JP2005002671A - Underpinning method and viaduct - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an underpinning method which need not construct temporary slabs or temporary piles under the ground in an area immediately below a viaduct, and allows formation of a shield tunnel in an area where overburden is shallow, and to provide the viaduct. <P>SOLUTION: A bearing slab 13 is set on the ground 7 around columns 5 of the viaduct 1, and reinforcing walls 23, 17 are set between the columns 5 in a manner sequentially extending from the bearing slab 13, followed by setting a reinforcing slab 15 on a lower side of a floor slab 3 in a manner sequentially extending from the reinforcing walls 23, 17. Then an encasing concrete portion which encases each column 5 is formed on the bearing slab 13, and PC steel rods 27 are penetrated through the encasing concrete portion 25 and the reinforcing wall 23, to thereby connect each column 5 and the reinforcing wall 23 together in one body. Next a shield machine is passed through in the ground 7 in the area immediately below the viaduct 1 to construct a tunnel 29 while cutting part of existing piles 9 and removing the same. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an underpinning method and high crosslinking.
[0002]
[Prior art]
Conventionally, when constructing a tunnel that passes directly under a structure, provisional protection called underpinning (replacement method) is performed so as not to affect the structure. Many of them are to install new provisional girders, slabs and piles for underpinning in the underground, and to transfer loads from existing piles. On the viaducts on land, several works have been undertaken to temporarily receive the viaduct with temporary piles and temporary beams while taking into account the safety of passengers and trains and the impact on nearby and surrounding structures. Patent Document 1).
[0003]
[Non-Patent Document 1]
"Public Works Engineering Handbook" edited by Japan Society of Civil Engineers, Ohmsha, p. 384-391
[0004]
[Problems to be solved by the invention]
However, it is difficult to apply a general underpinning method when constructing a tunnel that runs through a viaduct directly under the viaduct under a condition where the earth covering is shallow.
[0005]
The present invention has been made in view of such problems, and the purpose of the present invention is that it is not necessary to newly install a temporary slab or a temporary pile in the underground part directly under the viaduct, and even in a shallow part of the earth covering. An object of the present invention is to provide an underpinning method and a viaduct capable of passing through a shield tunnel.
[0006]
[Means for Solving the Problems]
A first invention for achieving the above-described object is a method of underpinning an existing structure in which opposing pillar portions are continuously provided and a floor slab is supported by the pillar portions, and the surroundings of the pillar portions are provided. A step (a) of installing a pressure-resistant plate on the ground of the step, a step (b) of installing a reinforcing wall between the opposing pillars, and a reinforcing slab on the lower side of the floor slab, the pillars and the A step (c) of integrating the reinforcing wall with the reinforcing wall.
[0007]
The existing structure is, for example, a viaduct composed of a pier that is a pillar and a floor slab supported by the pier. In the step (b), a reinforcing wall is installed along the inside of the column portion. When the existing structure is a viaduct, for example, a longitudinal reinforcing wall and a transverse reinforcing wall are installed. In the step (c), the PC steel rod is passed through the concrete wound around the outer periphery of the column portion and the reinforcing wall, and the column portion and the reinforcing wall are integrated. At the end of the section where underpinning is performed, a support pile is installed below the pressure plate.
[0008]
In the first invention, a pressure-resistant plate is installed on the ground around the column portion, a reinforcement wall is installed between two adjacent column portions, and a reinforcement slab is installed below the floor slab. And concrete is wound up along the outer periphery of a pillar part, By integrating this concrete reinforcement wall, the existing structure which is a pile foundation structure is converted into a direct foundation structure by a pressure-resistant plate.
[0009]
2nd invention is an underpinning method of the existing structure in which the opposing pillar part is continuously provided, and supports a floor slab by the said pillar part, Comprising: The ground between the said pillar parts is improved, and it is a pile shape Forming a body, and improving the surface layer of the upper part of the pile-shaped body in a strip shape (a), installing the first pressure-resistant plate on the ground surface improved in the step (a) (b), A step (c) of installing a reinforcing wall between opposing column portions and a reinforcing slab on the lower side of the floor slab, and a step of excavating the periphery of the footing portion of the column portion to remove the footings and existing piles ( d), a step (e) of backfilling the portion excavated in the step (d), and a step (f) of installing a second pressure plate on the portion backfilled in the step (e). The underpinning method is characterized by:
[0010]
The existing structure is, for example, a viaduct composed of a pier that is a pillar and a floor slab supported by the pier. In the step (a), a pile-shaped body is formed by a high-pressure jet agitator. In the step (c), a reinforcing wall is installed along the inside of the column portion. When the existing structure is a viaduct, for example, the reinforcing wall is installed in the longitudinal direction. In the step (d), the inside of the steel sheet pile installed around the footing is excavated before the step (d). The used steel sheet pile is pulled out after the step (e). In step (e), backfilling is performed using soil cement.
[0011]
In 2nd invention, the ground between pillar parts is improved, a pile-shaped body is formed, the upper part of a pile-shaped body is surface-layer-modified in a strip | belt shape, and a 1st pressure-resistant plate is installed on the ground improved. Next, a reinforcing wall is installed between the pillars, and a reinforcing slab is installed below the floor slab. And after excavating the circumference | surroundings of the footing part of a pillar part and removing a footing and an existing pile, and refilling the excavated part, a 2nd pressure-resistant plate is installed on the refilled part. Thereby, the existing structure which is a pile foundation structure is converted into the direct foundation structure by a pressure-resistant plate.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of the viaduct 1 in the longitudinal direction, and FIG. 2 is a perspective view of the viaduct 1 after underpinning.
[0013]
As shown in FIG. 1, the viaduct 1 that performs underpinning includes a pillar portion 5 that is a pier, an existing pile 9, a floor slab 3, and the like. The column parts 5 are juxtaposed in two rows in the longitudinal direction of the viaduct 1. The floor slab 3 is installed on the column portion 5. The existing pile 9 is installed in the ground 7 below the column part 5. The viaduct 1 is a pile foundation structure that supports the column portion 5, the floor slab 3, and the like with the existing pile 9.
[0014]
In the first embodiment, an underpinning method when the tunnel planned position 11 is at a relatively deep position of the ground 7 and overlaps the existing pile 9 will be described.
[0015]
As shown in FIG. 2, the underpinning of the viaduct 1 includes the pressure plate 13, the reinforcing slab 15, the reinforcing wall 17, the reinforcing wall 23, the root winding concrete 25, the PC steel rod 27, the pressure plate end support pile 21 (FIG. 3). ) Etc. are performed.
[0016]
3 and 4 are cross-sectional views in the longitudinal direction of the viaduct 1 subjected to underpinning, FIG. 5 is a cross-sectional view in the transverse direction of the viaduct 1, and FIG. 6 is a cross-sectional view in the vicinity of the column portion 5. FIG. 3 is a side view of the viaduct 1 as viewed from the side, and is a cross-sectional view taken along line BB of FIG. 4 is a view of the viaduct 1 as viewed from above, and is a cross-sectional view taken along line AA of FIG. 5 is a cross-sectional view taken along the line CC of FIG. FIG. 6 is an enlarged view of a portion indicated by E in FIG. 4 is the same as the end face of FIG.
[0017]
To perform underpinning of the viaduct 1, first, the ground 7 around the pillar 5, that is, the ground 7 between the pillars 5 installed in two rows and the ground 7 outside the pillar 5 are covered. Thus, the pressure plate 13 is installed (FIGS. 2, 3, and 5). And the reinforcement wall 23 which reinforces between the pillar parts 5 adjacent to the longitudinal direction of the viaduct 1 is installed along the inner side of the pillar part 5 (FIG. 2, FIG. 4, FIG. 5). Moreover, the reinforcement wall 17 which reinforces between the pillar parts 5 adjacent to a cross direction is installed (FIGS. 2-5). Furthermore, the reinforcement slab 15 is installed under the floor slab 3 (FIGS. 2, 3, and 5).
[0018]
As shown in FIG. 2, the pressure plate 13, the reinforcing slab 15, the reinforcing wall 17, and the reinforcing wall 23 are continuous, and a load is transmitted along the inside of the column part 5 and the floor slab 3. The pressure plate 13, the reinforcing slab 15, the reinforcing wall 17, and the reinforcing wall 23 are reinforced concrete or the like.
[0019]
Next, the root-wrapped concrete 25 is installed around three surfaces on which the reinforcing wall 23 and the reinforcing wall 17 are not installed among the four surfaces of the column portion 5 (FIGS. 4, 5, and 6). The root-wrapped concrete 25 is installed on the upper surface of the pressure plate 13. Then, a plurality of PC steel bars 27 are installed so as to penetrate through the root-wrapped concrete 25 and the reinforcing wall 23 (FIGS. 2 and 6). The PC steel rod 27 is a member for integrating the column portion 5 and the reinforcing wall 23.
[0020]
In the vicinity of the end 19 of the construction section of the reinforcing wall 23, the pressure plate end support pile 21 is installed below the pressure plate 13 (FIG. 3). The pressure plate end support pile 21 suppresses the deformation amount of the viaduct 1 at the end of the construction section.
[0021]
The steps from the installation of the pressure plate 13 and the like to the installation of the PC steel rod 27 are repeated between the column portions 35 to complete the underpinning of the viaduct 1 as shown in FIGS. By performing underpinning, the viaduct 1 that was the pile foundation structure supported by the existing pile 9 is converted into a direct foundation structure supported by the pressure plate 13.
[0022]
FIG. 7 shows a cross-sectional view in the longitudinal direction of the viaduct 1 after the tunnel 29 is formed. FIG. 7 is a view of a cross section at a position including the column portion 5 as viewed from the side of the viaduct 1. After underpinning as shown in FIGS. 2 to 6, the shield machine is passed through the tunnel planned position 11 (FIG. 1) below the viaduct 1 to form a tunnel 29 (FIG. 7).
[0023]
As described above, the viaduct 1 subjected to the underpinning is directly converted into a basic structure by the pressure plate 13, and the rigidity of the existing frame and the continuous pressure plate 13, the reinforcing wall 17, the reinforcing wall 23, and the reinforcing slab 15 is converted. To ensure stability. Therefore, when forming the tunnel 29, as shown in FIG. 7, a part of the existing pile 9 can be cut and removed by the shield machine. If necessary, a part of the newly installed pressure-resistant plate end support pile 21 is also cut and removed.
[0024]
In the first embodiment, since the pressure plate 13, the reinforcing slab 15, the reinforcing wall 17, and the reinforcing wall 23 are installed on the viaduct 1 and a method of converting from a pile foundation structure directly to a foundation structure is used, the tunnel 29 is formed. There is no need to remove the existing enclosure prior to Further, when the tunnel 29 is formed, the existing pile 9 can be cut and removed by the shield machine.
[0025]
The underpinning method according to the first embodiment does not perform excavation and does not require a retaining wall or a supporting work. Therefore, the influence on the surrounding environment is small and the workability is excellent. In addition, construction is possible without affecting the track. Furthermore, compared with the conventional underpinning method by open-cutting, construction can be performed in a narrow work yard, night work hours can be shortened, construction safety can be improved, and the overall construction period can be reduced.
[0026]
Next, a second embodiment will be described in detail. FIG. 8 is a cross-sectional view of the viaduct 31 in the longitudinal direction, and FIG. 9 is a perspective view of the viaduct 31 after underpinning.
[0027]
As shown in FIG. 8, the viaduct 31 for underpinning includes a pillar portion 35 that is a bridge pier, an existing pile 39, a floor slab 33, and the like. The column portions 35 are juxtaposed in two rows in the longitudinal direction of the viaduct 31. The floor slab 33 is installed on the column portion 35. The existing pile 39 is installed in the ground 37 below the column part 35. The viaduct 31 is a pile foundation structure that supports the column portion 35, the floor slab 33, and the like with the existing pile 39.
[0028]
In the second embodiment, an underpinning method when the tunnel planned position 41 is at a shallow position on the ground 37 and overlaps with the existing pile 39 and the footing 59 of the column part 35 will be described.
[0029]
As shown in FIG. 9, the underpinning of the viaduct 31 is performed by installing a pressure plate 43, a reinforcing slab 45, a reinforcing wall 53, a surface layer improvement 49, a pile-shaped body 47, and the like. The pressure plate 43 includes a pressure plate 43a and a pressure plate 43b.
[0030]
10 shows a cross-sectional view in the longitudinal direction of the viaduct 31 in which the pile-shaped body 47 is formed, the surface layer improvement 49 is performed, and the pressure plate 43a, the reinforcing slab 45, and the reinforcing wall 53 are installed. FIG. 10 is a view of a cross section at a position including the column portion 35 as viewed from the side of the viaduct 1. The cross section by FF of FIG. 10 is the same as that of the end surface of FIG.
[0031]
In order to perform underpinning of the viaduct 1, first, as shown in FIGS. 9 and 10, a pile-like body 47 is installed between the column portions 35 adjacent to each other in the longitudinal direction of the viaduct 1. The pile-like body 47 is formed by, for example, a high-pressure jet agitation (column jet grouting). Next, the surface layer improvement 49 of the ground 37 is performed so that the upper part of the two pile-shaped bodies 47 adjacent to a cross direction may be connected. As shown in FIG. 9, both end portions of the surface layer improvement 49 reach the outside of the pile-shaped body 47.
[0032]
After the surface layer improvement 49 is performed, the pressure plate 43a is installed on top of the surface layer improvement 49 (FIGS. 9 and 10). And the reinforcement wall 53 which reinforces between the column parts 35 adjacent to the longitudinal direction of the viaduct 31 is installed along the inner side of the column part 35 (FIG. 9, FIG. 10). Further, a reinforcing slab 45 is installed below the floor slab 33 (FIG. 9).
[0033]
As shown in FIG. 9, the pressure plate 43 a, the reinforcement slab 45, and the reinforcement wall 53 are continuous, and a load is transmitted along the inside of the column part 35 and the floor slab 33. The pressure plate 43a, the reinforcing slab 45, and the reinforcing wall 53 are reinforced concrete or the like.
[0034]
FIG. 11 is a longitudinal sectional view of the viaduct 31 where the footing 59 of the column part 35 is being removed. After the pressure plate 43a, the reinforcing slab 45, and the reinforcing wall 53 are installed, a steel sheet pile 51 is placed on the ground 37 as shown in FIG. The steel sheet pile 51 is installed so as to surround the footing 59 of the two column portions 35 adjacent to each other in the transverse direction of the viaduct 31.
[0035]
FIG. 12 is a cross-sectional view in the transverse direction of the viaduct 31 from which the footing 59 has been removed. 12 is a cross-sectional view taken along line GG in FIG. After placing the steel sheet pile 51 as shown in FIG. 11 (a), the ground 37 in the portion surrounded by the steel sheet pile 51 is placed under the footing 59 as shown in FIG. 11 (b) and FIG. Drill until. And the underground part of the footing 59 and the pillar part 35 is removed.
[0036]
Next, as shown in FIG. 11C, the existing pile 39 embedded in the lower part of the excavation part 55 is removed. After removing the existing pile 39, cement bentonite is poured into the loose ground. Then, as shown in FIG. 11D, a backfill 57 is performed in the space 55 generated by excavating the ground 37 and removing the footing 59 and the like. For the backfill 57, for example, soil cement is used. After performing the backfill 57, the steel sheet pile 51 is removed as shown in FIG.
[0037]
FIG. 13 is a cross-sectional view in the transverse direction of the viaduct 31 provided with the pressure plate 43b. 13 is a cross-sectional view taken along the line H-H in FIG. After removing the steel sheet pile 51 as shown in FIG. 11 (e), as shown in FIG. 11 (f) and FIG. 13, the pressure plate 43b is placed on the portion where the backfill 57 has been performed.
[0038]
As shown in FIGS. 9 and 11 (f) and FIG. 13, the pressure plate 43 b is continuously formed on the pressure plate 43 a and the reinforcing wall 53. The pressure plate 43b is reinforced concrete or the like, like the pressure plate 43a. The pressure plate 43 is a combination of the pressure plate 43a and the pressure plate 43b. A load is transmitted to the pressure plate 43 along the inside of the column portion 35 and the floor slab 33.
[0039]
As shown in FIGS. 10 and 11, the steps from the formation of the pile body 47 to the installation of the pressure plate 43 b are repeated between the pillar portions 35 to complete the underpinning of the viaduct 31 as shown in FIG. 9. By performing underpinning, the viaduct 31 that was the pile foundation structure supported by the existing pile 39 is converted into a direct foundation structure supported by the pressure plate 43.
[0040]
14 is a cross-sectional view in the longitudinal direction of the viaduct 31 after the tunnel 61 is formed, and FIG. 15 is a cross-sectional view in the transverse direction of the viaduct 31 after the tunnel 61 is formed. FIG. 14 is a view of a cross section at a position including the column portion 35 as viewed from the side of the viaduct 1. 15 is a cross-sectional view taken along the line II of FIG.
[0041]
After underpinning as shown in FIG. 9, the shield machine is passed through the tunnel planned position 41 (FIG. 10) below the viaduct 31 to form the tunnel 61 (FIG. 14).
[0042]
As described above, the viaduct 31 subjected to underpinning is directly converted into a basic structure by the pressure plate 43, and stability is ensured by the rigidity of the existing casing and the continuous pressure plate 43, the reinforcing wall 53, and the reinforcing slab 45. Has been. Therefore, at the time of forming the tunnel 61, as shown in FIGS. 14 and 15, a part of the pile-shaped body 47, the surface layer improvement 49, and the backfill 57 can be cut and removed by the shield machine.
[0043]
In the second embodiment, a pressure plate 43, a reinforcing slab 45, and a reinforcing wall 53 are installed on the viaduct 31 and a footing 59 and the like are removed to directly convert the pile foundation structure into a foundation structure. At this time, since the excavation work of the ground 37 and the removal work of the existing frame performed prior to the formation of the tunnel 61 are small, the influence on the surrounding environment is small and the workability is excellent. In addition, construction is possible without affecting the track.
[0044]
In the underpinning method according to the second embodiment, the ground 37 is shallow because the formation of the pile-like body 47 and the surface layer improvement 49 by the high-pressure jet agitation is not performed in the ground 37, and no temporary piles or provisional girders are installed. A shield machine can be passed to a part, and the reach of a shield machine becomes unnecessary. In addition, compared with the conventional underpinning method by open cutting, construction can be performed in a narrow work yard, night working hours can be shortened, construction safety can be improved, and the overall construction period can be reduced.
[0045]
【The invention's effect】
As described above in detail, according to the present invention, it is not necessary to newly install a temporary slab or a temporary pile in the underground part directly under the viaduct, and the shield tunnel can be passed through a shallow part of the earth covering. Underpinning methods and high crosslinks can be provided.
[Brief description of the drawings]
1 is a cross-sectional view of the viaduct 1 in the longitudinal direction. FIG. 2 is a perspective view of the viaduct 1 after underpinning. FIG. 3 is a cross-sectional view of the viaduct 1 that is underpinned. Cross-sectional view of pinned viaduct 1 in the longitudinal direction [FIG. 5] Cross-sectional view of viaduct 1 in the transverse direction [FIG. 6] Cross-sectional view in the vicinity of pillar 5 [FIG. 7] In the longitudinal direction of viaduct 1 after tunnel 29 formation Sectional view [Fig. 8] Cross-sectional view of viaduct 31 in longitudinal direction [Fig.9] Perspective view of viaduct 31 after underpinning [Fig. 43a, a sectional view in the longitudinal direction of the viaduct 31 provided with the reinforcing slab 45 and the reinforcing wall 53. FIG. 11 is a sectional view in the longitudinal direction of the viaduct 31 where the footing 59 of the column part 35 is being removed. Crossing direction of removed viaduct 31 13 is a cross-sectional view in the transverse direction of the viaduct 31 provided with the pressure plate 43b. FIG. 14 is a cross-sectional view in the longitudinal direction of the viaduct 31 after the tunnel 61 is formed. Sectional view of direction [Explanation of symbols]
1, 31 ………… Viaduct 3, 33 …… Floor slab 5, 35 …… Column 7, 37 …… Ground 9, 39 …… Existing pile 11, 41 …… Tunnel planned position 13, 43 , 43a, 43b ......... Pressure proof plates 15, 45 ......... Reinforcement slabs 17, 23, 53 ......... Reinforcement walls 21 ......... Pressure plate end support piles 25 ......... Neck wound concrete 27 ......... PC steel Rod 47 ... Pile-shaped body 49 ... Surface improvement 51 ... Steel sheet pile 57 ... Backfill

Claims (12)

Opposing column portions are continuously provided, and an underpinning method for an existing structure that supports a floor slab with the column portions,
A step (a) of installing a pressure-resistant plate on the ground around the pillar part;
A step (b) of installing a reinforcing wall between the opposing pillars and a reinforcing slab on the lower side of the floor slab;
A step (c) of integrating the column portion and the reinforcing wall;
An underpinning method comprising: The underpinning method according to claim 1, wherein the existing structure is a viaduct. The underpinning method according to claim 1, wherein in the step (b), the reinforcing wall is installed along the inner side of the column portion. In the step (c), concrete is wound up along the outer periphery of the pillar part, a PC steel rod is passed through the concrete and the reinforcing wall, and the pillar part and the reinforcing wall are integrated. The underpinning method according to claim 1, wherein The underpinning method according to claim 1, wherein a support pile is installed at a lower portion of the pressure-resistant plate at an end of a section where underpinning is performed. Opposing column portions are continuously provided, and an underpinning method for an existing structure that supports a floor slab with the column portions,
Improving the ground between the pillars to form a pile-like body, and improving the surface of the upper part of the pile-like body in a strip shape (a);
A step (b) of installing a first pressure-resistant plate on the ground improved in the step (a);
A step (c) of installing a reinforcing wall between the opposing pillars and a reinforcing slab on the lower side of the floor slab;
A step (d) of excavating the periphery of the footing portion of the pillar portion and removing the footing and the existing pile;
A step (e) of refilling a portion excavated in the step (d);
A step (f) of installing a second pressure-resistant plate on the portion backfilled in the step (e);
An underpinning method comprising: The underpinning method according to claim 6, wherein the existing structure is a viaduct. The underpinning method according to claim 6, wherein in the step (a), the pile body is formed by a high-pressure jet agitator. The underpinning method according to claim 6, wherein in the step (c), the reinforcing wall is installed along the inner side of the column portion. 7. The underpinning method according to claim 6, wherein a steel sheet pile is installed around the footing before the step (d), and the steel sheet pile is pulled out after the step (e). The underpinning method according to claim 6, wherein in the step (e), backfilling is performed using a soil cement. A high bridge characterized in that the foundation is replaced using the underpinning method according to any one of claims 1 to 11.

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