JP3837659B2 - Foundation pile - Google Patents

Description

[0001]
BACKGROUND 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]
[Prior art]
As this type of foundation pile, for example, ready-made piles such as steel pipe piles and PHC piles are known. Such a pre-made pile may be formed of a single member, or may be formed by rigidly joining a plurality of pile constituent bodies made of steel pipes or concrete pipes.
[0003]
[Problems to be solved by the invention]
By the way, generally in the event of an earthquake, the axial force acting on the foundation pile fluctuates due to the horizontal force acting on the building, resulting in a large tower ratio (the ratio of the height to the building width) or seismic elements such as walls. In the foundation piles that are attached to, the fluctuating axial force exceeds the long-term axial force, and the pulling force may act. Therefore, in order to counter such pull-out force, conventionally, a method has been adopted in which a long-term axial force is increased by a counterweight (weight) or lifting is prevented by a ground anchor. However, these methods are not only costly, but can only be handled within the range of the assumed design seismic force.
[0004]
On the other hand, recently, construction methods that reduce the seismic energy input to buildings during an earthquake by designing to allow for the lifting of columns and foundations have begun to be adopted. These do not rigidly connect the column bases or the pile heads, but they can be lifted up by adopting vertically movable joints in these parts.
However, joints that allow such lifting also serve as joints for different members such as column bases that are attached to the beams and pile heads that are attached to the foundation. There is concern.
[0005]
In view of the above circumstances, in the present invention, by providing a mechanism that allows the foundation pile to lift, it is possible to cope with various seismic forces and to avoid an increase in cost.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the present invention employs the following means.
That is, the foundation pile according to claim 1 is a foundation pile used to transmit the load of the upper structure of the building to the ground, and includes a pile body whose upper end is joined to the upper structure, Is formed by connecting a plurality of pile constituents to each other vertically, and among these pile constituents, at least two pile constituents adjacent to each other in the vertical direction are relative to each other in the direction in which these two pile constituents approach each other. It is characterized by being connected via a connection mechanism that regulates displacement and allows relative displacement in the direction of separation.
[0007]
With such a configuration, the pile structural members are separated from each other in the vertical direction, whereby the length dimension of the pile main body can be extended, and the lifting of the upper structure can be dealt with.
[0008]
Moreover, said connection mechanism is arrange | positioned so that the lower end of the 1st pile structure body located above among the pile structures adjacent to the upper and lower sides and the upper end of the 2nd pile structure body located below may be surrounded. A cylindrical joining ring that is joined to the inner peripheral surface of the joining ring and interposed between the lower end of the first pile structure and the upper end of the second pile structure, An axial force transmission member that transmits a compression axial force acting on the pile body between the pile structure and the second pile structure is provided.
[0009]
With such a configuration, 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 end of the first pile structure and the upper end of the second pile structure are held. The compression axial force can be transmitted between the two.
[0010]
Moreover, said joining ring is characterized by the internal diameter dimension being made larger than the external dimension of at least one of the lower end of a 1st pile structure, and the upper end of a said 2nd pile structure. In such a configuration, the joining ring does not restrain both the first pile structure and the second pile structure, and therefore the axis of the first pile structure is the second pile structure. The first pile structure and the second pile structure are relatively displaced so as to be inclined with respect to the axis of the first pile structure (the first pile structure is rotationally displaced with respect to the second pile structure). Is not restricted by the joining ring.
[0011]
The axial force transmission member is characterized in that at least a part thereof is formed of an elastic member. With such a configuration, the axial force transmission member can satisfactorily follow the relative displacement / rotation angle of the first and second pile components.
[0012]
Furthermore, when the above-mentioned joining ring and the lower end of the first pile structure and the upper end of the second pile structure are separated by a predetermined dimension from the joining ring, the first pile structure and the second pile structure It is characterized by being locked to each other. With such a configuration, it is possible to prevent the first pile structure from coming off from the second pile structure.
[0013]
The foundation pile according to claim 2 is the foundation pile according to claim 1 , wherein the lower end of the first pile structure and the upper end of the second pile structure are outwardly orthogonal to the axial direction of the pile body. Is provided on the inner peripheral surface of the joining ring to prevent the detachment of the joining ring from the first pile structure and the second pile structure. An engaging portion is provided.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described 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 the structure which formed the pile main body 4 by connecting the several pile structure body 2 which consists of steel pipes, for example, up and down via the connection mechanism 3. As shown in FIG. And in this foundation pile 1, the upper end 4a of the pile main body 4 is joined with the footing 5 which makes a part of the upper structure of a building, thereby compressing the load of the upper structure of the building. It is transmitted to the ground as an axial force.
[0015]
FIG. 1 is an elevational sectional view showing a configuration in the vicinity of the connection mechanism 3, and FIG. 2 is a sectional view taken along the line I-I in FIG. 1. As shown in the figure, the connection mechanism 3 is configured to include a joining ring 6 and an axial force transmission member 7 joined to the inner peripheral surface 6 a of the joining ring 6.
[0016]
Among these, the joining ring 6 is formed of a cylindrical steel material, and is located below the lower end 2Aa and the lower end of the first pile constituent body 2A located above the pile constituent bodies 2 and 2 adjacent in the vertical direction. It arrange | positions so that upper end 2Ba of the 2nd pile structure 2B to perform may be surrounded.
[0017]
In addition, the axial force transmission member 7 is disposed horizontally, and the outer peripheral edge 8a is welded to the inner peripheral surface 6a of the joining ring 6 and the rib plate 8 is sandwiched from above and below. An elastomer member (elastic member) 9 is provided, and a rib plate 8 and a loading plate 10 that is horizontally arranged so as to sandwich the upper and lower elastomer members 9 from above and below. The elastomer member 9 and the loading plate 10 are configured to be movable relative to the rib plate 8.
[0018]
Further, in the connection mechanism 3, a C-shaped reinforcing ring (protruding portion) 12 in a plan view is formed on the outer peripheral portion of the lower end 2Aa of the first pile structure 2A and the upper end 2Ba of the second pile structure 2B. However, it is being fixed in the state which protruded to the outward (the radial direction outward of the pile structure 2) orthogonal to the axial direction of the pile main body 4. FIG. And the lower end 2Aa of 1st pile structure 2A and the reinforcement ring 12 fixed to the outer peripheral part contact | abut to the loading plate 10 of the upper side of the axial force transmission member 7, 1st pile structure The compression axial force of the body 2 </ b> A is transmitted to the axial force transmission member 7. Furthermore, this compression axial force is transmitted to the upper end 2Ba of the second pile constituting body 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 transmission member 7, thereby The axial force transmission between the first pile constituent body 2 </ b> A and the second pile constituent body 2 </ b> B is performed via the axial force transmission member 7.
[0019]
When such axial force transmission is performed, the axial force transmission member 7 is held 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 transmission member 7 is fixed in a state as shown in FIG. The joining ring 6 is formed so that its inner diameter is slightly larger than the outer diameter of the lower end 2Aa of the first pile structure 2A and the upper end 2Ba of the second pile structure 2B. Thus, the joining ring 6 is prevented from coming into direct contact with the first and second pile structures 2A and 2B.
[0020]
Further, a stopper (locking portion) 13, which is a steel annular member, is welded and fixed to the upper end portion 6 b and the lower end portion 6 c of the joining ring 6 so as to be positioned on the inner peripheral surface 6 a of the joining ring 6. The stopper 13 is formed so that the inner diameter dimension thereof is smaller than the outer diameter dimension of the reinforcing ring 12, whereby the first pile structure body 2A and the second pile structure body 2B are separated by a predetermined dimension. Sometimes it 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.
[0021]
Moreover, the sealing material 14 which consists of a water expansion rubber is filled into the clearance gap between the stopper 13 and the 1st pile structure 2A and the 2nd pile structure 2B. Thereby, earth and sand, mud and the like are prevented from entering the inside of the joining ring 6.
[0022]
Next, the construction method of the foundation pile 1 in this Embodiment is demonstrated.
In order to construct the foundation pile 1, the ground is excavated to form an excavation hole (not shown), and the pile body 4 formed by connecting the pile components 2 to each other is built inside the excavation hole. The footing 5 is formed at the upper end 4 a of the four and the footing 5 is integrated with the upper end 4 a of the pile body 4.
[0023]
Here, in order to form the pile main body 4, as shown in FIG. 4, the pile constituent bodies 2 (the first pile constituent body 2A and the second pile constituent body 2B) that are adjacent to each other in the vertical direction are used as the axial force transmission member. It connects so that the upper end 2Ba of the 1st pile structure 2B and the lower end 2Aa of the 2nd pile structure 2A may be inserted in the joining ring 6 to which 7 was attached.
Moreover, when connecting the pile structure 2 in this way, the reinforcement ring 12 (illustration omitted in FIG. 4) is previously fixed to lower end 2Aa of 2 A of 1st pile structures. For example, as shown in FIG. 5A, the reinforcing ring 12 is fixed by inserting the lower end 2Aa of the first pile structure 2A into the reinforcing ring 12 while slightly expanding the reinforcing ring 12, and further FIG. ) By integrating the two by fillet welding. Further, the reinforcing ring 12 is fixed to the upper end 2Ba of the second pile constituent body 2Ba by the same procedure (that is, the reinforcing ring 12 is fixed to the upper and lower ends as the pile constituent body 2). Will be used). Such a reinforcing ring 12 prevents the local buckling when the upper end 2Ba of the second pile structure 2B and the lower end 2Aa of the first pile structure 2A abut against the axial force transmission member 7. Also plays a role.
[0024]
When the pile structure 2 is inserted into the joining ring 6 as shown in FIG. 4, as shown in FIG. 1, the upper end 6b and the lower end 6c of the joining ring 6 are positioned on the inner peripheral surface 6a side. The stopper 13 is fixed by welding, and the sealing material 14 is loaded between the stopper 13 and the outer surface of the pile structure 2. Thereby, the connection mechanism 3 will be formed between 2 A of 1st pile structures and the 2nd pile structure 2B.
[0025]
After connecting a plurality of pile constituent bodies 2 by the procedure as described above, the pile constituent body 2 located at the uppermost position is lifted by a crane or the like. In this case, in the connection mechanism 3, the stopper 13 and the first pile structure 2 </ b> A welded to the joining ring 6, although the second pile structure 2 </ b> B tries to drop off from the first pile structure 2 </ b> A by gravity. And the reinforcement ring 12 fixed to the second pile structure 2B is locked to each other, thereby preventing the first pile structure 2A and the second pile structure 2B from being separated more than necessary. This prevents the second pile structure 2B from falling off the first pile structure 2A. Therefore, the pile main body 4 composed of a plurality of pile constituent bodies 2 can be easily lifted and built into the excavation hole.
[0026]
After building the pile body 4 in the excavation hole in this way, an upper structure of the building is formed on the pile body 4, and a footing 5 that is a part of the upper structure is attached to the pile body 4. The foundation pile 1 as shown in FIG. 3 is obtained by integrating with the upper end 4a.
[0027]
In the above-described foundation pile 1, two pile constituent bodies 2 (first pile constituent body 2 </ b> A and second pile constituent body 2 </ b> B) that are adjacent vertically are in contact with each other via the axial force transmission member 7 in the connection mechanism 3. Therefore, these two pile structural bodies 2 are connected in a state where the relative displacement in the approaching direction is restricted and the relative displacement in the separating direction is allowed. Therefore, even if the pulling force acts on the foundation pile 1 when the variable axial force of the foundation pile 1 exceeds the long-term axial force at the time of an earthquake, the pile body 4 is separated by the pile constituent bodies 2 apart from each other. As a result, the pile body 4 is deformed following the rise of the upper structure. Thereby, the earthquake input energy to the building at the time of an earthquake can be reduced, and it becomes possible to cope with various seismic forces.
[0028]
In this case, the connection mechanism 3 is joined to the cylindrical joining ring 6 and the inner peripheral surface of the joining ring 6, and between the first pile constituting body 2 </ b> A and the second pile constituting body 2 </ b> B, the pile body The connecting mechanism 3 is completed simply by inserting upper and lower piles into the joining ring 6. Since it can be used, the workability is very high. In addition, since the welding of the joining ring 6 and the rib plate 8 of the axial force transmission member 7 can be performed not only in the field but also in a factory or the like, a reliable and strong structure can be realized as the connection mechanism 3. In addition, the connection mechanism 3 only connects the first and second pile structural bodies 2A and 2B having the same diameter, and does not involve special materials or complicated processing, so it can be realized at low cost. is there.
[0029]
Moreover, in this Embodiment, it forms so that the internal diameter dimension of the joining ring 6 may become larger than the external dimension of lower end 2Aa of 1st pile structure 2A, and upper end 2Ba of 2nd pile structure 2B. ing. 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 first pile structure 2A and the second pile structure 2B are allowed to be relatively displaced and rotated so as to be inclined with respect to the axis of 2B.
[0030]
That is, this enables the connection mechanism 3 to be rotationally deformed as a whole, the rotational rigidity of the connection mechanism 3 is reduced, and the first pile structure 2A and the second pile structure 2B are close to pin joints. Since it will be connected in a state, the stress which arises in the pile main body 4 can be reduced. Furthermore, this makes it possible for the pile body 4 to follow the deformation of the ground and rotate and deform at the joint. Therefore, even if the ground is liquefied, no excessive stress is generated on the pile body 4. It is possible to continue to maintain the building load support capability.
[0031]
Moreover, since the inner diameter dimension of the joining ring 6 is larger than the outer dimensions of the lower end 2Aa of the first pile constituent body 2A and the upper end 2Ba of the second pile constituent body 2B, accuracy control during construction is possible. In addition to being easy, it is possible to attach a stopper 13 for preventing excessive lifting.
[0032]
Furthermore, since the elastomer member 9 is provided in a part of the axial force transmission member 7, the rotational rigidity of the connection mechanism 3 can be reduced more favorably, and the first pile structure 2A can be When it floats with respect to the pile structure 2B, it becomes possible to relieve the impact which arises at the time of subsequent re-contact, and a highly safe structure can be implement | achieved.
[0033]
Moreover, in this Embodiment, with respect to the reinforcement ring 12 provided in lower end 2Aa of 1st pile structure 2A, and upper end 2Ba of 2nd pile structure 2B, it is on inner peripheral surface 6a of joining ring 6 When the provided stopper 13 is locked, the joining ring 6 is prevented 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 2Ba of the second pile structure 2B are the first pile structure 2A and the second pile structure. When 2B is separated from the joining ring 6 by a predetermined dimension, the two piles are locked to each other, so that excessive pull-up of the first pile structure 2A from the second pile structure 2B can be prevented. it can. Further, by adjusting the distance between the stopper 13 and the reinforcing ring 12, it is possible to easily control the allowable amount of lifting.
[0034]
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 said embodiment, you may make it enlarge the allowable floating amount in the foundation pile 1 by providing the some connection mechanism 3 in the one foundation pile 1. FIG.
[0035]
Moreover, the structure close | similar to a pile head pin joint is easily realizable by providing the connection mechanism 3 of the said embodiment in the pile head vicinity of the foundation pile 1. FIG. In this case, the bending stress generated at the joint between the pile head and the foundation of the upper structure (footing 5) is very small, and the axial force is allowed to lift and no tensile force is generated. The cross-section design of the part becomes easy and the cost of the foundation pile 1 as a whole can be reduced. In addition, if the effect close to the pile head pin joint can be exhibited in this way, the stress of the foundation beam and mat mated to the foundation pile 1 can be greatly reduced, and the cross section of these frames can be rationalized. Since the amount of excavation and mountain retaining can be reduced by reducing the formation, further cost reduction becomes possible.
[0036]
Moreover, in the said embodiment, although the pre-boring method which provided the excavation hole in the ground beforehand and built the pile main body 4 in the excavation hole was employ | adopted, the joining ring 6 and the axial force transmission member 7 (rib plate 8) are adopted. ) Is a hollow ring shape, it is also possible to adopt an intermediate excavation method in which the pile body 4 is built into the excavation hole while excavating the excavation hole.
[0037]
Moreover, although the said embodiment was an example at the time of employ | adopting a steel pipe as the pile structure 2, instead of this, concrete is used as the pile structure 2 'like the foundation pile 1' shown in FIGS. It is good also considering foundation pile 1 'as a PHC pile by employ | adopting a pipe | tube.
[0038]
The foundation pile 1 ′ shown in FIG. 6 has a configuration in which a pile body 4 ′ is formed by connecting a plurality of pile constituent bodies 2 ′ made of concrete pipes up and down via a connection mechanism 3 ′. FIG. 7 is a vertical sectional view showing a configuration in the vicinity of the connection mechanism 3 ′, and FIG. 8 is a sectional view taken along the line II-II in FIG. As shown in the figure, in the connection mechanism 3 ′, an axial force transmission member 7 ′ joined to the inner peripheral surface 6 a of the joining ring 6 is fixed to the rib plate 8 and the elastomer member 9 fixed above and below the rib plate 8. And is formed by.
[0039]
The elastomer member 9 is in contact with the end plate 20 of the pile constituent body 2 ′, and thereby the ribs from the end plate 20 of the first pile constituent body 2A ′ positioned above the pile constituent body 2 ′. An axial force can be transmitted to the end plate 20 of the second pile constituting body 2B ′ positioned below through the plate 8 and the upper and lower elastomer members 9. Moreover, in this foundation pile 1 ', since the pile structure 2' is a concrete pipe and has a certain thickness dimension, unlike the said embodiment, the local seat of the edge part of the pile structure 2 'is used. There is no need to provide the reinforcing ring 12 to prevent bending. 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 this round steel ring 21 is provided on the inner peripheral surface 6 of the joining ring 6. The stopper 13 can be locked.
[0040]
As shown in FIG. 9, the round steel ring 21 is fixed to the pile structure 2 ′ by inserting the end of the pile structure 2 ′ into the round steel ring 21 while slightly expanding the round steel ring 21. Furthermore, it can carry out by integrating the end plate 20 and the round steel ring 21 of pile structure 2 'by flare welding.
Even with such a configuration, it is possible to obtain the same effect as that of the above embodiment.
[0041]
Alternatively, an elastic member formed of another synthetic rubber or natural rubber may be used in place of the elastomer member 9 used in the above embodiment and its modifications.
[0042]
In addition, in the foundation pile 1 (1 ′), the stopper 13, the reinforcing ring 12, and the round steel ring 21 can be omitted when a tensile force does not act from the time of construction to after completion.
[0043]
Furthermore, in order to connect the pile structure 2 (2 ′) in one foundation pile 1 (1 ′), both the connection mechanism 3 (3 ′) and the conventional rigid joint are adopted. Also good. Moreover, among the foundation piles used for a building, a part can be used as the foundation pile 1 (1 '), and others can be mixed and used as a conventional foundation pile. This broadens design options and enables more rational design. Therefore, the present invention can be widely used for mitigating stress concentration on short piles when the surface layer and support layer are inclined, and for dealing with small-diameter cross sections when piles with different pile diameters are used in combination. .
[0044]
【The invention's effect】
As described above, according to the present invention, it is possible to cope with various seismic forces while avoiding an increase in cost by providing a mechanism that allows the foundation pile to lift.
[Brief description of the drawings]
FIG. 1 is an enlarged vertical sectional view of a foundation pile connecting mechanism schematically showing an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line II in FIG.
FIG. 3 is an elevation view showing the entire foundation pile shown in FIGS. 1 and 2;
4 is a perspective view showing a procedure when constructing the foundation pile shown in FIGS. 1 to 3. FIG.
FIG. 5 is a perspective view showing another procedure.
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 foundation pile connecting mechanism shown in FIG. 6;
8 is a cross-sectional view taken along line II-II in FIG.
FIG. 9 is a perspective view showing a procedure when the foundation pile shown in FIGS. 6 to 8 is constructed.
[Explanation of symbols]
1, 1 'foundation pile 2, 2' pile structure 2A, 2A 'first pile structure 2Aa lower end 2B, 2B' second pile structure 2Ba upper end 3, 3 'connection mechanism 4 pile body 4a upper end 5 footing 6 Joining ring 6a Inner peripheral surface 7, 7 'Axial force transmission member 9 Elastomer member (elastic member)
12 Reinforcement ring (protrusion)
13 Stopper (locking part)
21 Round steel ring (protrusion)

Claims (2)

A foundation pile used to transmit the load of the superstructure of the building to the ground,
The pile body is formed by connecting a plurality of pile structures up and down, and at least two of the pile structures adjacent to each other vertically. The pile structure is connected via a connection mechanism that regulates the relative displacement of the two pile structures in the direction of approaching each other and allows the relative displacement in the direction of separation .
The connection mechanism is disposed so as to surround the lower end of the first pile structure located above and the upper end of the second pile structure located below among the two pile structures adjacent vertically. A cylindrical joining ring to be joined to the inner peripheral surface of the joining ring, and interposed between the lower end of the first pile structure and the upper end of the second pile structure, and a axial force transmitting member for transmitting a compressive axial force acting on the pile body between the first pile structure and said second pile structure,
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 ,
At least a part of the axial force transmission member is formed by an elastic member ,
The joining ring and the lower end of the first pile structure and the upper end of the second pile structure are separated from the joining ring by a predetermined dimension from the first pile structure and the second pile structure. A foundation pile characterized by locking together. The lower end of the first pile structure and the upper end of the second pile structure are provided with protrusions projecting outwardly perpendicular to the axial direction of the pile body, and the inner circumference of the joining ring The surface is provided with a locking portion that is locked to the protrusion and prevents the joining ring from being detached from the first pile structure and the second pile structure. The foundation pile according to claim 1 .

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