connection mechanism 3, the first pile structure 2
The outer periphery of the lower end 2Aa of A and the upper end 2 of the second pile structure 2B
In a state in which a C-shaped reinforcing ring (protruding portion) 12 in a plan view is protruded outward (radially outward of the pile constructing body 2) orthogonal to the axial direction of the pile main body 4 on the outer peripheral portion with Ba. It is fixed. Then, the lower end 2Aa of the first pile structure 2A and the reinforcing ring 12 fixed to the outer peripheral portion of the first pile structure 2A come into contact with the upper loading plate 10 of the axial force transmission member 7, whereby the first pile structure is formed. The compressive axial force of the body 2A is the axial force transmitting member 7
To be transmitted to. Further, this compressive axial force is transmitted to the upper end 2Ba of the second pile structure 2B and the reinforcing ring 12 fixed to the outer peripheral portion thereof via the loading plate 10 on the lower side of the axial force transmitting member 7, and thereby, Axial force transmission between the first pile structure 2A and the second pile structure 2B is performed via the axial force transmission member 7.

When such axial force transmission is performed, the axial force transmission member 7 is sandwiched between the first pile structure 2A and the second pile structure 2B. Therefore,
In this case, the joining ring 6 fixed to the rib plate 8 of the axial force transmitting member 7 is fixed in a state where the position thereof is as shown in FIG. The joining ring 6 is formed such that its inner diameter is slightly larger than the outer diameters of the lower end 2Aa of the first pile structure 2A and the upper end 2Ba of the second pile structure 2B. Thereby, the joining ring 6 is prevented from directly contacting the first and second pile structures 2A and 2B.

Further, a stopper (locking portion) 13 which is an annular member made of steel is welded and fixed to the upper end portion 6b and the lower end portion 6c of the joining ring 6 so as to be positioned on the inner peripheral surface 6a of the joining ring 6. ing. The stopper 13 is formed such that the inner diameter thereof is smaller than the outer diameter of the reinforcing ring 12, whereby the first pile structure 2A and the second pile structure 2B are separated by a predetermined distance. It sometimes engages with the reinforcing ring 12 to prevent further separation of the first pile structure 2A and the second pile structure 2B from the joining ring 6.

Also, the stopper 13 and the first pile structure 2
A sealing material 14 made of water-expanded rubber is filled in the gap between A and the second pile structure 2B. This prevents dirt, mud, etc. from entering the inside of the joining ring 6.

Next, a method of constructing the foundation pile 1 in this embodiment will be described. In order to construct the foundation pile 1, the ground is excavated to form an excavation hole (not shown), and the pile main body 4 formed by connecting the pile constituents 2 to each other is built inside the excavation hole, and further the pile main body. The footing 5 is formed on the upper end 4a of the pile 4, and the footing 5 is attached to the upper end 4a of the pile body 4.
Will be integrated with.

Here, in order to form the pile main body 4, as shown in FIG. 4, the vertically adjacent pile constituents 2 (the first pile constituent 2A and the second pile constituent 2B) are axially moved. Force transmission member 7
The first pile structure 2B in the joining ring 6 fitted with
The upper end 2Ba of the second pile structure 2A and the lower end 2Aa of the second pile structure 2A are inserted so as to be connected. Moreover, when connecting the pile structures 2 to each other in this way, the first pile structure 2A is connected.
The reinforcing ring 12 (not shown in FIG. 4) is previously fixed to the lower end 2Aa of the. For example, as shown in FIG. 5 (a), the reinforcement ring 12 is fixed by inserting the lower end 2 </ b> Aa of the first pile construction body 2 </ b> A into the reinforcement ring 12 while slightly expanding the reinforcement ring 12, and further as shown in FIG. ), The two are integrated by fillet welding.
Further, the reinforcement ring 12 is fixed to the upper end 2Ba of the second pile structure 2Ba by the same procedure (that is, the pile structure 2 having the reinforcement rings 12 fixed to the upper and lower ends thereof). Will be used.) In addition, such a reinforcing ring 12 is provided at the upper end 2B of the second pile structure 2B.
When a and the lower end 2Aa of the first pile structure 2A come into contact with the axial force transmitting member 7, they also serve to prevent local buckling of these.

When the pile structure 2 is inserted into the joining ring 6 as shown in FIG. 4, the upper end portion 6b and the lower end portion 6c of the joining ring 6 are positioned on the inner peripheral surface 6a side as shown in FIG. The stopper 13 is welded and fixed to the
A sealing material 14 is loaded between the stopper 13 and the outer surface of the pile structure 2. Thereby, the connection mechanism 3 is formed between the first pile structure 2A and the second pile structure 2B.

By the above procedure, a plurality of pile structures 2
After connecting, the pile structure 2 located at the highest position is lifted by a crane or the like. In this case, in the connection mechanism 3, the second pile structure 2B tends to drop from the first pile structure 2A due to gravity, but the stopper 13 welded to the joining ring 6 and the first pile structure 2A. And the reinforcing ring 12 fixed to the second pile structure 2B are locked to each other, thereby preventing the first pile structure 2A and the second pile structure 2B from separating more than necessary. This prevents the second pile structure 2B from falling off the first pile structure 2A. Therefore, a plurality of pile structures 2
The pile body 4 made of can be easily lifted and built in the excavation hole.

After the pile main body 4 is built in the excavation hole in this way, an upper structure of the building is formed on the upper part of the pile main body 4, and the footing 5 which is a part of the upper structure is formed.
Is integrated with the upper end 4a of the pile body 4 to obtain the foundation pile 1 as shown in FIG.

In the above-mentioned foundation pile 1, two vertically adjacent pile constituents 2 (first pile constituent 2A and second pile constituent 2B) are connected via the axial force transmitting member 7 in the connecting mechanism 3. Since the two pile structures 2 are connected only by contacting each other, relative displacement in the direction of approaching each other is restricted, and relative displacement in the direction of separation is permitted. Therefore, even if the pulling force acts on the foundation pile 1 due to the varying axial force of the foundation pile 1 exceeding the long-term axial force during an earthquake, the pile structures 2 are vertically separated from each other and the pile body 4 is separated. The length dimension of
As a result, the pile body 4 is deformed following the lifting of the upper structure. As a result, it is possible to reduce the earthquake input energy to the building during an earthquake,
It is possible to deal with various seismic forces.

In this case, the connecting mechanism 3 is joined to the cylindrical joining ring 6 and the inner peripheral surface of the joining ring 6, and
The axial force transmission member 7 for transmitting the compressive axial force acting on the pile main body 4 between the first pile structure 2A and the second pile structure 2B has a simple structure. Moreover,
The connecting mechanism 3 can be obtained by simply inserting the upper and lower piles into the joining ring 6.
Because it can be completed, the workability is very high. Further, since the welding of the joining ring 6 and the rib plate 8 of the axial force transmitting member 7 can be performed not in the field but in a factory or the like, it is possible to realize a reliable and strong structure as the connection mechanism 3. Further, since the connection mechanism 3 only connects the first and second pile components 2A and 2B having the same diameter and does not involve any special material or complicated processing, it can be realized at low cost. is there.

Further, in this embodiment, the inner diameter of the joining ring 6 is larger than the outer dimensions of the lower end 2Aa of the first pile structure 2A and the upper end 2Ba of the second pile structure 2B. Is formed in. Therefore, the joining ring 6 does not restrain the lower end 2Aa of the first pile structure 2A and the upper end 2Ba of the second pile structure 2B, and the axis of the first pile structure 2A is the second pile structure. The relative displacement / rotation of the first pile structure 2A and the second pile structure 2B is allowed to incline with respect to the axis of 2B.

In other words, this allows the connecting mechanism 3 to be rotationally deformed as a whole, the rotational rigidity of the connecting mechanism 3 is reduced, and the first pile structure 2A and the second pile structure 2B are pinned. Since the connection is made in a state close to joining, the stress generated in the pile body 4 can be reduced. Further, this allows the pile body 4 to follow the deformation of the ground and be rotationally deformed at the joint portion, so that even if the ground is liquefied, excessive stress is not generated in the pile body 4. Thus, it becomes possible to maintain the ability to support building loads.

Further, since the inner diameter of the joining ring 6 is larger than the outer dimensions of the lower end 2Aa of the first pile structure 2A and the upper end 2Ba of the second pile structure 2B,
The accuracy control during construction is easy, and the stopper 13 can be attached to prevent excessive lifting.

Further, since the elastomer member 9 is provided in a part of the axial force transmitting member 7, the rotational rigidity of the connecting mechanism 3 can be more favorably reduced, and the first pile structure 2A is When the second pile structure 2B is lifted up, it is possible to mitigate the impact that occurs during subsequent re-contact, and it is possible to realize a highly safe structure.

Further, in the present embodiment, the inner circumference of the joining ring 6 is different from the reinforcing ring 12 provided at the lower end 2Aa of the first pile structure 2A and the upper end 2Ba of the second pile structure 2B. The stopper 13 provided on the surface 6a is locked to prevent the joining ring 6 from being detached from the first pile structure 2A and the second pile structure 2B. That is, in the present embodiment, the joining ring 6, the lower end 2Aa of the first pile structure 2A and the upper end 2 of the second pile structure 2B.
Ba is the first pile structure 2A and the second pile structure 2
Since B is locked to each other when separated from the joining ring 6 by a predetermined dimension, it is possible to prevent the first pile structure 2A from being excessively pulled out from the second pile structure 2B. it can. In addition, the stopper 13 and the reinforcing ring 12
By adjusting the distance dimension between and, it is possible to easily control the allowable lift amount.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and other configurations can be adopted without departing from the spirit of the present invention. For example, in the above-described embodiment, the allowable lifting amount of the foundation pile 1 may be increased by providing a plurality of connection mechanisms 3 on one foundation pile 1.

Further, by providing the connection mechanism 3 of the above-mentioned embodiment in the vicinity of the pile head of the foundation pile 1, it is possible to easily realize a structure close to the pile head pin connection. In this case, the bending stress generated at the joint between the pile head and the foundation of the upper structure (footing 5) becomes extremely small, and the axial force is also allowed to rise, so that no tensile force is generated. The cross-sectional design of the portion is facilitated, and the cost of the foundation pile 1 as a whole can be reduced. Moreover, if it is possible to exert an effect close to the pile head pin joint in this way, the stress of the foundation beam and the mat which are fitted to the foundation pile 1 can be greatly reduced, and the ratio of the cross section of the frame can be rationalized. However, since the amount of excavation and the amount of excavation can be reduced by reducing the success rate, further cost reduction is possible.

Further, in the above-mentioned embodiment, the pre-boring method in which the excavation hole is provided in the ground in advance and the pile main body 4 is built in the excavation hole is adopted, but the joining ring 6 and the axial force transmitting member 7 ( Since the rib plate 8) has a hollow ring shape, it is also possible to adopt a middle excavation method in which the pile main body 4 is built in the excavation hole while excavating the excavation hole.

In the above-mentioned embodiment, the steel pipe is adopted as the pile structure 2, but instead of this, the pile structure 2 is used as the foundation pile 1'shown in FIGS. 6 to 8. By adopting concrete pipe as'P foundation pile 1 '
It may be an HC pile.

The foundation pile 1'shown in FIG. 6 has a construction in which a pile body 4'is formed by vertically connecting a plurality of pile construction bodies 2'made of concrete pipes through a connecting mechanism 3 '. There is. FIG. 7 is a vertical cross-sectional view showing the configuration in the vicinity of the connection mechanism 3 ′, and FIG. 8 is a cross-sectional view taken along the line II-II in FIG. As shown in the figure, in the connection mechanism 3 ′, the axial force transmitting member 7 ′ joined to the inner peripheral surface 6 a of the joining ring 6 includes a rib plate 8 and an elastomer member 9 fixed above and below the rib plate 8. It is formed by and.

The elastomeric member 9 is in contact with the end plate 20 of the pile structure 2 ', whereby the end plate 20 of the first pile structure 2A' located above the pile structure 2'is. From the rib plate 8 and the elastomer members 9 above and below it.
It is possible to transmit the axial force to the end plate 20 of the second pile structure 2B ′ located below via the.
Further, in this foundation pile 1 ', since the pile constructing body 2'is a concrete pipe and has a certain thickness dimension, unlike the above-mentioned embodiment, the local seat at the end of the pile constructing body 2'is. It is not necessary to provide the reinforcing ring 12 to prevent buckling. Therefore, instead of the reinforcing ring 12, as shown in FIG. 7, a round steel ring (protruding portion) 21 is fixed to the outer peripheral portion of the end plate 20, and the round steel ring 21 is fixed to the inner peripheral surface 6 of the joining ring 6.
It can be locked with the stopper 13 provided on the.

In addition, as shown in FIG. 9, the round steel ring 21 is fixed to the pile structure 2'by pushing the round steel ring 21 slightly and spreading the end of the pile structure 2'into the round steel ring 21. It can be performed by inserting and further integrating the end plate 20 of the pile structure 2 ′ and the round steel ring 21 by flare welding. With such a configuration, it is possible to obtain the same effect as that of the above-described embodiment.

Apart from this, an elastic member made of other synthetic rubber or natural rubber may be used instead of the elastomer member 9 used in the above-mentioned embodiment and its modification.

Further, in the foundation pile 1 (1 '), when the tensile force does not act from the time of construction to after completion, the stopper 13, the reinforcing ring 12, and the round steel ring 21 can be omitted. .

Furthermore, in one foundation pile 1 (1 '),
The connection mechanism 3 is used to connect the pile structure 2 (2 ').
Both (3 ′) and the conventional rigid joint may be adopted. It is also possible to use some of the foundation piles used in the building as foundation piles 1 (1 ') and the others as conventional foundation piles. This expands design options and enables more rational design. Therefore,
INDUSTRIAL APPLICABILITY The present invention can be widely used for relieving stress concentration on short piles when the surface layer or support layer is inclined, and for coping with small-diameter cross sections when piles with different pile diameters are used together.

[0044]

As described above, according to the present invention,
By installing a mechanism that allows the foundation piles to float, it is possible to cope with various earthquake forces while avoiding cost increase.

[Brief description of drawings]

FIG. 1 is an enlarged vertical sectional view of a foundation pile connection mechanism schematically showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line I-I of FIG.

FIG. 3 is an elevational view showing the entire foundation pile shown in FIGS. 1 and 2.

FIG. 4 is a perspective view showing a procedure for constructing the foundation pile shown in FIGS. 1 to 3.

FIG. 5 is a perspective view showing another procedure of the same.

FIG. 6 is an elevation view of a foundation pile showing another embodiment of the present invention.

FIG. 7 is an enlarged vertical sectional view of the connection mechanism of the foundation pile shown in FIG.

8 is a cross-sectional view taken along the line II-II in FIG.

9 is a perspective view showing a procedure for constructing the foundation pile shown in FIGS. 6 to 8. FIG.

[Explanation of symbols]

1,1 'foundation pile 2,2 'pile construction 2A, 2A 'First pile structure 2Aa bottom 2B, 2B 'Second pile structure 2Ba top 3,3 'connection mechanism 4 pile body 4a upper end 5 footing 6 joining ring 6a Inner surface 7,7 'Axial force transmitting member 9 Elastomer member (elastic member) 12 Reinforcement ring (projection) 13 Stopper (locking part) 21 Round Steel Ring (Projection)

Claims (6)

[Claims] 1. A foundation pile used for transmitting a load of an upper structure of a building to the ground, comprising a pile main body having an upper end joined to the upper structure, the pile main body including a plurality of piles. It is formed by connecting constituents to each other in the vertical direction, and among the pile constituents, at least two pile constituents vertically adjacent to each other regulate the relative displacement of these two pile constituents in the approaching direction. , A foundation pile which is connected via a connection mechanism which allows relative displacement in the separating direction. 2. The connecting mechanism connects the lower end of the first pile structure located above and the upper end of the second pile structure located below among the two vertically adjacent pile structures. A tubular joining ring arranged so as to surround it, and joined to the inner peripheral surface of the joining ring, between the lower end of the first pile structure and the upper end of the second pile structure. An axial force transmission member that is interposed and that transmits a compressive axial force acting on the pile body between the first pile structure and the second pile structure is provided. The foundation pile according to item 1. 3. The joining ring has an inner diameter dimension larger than an outer dimension of at least one of a lower end of the first pile structure and an upper end of the second pile structure. The foundation pile according to claim 2. 4. The foundation pile according to claim 2, wherein at least a part of the axial force transmitting member is formed of an elastic member. 5. The joining ring, the lower end of the first pile structure and the upper end of the second pile structure form a joining ring with the first pile structure and the second pile structure. The foundation pile according to any one of claims 2 to 4, wherein the foundation piles are locked to each other when separated from each other by a predetermined dimension. 6. The lower end of the first pile structure and the upper end of the second pile structure are provided with protrusions projecting outwardly orthogonal to the axial direction of the pile body, The inner peripheral surface of the joining ring is provided with a locking portion that is locked to the protrusion to prevent the joining ring from being separated from the first pile structure and the second pile structure. The foundation pile according to claim 5, wherein: