JP2012112121A - Excavation method of ground under spread foundation and base-isolating method of existing building - Google Patents

Abstract

PROBLEM TO BE SOLVED: To excavate the ground under a spread foundation without constructing a temporary receiving pile.SOLUTION: After constructing a shaft, excavation of the ground 29 under a spread foundation 22 of an existing building 20 is started from an entrance at the depth to an excavation bottom surface 48. That is, the excavation is advanced from a footing 24A to a footing 24B. When the front side in an excavation direction of the footing 24B is excavated, the footing 24B is obliquely received by an inclined support 54 inclined in the same direction as a slope face 50. The lower part of the inclined support 54 is received by a slide-stop support 56. When the excavation is advanced further to the center part of the footing 24B, the footing 24B is obliquely supported similarly by an inclined support 55, and the lower part of the inclined support 55 is received by a slide-stop support 57. Thereafter, the inclined support 54 and the slide-stop support 56 are detached, and a part which has been received by the inclined support 54 is received again in the vertical direction by a vertical support 60. As a result, the footing 24B is continuously supported by the inclined support 55, the vertical support 60 and the ground 29.

Description

  The present invention relates to a direct foundation foundation excavation method and an existing building seismic isolation method.

  For seismic isolation of existing foundations, expansion of underground spaces, construction of underground passages, etc., it is necessary to excavate the ground beneath the foundations of existing buildings. For example, in seismic isolation repair, it is common to install a seismic isolation device in the seismic isolation pit after excavating the foundation and constructing the seismic isolation pit. At this time, excavation under the foundation is performed by newly constructing a temporary receiving pile (Patent Document 1).

  Specifically, the foundation of the existing building is supported by a newly constructed temporary support pile, and the foundation below the temporary support pile is excavated. In other words, the construction of seismic isolation pits will be promoted while constructing temporary support piles. After installing the seismic isolation device in the seismic isolation pit, the temporary support pile is removed from the seismic isolation pit.

  However, since the seismic isolation pit is required to have a low height in order to reduce excavation costs, the method of Patent Document 1 employs a method of connecting short piles as temporary support piles, which increases costs. It was. Also, after installing the seismic isolation device, it takes time to remove the temporary support pile.

JP 2009-155794 A

  An object of this invention is to provide the excavation method which can excavate a foundation | foundation foundation board directly, without constructing a temporary receiving pile in view of the said fact.

  A method for excavating a direct foundation foundation of an existing building according to the invention described in claim 1 includes a vertical shaft construction process for constructing a vertical shaft, and the ground from the vertical shaft to the bottom of the direct foundation of the existing building. A excavation process for excavating at a depth; and a support process for supporting the existing building on the ground of the excavation bottom surface via the strut in response to the progress of the excavation process. It is characterized by.

According to the first aspect of the present invention, after constructing the vertical shaft, the ground directly under the foundation of the existing building is excavated to the bottom of the excavation. Then, when excavation proceeds by a predetermined distance, a column is set up on the bottom of excavation, and the existing building is supported on the bottom of excavation via the column. At this time, the diameter of the column, the area of the bottom of the column that comes into contact with the bottom of the excavation, and the like are determined according to the load from the existing building, the support strength of the ground on the bottom of the excavation, and the like.
That is, it is possible to efficiently advance the excavation work and the support work by standing the pillar directly on the ground at the bottom of the excavation and proceeding with the excavation while supporting the existing building with the pillar.
Thereby, even if it does not construct a temporary receiving pile, a foundation ground board can be directly excavated.

  According to a second aspect of the present invention, in the method for excavating a direct foundation foundation of an existing building according to the first aspect, the supporting step includes a step of receiving the existing building substantially vertically by a vertical column, and When the slope of the slope of the ground of the base reaches the support member of the direct foundation, the step of tilting the inclined support in the same direction as the slope and receiving the support by the inclined support with the inclined support, A step of providing a non-slip column between the direct foundation and the bottom of the excavation, and receiving a lower end portion of the inclined column with the non-slip column.

  According to the second aspect of the present invention, the supporting step includes a step of receiving the bottom of the direct support of the base substantially vertically by the vertical support and an oblique support of the bottom of the direct support of the base by the inclined support. And a step of providing a non-slip strut that receives the lower end of the inclined strut directly between the foundation and the bottom of the excavation.

  In other words, not only the vertical pillars receive the bottom of the foundation column directly, but also the slanted pillars receive the lower part of the pillar diagonally. At this time, the lower end portion of the inclined support column is received by a non-skid support column that is erected directly between the bottom of the excavation and the foundation. As a result, the anti-skid column fixed between the bottom of the excavation and the foundation directly prevents the inclined column from sliding, and the inclined column can directly receive the lower part of the column from the diagonal.

  According to a third aspect of the present invention, in the excavation method for the direct foundation foundation of the existing building according to the second aspect, when the direct foundation board of the column receiving portion received by the inclined column is excavated to the bottom of the excavation The step of receiving the column support portion substantially vertically by the vertical column, and the step of removing the inclined column and the anti-skid column after receiving the column support portion by the vertical column. It is said.

According to the third aspect of the present invention, when the direct base plate of the column receiving part received by the inclined column is excavated to the excavation bottom surface, the vertical column is stood on the excavation bottom surface and the column receiving unit is received substantially vertically.
Thereby, the load of an inclination support | pillar can be changed with a vertical support | pillar. As a result, the inclined column and the anti-skid column can be removed.

The invention according to claim 4 is the excavation method of the direct foundation foundation of the existing building according to claim 2 or 3, wherein the strut receiving part is a column lower part or a foundation beam lower part of the existing building. It is said.
According to invention of Claim 4, the support | pillar receiving part is made into the pillar lower part or foundation beam lower part of the existing building. Thereby, the vertical load of the existing building can be efficiently supported on the ground on the bottom of the excavation with a small number of columns.

  The invention according to claim 5 is the excavation method for a direct foundation foundation of an existing building according to any one of claims 1 to 4, wherein the earth retaining around the existing building before the vertical shaft construction step. A step of constructing a wall, a step of excavating the ground between the retaining wall and the outer peripheral wall of the building directly to the foundation surface, a pile is constructed along the outer peripheral wall of the building, and an upper portion of the pile and the outer peripheral wall of the building And a step of constructing a sleeve wall integrally formed.

  According to the fifth aspect of the present invention, the retaining wall is constructed around the existing building and the ground between the retaining wall and the outer peripheral wall of the building is directly excavated to the foundation surface before the vertical shaft construction step. Next, a pile is constructed along the outer peripheral wall of the building, and a sleeve wall in which the upper part of the pile and the outer peripheral wall of the building are integrated is constructed. Thereby, the execution of the vertical shaft construction process, and further the excavation process and the support process can be performed.

The seismic isolation method for an existing building according to the invention described in claim 6 is characterized in that the seismic isolation device is installed on the direct foundation foundation board after excavation according to any one of claims 1 to 5, and the existing building It is characterized by seismic isolation.
According to invention of Claim 6, a seismic isolation apparatus is installed in the direct foundation ground board after excavation.
Thereby, the existing building can be seismically isolated without constructing the temporary support pile.

  Since this invention is set as the said structure, it can excavate a foundation foundation board directly, without constructing a temporary receiving pile.

It is a figure which shows the procedure of the excavation method of the direct foundation ground board of the existing building which concerns on the 1st Embodiment of this invention. It is a figure explaining the retaining wall construction process of the excavation method of the direct foundation ground board concerning the 1st embodiment of the present invention. It is a figure explaining the retaining wall construction process of the excavation method of the direct foundation ground board concerning the 1st embodiment of the present invention. It is a figure explaining the retaining wall construction process of the excavation method of the direct foundation ground board concerning the 1st embodiment of the present invention. It is a figure explaining the vertical shaft construction process of the excavation method of the direct foundation ground board which concerns on the 1st Embodiment of this invention. It is a figure explaining the vertical shaft construction process of the excavation method of the direct foundation ground board which concerns on the 1st Embodiment of this invention. It is a figure explaining the excavation process of the excavation method of the direct foundation ground board which concerns on the 1st Embodiment of this invention. It is a figure explaining the excavation process of the excavation method of the direct foundation ground board which concerns on the 1st Embodiment of this invention. It is a figure explaining the support process of the excavation method of the direct foundation ground board which concerns on the 1st Embodiment of this invention. It is a figure explaining the support process of the excavation method of the direct foundation ground board which concerns on the 1st Embodiment of this invention. It is a figure explaining the excavation process of the excavation method of the direct foundation ground board which concerns on the 1st Embodiment of this invention. It is a figure explaining the excavation process of the excavation method of the direct foundation ground board which concerns on the 1st Embodiment of this invention. It is a figure explaining the support process of the excavation method of the direct foundation ground board which concerns on the 1st Embodiment of this invention. It is a figure explaining the procedure of the seismic isolation method of the existing building which concerns on the 2nd Embodiment of this invention. It is a figure explaining the procedure of the seismic isolation method of the existing building which concerns on the 2nd Embodiment of this invention. It is a figure explaining the procedure of the seismic isolation method of the existing building which concerns on the 2nd Embodiment of this invention.

(First embodiment)
The direct foundation ground excavation method for an existing building according to the first embodiment is executed according to the procedure shown in the construction flow of FIG.

First, the retaining wall construction step 10 is executed.
Specifically, as shown in FIG. 2, a mountain retaining wall 36 is constructed surrounding the outer peripheral wall 27 of the existing building 20. FIG. 2A is a side view of the existing building 20 and the ground 29, and FIG. 2B is a plan view. 2A is a cross-sectional view taken along line X2-X2 in FIG. 2B, and FIG. 2B is a cross-sectional view taken along line X1-X1 in FIG.

  The foundation portion 22 of the existing building 20 is directly used as a foundation, and a concrete bottom slab 26 is constructed on the bottom surface of the foundation portion 22 to partition the existing building 20 and the ground 29. In addition, footings 23 and 24 are provided under the pillars 28 of the existing building 20 to transmit the building load to the ground 29. The footings 23 and 24 are connected by a foundation beam 25, respectively.

The ground 29 will be described by taking as an example a case where the surface soil 30, the gravel soil 32, and the soft rock 34 are formed in this order from the top. The configuration of the ground 29 may be another configuration.
The mountain retaining wall 36 has H-shaped steel built vertically. Corresponding to the progress of excavation, a cross sheet pile is bridged between the H-section steels to prevent the ground 29 from collapsing.

  In addition, a vertical shaft is excavated in the ground P portion where a pier for excavation work is formed. The vertical shaft is excavated in contact with the outer peripheral wall 27 in which the entry pile 38 is built. One entry pile 38 is provided on each side of the footings 23A, 24A, and supports the footings 23A, 24A, and thus directly supports the foundation 22. The upper end portion of the entry pile 38 extends above the footings 23 </ b> A and 24 </ b> A, reaches a height that reaches the outer peripheral wall 27, and the lower portion of the entry pile 38 is solidified by the soft rock 34.

  Next, as shown in FIG. 3, the primary outer periphery excavation is performed. That is, the surface soil 30 is excavated and removed across the entire circumference of the existing building 20 between the outer peripheral wall 27 and the mountain retaining wall 36. Thereafter, a concrete retaining wall 40 is constructed on the inner peripheral side of the excavated mountain retaining wall 36. Then, the upper part of the entry pile 38 and the outer peripheral wall 27 are fixed with a sleeve wall 46 made of concrete.

  Further, the first stage horizontal restraint slab 42 is constructed horizontally at the height of the ground surface, surrounding the outer peripheral wall 27. The horizontal constraining slab 42 is provided so as to surround the outer peripheral wall 27 except between the stake piles 38 that serve as the entrance, and connects the outer peripheral wall 27 and the retaining wall 40. Thereby, even if an earthquake occurs during the period of excavation work, vibration of the existing building 20 can be suppressed.

  Subsequently, as shown in FIG. 4, secondary outer periphery excavation is executed. That is, the space between the outer peripheral wall 27 and the mountain retaining wall 36 is excavated to the bottom surface of the foundation portion 22. The retaining wall 40 is extended to the excavated mountain retaining wall 36 for construction. Further, the upper sleeve wall 46 of the entry pile 38 is also extended and fixed. Further, the second stage horizontal restraint slab 44 is constructed below the first stage horizontal restraint slab 42 so as to surround the outer peripheral wall 27. Thereby, the vibration of the foundation part 22 of the existing building 20 is also suppressed.

Next, the vertical shaft construction process 12 is executed.
Specifically, as shown in FIG. 5, the ground 29 around the outer peripheral wall 27 of the entrance portion (between the footing 23 </ b> A and the footing 24 </ b> A) is excavated to the excavation bottom surface 48. Here, the excavation bottom surface 48 refers to the bottom surface of the excavation portion excavated from the bottom surface of the foundation portion 22 downward to ensure the required excavation height. In the plan view, the ground 29 during excavation is indicated by thin dots, and the ground 29 whose excavation depth has reached the excavation bottom surface 48 is indicated by white.

Next, the ground 29 below the footing 24 </ b> A supported on both sides by the entry pile 38 is excavated. The footing 24A is supported on both sides by the stake pile 38, and the supporting force is maintained even if the ground 29 is deleted.

  The excavation of the ground 29 is advanced from the entrance to the opposing outer peripheral wall. That is, it is advanced in the direction of the footings 24A, 24B, 24C. At this time, the excavation angle α of the ground 29 is excavated at an angle at which the ground 29 does not naturally collapse due to the load from the base portion 22. In other words, the excavated ground surface (slope) 30 is excavated with an inclination (horizontal plane H and angle α) in the direction of excavation toward the upper part in the direction of excavation. The angle α has different values depending on the type of soil layer constituting the ground 29, the water content, and the like.

  Subsequently, as shown in FIG. 6, the footing 24 </ b> A is supported by a column 52 with a jack. That is, after excavating the ground 29 immediately below the footing 24 </ b> A to the excavation bottom surface 48, the column 52 is vertically set on the excavation bottom surface 48 and the bottom surface of the footing 24 </ b> A is received by the column 52. In the column 52, the diameter of the column 52 and the area of the column bottom that is in contact with the bottom of the excavation are determined in accordance with the load from the existing building 20, the support strength of the excavation bottom 48, and the like.

Further, a jack is attached to the support column 52, and an appropriate axial force is applied by the jack to be attached between the excavation bottom surface 48 and the footing 24A.
The bottom surface of the footing 24A on the back side of the footing 24A, to which the entry pile 38 is not attached, is sequentially supported by the three support columns 52 so as to correspond to the progress of excavation. Thereby, even if the ground 29 is removed, the footing 24 </ b> A can be continuously supported by the entry pile 38 and the support column 52, and the vertical load of the existing building 20 can be supported on the ground of the excavation bottom surface 48.
Note that the column 52 is intended to receive the footing 24A, and the angle to stand in the vertical direction is not required to be excessively accurate and may be within a range in which a necessary supporting force can be secured.

Next, the excavation process 14 is performed.
Specifically, as shown in FIG. 7, excavation is advanced to the bottom of the footing 24B on the back side of the footing 24A. When the excavation progresses and the shoulder 51 of the slope 50 of the ground 29 reaches the footing 24B, and the bottom surface of the footing 24B is excavated to about 1/3 of the bottom surface in the traveling direction, the column 54 is used as the law. Inclined in the same direction as the surface 50 (hereinafter referred to as an inclined column), the bottom surface of the footing 24A is received by the inclined column 54.

Thereafter, a strut 56 (hereinafter referred to as a non-slip strut) is directly provided between the foundation 22 and the excavation bottom surface 48, and the bottom end of the inclined strut is received by the non-slip strut 56. The anti-skid column 56 has the same structure as the above-described column 52 and is brought into contact with the diameter of the anti-skid column 56 and the bottom of the excavation necessary to secure the axial force necessary to stop the sliding of the inclined column 54. The area of the bottom of the column is determined.

That is, the footing 24 </ b> B is supported by the ground 29 and the sloped support 54 by the tilted support 54 receiving a part of the footing 24 </ b> B.
Further, excavation is also started from the lower part of the footing 23A on the front side of the footing 24A, and the footing 23A is supported by the entry pile 38 and the three support columns 52 in the above-described procedure.

  Next, as shown in FIG. 8, excavation is advanced in the direction of travel. That is, when the excavation further proceeds and the bottom surface of the footing 24B is excavated to about 2/3 of the width in the traveling direction, the central portion of the bottom surface of the footing 24B is received by another inclined column 55. In FIG. 8, there are two inclined columns 54 and three inclined columns 55. These numbers are only examples, and the number used is determined by the footing load to be supported.

Further, the lower end portion of the inclined column 55 is received by another antiskid column 57. The inclined column 55 is provided between the inclined columns 54 that already support the footing 24B.
Thereby, the footing 24B is supported by the two types of inclined columns 54 and 55 and the ground 29 whose support positions are shifted.
Thereafter, the three struts 52 under the footings 23A, 24A are restrained by the horizontal restraint reinforcing member 58 so as to be integrated.

Next, the support process 16 is performed.
Specifically, excavation is further advanced as shown in FIG. The inclined column 54 and the anti-slip column 56 previously attached are removed from the bottom surface of the footing 24B, and the column 60 is received in the vertical direction by the column 60 (hereinafter referred to as a vertical column). That is, the inclined column 54 and the vertical column 56 are replaced by the vertical column 60.
Thereby, the footing 24 </ b> B is supported by the inclined column 55, the vertical column 60, and the ground 29.

  Next, as shown in FIG. 10, the excavation is further advanced, and the excavation bottom surface is expanded to just below the end of the footing 24 </ b> B on the traveling side. After the excavation is completed, the vertical support 62 is set up on the ground of the excavation bottom surface 48, and the excavation front side of the bottom of the footing 24B is received by the vertical support 62.

Thereby, the footing 24B is supported only by the support columns 55, 60, and 62. That is, the central portion is supported by the inclined support column 55, and the front and rear portions of the footing bottom surface in the direction of excavation are supported by the vertical support columns 60 and 62, respectively.
Further, when the lower part of the footing 23B is excavated and the lower part of the footing 23B is excavated by about 1/3, the footing 23B is supported by the inclined column 54 and the non-sliding column 56 in the manner described above.

Next, determination step 18 is executed.
That is, it is determined whether or not excavation is advanced to the adjacent footing 23C. If it is not necessary to proceed to the footing 23C, the excavation is terminated. In the case of further excavation, the excavation process 14 and the support process 16 are repeatedly executed as described above.

That is, as shown in FIG. 11, when further excavation is performed, excavation is advanced to the lower part of the footing 23C adjacent to the footing 23B. When the slope shoulder 51 of the slope 50 of the excavated ground 29 reaches the lower part of the footing 23C and the bottom surface of the footing 23C is excavated to about 1/3 of the width in the traveling direction, the sloped column 54 is sloped. Tilt in the same direction as 50 to support the excavated bottom surface behind the direction of travel. Thereafter, a non-slip column 56 is provided directly between the foundation 22 and the excavation bottom surface 48, and the bottom end of the inclined column is received by the non-slip column 56.
Accordingly, the lower portion of the footing 24 </ b> C is received by the inclined column 54, and the footing 24 </ b> C is supported by the ground 29 and the inclined column 56.

  Subsequently, as shown in FIG. 12, the excavation process is further advanced. That is, when excavation progresses and the bottom surface of the footing 24C is excavated to about 2/3, the center portion of the bottom surface of the footing 24C is received by another inclined column 55, and the non-sliding column 57 Receive the lower end.

At this time, the inclined column 55 and the antiskid column 57 supporting the footing 24B may be removed and used.
Accordingly, the lower portion of the footing 24C is supported by the inclined column 55, and the footing 24C is supported by the ground 29 and the inclined columns 54 and 55. Further, the lower portion of the footing 23B is supported by the vertical support 60.

  Further, as shown in FIG. 13, the excavation process is further advanced, the inclined column 54 and the anti-skid column 56 that have received the bottom surface of the footing 24C are removed, and the vertical column 60 is installed at the place where the inclined column 54 was supported. Stand and receive the bottom of the footing 24C. That is, the inclined column 54 is replaced with the vertical column 60.

  Accordingly, the lower portion of the footing 24 </ b> C is supported by the ground 29, the inclined column 55, and the vertical column 60. Thereafter, the four vertical struts 60 and 62 that support the bottom surface of the footing 24B are restrained by the horizontal restraint reinforcing material 58 and reinforced.

Further, the bottom surface of the footing 23B is supported by the vertical support 62. Thereby, the footing 23B is supported not by the ground 29 but only by the columns 54, 60, 62. That is, the existing building 20 is supported by only the columns 54, 60, and 62 sequentially.
Thereafter, the excavation process 14 and the support process 16 are repeated until the end of excavation, that is, until the opposite outer peripheral wall 27 is reached.
Thereby, even if it does not construct a temporary receiving pile, the existing building 20 can be supported by the ground on the bottom of excavation via the support column, and the foundation base can be directly excavated.
In the present embodiment, the bottom surface of the footing is the support column receiving portion, but the present invention is not limited to this, and may be the bottom surface of the foundation beam, for example. Moreover, when the vertical load from the existing building 20 is small, the arbitrary bottom face of a direct foundation may be sufficient.

In addition, there may be a plurality of entrances, and excavation is started from both opposing outer peripheral walls 27 toward the center of the existing building 20, and the excavation process 14 and the support process 16 are completed at the center of the existing building 20. Also good.
In the present embodiment, the case of the footing foundation has been described as an example. However, the present invention is not limited to this, and may be a direct foundation. For example, it can be applied to a solid foundation.

(Second Embodiment)
In the seismic isolation method for an existing building according to the second embodiment, the seismic isolation device is installed on the ground excavated by the excavation method for the direct foundation foundation of the existing building described in the first embodiment. This is a method for seismic isolation of existing buildings. Since the method for directly excavating the foundation foundation has been described, it will be omitted, and the method for installing the seismic isolation device will be described with reference to FIGS.

  As shown in FIG. 14, after excavation of the lower portion of the foundation portion 22 is completed and all the vertical columns 60 and 62 are reinforced with the horizontal restraint reinforcing material 58, a concrete pressure plate 64 is placed on the excavation bottom surface 48. To construct.

  At this time, anchor bolts 74 are embedded in positions below the footings 23 and 24 where a seismic isolation lower foundation 66 described later is constructed. Further, the lower portion of the retaining wall 40 is integrated with the pressure plate 64, and the footings 23 and 24 and the foundation beam 25 around the footings 23 and 24 are reinforced by the reinforcing material 70.

  Next, as shown in FIG. 15, the horizontal restraint reinforcing material 58 is removed, and a concrete seismic isolation lower foundation 66 is constructed on the pressure plate 64. The seismic isolation lower foundation 66 is constructed in an inner central portion surrounded by the vertical columns 60 and 62. After the emergence of the strength of the base isolation base 66, the base isolation device body 68 is installed on the base isolation base 66, and the lower part of the base isolation device base 68 is fixed to the base isolation base 66. Moreover, in order to fix the upper part of the seismic isolation apparatus main body 68, the anchor bolt 74 is embedded in the position where the seismic isolation upper foundation 72 is constructed.

Finally, as shown in FIG. 16, after the seismic isolation device main body 68 is cured, the seismic isolation upper foundation 72 is constructed on the seismic isolation device main body 68 with concrete.
Thereafter, although not shown, the vertical columns 60 and 62 are removed from the upper portion of the pressure plate 64, the horizontal restraint slabs 42 and 44 are removed, and the base portion 22 is received by the seismic isolation device main body 68. Thereby, the seismic isolation repair of the existing building 20 is completed.
In addition, as an example of development of the embodiment, the present invention can be applied to, for example, extension of an underground space, construction of an underground passage, and the like. That is, although illustration is omitted, a basement board excavated by this excavation method may be used to build a column to extend the underground space. Further, a wall body may be constructed on the foundation foundation board excavated by the present excavation method, and an underground passage may be formed between the wall bodies.

14 Excavation process 16 Support process 20 Existing building 22 Foundation part 23 Footing
24 Footing (post support)
27 Peripheral wall 29 Ground 36 Yamadome wall 38 Pile
48 Drilling bottom 50 Slope 51 Shoulder 52 Vertical strut 54 Inclined strut 55 Inclined strut 56 Non-slip strut 57 Non-slip strut 60 Vertical strut 62 Vertical strut 68 Seismic isolation device

Claims (6)

Vertical shaft construction process for constructing vertical shafts,
An excavation process for excavating the ground directly below the existing foundation from the vertical shaft to a depth to the excavation bottom;
A supporting step of standing a pillar on the bottom surface of the excavation in accordance with the progress of the excavation step, and supporting the existing building on the ground of the bottom surface of the excavation via the pillar,
Excavation method for direct foundation foundation of existing building with The supporting step includes
Receiving the existing building substantially vertically with a vertical support;
When the slope of the slope of the ground directly below the foundation reaches the support receiving part of the direct foundation, the inclined support is inclined in the same direction as the slope, and the support is inclined by the inclined support. Receiving process,
Providing a non-slip strut between the direct foundation and the bottom of the excavation, and receiving the lower end of the inclined strut with the non-skid strut;
The method for excavating a direct foundation foundation of an existing building according to claim 1. A step of receiving the strut receiving portion substantially vertically by the vertical strut when the direct base plate of the strut receiving portion received by the inclined strut is excavated to the bottom surface of the excavation;
After receiving the column support part with the vertical column, removing the inclined column and the anti-skid column;
The excavation method of the direct foundation ground board of the existing building of Claim 2 which has these.   The method for excavating a direct foundation foundation of an existing building according to claim 2 or 3, wherein the support column receiving portion is a column lower portion or a foundation beam lower portion of the existing building. Before the shaft construction process,
Building a retaining wall around the existing building;
Excavating the ground between the retaining wall and the outer peripheral wall of the building directly to the foundation surface;
Constructing a pile along the outer peripheral wall of the building, and building a sleeve wall that integrates the upper portion of the pile and the outer peripheral wall of the building;
The excavation method of the direct foundation ground board of the existing building of any one of Claims 1-4 which has these.   A seismic isolation method for an existing building, wherein a seismic isolation device is installed on the direct foundation foundation after excavation according to any one of claims 1 to 5 to make the existing building seismic isolation.

Images