JP5485085B2 - Axial force replacement method for existing piles - Google Patents

Description

  The present invention relates to a method for replacing an axial force of an existing pile used for seismic isolation repair of an existing building.

  Conventionally, when performing seismic isolation repair (foundation isolation isolation) of an existing building constructed with a cast-in-place concrete pile and a foundation made of foundation, temporary steel pipe piles, etc. in the vicinity of the pile foundation (temporary A method is often used in which a pile is connected to an existing foundation and the axial force of the existing pile is exchanged with a temporary pile (see, for example, Patent Document 1 [Prior Art]).

  That is, after placing the temporary pile near the existing foundation body, excavating the ground below the foundation body to expose a part of the existing pile, while temporarily supporting the foundation body and the upper structure with the temporary pile, Dismantle and remove part of the exposed existing pile. And after installing a new structure such as a seismic isolation device in the space between the new foundation formed by dismantling and removing a part of the existing pile, canceling the temporary support state by the temporary pile, A new foundation and a new frame formed by dismantling and removing a part of the foundation will support the existing foundation and the superstructure. By installing the new frame on the new foundation formed by dismantling and removing a part of the existing piles, the existing building is seismically isolated.

JP 2003-343092 A

  However, the conventional seismic isolation repair method (conventional axial force replacement method for existing piles) requires temporary piles, which increases the overall construction period and increases construction costs. It was. In addition, depending on the construction conditions of the temporary piles, the existing foundation may need to be reinforced.

  In view of the above circumstances, the present invention can replace the axial force of an existing pile without performing construction such as a temporary pile and without requiring reinforcement of an existing foundation body, and perform seismic isolation repair, etc. The purpose is to provide a method for exchanging the axial force of existing piles, which makes it possible to shorten the overall construction period and reduce the construction cost.

  In order to achieve the above object, the present invention provides the following means.

  The method for exchanging the axial force of an existing pile according to the present invention is a method for exchanging the axial force of an existing pile of a building constructed with a pile foundation composed of a pile and a foundation body, the surrounding ground of the pile foundation being Excavating and exposing a part of the existing pile to the ground excavation step, and passing through the central axis from the exposed outer peripheral surface of the existing pile, or from the exposed outer peripheral surface of the existing pile to the central axis side An installation hole forming step for forming an installation hole so as to be recessed, and a temporary support post and jack installation step for inserting and installing a temporary support post and a temporary support jack for temporarily receiving and supporting the axial force of the existing pile. And driving the temporary support jack, pressing the temporary support post and the temporary support jack to support the existing foundation body of the pile foundation and the existing pile, and at least the installation hole of the exposed existing pile. Left on either side or one side The remaining part dismantling and removing process for dismantling the remaining part, the new foundation constructing process for constructing a new foundation by placing concrete on the ground surface excavated in the ground excavation process, the new foundation and the existing foundation A newly installed chassis installation step for installing a newly installed chassis, driving the temporary support jack, releasing the support state of the existing foundation body and the existing pile by the temporary support post and the temporary support jack, and And an axial force replacement step of replacing the axial force of the pile with the newly installed frame.

  In the method for exchanging the axial force of the existing pile according to the present invention, the outer peripheral surface of the exposed existing pile is penetrated through the central axis, or the outer peripheral surface of the exposed existing pile is recessed toward the central axis. A temporary support post and a temporary support jack can be installed in the formed installation hole, and the axial force of the existing pile can be transferred to a new structure such as a seismic isolation device using these temporary support support post and temporary support jack. Compared with the case where the axial force of an existing pile is replaced using a temporary pile, it is possible to improve workability (workability). Moreover, since a temporary pile is unnecessary, it becomes possible to eliminate the reinforcement with respect to the existing foundation. This makes it possible to shorten the overall construction period and reduce construction costs when performing seismic isolation repair or the like.

It is a figure (figure showing an existing building before performing seismic isolation repair etc.) which shows an existing building concerning one embodiment of the present invention. It is a figure which shows the pile foundation of the existing building which concerns on one Embodiment of this invention (figure which shows the pile foundation of the existing building before performing seismic isolation repair etc.). It is a figure which shows the state which installed the temporary support support | pillar and the temporary support jack in the installation hole in the axial force replacement | exchange method of the existing pile which concerns on one Embodiment of this invention. FIG. 4 is a view taken along line X1-X1 in FIG. 3. It is a figure which shows the state which disassembled and removed the remainder and constructed the new foundation body in the axial force transfer method of the existing pile which concerns on one Embodiment of this invention. In the method for exchanging axial force of an existing pile according to an embodiment of the present invention, a new structure (such as a seismic isolation device) is installed between the new foundation and the existing foundation, and the new pile receives the axial force of the existing pile. It is a figure (figure which shows the existing building after performing seismic isolation repair etc.) which shows the changed state. It is a X1-X1 line arrow directional view of FIG. It is a figure which shows the example of a change of the axial force exchange method of the existing pile which concerns on one Embodiment of this invention. It is a figure which shows the example of a change of the axial force exchange method of the existing pile which concerns on one Embodiment of this invention. It is a figure which shows the example of a change of the axial force exchange method of the existing pile which concerns on one Embodiment of this invention. It is a figure which shows the example of a change of the axial force exchange method of the existing pile which concerns on one Embodiment of this invention.

  Hereinafter, with reference to FIG. 1 to FIG. 7, a method for replacing the axial force of an existing pile according to an embodiment of the present invention will be described. Here, this embodiment relates to a method for exchanging the axial force of an existing pile used for base isolation isolation of an existing building constructed with a pile foundation composed of a pile and a foundation (existing pile and existing foundation). Is.

  As shown in FIGS. 1 and 2, the existing building T of the present embodiment is constructed with a pile foundation T <b> 1 composed of a cast-in-place concrete pile and a foundation (existing pile 1 and existing foundation 2).

  And in the axial force receiving method of this embodiment which changes the axial force of the existing pile 1 of the existing building T constructed | assembled with such a pile foundation T1, first, as shown in FIG.2 and FIG.3. The ground G below the existing foundation body 2 of the pile foundation T1 is excavated, and the pile head side of the existing pile 1 is exposed. That is, the surrounding ground G of the pile foundation T1 is excavated to expose a part of the existing pile 1 (ground excavation process).

  Next, as shown in FIG.3 and FIG.4, the through-hole (installation hole) 3 is formed in the existing pile 1 so that it may penetrate through the central axis O1 from the outer peripheral surface of the exposed existing pile 1 (installation hole). Forming step). Then, a temporary receiving support column 4 and a temporary receiving jack 5 for temporarily receiving and supporting the axial force of the existing pile 1 are inserted and installed in the through hole 3 formed in this way (temporary receiving support column and jack installation process). For this reason, the through hole (installation hole) 3 is formed in a size (height and width) corresponding to the height and width of the temporary receiving support column 4 and the temporary receiving jack 5.

  Next, the temporary support jack 5 is driven to extend, and the existing base body 2 and the existing pile 1 above and below the upper end surface and the lower end surface of the through hole 3 (in the direction of the axis O1 (center axis O1 direction) across the through hole 3). ), The temporary support column 4 and the temporary support jack 5 are pressed, and the existing foundation body 2 and the existing pile 1 are supported by the temporary support column 4 and the temporary support jack 5. Further, at the stage where the existing pile 1 is supported by the temporary receiving support column 4 and the temporary receiving jack 5 in this way, as shown in FIG. 5, the remaining portion 1a left on both sides across the exposed through hole 3 of the existing pile 1 Is dismantled and removed (remaining dismantling and removal process).

  Next, as shown in FIG. 5, the new foundation body 6 is constructed by placing concrete on the ground surface G1 excavated in the ground excavation process (new foundation foundation construction process). At this time, in this embodiment, the new foundation body 6 is constructed with a thickness such that the upper surface (new foundation body surface) 6a of the new foundation body 6 is disposed below the upper end of the temporary support column 4 from the ground surface G1. That is, the new foundation body 6 is constructed so that the temporary receiving jack 5 is not embedded and a part of the temporary receiving support column 4 is embedded.

  At the stage of constructing the new foundation 6 in this way, as shown in FIGS. 6 and 7, the new foundation 6 and the existing foundation 2 of the pile foundation T1 are connected to the upper and lower ends, respectively. A new housing 7 such as a seismic isolation device is installed between the existing basic bodies 2 (new housing installation process).

  Then, the temporary support jack 5 is driven to be contracted, and the support state of the existing pile 1 by the temporary support support column 4 and the temporary support jack 5 is released. Thereby, the axial force of the existing pile 1 is transferred to the newly installed frame (such as a seismic isolation device) 7 (axial force replacement step).

  Therefore, in the method for replacing the axial force of the existing pile according to the present embodiment, the temporary support column is placed in the through-hole (installation hole) 3 formed so as to penetrate from the exposed outer peripheral surface of the existing pile 1 through the central axis O1. 4 and the temporary receiving jack 5 can be inserted and installed, and the axial force of the existing pile 1 can be transferred to the newly installed frame 7 such as a seismic isolation device by using the temporary receiving column 4 and the temporary receiving jack 5. Compared with the case where the axial force of the existing pile 1 is exchanged using, it becomes possible to improve the workability (workability). Moreover, since a temporary pile is unnecessary, it becomes possible to make the reinforcement with respect to the existing foundation 2 unnecessary. This makes it possible to shorten the overall construction period and reduce construction costs when performing seismic isolation repair or the like.

  As in the present embodiment, a through hole (installation hole) 3 that penetrates from the exposed outer peripheral surface of the existing pile 1 through the central axis O <b> 1 is formed, and a temporary support column 4 and a temporary support jack 5 are formed in the through hole 3. To prevent bending cracks due to eccentric compression of the existing pile 1 (when the center O1 of the existing pile 1 is partially cut and the temporary support post 4 and the temporary support jack 5 are disposed at the center of the existing pile 1). It becomes possible to do.

  When the center O1 of the existing pile 1 is partially cut and the temporary support column 4 and the temporary support jack 5 are arranged at the center of the existing pile 1 as in the present embodiment, the concrete allowable bearing stress level of the existing pile 1 is determined. It becomes possible to adopt, and it becomes possible to exchange the axial force safely.

  As mentioned above, although one Embodiment of the axial force replacement | exchange method of the existing pile concerning this invention was described, this invention is not limited to said one Embodiment, It can change suitably in the range which does not deviate from the meaning. is there.

  For example, in this embodiment, although the installation hole which concerns on this invention shall be formed as the through-hole 3 which penetrates through the central axis O1 from the outer peripheral surface of the exposed existing pile 1, for example, FIG. ), (B), as shown in FIGS. 9A to 9E, the installation hole 3 is formed so as to be recessed from the outer peripheral surface of the exposed existing pile 1 toward the central axis O1, and thus formed. The temporary support post 4 and the temporary support jack 5 may be inserted and installed in the installation hole 3, and the temporary support jack 5 may be driven to support the existing pile 1. In this case, the remaining portion 1a left on both sides or one side of at least the installation hole 3 of the exposed existing pile 1 is dismantled and removed, and the temporary support jack 5 is driven to move the temporary support post 4 and the temporary support jack. By releasing the support state of the existing pile 1 by 5, it is possible to replace the axial force of the existing pile 1 with the newly installed frame 7 as in this embodiment.

  Further, in the present embodiment, explanation (illustrated) is made on the assumption that the existing building T is subjected to basic seismic isolation, and that the new housing 7 is a seismic isolation device. For example, as shown in FIG. The present invention may be applied when the basement is extended. In such an extension of the basement, as shown in FIG. 11, the new housing 7 may be a column (columnar body).

  Furthermore, in this embodiment, as shown in FIG. 5, the existing pile 1 between the existing foundation bodies 2 is dismantled and removed from the new foundation body surface 6a of the new foundation body 6, but the existing pile 1 exposed. Only the remaining portion 1a left on both sides or one side of the installation hole 3 is disassembled and removed, and the temporary support post 4 and the temporary support jack 5 are replaced with a position away from directly above the existing pile 1, The axial force of 1 may be directly received by the newly installed housing (such as a seismic isolation device) 7.

1 Existing pile (pile)
1a Remaining part 2 Existing foundation (basic body)
3 Through hole (installation hole)
4 Temporary receiving support column 5 Temporary receiving jack 6 New foundation body 6a New foundation body surface 7 New housing (seismic isolation device, etc.)
G Surrounding ground (ground)
G1 Ground surface O1 Center axis T of existing pile T Existing building T1 Pile foundation

Claims (1)

A method for changing the axial force of an existing pile of a building constructed with a pile foundation composed of a pile and a foundation body,
Excavating the surrounding ground of the pile foundation and exposing a part of the existing pile;
An installation hole forming step of forming an installation hole so as to penetrate from the outer peripheral surface of the exposed existing pile through the central axis, or to be recessed from the outer peripheral surface of the exposed existing pile toward the central axis;
Temporary receiving support and jack installation step of inserting and installing a temporary receiving support and a temporary receiving jack into the installation hole for temporarily receiving and supporting the axial force of the existing pile;
The temporary support jack is driven, the temporary support post and the temporary support jack are pressed to support the existing foundation body of the pile foundation and the existing pile, and at least the installation hole of the exposed existing pile is sandwiched between The remaining part dismantling and removing step of dismantling and removing the remaining part on both sides or one side;
A new foundation construction process for constructing a new foundation by placing concrete on the ground surface excavated in the ground excavation process;
A new housing installation step of installing a new housing between the new foundation and the existing foundation;
Axial force receiver that drives the temporary receiving jack, releases the support state of the existing foundation and the existing pile by the temporary receiving column and the temporary receiving jack, and converts the axial force of the existing pile to the newly installed frame. A method for replacing the axial force of an existing pile, comprising a replacement step.

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