JPH07189246A - Joint structure of pile - Google Patents

Abstract

PURPOSE:To enable stable fitting by externally fitting an outer ring having an internal surface taper clasping an inner ring to the inner ring having a circumferential recessed strip having width broader than the total thickness of an end plate in an internal surface and having an external surface taper in the longitudinal direction of a pile. CONSTITUTION:The outer circumferential surfaces 5a, 5b of end plates 2a and 2b are formed in finished surfaces having high accuracy, and abutted against the abutting section 10 of the recessed section 11 of the groove of an inner ring 9 externally fitted to the outer circumferential surfaces 5a, 5b. The circumference of the inner ring 9 is divided into the plural, width in the axial direction of a pile of the abutting section 10 of the recessed section 11 is made slightly wider than the total thickness of the two end plates 2a, 2b, and clearances 13 are formed. The external surface of the inner ring 9 is tapered 14 in the longitudinal direction of the pile. An outer ring 15 being externally fitted to the inner ring 14 and having a taper 16 is moved in the longitudinal direction of the pile, thus contact-bonding the inner ring 9 with the end plates 2a, 2b by the taper 16 and the taper 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint structure for a support pile that fits underground.

[0002]

2. Description of the Related Art According to past seismic damage surveys, lateral movement of the ground occurs almost at the point when liquefaction occurs. The amount of movement may reach several meters in some cases.
When such a large lateral movement occurs, the underground structure is damaged not only by rising and sinking but also by the destruction of the structure itself. Pile foundations are no exception.

As shown in FIG. 9, an excellent breakage 53 is often observed at the boundary between the liquefied layer 50 and the non-liquefied layers 51 and 52 above and below it. It was within the last ten years that the lateral movement phenomenon 54 of this ground was revealed.
The handling of this phenomenon in seismic design has not been established. Therefore, research is being actively conducted as one of the most important issues.

Conventional pile joint structures are generally welded joints. Such welded joints require a welding technician, the work is controlled by the weather, and the welding strength depends largely on the skill of the operator and lacks reliability. It is also difficult to secure technicians. In order to solve this, the applicants of the present invention
No. 81326 discloses a joint structure for piles. The joint structure has an annular groove in the vicinity of the end of each pile to be joined, and a plurality of divided cylindrical inner rings with an annular ridge that fits into this annular groove and has a tapered outer diameter. The outer ring is externally fitted to the joint part of the pile, and the outer diameter of this inner ring has the same taper on the inner surface.The outer ring is pressed in the pile longitudinal direction, and the inner ring is tightened by the taper. It is a structure that connects piles.

With the development of a so-called weld-free joint structure, which is a combination of an inner ring and an outer ring in place of the above-mentioned welded joint, the drawbacks of the welded joint have been solved.

[0006]

However, the non-welded joint is also designed for the purpose of rigid connection, and is not a joint structure that can flexibly deal with the lateral movement of the ground due to the earthquake as described above. Therefore, it is conceivable that the pile may be destroyed. For structures with low bending rigidity such as piles, lateral movement of the ground is extremely dangerous. The result shows that piles will be destroyed when the amount of ground movement is several tens of centimeters. Moreover, this is in good agreement with the actual damage. Therefore, it can be said that it is indispensable to develop a new type of pile that has a mechanism different from that of conventional piles and is capable of large deformation following ground changes.

Therefore, by utilizing the mechanism of the non-welded joint, a pile joint structure has been developed which can be used for the ground which is likely to be liquefied and which can also support the lateral movement of the ground while maintaining the supporting force. . It is an object of the present invention to provide such a pile joint structure.

[0008]

SUMMARY OF THE INVENTION According to the present invention, there is provided a circle having an inner peripheral surface having a circumferential concave line which is in contact with the outer peripheral surfaces of the end plates of the upper and lower piles and is wider than the total thickness of the end plates, and has a taper on the outer surface in the pile longitudinal direction. The joint structure of a pile includes an inner ring divided into a plurality of circumferences and an outer ring having an inner taper that is fitted onto the outer taper to tighten the inner ring.

Further, it is preferable that an elastic material is interposed in the gap between the end plate and the circumferential groove.

[0010]

The joint structure of the present invention does not have a completely rigid connection such as a welded joint, but has flexibility between the upper and lower piles. The joint structure of the present invention is such that an inner ring that is externally fitted to the end plates attached to the upper and lower pile ends is pressed against the outer peripheral surface of the end plate by the outer ring, and the friction force due to the pressing force between the end plate and the inner ring is applied. Connect the upper and lower piles. This pressing force is the taper tightening force of the outer ring.

In the present invention, the outer peripheral surface of the end plate and the inner surface of the inner ring are brought into contact with each other, and the other piles and the inner ring are not in contact with each other.
It may be a shape without finishing. Since the cross-sectional shapes of the inner ring and the outer ring are formed at the time of steel making by hot rolling, there is no need for complicated cutting after rounding, and the manufacturing effect is high. The joint structure of the present invention has the above-described structure, and when liquefaction occurs once due to an earthquake or the like and lateral movement of the ground occurs, the joint portion is end plate and inner ring while counteracting this lateral external force. It can be deformed by the gap of the recess of the inner diameter in the longitudinal direction of the pile, and the outer ring is appropriately elastically relaxed, allowing relative bending of the upper and lower piles. By providing a plurality of joints in this way, it is possible to cope with large deformation. At this time, the inner wall of the inner ring inner diameter concave portion serves as a stopper and does not relax beyond the gap in the pile longitudinal direction, and the upper and lower piles do not separate. In addition, since this joint structure is not a completely rigid connection, it does not break like welded piles and assists the bending rigidity of the piles, and can also follow the lateral movement of the ground while maintaining the function against axial force, that is, supporting force. Have an effect.

[0012]

1 is a partially cutaway side view showing a joint structure for a pile of the present invention, FIG. 2 (a) is a partially enlarged vertical sectional view thereof, and FIG. 2 (b) is a sectional shape view of an inner ring 9. Is. An embodiment of the present invention will be described in detail with reference to FIGS. The upper pile 1a is a precast concrete pile in which one end of the PC steel rod 3 is fixed to the end plate 2a at the lower end thereof and prestress is introduced into the concrete 4. The outer peripheral surfaces 5a and 5b of the end plates 2a and 2b are finished surfaces with high accuracy, and are brought into contact with the contact portions 10 of the recesses 11 of the groove of the inner ring 9 fitted onto the outer surfaces. The inner ring 9 has a plurality of divided circumferences, and the width in the pile axial direction of the contact portion 10 of the recess 11 is made slightly larger than the total thickness of the two end plates 2a and 2b, and the gap 13 is provided. is there.

Since the piles are buried vertically, the load of the upper piles 1a is applied to the lower piles 1b, and the end plates 2 are joined when the piles are joined.
The contact portion 10 of the concave portion 11 of the inner ring 9 abuts against the end plates 5a and 5b in a state where the a and the end plate 2b are in close contact with each other to be restrained and coupled. At this time, there is no problem even if the gap 13 is divided into upper and lower parts or is offset to the lower side. This gap 13 has the above-mentioned effect. The gap 13 may be filled with rubber or other elastic material that deforms while resisting lateral force to some extent. Chloroprene rubber having a high damping property is suitable as such an elastic material. Chloroprene rubber of synthetic natural rubber (polyisoprene rubber) _- is suitable as MenShinzai excellent aging resistance in place of CH ₃ group at one with the CL group. The outer surface of the inner ring 9 is tapered in the longitudinal direction of the pile. The outer ring 15 has this taper 14
It is a cylindrical ring having a taper 16 that fits over the. By moving the outer ring 15 in the longitudinal direction of the pile indicated by the arrow 18, the inner ring 9 is crimped to the end plates 2a, 2b by the taper 16 and the taper 14. At this time, the inner ring 9 is dimensioned such that the plurality of split seams have a small gap 17 even when the connection between the inner ring 9 and the pile is completely completed. Further, the lower end of the outer ring 15 is dimensioned so as to be above the lower end of the inner ring 9 when the outer ring 15 is fitted onto the inner ring 9 with a regular pressing force. 1 outer ring for each pile diameter
The fitting pressure (jack pressure) of 5 is determined, and the hoop tension is generated so that the strain of the outer ring is about 300 μ (300 × 10 ⁻⁶ ) so as to satisfy the long-term stress and the short-term stress in all cases. The inner diameter of the outer ring 15 is set as described above.

This cylindrical taper is manufactured at 1/20. The manufacturing tolerance of the end plates 2a, 2b and the inner ring 9 is ± 0.
When it is 45 mm, the tolerance of the position of the outer ring 15 in the axial direction is about ± 4.5 mm. Therefore, if the width of the pile of the inner ring 9 in the longitudinal direction is set to be 10 mm longer than the width of the outer ring 15, the lower end of the outer ring 15 is above the lower end of the inner ring 9 in all cases. Further, the upper end of the outer ring 15 does not protrude beyond the upper end of the inner ring 9.

The taper 14 on the outer surface of the inner ring 9 and the taper 16 on the inner surface of the outer ring 15 are formed with circumferential ridges having a saw-tooth cross section and meshing with each other. This circumferential projection is shown in FIG. 6 (a) as an inner ring-side projection 14 'and in FIG. 6 (b) as a partially enlarged vertical sectional view of the outer ring-side projection 16'. This sawtooth tooth profile moves on the slope of the tooth profile when moving the outer ring 15 in the direction of arrow 18 with respect to the inner ring 9 in FIG. When moving in the direction of the taper, that is, in the direction in which the taper is loosened, the ridges 14 'and 16' mesh with each other and do not move. The specific dimensions of the tooth profile of the ridges 14 'and 16' are about 3 mm in the pitch of the tooth and about 0.7 mm in the height of the tooth.

It is preferable that the coated metal cylinder 6 is formed such that the diameter in the vicinity of the end plate 2a attached to the end plate 2a is processed like a diaphragm 7 because the rigidity of the cylinder 6 is improved and the concave groove is easily formed. If cylinders having different diameters are superposed and welded to form a groove similar to this drawing structure, it is difficult to expect the improvement of rigidity as compared with the drawing structure because it requires welding work. In the coated metal cylinder 6, the circumferential reinforcing groove 8 (stringing process) not only increases the rigidity, but also penetrates into the concrete to improve the adhesion and exerts a great effect in preventing the metal from coming off.

FIG. 3 shows an embodiment in the case of a large diameter pile, in which the outer surface of the inner ring 9 has both tapers 14a and 14b facing each other at the center of the longitudinal width of the pile, and the outer rings 15a and 15b are
One combination is shown at the top and one at the bottom. Since the outer ring becomes heavy when the diameter is about 800 mm or more and about 1000 mm, the workability is improved by dividing the outer ring into two.

FIGS. 4 and 5 show an embodiment in which the outer diameters of the joint portions 2a and 2b are not the same as the outer diameters of the piles 1a and 1b and may be small or large. FIG. 4 shows a case where the diameter is smaller than the pile diameter, and the seats 5a and 5b on the outer peripheral surface form extremely gentle convex tapers facing each other around the connecting surface of the end plates 2a and 2b, and the inner ring 9 that abuts against this. The abutting portions 10a and 10b are also tapered following 5a and 5b. Such an abutment surface is an example in which the outer ring sequentially elastically relaxes and rotates while promoting resistance to a lateral external force, and such an abutment surface may be used. FIG. 5 shows an example in which the diameter is larger than the pile diameter. The upper and lower piles 1a, 1
Of course, it can be applied to the case where b is a different type of pile, such as a steel pipe pile and a concrete pile.

7 (a), (b), (c), and (d) are vertical sectional views of an embodiment of the inner ring. The contact portion 10 of the concave portion 11 of the inner ring 9 has the outer peripheral surface 5 of the end plates 2a and 2b.
Any shape may be used as long as it conforms to a and 5b. It suffices that the end plates 2a and 2b are crimped, and the piles are formed in a shape and dimensions that allow the outer ring to elastically relax while resisting a lateral external force in the event of an earthquake and allow bending and rotation. The other portions may have any suitable shape.

FIG. 8 shows an example of the end plate of the example and the end plate of the comparative example. Considering a case where the end plates 2a and 2b have the same total thickness, in the conventional end plate shown in FIG.
The thickness 21 between the end plates 2a and 2b is small, the fitting accuracy of the groove and the projection is low, and the entire thickness of the end plates 2a and 2b is not fully utilized. On the other hand, in the embodiment of the present invention, the thickness 20 close to the total thickness of the end plates 2a and 2b can be utilized to the maximum extent, and the joint portion, particularly the end plate portion becomes extremely strong.

[0021]

According to the present invention, only the outer peripheral surface of the end plate of the pile is finished and the inner ring concave portion that abuts against the end plate is made a little wider than the total thickness of the end plate, and the other shapes do not interfere with each other. Therefore, the pile joint structure can be simplified,
Even in the field construction, stable fitting is always possible with the specified fitting pressure, and a joint structure that does not break during an earthquake can be obtained.

In the conventional pile, a lateral moment of the ground causes a bending moment to act on the pile, and the pile cannot escape. The location where this lateral movement occurs is the boundary between the liquefied layer and the non-liquefied layer, so the groundwater level or the standard penetration test N
It is possible to estimate from the value distribution before construction, if the pile of the joint structure of the present invention is used here, the bending moment generated in the pile due to easy deformation can be reduced, and by using a plurality of joints, large deformation can be achieved. It is also possible to follow, and it is possible to secure safety. Moreover, it is a seismic-resistant pile joint structure with high toughness, which is excellent in economic efficiency and practicality with almost no increase in cost.

[Brief description of drawings]

FIG. 1 is a partially enlarged vertical sectional view showing a joint structure for a pile according to an embodiment of the present invention.

FIG. 2 is a partially enlarged vertical sectional view showing a joint structure for a pile according to an embodiment of the present invention.

FIG. 3 is a partially enlarged vertical sectional view of another embodiment.

FIG. 4 is a partially enlarged vertical sectional view of another embodiment.

FIG. 5 is a partially enlarged vertical sectional view of another embodiment.

FIG. 6 is a partially enlarged vertical sectional view of an inner ring and an outer ring of an embodiment.

FIG. 7 is a vertical cross-sectional view of an inner ring (a) according to an embodiment and vertical cross-sectional views of inner rings (b), (c), and (d) according to another embodiment.

FIG. 8 is a comparative explanatory view of the joint end plate of the present invention and the end plate of the conventional joint.

FIG. 9 is an explanatory diagram of a reference example of a mechanism for lateral movement of the ground.

[Explanation of symbols]

 1a, 1b Pile 2a, 2b End plate 3 PC steel rod 4 Concrete 5a, 5b End plate outer peripheral surface seat 6a, 6b Coated metal cylinder 7 Drawing 8 Circumferential reinforcing groove 9 Inner ring 10 Contact part 11 Inner ring recess 12a, 12b Inner ring recess Inner wall 13 Gap 14 Taper 14 'Inner ring Outer diameter taper protrusion 15 Outer ring 16 Taper 16' Outer ring Inner diameter taper protrusion 17 Spacing 18 Arrow

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[Procedure amendment]

[Submission date] February 25, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

As shown in FIG. 9, a predominant destruction 53 at the boundary between the liquefied layer 50 and the non-liquefied layers 51 and 52 above and below it.
Is often observed. It was within the last ten years that the lateral movement phenomenon 54 of this ground was clarified. Regarding the handling of this phenomenon in seismic design,
It has not been decided yet. Therefore, research is being actively conducted as one of the most important issues.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006]

However, the non-welded joint is also designed for the purpose of rigid connection, and is not a joint structure that can flexibly deal with the lateral movement of the ground due to the earthquake as described above. Therefore, it is conceivable that the pile may be destroyed. Lateral movement of the ground is extremely dangerous for structures with low bending toughness such as shears . The result shows that piles will be destroyed when the amount of ground movement is several tens of centimeters. Moreover, this is in good agreement with the actual damage. Thus it can be said to have a different mechanism from the conventional pile, it is in the very form is a new form of the essential situation and development of the pile as possible to follow the ground deformation.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

In the present invention, the outer surface of the plate and the inner surface of the inner ring may be brought into contact with each other, and the other resistance and the inner ring may be in non-contact with each other, and a finish may not be applied. Since the cross-sectional shapes of the inner ring and the outer ring are formed at the time of steel making by hot rolling, there is no need for complicated cutting after rounding, and the manufacturing effect is high. The joint structure of the present invention has the above-described structure, and when liquefaction occurs once due to an earthquake or the like and lateral movement of the ground occurs, the joint portion resists this lateral external force and the joint portion has an end plate and an inner ring inner diameter. The outer ring can be appropriately elastically relaxed and deformed by the gap in the longitudinal direction of the concave portion of the pile, and relative bending of the upper and lower piles is allowed. By providing a plurality of joints in this way, it is possible to cope with large deformation. At this time, the inner wall of the inner ring inner diameter concave portion serves as a stopper and does not loosen more than the anti-longitudinal gap and the upper and lower piles do not separate. Also, since this joint structure is not a perfect rigid connection, it supports the bending toughness of the pile without breaking like conventional piles, and moves laterally of the ground while maintaining the function against axial force or supporting force. It also has the ability to follow.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

Since the piles are buried vertically, the load of the upper pile 1a is applied to the lower pile 1b, and when the piles are joined, the end plate 2a and the end plate 2b are in close contact with each other and the recess 11 of the inner ring 9 is adhered thereto.
The abutting portion 10 comes into contact with the end plates 5a and 5b to restrain and bond them. At this time, there is no problem even if the gap 13 is divided into upper and lower parts or is offset to the lower side. This gap 13 has the above-mentioned effect. The gap 13 may be filled with rubber or other elastic material that deforms while resisting lateral force to some extent. Chloroprene rubber having a high damping property is suitable as such an elastic material. Chloroprene rubber is a synthetic natural rubber (polyisoprene rubber) instead of -CH ₃ group.
It has a -C1 group and has excellent aging resistance and is suitable as a seismic isolation material. The outer surface of the inner ring 9 is tapered in the longitudinal direction of the pile. The outer ring 15 has this taper 1
4 is a cylindrical ring having a taper 16 which is fitted onto the outer circumference of the cylinder 4. By moving the outer ring 15 in the longitudinal direction of the pile indicated by the arrow 18, the inner ring 9 is crimped to the end plates 2a, 2b by the taper 16 and the taper 14. Inner ring 9 at this time
Is dimensioned such that the split seams have a small gap 17 even when the connection with the pile is completed. Further, the lower end of the outer ring 15 is dimensioned so as to be above the lower end of the inner ring 9 when the outer ring 15 is fitted onto the inner ring 9 with a regular pressing force. The fitting pressure (jack pressure) of the outer ring 15 is determined for each pile diameter, and the strain of the outer ring is about 300 μ (300 × 10 ⁻⁶ ) so that long-term and short-term stresses are satisfied in all cases. The inner diameter of the outer ring 15 is set so as to generate hoop tension.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

In the conventional pile, the lateral movement of the ground causes a bending moment to act on the pile, which cannot avoid the destruction. Since the place where this lateral movement occurs is the boundary between the liquefied layer and the non-liquefied layer, it can be estimated from the groundwater level or the N value distribution of the standard penetration test before construction, and here the joint structure of the present invention is used. If the pile of is used, the joint part may be deformed.
Can absorb the energy of the earthquake. Further, by using a plurality of joints, it is possible to follow a large deformation, and it is possible to ensure safety. Moreover, it is a seismic-resistant pile joint structure with high toughness, which is excellent in economic efficiency and practicality with almost no increase in cost.

[Procedure correction 6]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiromichi Sougami 3-18-16 Towa, Adachi-ku (72) Inventor Takashi Matsumoto 3-32-3 Aoi, Adachi-ku -303 (72) Inventor Yoshitaka Ito Kanagawa 4-8-13, Kokubunjidai, Ebina-shi, prefecture (72) Inventor, Takaaki Miyasaka 5-2-11-1 Akitsu-cho, Higashimurayama-shi, Tokyo Izuna Building 402 (72) Satoru Yamada 1-400 Yoshino-cho, Omiya-shi −14−605 (72) Inventor Masaaki Tada 3-14 Suehirocho, Yamagata City (72) Inventor Hiroshi Kasahara 4-57-15 Higashiomiya, Omiya City, Saitama Prefecture

Claims (2)

[Claims] 1. An inner ring having a plurality of circumferentially divided inner rings that are in contact with the outer peripheral surfaces of the end plates of the upper and lower piles and have a circumferential groove that is wider than the total thickness of the end plates and that has an outer taper in the pile longitudinal direction. A joint structure for a pile, which comprises an outer ring having an inner taper that is fitted onto the outer taper to tighten the inner ring. 2. The pile joint structure according to claim 1, wherein an elastic material is interposed in a gap between the end plate and the circumferential groove.