JP4503082B2 - Pile expansion member - Google Patents

Description

  The present invention relates to a bottom expansion member provided at a lower end of a pile such as a steel pipe pile or a PHC pile in order to increase a supporting force and a pulling resistance.

  Foundation piles that support buildings, structures, etc. are required to have resistance to pulling out external forces due to earthquakes, etc., in addition to supporting force to support structures. Therefore, conventionally, a bottomed pile having a bottom expanded portion at the lower end of the pile is widely known (for example, Patent Document 1). In this case, after drilling a hole bottom widened portion having a diameter larger than the pile diameter in advance at the bottom of the pile hole, cement milk or concrete or the like is placed in the hole bottom widened portion to provide the widened portion.

  In Patent Document 1, a ground excavation member capable of expanding the diameter is provided at the lower end of the pile, and the pile is rotated and excavated to press into the ground, and when the predetermined depth is reached, the ground excavation member is expanded and expanded. By performing excavation, a hole bottom widening portion is formed at the bottom of the pile hole, and cement milk or the like is placed in a state where the diameter of the ground excavation member is expanded to form the bottom widening portion.

  However, in this method, since the ground excavation member for excavating the hole-bottom widened portion is buried as it is in the ground as a reinforcing material, the construction cost becomes high. Therefore, in Patent Document 2, after filling cement milk into the expanded portion of the pile hole in which the expanded portion is excavated at the bottom of the hole and mixing it with earth and sand, a plurality of sets of expanded portions are formed at the lower end portion in the pile hole. The piles with open reinforcing bars are inserted to the bottom of the pile while rotating in such a direction that each of the expanded reinforcing bars is in close contact with the outer peripheral surface of the pile and closed, and the expanded reinforcing bars are When it is located in the expanded portion, the pile is reversely rotated to expand the expanded rebar, and is fixed with cement milk to form the expanded bottom portion.

Japanese Patent Laid-Open No. 6-287943 Japanese Patent Laid-Open No. 11-61811

  In the above-mentioned Patent Document 2, the expanded reinforcing bar provided at the lower end of the pile is specifically provided with a pair of upper and lower bands, and is curved along the length direction of the band at the vertically symmetrical position of the outer peripheral surface of the band. A plurality of arms are pivotally mounted so that one end can be opened and closed so that one end rotates through a hinge and the other end rotates in the pile outer direction when viewed from the cross-sectional direction of the pile. In this configuration, a plurality of vertical bars along the length direction are connected. Further, a chain is provided as a horizontal line between the vertical lines.

  However, although the expanded bottom pile described in patent document 2 can reinforce the bottom expanded part by cement milk with an expanded rebar, the load from the axial direction of a pile is a narrow arm among the expanded rebar fixed to the pile. It will be received by the horizontal line (chain), and there is a possibility that sufficient support force for the structure or the like cannot be obtained.

  This invention is made | formed in view of the said situation, The objective is to provide the bottom expansion member which can form the bottom expansion part provided with big supporting force and drawing-out resistance in a pile.

In order to solve the above problems, the bottom expansion member according to the present invention is:
A bottom expansion member provided at the lower end of the pile,
A support fixed to the pile that is the same as or smaller than the outer diameter of the pile;
A plurality of bottom expansion plates rotatably supported on the support,
The rotation axis of the bottom expansion plate is perpendicular to the plate surface of the bottom expansion plate and parallel to the axial direction of the pile,
The expansion plate is rotated so that the projection portion projected in the axial direction of the pile is accommodated inside the outer peripheral surface of the pile, and a part of the projection portion projected in the axial direction of the pile There Ri posture convertible der in the拡底posture projecting outward from the outer peripheral surface of the pile,
In the expanded bottom posture, adjacent expanded bottom plates are continuous to form an outer diameter portion of one disk as a whole .

  The operation and effect of the bottom expanding member with this configuration will be described. The bottom expansion member includes a support and a plurality of bottom expansion plates. The support is fixed to the pile and is the same as or smaller than the outer diameter of the pile. Thereby, the support body does not become an obstacle when the pile is inserted into the pile hole. The plurality of bottom expansion plates are pivotally supported by the support and can rotate with respect to the support. The expansion plate is rotated so that the projection position formed by projecting in the axial direction of the pile is accommodated inside the outer peripheral surface of the pile, and a part of the projection unit projected in the axial direction of the pile The posture can be converted into a bottomed posture protruding outward from the outer peripheral surface of the pile. According to this bottom expansion member, when the pile is inserted into the pile hole, the bottom expansion plate does not become an obstacle by adopting the housing posture. On the other hand, in the hole bottom widening portion formed at the bottom of the pile hole, the bottom expansion plate is projected in the axial direction of the pile by forming the bottom expansion portion in a state where the bottom expansion plate is in the bottom expansion posture. A part of can protrude outward from the outer peripheral surface of the pile and can receive an external force in the axial direction of the pile. Moreover, since the bottom expansion board is plate-shaped, compared with the arm and chain of the bottom expansion pile of a prior art, the bottom expansion part provided with a big support force and drawing resistance can be formed. Therefore, according to this bottom expansion member, the bottom expansion part provided with big supporting force and drawing-out resistance can be formed in a pile.

  In the present invention, the bottom expansion plate includes a resistance portion that receives resistance from the outside, and the resistance portion receives resistance by rotating the pile to which the support is fixed around the axis of the pile, and the accommodation posture It is preferable that the posture can be changed from the above to the widened posture.

  According to this configuration, the bottom expansion plate can convert the posture from the accommodation posture to the bottom expansion posture by rotating the pile around the axis of the pile. For example, the posture expansion means for converting the posture is separately provided. The posture can be easily changed without any problem.

  In the present invention, it is preferable that a pedestal connected to the support body by a connecting member is further provided, and the plurality of bottom expansion plates are rotatably supported on the pedestal.

  According to this configuration, since the bottom expansion member includes the bottom expansion plate pivotally supported by the support body and the bottom expansion plate pivotally supported by the pedestal, the bottom expansion portion having an even greater support force and pull-out resistance is piled up. Can be formed.

<Configuration of bottom expansion member>
A preferred embodiment of a bottom expanding member according to the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an external configuration of the bottom expanding member. FIG. 2 is a longitudinal sectional view showing the configuration of the bottom expanding member. In the following description, the central axis of the bottom expansion member is O, the upper side of FIG. 1 is the upper side of the bottom expansion member, and the lower side of FIG.

  A support plate 2 (corresponding to a support) is disposed on the upper portion of the bottom expanding member 1, and a seat plate 3 (corresponding to a pedestal) is disposed on the lower portion. The support plate 2 and the seat plate 3 are connected by a connecting member 4. A plurality of expanded base plates 5 are rotatably supported on the support plate 2 and the seat plate 3 by screws 6.

  The bottom expansion member 1 is attached by welding the support plate 2 to the lower end of the pile. Examples of the pile to which the bottom expansion member 1 is attached include steel pipe piles, concrete piles such as PHC piles (pretension type centrifugal force high-strength prestressed concrete piles), RC piles (centrifugal reinforced concrete piles), and the like.

  The support plate 2 has a disk shape with a through hole in the center. The outer diameter of the support plate 2 is formed to be the same as or smaller than the outer diameter of the pile to which the bottom expansion member 1 is attached. In consideration of workability and strength, the outer diameter of the support plate 2 is preferably the same as the outer diameter of the pile. Thereby, also when inserting the pile which attached the bottom expansion member 1 to the lower end in a pile hole, the support plate 2 does not become an obstacle. In addition, a through hole is provided in the center of the support plate 2, and a root hardening material such as earth and sand or cement milk can pass through the support plate 2. A plurality of screw holes for attaching the bottom expansion plate 5 with screws 6 are formed around the through hole of the support plate 2. In the present embodiment, eight screw holes are equally arranged in the circumferential direction.

  As with the support plate 2, the seat plate 3 has a disk shape with a through hole in the center. Although the outer diameter of the seat plate 3 is also formed to be the same as or smaller than the outer diameter of the pile to which the bottom expansion member 1 is attached, the outer diameter of the pile may be the same as the support plate 2. preferable. The seat plate 3 is also formed with eight screw holes for attaching the bottom expansion plate 5 with screws 6.

  The connecting member 4 has a cylindrical shape, and projecting portions 4 a are provided at upper and lower ends so as to be connected to the support plate 2 and the seat plate 3. The protruding portion 4 a protrudes outward of the cylinder, and is fastened to the lower surface side of the support plate 2 and the upper surface side of the seat plate 3 by screws 6 for pivotally supporting the expanded base plate 5 to the support plate 2 and the seat plate 3. Is done. In addition, the bottom expansion board 5 is pivotally supported in the form pinched | interposed between the protrusion part 4a and the support plate 2, and between the protrusion part 4a and the seat board 3. FIG.

  The shape of the bottom expansion plate 5 will be described with reference to FIG. FIG. 3 is a front view of one bottom expansion plate 5. Moreover, the attitude | position conversion of the bottom expansion board 5 is demonstrated using FIG. The bottom expansion plate 5 is pivotally supported by the support plate 2 and the seat plate 3, respectively. Here, the bottom expansion plate 5 pivotally supported by the seat plate 3 will be described. In addition, the shape of the bottom expansion plate 5 pivotally supported by the support plate 2 is mirror-symmetrical with the shape of the bottom expansion plate 5 pivotally supported by the seat plate 3, as shown in FIG.

  FIG. 4A shows a view in which the bottom expansion plate 5 rotates counterclockwise about the screw 6 and is stored from the upper side with respect to the outer diameter of the seat plate 3 as viewed from above. Further, FIG. 4B shows a view of the bottom-up position in which the bottom-up plate 5 rotates clockwise around the screw 6 and protrudes outside the outer diameter of the seat plate 3 from above. Here, the connecting member 4 is not shown for ease of explanation.

  As shown in FIG. 3, the bottom expansion plate 5 is formed from a substantially L-shaped plate obtained by cutting out a part of a fan shape. However, the bottom expansion plate 5 is not a flat plate, and one bottom expansion plate 5 partially overlaps the other bottom expansion plate 5 in both the housing posture and the bottom expansion posture. Is curved.

  The widened plate 5 is formed with a cutout portion 5a for cutting out a part of the fan shape. By forming the cutout portion 5a, it is possible to prevent the bottom expansion plate 5 and the screw 6 supporting the adjacent bottom expansion plate 5 from interfering with each other in the storage posture and the bottom expansion posture.

  Further, the bottom diameter plate 5 is formed with a minimum diameter portion 5b, and in the accommodation posture of FIG. 4A, the minimum diameter portions 5b of the adjacent bottom expansion plates 5 are continuously connected to each other as a whole. Configure the outer diameter. In this accommodated posture, the minimum diameter portion 5 b of the bottom expansion plate 5 coincides with the outer periphery of the seat plate 3.

  Furthermore, the maximum diameter part 5c is formed in the bottom expansion board 5, and in the bottom expansion attitude | position of FIG.4 (b), the maximum diameter part 5c of the adjacent bottom expansion board 5 continues, and one disk is formed as a whole. Configure the outer diameter. In the bottomed posture, the maximum diameter portion 5 c of the bottomed plate 5 protrudes from the outer periphery of the seat plate 3.

  Further, a resistance portion 5 d is formed on the maximum diameter portion 5 c of the bottom expansion plate 5. The plate-like resistance portion 5d is erected in the direction of the central axis O with respect to the surface of the bottom expansion plate 5, and by rotating the bottom expansion member 1 around the central axis O, an external resistance, specifically, It is subject to resistance, such as cement milk put into the earth and sand, pile holes, or a mixture of these. The resistance portion 5d has a predetermined inclination with respect to the circumferential direction of the bottom expanding member 1. When the bottom expanding member 1 is rotated clockwise about the central axis O, the resistance portion 5d receives resistance. The bottom expansion plate 5 is urged counterclockwise around the screw 6. On the other hand, when the bottom expansion member 1 is rotated counterclockwise about the central axis O, the resistance portion 5d receives resistance and urges the bottom expansion plate 5 clockwise about the screw 6. That is, when the bottom expanding member 1 is rotated clockwise around the central axis O, the bottom expanding plate 5 maintains the housing posture, while the bottom expanding member 1 is rotated counterclockwise around the central axis O. The bottom expansion plate 5 tries to maintain the bottom expansion posture.

<Construction procedure for expanded pile>
The construction procedure of the pile (bottom pile) with the bottom expanded member of the present invention attached to the lower end will be described with reference to FIG. As shown in FIG. 5A, first, a pile hole 11 for inserting the expanded bottom pile is excavated to a predetermined depth of the ground 10. Next, a hole bottom widening portion 12 having a diameter larger than the pile diameter is excavated at the bottom of the pile hole 11. As a method for excavating the hole bottom expanding portion 12, a known method can be used. For example, a method for expanding and excavating by expanding an expansion blade provided on an auger head is known. Cement milk is put into the hole bottom expanding portion 12, the expanding blade is repeated up and down, and the hole bottom expanding portion 12 is filled with a mixture 13 obtained by stirring and mixing cement milk and earth and sand.

  Next, as shown in FIG. 5 (b), the expanded bottom pile 14 having the expanded bottom member 1 fixed to the lower end of the pile is inserted into the pile hole 11. In addition, the bottom expansion member 1 is previously fixed to the lower end of a pile by welding or the like. A through hole is provided in the center of the seat plate 3 and the support plate 2, and these through holes are not blocked by the expanded base plate 5, and therefore, in the expanded pile 14, a mixture 13 of cement milk and earth and sand is provided. Is filled.

  When inserting into the pile hole 11, all the bottom expansion boards 5 are made into the accommodation attitude | position. Further, in the insertion process, the bottom expansion plate 5 is rotated clockwise so that the bottom expansion plate 5 receives resistance from the cement milk / sediment mixture 13 to the resistance portion 5d, and can maintain the accommodation posture. It is hard to become an obstacle.

  When the bottom expanded pile 14 is inserted into the pile hole 11 and the bottom expanded member 1 is located in the hole bottom expanded portion 12, the bottom expanded pile 14 is rotated in the reverse direction, that is, counterclockwise. When the expanded pile 14 is rotated counterclockwise, the expanded plate 5 receives resistance from the mixture 13 of cement milk and earth and sand at the resistance portion 5d, and moves from the stowed position to the expanded position as shown in FIG. 5 (c). change. The cement milk is solidified while the bottom expansion plate 5 is held in the bottom expansion posture. Thereby, since the bottom expansion board 5 forms the disk which protruded outside from the outer peripheral surface of a pile, according to this bottom expansion member 1, the bottom expansion part provided with big supporting force and extraction resistance can be formed in a pile. .

<Another embodiment>
As shown in FIG. 4B, the center hole of the seat plate 3 cannot be closed with the widened plate 5 in the widened posture. Therefore, the bottom expanding member 1 may further include a plate for closing the central hole of the seat plate 3. Specifically, as shown in the three views of FIG. 6, a plate 7 that is pivotally supported in the same manner as the bottom expansion plate 5 is provided on the lower surface side of the seat plate 3. The plate 7 is pivotally supported on the seat plate 3 by screws 7a. The plate 7 is provided with a resistance portion 7 b in the same manner as the bottom expansion plate 5. Further, the seat plate 3 is provided with an anti-sway member 8 having a U-shaped cross section for restricting the movement of the plate 7. The plate 7 can slide between the seat plate 3 and the steadying member 8.

  The plate 7 can change its posture by receiving resistance from the outside on the resistance portion 7b, similarly to the bottom expansion plate 5. The posture conversion of the plate 7 will be described with reference to FIG. As shown in FIG. 7A, the plate 7 does not block the center hole of the seat plate 3 in the accommodated position of the expanded base plate 5, and as shown in FIG. 7B in the expanded position of the expanded base plate 5. The posture is changed so as to close the central hole of the seat plate 3. Since the center hole of the seat plate 3 can be completely closed by the bottom expansion plate 5 and the plate 7 in the bottom expansion posture of the bottom expansion plate 5, the bottom expansion member 1 has a greater support force and pull-out resistance. An expanded bottom part can be formed in a pile.

  Further, as shown in FIG. 8A, the resistance portion 5d of the bottom expansion plate 5 that is pivotally supported by the support plate 2 and the resistance of the bottom expansion plate 5 that is pivotally supported by the seat plate 3 are opposed to each other in the central axis O direction. It is good also as one plate-like resistance part 5d by connecting the part 5d. Alternatively, for example, by another member such as a reinforcing bar, the resistance portion 5d of the bottom expansion plate 5 that is pivotally supported by the support plate 2 and the resistance portion of the bottom expansion plate 5 that is pivotally supported by the seat plate 3 are opposed to each other in the direction of the central axis O. You may connect 5d. In addition, you may directly connect the bottom expansion board 5 pivotally supported by the support plate 2, and the bottom expansion board 5 pivotally supported by the seat board 3 by another member, such as a reinforcing bar.

  Further, as shown in FIG. 8B, these members extending in the direction of the central axis O may be connected by a lateral member 9. According to these structures, the intensity | strength of the bottom expansion member 1 can be improved, and the bottom expansion part provided with much bigger supporting force and extraction resistance can be formed in a pile.

The perspective view which shows the external appearance structure of a bottom expansion member Longitudinal sectional view showing the structure of the bottom expansion member Front view showing the shape of the bottom expansion plate The figure for demonstrating posture conversion of a bottom expansion board Figure for explaining construction procedure of pile (expanded pile) Three views for explaining the plate that closes the center hole of the seat plate Diagram for explaining plate posture conversion The perspective view which shows the external appearance structure of the bottom expansion member of another embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Expanded member 2 Support plate 3 Seat plate 3 Base 4 Connection member 4a Protruding part 5 Expanded plate 5d Resistance part 6 Screw 9 Horizontal member 10 Ground 11 Pile hole 12 Hole bottom expanded part 14 Expanded pile

Claims (3)

A bottom expansion member provided at the lower end of the pile,
A support fixed to the pile that is the same as or smaller than the outer diameter of the pile;
A plurality of bottom expansion plates rotatably supported on the support,
The rotation axis of the bottom expansion plate is perpendicular to the plate surface of the bottom expansion plate and parallel to the axial direction of the pile,
The expansion plate is rotated so that the projection portion projected in the axial direction of the pile is accommodated inside the outer peripheral surface of the pile, and a part of the projection portion projected in the axial direction of the pile There Ri posture convertible der in the拡底posture projecting outward from the outer peripheral surface of the pile,
In the bottom-enlarging posture, the bottom-enlarging member is characterized in that the adjacent bottom-enlarging plates are continuous to form an outer diameter portion of one disk as a whole .   The bottom expansion plate includes a resistance portion that receives resistance from the outside, and the resistance portion receives resistance by rotating a pile to which the support is fixed around the axis of the pile, and the bottom expansion posture from the accommodation posture The bottom expansion member according to claim 1, wherein the posture can be changed.   The base expansion member according to claim 1, further comprising a pedestal connected to the support body by a connection member, wherein the base expansion plate is rotatably supported on the pedestal.

Images