JP6133621B2 - Yamadome wall - Google Patents

Description

  The present invention relates to a mountain retaining wall.

When building a new building in an urban area, there are very few cases that start from the ground. Also, even if the ground structure remains, even if the underground structure remains, after the existing underground outer wall is dismantled and removed by the removal work, the mountain retaining wall is expanded to the full boundary line of the site. A new underground outer wall was constructed inside the retaining wall.
On the other hand, recently, from the standpoint of shortening the construction period and reducing costs, there are some cases where the underground outer wall of an existing building is reused as a mountain retaining wall, and the removal work of underground structures is omitted. However, when the underground structure of a new building is built to a position deeper than the underground structure of an existing building, the depth of the existing building's underground outer wall is not sufficient, and a new It is necessary to construct a new retaining wall below.
For example, Patent Document 1 discloses a technique for constructing a new mountain retaining wall under an underground outer wall of an existing building.
The construction method of the underground structure of patent document 1 is the structure which builds the mountain retaining wall which receives earth pressure under the underground outer wall of the existing building. At this time, the mountain retaining wall is constructed inside the existing pile that supports the underground outer wall.

JP 2001-271365 A

For this reason, the floor area of the underground structure built on the inside of the mountain retaining wall and the above-ground structure built on the underground structure is reduced.
In view of the above facts, an object of the present invention is to omit the removal work of the underground structure and bring the outer wall of the newly installed underground structure close to the position of the existing pile.

The mountain retaining wall according to the invention of claim 1 is constructed between the existing pile supporting the underground outer wall of the existing frame and the existing pile, and the ground is excavated to the bottom of the excavation below the head of the existing pile. is characterized in that chromatic and wall, the receiving the soil pressure from the ground at state.

  According to invention of Claim 1, the earth pressure by the side of a natural ground is received by the wall body constructed | assembled between the existing pile and the existing pile. Thereby, it is possible to receive earth pressure at the mountain retaining wall without building a wall body inside the existing pile. As a result, the outer wall of the newly installed underground structure can be constructed to extend to the position of the existing pile, and a large floor area can be secured. In addition, since the removal work of underground structures can be omitted, the construction period and cost of the newly installed underground structure can be shortened.

  The invention according to claim 2 is the mountain retaining wall according to claim 1, wherein the wall is a sheet pile passed between the existing pile and the existing pile, and the existing pile and the existing pile Yamadori core material built between and the sheet pile passed between the mountain core material and the existing pile, or built between the existing pile and the existing pile. Yamashita core material, a sheet pile passed between the Yamadome core material and the existing pile, and a sheet pile passed between the Yamadome core material and the Yamato core material. Yes.

According to invention of Claim 2, the wall body which receives the earth pressure of the natural ground side is constructed | assembled by the sheet pile passed between the existing pile and the existing pile. Or, the wall body that receives earth pressure on the natural ground side is constructed by the pile core material built between the existing pile and the pile pile, and the sheet pile passed between the pile core material and the existing pile. The Or, the Yamato core material built between the existing pile and the existing pile, the sheet pile passed between the Yamadome core material and the existing pile, and between the Yamadome core material and the Yamadome core material The wall body that receives the earth pressure on the natural mountain side is constructed by the sheet pile passed to.
Thereby, the existing pile can be used as a retaining wall. At this time, when the pitch of the existing pile is large, it is possible to construct the wall body by building the mountain core material in between.
As a result, the construction period and cost of the newly installed underground structure can be shortened.

  The invention according to claim 3 is the mountain retaining wall according to claim 1, wherein the wall body is a ground improvement body constructed between the existing piles by a high-pressure jet stirring method.

According to invention of Claim 3, a wall body is constructed | assembled with the ground improvement body constructed | assembled between the said existing piles by the high-pressure jet stirring method. Thereby, the water stop function can be given to the wall body which receives the earth pressure on the natural ground side. Moreover, since the ground improvement body is constructed between the existing pile and the existing pile, the floor area of the newly installed underground structure can be secured widely. Furthermore, since the removal work of the underground structure can be omitted, the construction period and cost of the newly installed underground structure can be shortened.

  In the present invention, the construction for removing the underground structure can be omitted as described above, and the outer wall of the newly installed underground structure can be brought close to the position of the existing pile.

It is a perspective view which shows the basic composition of the mountain retaining wall which concerns on 1st Embodiment of this invention. It is XX sectional drawing of FIG. 1 which shows the basic composition of the mountain retaining wall which concerns on 1st Embodiment of this invention. It is sectional drawing in the position corresponded to the XX line of FIG. 1 which shows the basic composition of the conventional mountain retaining wall. (A) is sectional drawing which shows the comparison of the underground outer wall limit line position of the conventional mountain retaining wall and the mountain retaining wall which concerns on 1st Embodiment of this invention, (B) is a conventional mountain retaining wall FIG. It is XX sectional drawing of (A), (C) is the YY sectional view taken on the line of FIG. 4 (A) which is the mountain wall of this invention. It is a perspective view which shows the basic composition of the mountain retaining wall which concerns on 2nd Embodiment of this invention. It is XX sectional drawing of FIG. 5 which shows the basic composition of the mountain retaining wall which concerns on 2nd Embodiment of this invention. It is a MN curve figure of a mountain retaining wall concerning a 2nd embodiment of the present invention. (A) is a side view showing the deformation measurement position of the retaining wall of the present invention, (B) is an actual measurement result of the amount of mutation at the completion of the fifth excavation, (C) is the mutation at the completion of the sixth excavation It is the actual measurement result of quantity. It is a perspective view of an underground frame which shows the example of development of the mountain retaining wall concerning a 2nd embodiment of the present invention. (A) is sectional drawing in the position equivalent to the XX line of FIG. 1 which shows the basic composition of the mountain retaining wall which concerns on 3rd Embodiment of this invention, (B) shows the construction method of a mountain retaining wall. It is a side view.

(First embodiment)
As shown in the perspective view of FIG. 1 and the plan view of FIG. 2 (cross section taken along line XX of FIG. 1), the mountain retaining wall 10 according to the first embodiment is constructed under the underground outer wall 26 of the existing frame 36. ing. The underground outer wall 26 is supported by the existing pile 14, and the sheet pile 12 is inserted between the existing pile 14 and the existing pile 14.
Here, the existing frame 36 is an outer peripheral part of the underground part of the building whose ground part has been demolished for rebuilding, and the underground outer wall 26 is not demolished as a mountain retaining wall that receives earth pressure from the ground 18. It is kept in. Further, the existing pile 14 is also placed, and the head supports the bottom surface of the underground floor board 24 provided at the lower end of the underground outer wall 26.

The existing pile 14 shown in FIGS. 1 and 2 is a group pile, for example, and has a configuration in which the distance a between the existing pile 14 and the existing pile 14 is small. In this case, between the existing pile 14 and the existing pile 14, it is possible to pass the sheet pile 12 as a wall body which receives the earth pressure from the ground 18 directly in the horizontal direction, and both ends of the sheet pile 12 are It is supported by an angle member 50 attached to the existing pile 14 as a receiving member. For example, the angle member 50 is bolted to the existing pile 14 so that the sheet pile 12 does not move due to the earth pressure from the ground 18.
Here, the existing pile 14 may be a cast-in-place concrete pile or a steel pipe pile, and the pile type is not selected. The sheet pile 12 is made of wood or steel, and is passed between the existing pile 14 and the existing pile 14 in the horizontal direction.

With this configuration, the mountain retaining wall 10 constructed with the existing pile 14 and the sheet pile 12 receives the earth pressure from the ground 18, and below the underground floor 24 of the existing frame 36, the underground space 19 of the new building. Can be excavated to the excavation bottom surface 52.
As a result, it is possible to construct the underground outer wall 16 of the new building as close as possible to the position in contact with the existing pile 14. That is, since the mountain retaining wall 10 can be constructed without protruding to the underground space 19 side, the underground space 19 can be secured widely. As a result, it is possible to carry out underground work that avoids underground obstacle removal work while securing a newly built underground area.
In addition, in this embodiment, although the case where the sheet pile 12 was used as a wall body which receives the earth pressure from the ground 18 was demonstrated, it is not limited to this, and it replaces with the sheet pile 12 and an iron plate or H-shaped steel is used. You may use it toward the direction.

Next, the effects of the present embodiment will be specifically described in comparison with a conventional method.
In the rebuilding of buildings in narrow urban areas, it is important to handle the outer peripheries of existing underground structures. In particular, when constructing a new underground structure under the foundation floor 24, which is the deepest part of the existing underground structure, the underground outer periphery of the existing structure 36 is dismantled by ground fault removal work, and a new mountain retaining wall is created. There are a method of constructing an underground frame by construction and a method of constructing an underground frame by constructing a new mountain retaining wall inside by leaving the underground outer peripheral portion of the existing frame 36. In the former case, there is a problem in terms of cost and construction period, and in the latter case, there is a problem in that the newly built underground area cannot be secured sufficiently.

The present embodiment is a new method that does not remove the existing pile 14 and sufficiently secures a newly built underground area.
FIG. 3 is a plan view of a conventional mountain retaining wall 30 (a cross section at a position corresponding to the line XX in FIG. 1). The mountain retaining wall 30 is formed in contact with the existing pile 14 on the underground space 19 side (newly excavated side) of the existing pile 14. The mountain retaining wall 30 is constructed by a columnar improvement body 28 constructed by improving the ground, and an H-section steel 32 as a core material is inserted into the columnar improvement body 28 at a predetermined interval as necessary. Thereby, the mountain retaining wall 30 can receive the earth pressure from the ground 18. Further, during excavation to the excavation bottom surface 52 (see FIG. 1) of the underground space 19, a part of the mountain retaining wall 30 on the underground space 19 side is cut out at the position of the flange surface of the H-section steel 32, and the thickness B It is said. A new underground outer wall 34 is constructed in contact with the surface of the mountain retaining wall 28 that has been cut and formed into a flat plate shape.

FIG. 4 (A) shows a result of comparing the conventional retaining wall 30 and the retaining wall 10 of the present embodiment on the underground outer wall limit line.
As shown in FIGS. 4 (A) and 4 (B), the conventional mountain retaining wall 30 has a configuration in which the mountain retaining wall 28 is constructed inside the existing pile 14 without the underground obstacle removal work. For this reason, the underground outer wall limit line P <b> 1 is set inside the mountain retaining wall 28. As a result, a new underground outer wall 34 is constructed inside the mountain retaining wall 28.
On the other hand, as shown to FIG. 4 (A) and (C), the mountain retaining wall 10 of this embodiment is the structure which inserts the sheet pile 12 between the existing pile 14 and the existing pile 14. FIG. For this reason, the underground outer wall limit line P2 is substantially flush with the end of the existing pile 14 on the underground space 19 side. As a result, the underground space 19 can be widened by a dimension substantially equal to the thickness B of the conventional mountain retaining wall 30.
That is, the mountain retaining wall 10 of the present embodiment uses the existing pile 14 on the outer peripheral portion as the mountain retaining wall 10 at a position deeper than the existing underground floor 24 due to excavation work in order to secure the maximum newly constructed underground area. doing. By utilizing the bending rigidity of the existing pile 14 as the mountain retaining wall 10, the underground outer wall limit line can be expanded to the inside of the existing pile 14 at the outer peripheral portion. Moreover, the continuity of a mountain retaining wall is ensured by arrange | positioning the sheet pile 12 between the existing pile 14 and the existing pile 14. FIG.

  In addition, the thickness of the conventional mountain retaining wall 30 is about 500 mm. Thereby, between the wall surfaces which the underground space 19 faces, the underground space 19 can be widely secured by about 1000 mm. That is, the outer wall 16 of the newly built frame can be constructed to extend to the position of the existing pile 14, and a large floor area can be secured at the new mountain wall position of the newly built frame. Furthermore, in this embodiment, since the removal work of the underground structure (for example, the removal work of the existing pile 14) can be omitted, it is possible to reduce the work period and cost of the underground structure of the newly built frame.

(Second Embodiment)
As shown in the perspective view of FIG. 5 and the plan view of FIG. 6 (cross-sectional view taken along line XX in FIG. 5), the mountain retaining wall 20 according to the second embodiment is used as a mountain retaining core between existing piles 14. An H-section steel 22 is provided. That is, the mountain retaining wall 20 is composed of the existing pile 14, the H-shaped steel 22, and the sheet pile 12. Here, the flange on the underground space 19 side of the H-section steel 22 is arranged on the same surface as the end portion on the underground space 19 side of the existing pile 14, and the sheet pile 12 includes the H-section steel 22 and the H-section steel 22. And the angle member 50 attached to the H-shaped steel 22 and the existing pile 14.
Thereby, even if the space | interval b of the existing pile 14 and the existing pile 14 is larger than the width | variety of the sheet pile 12 (a <b), the sheet pile 12 between the existing pile 14 and the existing pile 14 is supported with the H-section steel 22. Therefore, the mountain retaining wall 20 can receive the earth pressure from the ground 18. Further, the flange of the H-shaped steel 22 on the underground space 19 side is disposed on the same surface as the end of the existing pile 14 on the underground space 19 side, and the mountain retaining wall 20 is located on the underground space 19 side of the existing pile 14. It does not protrude greatly.

In addition, the number of the H-section steel 22 is provided between the existing pile 14 and the existing pile 14 in FIG. However, it is not limited to this, and is determined according to the distance b between the existing pile 14 and the existing pile 14. For example, if the distance b is large, it may be increased. By setting it as this structure, not only the existing underground outer wall 26 (refer FIG. 1) but the existing pile 14 can be utilized as a part of the mountain retaining wall 20. FIG.
As a result, on the underground space 19 side of the mountain retaining wall 20, the outer wall 16 of the newly constructed frame can be expanded to the position of the end of the existing pile 14, and the floor area at the mountain retaining wall position of the newly constructed frame can be increased. Can be secured.

Next, the bending rigidity of the dome 20 will be described.
The bending rigidity EI of the mountain retaining wall 20 in the present embodiment is obtained by adding the bending rigidity EcIc of the existing pile 14 and the bending rigidity EsIs of the H-shaped steel 22 and dividing the total value by the inter-pile distance a. . The calculation formula is shown in the following formula (1). Here, the bending rigidity EsIs of the H-section steel 22 is summed up when the plurality of H-section steels 22 are used.
EI = (EcIc + ΣEsIs) / a (1)
Here, EI: Bending stiffness of mountain wall (N · cm ² )
EcIc: Flexural rigidity of existing piles (N · cm ² )
EsIs: Flexural rigidity of H-section steel (N · cm ² )
a: Standard span of existing pile (cm)

FIG. 7 shows an example of stress evaluation of the retaining wall 20. FIG. 7 is an MN curve in which a part of the remaining existing underground outer wall portion is expected as an axial force, and was calculated based on the “Construction Standards for Reinforced Concrete Structures / Description” of the Architectural Institute of Japan. The horizontal axis in FIG. 7 is the axial force N (kN) applied to the existing pile 14, and the vertical axis is the allowable bending moment M (kN · m) generated in the existing pile 14.
A curve G in FIG. 7 sets an allowable bending moment (final) of the existing pile 14. From the examination results, as shown in FIG. 7, the existing pile 14 has a bending moment sufficient as the mountain retaining wall 20, and can be said to be sufficiently utilized as the mountain retaining wall 20.

Next, the displacement amount of the mountain retaining wall 20 will be described.
FIG. 8 shows the measurement results. FIG. 8A shows the measurement position. The measurement point 54 is the position of the existing pile 14 from the outer wall 26 of the existing frame to the outer wall 16 of the newly built frame, and a plurality of points were measured at a predetermined depth. Similarly, the measurement points 56 are a plurality of positions at a predetermined depth of the mountain core material 22.
FIG. 8B shows an actual measurement result when the fifth excavation is completed. The horizontal axis is the displacement (cm), and the vertical axis is the depth (m) from the ground surface. The actual measurement result of the Yamatome core material 22 is shown in D1, and the actual measurement result of the existing pile 14 is shown in D2. At any depth of the mountain core 22 and the existing pile 14, the deformation of the mountain wall is within a sufficiently small range (0.3 cm or less) and has sufficient strength against earth pressure. I can say that.
FIG. 8C shows an actual measurement result when the sixth excavation is completed. The horizontal axis is the displacement (cm), and the vertical axis is the depth (m) from the ground surface. The actual measurement result of the Yamatome core material 22 is shown in D1, and the actual measurement result of the existing pile 14 is shown in D2. At any depth of the mountain core 22 and the existing pile 14, the deformation of the mountain wall is within a sufficiently small range (0.7 cm or less) and has sufficient strength against earth pressure. I can say that.
By adopting this configuration, it is easy to construct the mountain retaining wall 20 that receives the earth pressure on the ground 18 side, and it is possible to reduce the work period and cost of the underground structure of the new building.

Further, as in the development example shown in the perspective view of FIG. 9, in the newly built underground structure 60, a part of the column 58D below the beam 62 of the newly built column portion 58U is placed outside the ground wall (the ground side). It is good also as a construction that protrudes (hashed). That is, in order to widen the underground space 19 of the underground structure 60, the column 58D is desirably provided on the ground 18 side as much as possible, and the position of the beam 62 is maintained in order to maintain the strength to receive the vertical load from the column 58U. It is good also as the haunch shape formed diagonally toward the downward direction. Thereby, it is not necessary to decenter the beam 62 and receive the vertical load from the column 58U and transmit it to the column 58D, and the beam 62 can be formed small.
As a result, the cost of the underground structure 60 can be reduced. Other configurations are the same as those of the first embodiment, and a description thereof will be omitted.

(Third embodiment)
As shown in the plan view of FIG. 10 (A) and the side view of FIG. 10 (B), the mountain retaining wall 40 according to the third embodiment is improved between the existing pile 14 and the existing pile 14 (distance C). The body 42 is constructed continuously. The ground improvement body 42 is provided with H-section steel 32 as a mountain core material at predetermined intervals. That is, the mountain retaining wall 40 is constructed by the existing pile 14 and the ground improvement body 42.
Here, the ground improvement body 42 is constructed by a high-pressure jet stirring method. In the high-pressure jet agitation method, the ground improvement body 42 can be constructed by inserting a casing 44 having a small diameter d into the ground. Thereby, the casing 44 can be brought close to the existing outer wall 26 and the ground improvement body 42 can be constructed at the lower part of the existing outer wall 26.

The construction procedure of the ground improvement body 20 is as follows. First, a guide hole 44 is drilled in the ground 42 using a guide hole drilling machine (not shown) installed on the ground, and the casing 44 is moved from the excavation start surface 48 to a predetermined depth. Is inserted up to H (arrow R1 direction). A drill bit 46 for discharging compressed air and a solidifying agent is attached to the tip of the casing 46.
Next, using a jet cleat construction machine (not shown) installed on the ground, the compressed bit and the solidifying agent are sent to the drill bit 46 through the casing 44 while rotating the drill bit 46, and from the tip of the drill bit 46. Discharge. Thereby, the ground 18 around the drill bit 46 is improved in the radial direction, and the construction of the ground improved body 42 having the diameter D is started.

  Next, the drill bit 48 is gradually pulled up while rotating (in the direction of arrow R2). Thereby, the ground improvement body 42 is built sequentially from the bottom to the top. The ground improvement body 42 having a height H2 is constructed by discharging compressed air and a solidifying agent from the drill bit 48 to the excavation start surface 48. Subsequently, after the construction of the ground improvement body 42 is completed, the casing 44 is pulled out. Then, the H-section steel 32 as a mountain core material is inserted into the ground improvement body 42 at a predetermined position. Thereby, construction of the ground improvement body 42 is complete | finished, waiting for hardening of a solidification agent. The mountain retaining wall 40 can be provided with a water shielding function by continuously building a part of the ground improvement body 42 in an overlapping manner.

Next, a part of the ground improvement body 42 on the underground space 19 side is cut out at a flange position on the underground space 19 side (the width of the ground improvement body 42 is set to B). Thereby, the mountain retaining wall 40 is constructed. The mountain wall 40 can obtain the same effect as the first embodiment.
Thereby, the outer wall 16 of a newly built frame can be subsequently constructed in contact with the notched surface of the ground improvement body 42. Other configurations are the same as those of the first embodiment, and a description thereof will be omitted.

10 Yamadome wall 12 Sheet pile (wall)
14 Existing pile 16 Underground wall 22 H-section steel (Yamadome core)
26 Existing building outer wall 28 Ground improvement body

Claims (3)

The existing pile for supporting the underground external wall of an existing building frame,
A wall body that is constructed between the existing piles and receives earth pressure from the ground in a state where the ground is excavated to the bottom of the excavation below the head of the existing pile ,
To have a YamaTomekabe. The wall body is a sheet pile passed between the existing pile and the existing pile,
A pile core material built between the existing pile and the existing pile, and a sheet pile passed between the pile core material and the existing pile,
Or, a pile core material built between the existing pile and the pile, a sheet pile passed between the pile core material and the existing pile, and the pile core material and the pile The mountain retaining wall according to claim 1, which is a sheet pile passed between the core material.   The mountain retaining wall according to claim 1, wherein the wall body is a ground improvement body constructed between existing piles by a high-pressure jet stirring method.

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