JP2016089481A - Extension method for underground facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an extension method for an underground facility that may be executed relatively simply at a low cost.SOLUTION: An extension method for an underground facility is for installing an additional seismic isolator 7 in an existing building having an existing pile 1 and an existing foundation body 2, and includes: an excavation step in which excavation is performed underneath the existing foundation body 2 for exposing a part of the existing pile 1; a cutting step in which an outer periphery of the exposed portion of the existing pile 1 is cut; a new foundation body installation step in which a new foundation body 4 is formed underneath the existing foundation body 2; a first replacement step in which the existing foundation body 2 is supported by a temporary support member 6 erected on the new foundation body 4; an existing pile removal step in which the exposed portion of the existing pile 1 is removed; an extension step for the underground facility in which the additional seismic isolator 7 is installed between the new foundation body 4 and the existing foundation body 2; a second replacement step in which the existing foundation body 2 is supported by the seismic isolator 7; and a temporary support member removal step in which the temporary support member 6 is removed.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an underground facility expansion method.

  When adding an underground floor to an existing building or making an existing building seismic isolation under an existing foundation, add a new foundation below the newly installed underground facility such as the expanded basement or seismic isolation device, It is necessary to replace the working load of the existing foundation with the new foundation.

  For example, in Patent Document 1, after arranging a plurality of temporary piles around an existing pile, excavating around the pile head of the existing pile to form a work pit, the weight of the superstructure is replaced by the temporary pile. Later, a method of installing a seismic isolation device between an existing foundation and an existing pile is disclosed.

  Further, in Patent Document 2, the lower part of the existing foundation is excavated to expose the pile head of the existing pile, and stud bolts are planted on the side surfaces of the existing pile, and the stud bolt is inserted into the excavation bottom so that the stud bolt is wound. After forming a flat slab, the method of installing a seismic isolation apparatus between an existing foundation body and a flat slab in the state which supported the existing foundation body by the temporary receiving jack erected on this flat slab is disclosed.

JP 2013-181322 A Japanese Patent No. 2819008

In the method described in Patent Document 1, since it is necessary to construct a plurality of temporary piles, there is a case where construction takes time and hinders shortening of the construction period.
Moreover, since the method of patent document 2 needs to increase the thickness of a flat slab when the number of existing piles is small, or when the pile surface area (side area) is small, it is necessary to construct a flat slab. It takes time and money.

  From such a viewpoint, an object of the present invention is to propose an underground facility expansion method that can be constructed relatively easily and inexpensively.

  The present invention is an underground facility expansion method for adding a new underground facility to an existing building having an existing pile and an existing foundation, and excavating the lower portion of the existing foundation to expose a part of the existing pile A cutting process for cutting the outer periphery of the exposed portion of the existing pile, a foundation new installation process for forming a new foundation below the existing foundation, and a temporary support material erected on the new foundation A first substituting process for supporting the existing foundation, an existing pile removing process for removing an exposed portion of the existing pile, and a basement for adding a new underground facility between the new foundation and the existing foundation It is characterized by comprising a facility expansion step, a second replacement step of supporting the existing foundation body in the newly installed underground facility, and a temporary support material removal step of removing the temporary support material.

According to such an underground facility expansion method, the new foundation is formed with the outer peripheral portion of the existing pile being cut, so that the new foundation can be formed on the existing pile.
Therefore, even if the thickness of the new foundation is not increased, or even if the surface area of the existing pile is small, the force can be effectively transmitted between the foundation pile and the new foundation, As a result, construction can be performed easily and inexpensively.

In the existing pile removing step, it is desirable to remove a portion above the lower end surface of the new foundation body of the existing pile.
Moreover, it is desirable to use a jack as the temporary support material.
Furthermore, you may form a reinforcement beam along the lower surface of the said existing foundation as needed.

  According to the underground facility extension method of the present invention, it is possible to add an underground facility to an existing building relatively easily and inexpensively.

It is sectional drawing which shows the excavation process of the underground facility extension method of embodiment of this invention. It is sectional drawing which shows the same cutting process. It is sectional drawing which shows the same foundation new installation process and a reinforcement beam formation process. It is sectional drawing which shows the 1st replacement process. It is sectional drawing which shows the existing pile removal process. It is sectional drawing which shows the existing pile removal process following FIG. It is sectional drawing which shows the underground facility expansion process and a 2nd replacement process. It is sectional drawing which shows the 2nd replacement process. (A) is sectional drawing which shows the excavation process of 2nd embodiment, (b) is the perspective view. It is sectional drawing which shows the same basic body new installation process. It is sectional drawing which shows the 1st replacement process. It is sectional drawing which shows the existing pile removal process. It is sectional drawing which shows the underground facility expansion process and a 2nd replacement process.

<First embodiment>
In 1st embodiment, the case where seismic isolation repair is performed about the existing building provided with an existing pile and an existing foundation is illustrated.
The underground facility expansion method of the present embodiment includes an excavation process, a cutting process, a foundation body installation process, a reinforcing beam formation process, a first replacement process, an existing pile removal process, an underground facility expansion process, A second replacement process and a temporary support material removal process are provided.

As shown in FIG. 1, the excavation process is a process of excavating the lower side of the existing foundation body 2 to form the work space 3 and exposing the pile head 10 of the existing pile 1.
In addition, the height (excavation depth) of the work space 3 is not limited.

When the excavation of the work space 3 is completed, the crushed stone 31 is spread on the bottom surface (floor surface) and leveled, and the discarded concrete (leveled concrete) 32 is placed.
What is necessary is just to set the layer thickness of the crushed stone 31 and the discarded concrete 32 suitably. In addition, what is necessary is just to construct the crushed stone 31 and the discarded concrete 32 as needed. Moreover, you may perform the placement of the discarded concrete 32 after a cutting process (after the cutting of the existing pile 1).

A cutting process is a process of cutting the outer peripheral part of the exposed part (pile head 10) of the existing pile 1, as shown in FIG.
In the present embodiment, the periphery of the pile head 10 is cut in a range corresponding to a section between the upper surface of the discarded concrete 32 and the lower surface of the existing foundation body 2. Note that the pile head 10 may be cut upward from the bottom surface (floor surface) of the work space 3.

In the existing pile 1, the pile head 10 becomes smaller in diameter than the underground portion 11 by cutting the pile head 10 (exposed portion).
The pile head 10 is cut using, for example, a cutting machine such as a wire saw or a breaker. The cutting width is not limited and may be set as appropriate.
In the present embodiment, the entire circumference of the pile head 10 is cut, but the cutting of the pile head 10 is not necessarily performed over the entire circumference. For example, although illustration is omitted, the concrete of the pile head 10 may be left partially (for example, radially).

As shown in FIG. 3, the foundation body new installation step is a step of forming a new foundation body 4 below the existing foundation body 2.
The new foundation 4 is formed by placing concrete after placing reinforcing bars (not shown).

  The new foundation body 4 is formed so as to surround the pile head 10 (so as to contact the side surface of the pile head 10). That is, the new foundation 4 is formed in a state where it is placed on the underground portion 11 (the outer peripheral portion of the existing pile 1) below the floor surface of the work space 3.

Note that the thickness of the new foundation body 4 is not limited, and may be set as appropriate.
Moreover, the reinforcing bar arrangement pitch and the reinforcing bar diameter may be set as appropriate. Further, reinforcing bars may be arranged as necessary and may be omitted.

The reinforcing beam forming step is a step of forming the reinforcing beam 5 along the lower surface of the existing foundation 2 as shown in FIG.
The reinforcing beam 5 is formed by placing reinforcing bars and a formwork along the lower surface of the existing foundation 2 and then placing concrete in the formwork.

The member height and position of the reinforcing beam 5 are not limited. If construction is possible, you may form in the side surface of the existing beam (existing foundation body 2). Further, the reinforcing beam 5 may be formed of strength or material according to need, and may be a steel material, for example. That is, the reinforcing beam 5 may be a reinforcement for increasing the rigidity and proof strength of the existing foundation 2.
In the present embodiment, the plurality of reinforcing beams 5 are formed in a lattice shape with the center position of the superstructure column 21 as an intersection, but the reinforcing beams 5 are not necessarily formed in a lattice shape.

As shown in FIG. 4, the first replacement process is a process of supporting the existing base body 2 with a temporary support material 6 that is erected on the new base body 4.
The temporary support member 6 is interposed between the new foundation body 4 and the reinforcing beam 5. In the present embodiment, the pair of temporary support members 6 are disposed so as to face each other with the pile head 10 interposed therebetween. The temporary support member 6 may be interposed between the existing foundation body 2 and the new foundation body 4.

In the present embodiment, a jack is employed as the temporary support member 6. When the temporary support material 6 is extended, the force (existing foundation body 2) acting on the existing pile 1 can be replaced with the temporary support material 6.
In addition, the structure of the temporary support material 6 is not limited to a jack, For example, a temporary support | pillar may be sufficient and what combined the jack and the support | pillar may be used.

The existing pile removing step is a step of removing the exposed portion (pile head 10) of the existing pile 1 as shown in FIG.
In the present embodiment, a portion above the flooring surface of the work space 3, that is, a portion located between the lower surface of the existing foundation body 2 and the lower surface of the new foundation body 4 is removed. In addition, the removal range of the existing pile 1 (pile head 10) will not be limited if the exposed part between the lower surface of the reinforcement beam 5 and the upper surface of the new foundation 4 is included.

The method for removing the pile head 10 is not limited. For example, the pile head 10 may be crushed by a breaker or the like, or may be cut by a concrete cutter or the like.
As the pile head 10 is removed, the recess 51 formed in the reinforcing beam 5 and the recess 41 formed in the new foundation 4 are filled (placed) with concrete as shown in FIG. At this time, reinforcing bars are arranged in the recesses 51 and 41 as necessary.

As shown in FIG. 7, the underground facility extension process is a process of adding a seismic isolation device (new underground facility) 7 between the new foundation 4 and the reinforcing beam 5 (existing foundation 2).
The seismic isolation device 7 includes a seismic isolation device main body 71, an upper concrete 72, and a lower concrete 73.

  Although the seismic isolation device main body 71 of this embodiment is comprised by laminated rubber, the structure of the seismic isolation device 7 is not limited, For example, you may employ | adopt a sliding bearing.

The upper concrete 72 is a reinforced concrete member interposed between the seismic isolation device main body 71 and the reinforcing beam 5, and is formed on the lower surface of the reinforcing beam 5.
The upper concrete 72 may be formed on the lower surface of the existing foundation 2. Further, the upper concrete 72 may be formed integrally with the concrete placing portion when the concrete is placed in the concave portion of the reinforcing beam 5 formed in the existing pile removing step.

The lower concrete 73 is a reinforced concrete member interposed between the seismic isolation device main body 71 and the new foundation body 4, and is formed on the upper surface of the new foundation body 4.
The lower concrete 73 may be formed integrally with the concrete placement portion when the concrete is placed in the recess of the new foundation 4 formed in the existing pile removal process.

As shown in FIG. 7, the second replacement process is a process of supporting the existing foundation 2 with a seismic isolation device (new underground facility) 7.
When the temporary support member 6, which is a jack, is contracted, the force acting on the temporary support member 6 is transferred to the seismic isolation device 7, and the existing base body 2 is supported by the seismic isolation device 7.

The temporary support member removal step is a step of removing the temporary support member 6 as shown in FIG.
That is, when the force (existing foundation body 2) acting on the temporary support material 6 is transferred to the seismic isolation device 7, the temporary support material 6 is removed.

According to the underground facility expansion method of the present embodiment, since the seismic isolation device 7 can be arranged without constructing temporary piles, the construction period can be shortened and the construction cost can be reduced.
Since the new foundation 4 is formed on the existing pile 1 (underground portion 11), the load received by the temporary support member 6 can be transmitted to the existing pile 1 via the new foundation 4. . Therefore, or even when the thickness of the new foundation 4 is small, the force is effectively transmitted between the existing pile 1 and the new foundation 4 regardless of the surface area of the existing pile 1. As a result, construction can be performed easily and inexpensively.

Moreover, in order to receive the axial force which acts on the existing pile 1 with the temporary support material 6 arrange | positioned around the existing pile 1, even if it is the structure which supports the load of one pillar 21 with one existing pile 1, The axial force of the existing pile 1 can be changed without requiring significant reinforcement work.
Moreover, since a relatively simple temporary receiving structure (temporary support material 6) is employed, the construction period can be shortened.

The plate-shaped new foundation 4 can be formed below the existing foundation 2 by cutting the pile head 10 of the existing pile 1 at a position below the lower surface of the new foundation 4.
Moreover, by using a jack as the temporary support member 6, it is possible to easily perform replacement of the force (existing foundation body 2) acting on the existing pile 1 (first replacement process and second replacement process). .

  Moreover, since the seismic isolation device 7 is installed on the extension line of the central axis of the existing pile 1, the interval between the existing piles 1 is narrow, and the seismic isolation device 7 cannot be installed between the existing piles 1. Even if there is, the existing building can be seismically isolated.

<Second Embodiment>
In the second embodiment, with respect to the existing building including the existing pile 1 and the existing foundation 2 shown in FIGS. 9A and 9B, an isolation device (new underground facility) is added to improve the isolation. The case where it performs is illustrated.
The existing foundation body 2 of the present embodiment includes a foundation beam 22, a pressure platen 23, and a footing 24. In addition, the structure of the existing base body 2 is not limited, For example, a plate-shaped member may be sufficient.

The foundation beam 22 is a lattice-shaped member made of reinforced concrete formed so as to intersect on the extension line of the central axis of the existing pile 1. The configuration of the foundation beam 22 is not limited.
The pressure board 23 is a reinforced concrete board-like member interposed between the upper end of the existing pile 1 and the lower surface of the foundation beam 22. In addition, the structure of the pressure | voltage resistant board 23 is not limited.
The footing 24 is a reinforced concrete member that is formed on the pressure platen 23 and to which the lower end of the existing column 21 is connected. The configuration of the footing 24 is not limited.
The underground facility expansion method of the present embodiment includes an excavation process, a cutting process, a foundation body installation process, a first replacement process, an existing pile removal process, an underground facility expansion process, and a second replacement process. And a temporary support material removal step.

As shown in FIG. 9A, the excavation process is a process of excavating the lower side of the existing foundation body 2 to form the work space 3 and exposing the pile head 10 of the existing pile 1.
In addition, the height (excavation depth) of the work space 3 is not limited.

When the excavation of the work space 3 is completed, the crushed stone 31 is spread on the bottom surface (floor surface) and leveled, and the discarded concrete (leveled concrete) 32 is placed.
What is necessary is just to set the layer thickness of the crushed stone 31 and the discarded concrete 32 suitably. In addition, what is necessary is just to construct the crushed stone 31 and the discarded concrete 32 as needed. Moreover, you may perform the placement of the discarded concrete 32 after a cutting process (after the cutting of the existing pile 1).

A cutting process is a process of cutting the outer peripheral part of the exposed part (pile head 10) of the existing pile 1, as shown in FIG.
In the present embodiment, the periphery of the pile head 10 is cut in a range corresponding to a section between the upper surface of the discarded concrete 32 and the lower surface of the existing foundation body 2. Note that the pile head 10 may be cut upward from the bottom surface (floor surface) of the work space 3.
Since the details of the cutting process are the same as the contents shown in the first embodiment, the detailed description is omitted.

As shown in FIG. 10, the base body new installation step is a step of forming the new base body 4 below the existing base body 2.
The new foundation 4 is formed by placing concrete after placing reinforcing bars (not shown).
Since the details of the basic body installation process are the same as the contents shown in the first embodiment, detailed description thereof is omitted.

As shown in FIG. 11, the first replacement process is a process of supporting the existing base body 2 by a temporary support material 6 that is erected on the new base body 4.
The temporary support member 6 is interposed between the existing foundation body 2 and the new foundation body 4. In the present embodiment, the pair of temporary support members 6 are disposed so as to face each other with the pile head 10 interposed therebetween. The temporary support material 6 is disposed at a position directly below the footing 24.

In the present embodiment, a jack 61 having a support 62 is employed as the temporary support member 6. When the temporary support material 6 is extended, the force (existing foundation body 2) acting on the existing pile 1 can be replaced with the temporary support material 6.
In addition, the structure of the temporary support material 6 is not limited.

The existing pile removal step is a step of removing the exposed portion (pile head 10) of the existing pile 1 as shown in FIG.
In the present embodiment, a portion above the flooring surface of the work space 3, that is, a portion located between the lower surface of the existing foundation body 2 and the lower surface of the new foundation body 4 is removed.

The method for removing the pile head 10 is not limited. For example, the pile head 10 may be crushed by a breaker or the like, or may be cut by a concrete cutter or the like.
As the pile head 10 is removed, the recess 41 formed in the new foundation body 4 is filled with concrete as shown in FIG. At this time, reinforcing bars are arranged in the recess 41 as necessary.

As shown in FIG. 13, the underground facility expansion process is a process of adding a seismic isolation device (new underground facility) 7 between the new foundation 4 and the existing foundation 2.
The seismic isolation device 7 includes a seismic isolation device main body 71, an upper concrete 72, and a lower concrete 73.

  Although the seismic isolation device main body 71 of this embodiment is comprised by laminated rubber, the structure of the seismic isolation device 7 is not limited, For example, you may employ | adopt a sliding bearing.

The upper concrete 72 is a reinforced concrete member interposed between the seismic isolation device main body 71 and the existing foundation body 2, and is formed on the lower surface of the existing foundation body 2.
The lower concrete 73 is a reinforced concrete member interposed between the seismic isolation device main body 71 and the new foundation body 4 and is formed on the upper surface of the new foundation body 4.
The lower concrete 73 may be formed integrally with the concrete placement portion when the concrete is placed in the recess of the new foundation 4 formed in the existing pile removal process.

As shown in FIG. 13, the second replacement process is a process of supporting the existing foundation 2 with a seismic isolation device (new underground facility) 7.
When the temporary support member 6 including the jack is contracted, the force acting on the temporary support member 6 is transferred to the seismic isolation device 7, and the existing base body 2 is supported by the seismic isolation device 7.

The temporary support material removal step is a step of removing the temporary support material 6.
That is, when the force (existing foundation body 2) acting on the temporary support material 6 is transferred to the seismic isolation device 7, the temporary support material 6 is removed.

  According to the underground facility expansion method of the present embodiment, the same effects as the underground facility expansion method of the first embodiment can be obtained.

  The embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and the above-described components can be appropriately changed without departing from the spirit of the present invention.

For example, in the above-described embodiment, the case where the seismic isolation device is installed as the newly installed underground facility has been described. However, the newly installed underground facility is not limited to the seismic isolation device such as a newly installed underground floor.
Further, the configuration of the existing building and the purpose of use are not limited.

In the first embodiment, the case where the existing foundation body is reinforced by forming the reinforcement beam along the lower surface of the existing foundation body has been described. However, the reinforcement beam may be formed as necessary, for example, If the foundation body has sufficient proof stress, it may be omitted.
Further, the existing foundation may be reinforced by forming a reinforcing beam on the upper surface of the existing foundation or increasing the thickness of the existing foundation.

DESCRIPTION OF SYMBOLS 1 Existing pile 10 Pile head 11 Underground part 2 Existing foundation 3 Work space 4 New foundation 5 Reinforcement beam 6 Temporary support material 7 Seismic isolation device (new underground facility)

Claims (4)

An underground facility expansion method for adding a new underground facility to an existing building having an existing pile and an existing foundation,
A drilling step of excavating a lower portion of the existing foundation to expose a part of the existing pile;
A cutting step of cutting the outer periphery of the exposed portion of the existing pile;
A base body new process for forming a new base body below the existing base body;
A first replacement step of supporting the existing foundation by a temporary support material erected on the new foundation;
An existing pile removal step of removing the exposed portion of the existing pile;
An underground facility expansion step of adding a new underground facility between the new foundation and the existing foundation;
A second replacement step of supporting the existing foundation in the newly installed underground facility;
And a temporary support material removal step of removing the temporary support material.   The underground facility expansion method according to claim 1, wherein, in the existing pile removing step, a portion of the existing pile that is above the lower end surface of the new foundation is removed.   The underground facility expansion method according to claim 1, wherein a jack is installed as the temporary support member.   The underground facility expansion method according to any one of claims 1 to 3, wherein a reinforcing beam is formed along a lower surface of the existing foundation.

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