JP3904882B2 - Foundation structure that supports the structure on the existing roadbed and its construction method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a foundation structure that supports a structure on an existing roadbed surface and its construction method, and in particular, performs construction with high accuracy while suppressing mortar outburst, ground uplift and settlement of existing roadbed surface. The present invention relates to a foundation structure that supports a structure on an existing roadbed surface that reduces the construction cost of cast-in-place concrete piles, and its construction method.
[0002]
[Prior art]
As an example of a conventional foundation structure, as shown in FIG. 14, a foundation structure 30 is formed in the ground 5 below the existing roadbed surface 3 to support a structure on the roadbed surface such as a bridge 4 for a track. It was constructed by the following process.
(1) A pair of vertical shafts is constructed at a predetermined distance in the ground 5 below the existing roadbed surface 3.
(2) After injecting the chemical solution 14 in the horizontal direction from one of the pair of vertical shafts toward the propulsion embedding portion of the tubular steel pipe 31, the tubular steel pipe 31 is constructed in a gate shape and made of tubular steel. Concrete 32 is placed in the pipe 31.
(3) Horizontal or diagonally below one of the shafts so that the cylindrical steel pipe constructed in the gate type does not sink even if the inner surface of the portal type is excavated below the cylindrical steel pipe constructed in the portal type. The soil is improved by a soil cement improved body or the like that can be formed by cement milk injected into the ground and the local soil, and a work space 34 is formed by excavating the gate-shaped inner surface.
(4) After the cast-in-place concrete pile 36 is constructed toward the lower ground 35 of the work space 34, the concrete 37 is placed in the work space to integrate the tubular steel pipe 31 and the cast-in-place concrete pile 36. To do.
[0003]
In this construction example, although there is a merit that the ground is not loosened as a ground improvement method that allows horizontal construction, it is necessary to inject chemicals and improve the ground. It was necessary to construct so as not to loosen the ground while constructing the mold, so that the mortar would not erode and the ground would not rise, and the following points had to be dealt with carefully.
(1) Take measures to control the amount of subsidence on the existing roadbed.
(2) Take measures to confirm the improved ground strength.
(3) Take measures to prevent the construction period from reaching the long term.
[0004]
[Problems to be solved by the invention]
The present invention is proposed in order to alleviate the necessity in view of the problems of the above-mentioned example, and it is possible to suppress the occurrence of mortar outbreak, ground uplift or subsidence of existing roadbed surface due to ground improvement. In addition to constructing with precision, placing a ready-made pile at the lower end of the side wall of the gate-type support body prevents the subsidence of the existing roadbed surface when forming a working space for cast-in-place concrete piles in the gate-type support body. After formation of cast-in-place concrete piles, the structure on the existing roadbed surface that can support the structure on the existing roadbed surface and reduce the scale of the cast-in-place concrete piles, such as the diameter and number of piles, to reduce the overall cost. We provide foundation structures that support objects and their construction methods.
[0005]
[Means for Solving the Problems]
  The foundation structure that supports the structure on the existing roadbed surface according to claim 1 is configured in the ground below the existing roadbed surface, and supports the structure on the existing roadbed surface.BecauseThe gate-type support body installed between the side walls of the gate-type support body buried in the ground below the existing roadbed surface and the plurality of pre-made piles and the gate-type support body arranged at the lower end of the side wall of the gate-type support body. From cast-in-place concrete piles that are united withThe cast-in-place concrete pile is composed of concrete filled in the space formed between the two side walls of the gate-type support, and is united with the gate-type support.It is constructed and eliminates the need for ground improvement work, so it can be constructed with high accuracy by suppressing the occurrence of mortar, ground uplift and subsidence of the road surface support mechanism, and the diameter of cast-in-place concrete piles can be reduced.In addition, the strength of the foundation structure is secured.
[0006]
The foundation structure for supporting the structure on the existing roadbed surface according to the invention described in claim 2 is the foundation structure according to claim 1, wherein the gate-type support is embedded in the ground below the existing roadbed surface. In addition to the above functions, the durability of the foundation structure is improved.
[0007]
The foundation structure supporting the structure on the existing roadbed surface according to claim 3 is the foundation structure according to claim 1 or 2, wherein the filled concrete tubular steel pipe is perpendicular to the tubular steel pipe axis. It is possible to transmit horizontal force in the direction, and it is characterized in that it is rigidly connected to the upper end of a prefabricated pile embedded in the vertical direction of the ground at the lower end of the side wall of the portal support. The stability of the structure is secured by controlling the amount of settlement of the structure.
[0009]
  Claim 4Method of construction of foundation structure supporting structure on existing roadbed surface which is invention described inBelow the existing roadbedA process for forming a work space at the lower end of the side wall of the gate support, and forming a plurality of ready-made piles in the vertical direction from the work space to the lower ground. Process, filling the work space at the lower end of the side wall of the gate-type support body with concrete, integrating the gate-type support body and the ready-made pile, forming the work space between both side walls of the gate-type support body, It consists of a step of constructing a cast-in-place concrete pile in the vertical direction of the lower ground from the work space and a step of filling the work space of the gate-type support body with concrete and integrally connecting the gate-type support body and the cast-in-place concrete pile, The foundation structure is constructed safely and with high accuracy while suppressing dredging of the mortar, uplift of the ground, and subsidence of the road surface support mechanism without the need for ground improvement work.
[0010]
  Claim 5The construction method of the foundation structure that supports the structure on the existing roadbed surface that is the invention described inClaim 4In the construction method of the foundation structure described in the above, the ceiling and the ceiling of the gate-shaped support body, in which the work space formed at the gate-shaped support body and the lower end portion of the side wall is filled with a tubular steel pipe made of filled concrete in the horizontal direction. In addition to the above functions, subsidence is made up of a work space formed on the side wall of a portal-type support body in which a cylindrical steel pipe made of filled concrete is embedded in the vertical direction. A stable construction state is maintained while restrained.
[0011]
  Claim 6The construction method of the foundation structure that supports the structure on the existing roadbed surface that is the invention described inClaim 4 or 5In the construction method of the foundation structure described in 1., the ready-made piles divided by using the jack device arranged on the upper surface of the work space formed at the lower end of the side wall are press-fitted in the vertical direction toward the lower ground in order while adding In addition to the above functions, the construction of ready-made piles is made smooth and reliable while avoiding settlement of the foundation structure.
[0012]
  Claim 7The construction method of the foundation structure that supports the structure on the existing roadbed surface that is the invention described inClaims 4 to 6In the construction method of the foundation structure according to any one of the above, the step of forming a work space between both side walls of the gate-type support is calculated by calculating the amount of subsidence at the ceiling of the gate-type support made of filled concrete tubular steel pipe. It is characterized by excavating the internal ground of the portal support while measuring, and in addition to the above functions, the subsidence of the foundation structure is suppressed and stable support of the structure on the existing roadbed surface is ensured. I have to.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The foundation structure for supporting the structure on the existing roadbed surface according to the present invention is basically configured in the ground below the existing roadbed surface, and the foundation structure for supporting the structure on the existing roadbed surface is the above-mentioned existing structure. A gate-type support buried in the ground below the roadbed surface, a plurality of prefabricated piles arranged at the lower end of the side wall of the gate-type support, and a gate-type support installed between both side walls of the gate-type support Concretely, it is composed of cast-in-place concrete piles that are bonded to the concrete. Specifically, the portal support is composed of a combination of filled concrete tubular steel pipes embedded in the ground below the existing roadbed surface. The concrete tubular steel pipe is capable of transmitting a horizontal force in the direction perpendicular to the tubular steel pipe axis, and is rigidly joined to the upper end of a prefabricated pile buried in the vertical direction of the ground at the lower end of the side wall of the portal support. Cast a cast-in-place concrete pile between both side walls of a gate-type support Has the feature that the coupling together with the gate-shaped support of concrete filled in the space to be.
[0014]
In the following, an embodiment of a foundation structure for supporting a structure on an existing roadbed surface according to the present invention will be described in detail with reference to the drawings. However, in order to facilitate understanding, the same parts are the same as in the conventional example. Is used.
[0015]
FIG. 1 shows an embodiment in which a foundation structure for supporting a structure on an existing roadbed surface according to the present invention is applied to a railway bridge, and only one side of the railway bridge is shown in cross section.
[0016]
In the figure, the foundation structure 1 supports the bridge 4 for a track constructed on the existing roadbed surface 3 having a large span because it crosses over the road 2 at both ends.
[0017]
The foundation structure 1 includes a plurality of gate-type supports 6 embedded in the ground 5 of the existing roadbed surface 3 and a plurality of lower ends 8 of the side walls 7 and 7 constituting the gate-type support 6. The cast-in-place pile 9 and the cast-in-place concrete pile 26 are integrated with the gate-type support 6 by placing the concrete 37 by placing the concrete 37 inside the gate-type support 6.
[0018]
The gate-type support body 6 is composed of a ceiling portion 12 formed by connecting filled concrete tubular steel pipes 11 in the horizontal direction and side walls 7 and 7 formed by vertically stacking on both sides of the ceiling portion 12. ing. The filled concrete tubular steel pipes 11 arranged in the horizontal direction as the ceiling portion 12 and laminated in the vertical direction as the side walls 7 and 7 have a horizontal force and a compressive force in the vertical direction in the direction perpendicular to the tubular steel pipe axis. It is firmly connected so that it can be transmitted, and the holding force for the bridge 4 for the line is reinforced by forming a gate shape.
[0019]
A plurality of ready-made piles 9 embedded in the vertical direction of the ground are respectively arranged at the lower ends 8 of the side walls 7, 7 formed on both sides of the gate-type support 6. The upper end of the ready-made pile 9 is integrated by rigid joining, and the gate-type support body 6 is supported by the ready-made pile 9, thereby preventing the foundation structure 1 from sinking.
[0020]
The formation of the filled concrete tubular steel pipe 11 can adopt various forms such as an embedding method of a PC steel pipe pile and a method of filling concrete after drilling only the tubular steel pipe, but in any form, If it is a form which can establish the function which can transmit the horizontal force in the orthogonal direction of a cylindrical steel pipe axis, and the compressive force of a perpendicular direction, the portal support body 6 with which the foundation structure 1 is comprised can be constructed | assembled.
[0021]
The gate-type support body 6 has a plurality of ready-made piles 9 rigidly joined to the lower end portions 8 of the side walls 7 and 7 formed on both sides as described above to prevent the settlement thereof, and the inside of the gate-type support body 6 The cast-in-place concrete piles 26 are arranged in the base, and the gate-type support body 6 and the cast-in-place concrete piles 26 are integrated by the concrete 37 filled, whereby the foundation structure 1 is combined with the plurality of ready-made piles 9 and the cast-in-place concrete. The pile 26 can be supported and complemented with each other to form a solid form.
[0022]
As is clear from the detailed description based on the above embodiments, the foundation structure according to the present invention, together with support by a plurality of ready-made piles arranged on the gate-type support body, eliminates the need for ground improvement work. As a result, it is possible to suppress the occurrence of mortar, the rise of the ground and the subsidence of the road surface support mechanism with high accuracy, and it is possible to reduce the diameter of the cast-in-place concrete pile while improving the strength and durability.
[0023]
Next, the construction method of the foundation structure which supports the structure on the existing roadbed surface by this invention is demonstrated.
[0024]
The construction method according to the present invention basically comprises a gate-type support body embedded horizontally in the ground below the existing roadbed surface, and a work space is formed at the lower end of the side wall of the gate-type support body. A step of press-fitting a plurality of ready-made piles in a vertical direction from the bottom to the ground, a step of filling the work space at the lower end of the side wall of the gate-type support body and integrating the gate-type support body and the ready-made piles, The process of forming a working space between both side walls of the gate-type support, the process of building a cast-in-place concrete pile from the work space in the vertical direction of the lower ground, and the work space of the gate-type support are filled with concrete to support the gate It consists of the process of integrally joining the body and cast-in-place concrete pile, specifically, the work space formed at the gate-type support and the lower end of the side wall is filled with a filled concrete tubular steel pipe in the horizontal direction From the ceiling and the ceiling of the portal support It consists of a work space formed in the side wall of the gate-type support body and the lower end of the side wall formed by embedding a cylindrical steel pipe made of filled concrete, and press-fitting the prefabricated pile in the vertical direction toward the lower ground Filled concrete cylinder is a process of forming a working space between both side walls of a gate-type support body by sequentially carrying out a prefabricated pile divided using a jack device arranged on the upper surface of the working space formed in the section It is characterized by excavating the internal ground of the portal support while measuring the amount of settlement at the ceiling of the portal support composed of a steel pipe.
[0025]
Below, embodiment of the construction method by this invention is described in detail based on FIGS.
[0026]
FIG. 2 is a cross-sectional view of a shaft constructed on both sides of a planned construction portion of a gate-type support before the foundation structure is constructed in the ground below the existing roadbed surface.
[0027]
In the present embodiment, the railway bridge 4 is constructed on the upper surface of the existing roadbed surface 3, and the left and right sides of the railway bridge 4 have a portal type on the existing roadbed surface 3 on both sides of the railway bridge 4. In order to carry out operations such as constructing a support body, a pair of shafts 13 and 13 are constructed on the front and rear sides across the planned construction part of the gate-type support body.
[0028]
FIG. 3 is a cross-sectional view below the existing roadbed surface for constructing the gate-type support of the foundation structure.
In this process, the steel pipe propulsion is performed by injecting the chemical solution 14 from each vertical shaft 13 in the horizontal direction to the planned part for constructing the gate support as a countermeasure against water stoppage at the time of steel pipe propulsion excavation. The drilling is safe.
[0029]
The gate-type support 6 is composed of a ceiling portion 12 and side walls 7 and 7 constituting both sides thereof. In this embodiment, a concrete steel tubular steel pipe filled in the ground of a reinforced existing roadbed surface 5 is used. By embedding 11 in the horizontal direction, the portal support 6 is configured.
[0030]
The ceiling 12 of the portal support 6 is formed by embedding a filled concrete cylindrical steel pipe 11 in the horizontal direction and firmly bonding the horizontal force in the direction perpendicular to the cylindrical steel pipe axis so that they can be transmitted to each other. Has been. Similarly, the side wall 7 of the gate-type support 6 is configured so that a compressive force can be transmitted by vertically laminating a cylindrical steel pipe 11 made of filled concrete, but is positioned at the lower end portion 8 of the side wall 7. With respect to the individual cylindrical hollow steel pipes 15, 15, the work space 16 is configured without filling with concrete.
[0031]
The burial of the cylindrical hollow steel pipe 15 employs a construction method different from that of the filled concrete cylindrical steel pipe 11, and in this embodiment, as shown in FIG. The tubular hollow steel pipe 15 is pulled by the traction devices 17 ′ and 17 ′. A drilling device 18 is provided at the tip of the cylindrical hollow steel pipe 15, and exhibits the advantage of being able to construct the cylindrical hollow steel pipe 15 at high speed and with high accuracy.
[0032]
Therefore, the burying of the cylindrical hollow steel pipe 15 can be adopted also when the ceiling portion 12 and the side walls 7 and 7 in the above-mentioned gate-type support body 6 are configured, and as shown in FIG. Instead of embedding the concrete tubular steel pipe 11, it is also possible to implement a construction method in which a tubular hollow steel pipe 15 is first buried and then filled with concrete 19 to be equivalent to the filled concrete tubular steel pipe 11. .
[0033]
In the construction method of the foundation structure according to the present invention, a process of press-fitting a plurality of ready-made piles after forming a work space at the lower end of the side wall of the gate-type support is adopted. It is constructed as shown.
[0034]
FIG. 6 shows a process of constructing a ready-made pile from the work space formed at the lower end of the side wall of the portal support.
[0035]
In this process, the vertical ready-made pile 9 is press-fitted from the work space 16 formed in the two cylindrical hollow steel pipes 15 and 15 located at the lower end portion 8 of the side wall 7 toward the lower ground. The press-fitting of the ready-made pile 9 is sequentially performed by adding the divided straight pipes 21 while using the jack device 20 disposed on the upper surface of the work space 16, and the supporting force of the existing pile 9 at the time of the press-fitting. Is measured.
[0036]
When the ready-made pile 9 is press-fitted to a predetermined depth, the gate-type support body and the ready-made pile are integrated, and these steps are shown in FIG.
[0037]
Fig.7 (a) is sectional drawing which shows the state with which the gate-type support body and the ready-made pile were integrated, FIG.7 (b) is an enlarged view in the (B) part of Fig.7 (a), FIG.7. FIG. 7C is an enlarged view of a portion (C) of FIG.
[0038]
Since the cylindrical hollow steel pipes 15 and 15 forming the work space 16 are punched through the bottom plate between them, the prefabricated pile is press-fitted. 7 (b), the hole is filled with a lid 22.
[0039]
On the other hand, FIG. 7C shows a state in which the fixing mechanism 23 is used to integrate the lower end portion 8 of the side wall 7 and the tip of the ready-made pile 9 and is covered by the lid member 24 after construction. ing.
[0040]
After the above construction is performed, the entire work space 16 is filled with the filled concrete 25 as shown in FIG. 7A, and the gate-type support 6 and the ready-made pile 9 are integrated. It is configured.
[0041]
FIG. 8 shows a process of forming a working space for constructing a cast-in-place concrete pile inside the gate-type support, which is performed after the gate-type support is constructed.
In order to construct a cast-in-place concrete pile inside the gate-type support 6 as the next step, when the gate-type support 6 is integrated with the ready-made pile 9 and the installation in the ground is firmly configured A work space 10 is formed.
[0042]
The work space 10 is formed by establishing the installation state of the both side walls by supporting the ready-made piles 9, so that the support state of the gate-type support body 6 is firm, and intrinsically safe construction is possible.
[0043]
However, in the construction method of the foundation structure according to the present invention, in addition to this, the amount of settlement is within the safe range by measuring the ceiling portion 12 of the gate-type support 6 made of the filled concrete tubular steel pipe 11. The excavation work is being promoted while excavating the internal ground of the gate-type support body while confirming this, and further confirming its safety.
[0044]
FIG. 9 shows a process of constructing a cast-in-place concrete pile inside the portal support.
[0045]
The construction of the cast-in-place concrete pile 26 is performed by a normal construction method with the chemical injection 14 as necessary. However, the work space 10 formed inside the portal support 6 has both side walls 7, 7. However, since the installation state is established by the support of the ready-made pile 9, the support state of the gate-type support body 6 is firm, and the safe construction of the cast-in-place concrete pile 26 is enabled.
[0046]
The cast-in-place concrete pile 26 to be constructed at this time is combined with a complementary function of the ready-made pile 9 supporting the gate-type support body 6 and the scale of the pile diameter, the number of piles, etc. is compared with the conventional one. This makes it possible to significantly reduce the cost of the foundation structure.
[0047]
FIG. 10 shows a process of filling the inside of the gate-type support with concrete and integrating the gate-type support and the cast-in-place concrete pile.
[0048]
When the construction of the cast-in-place concrete pile 26 is completed in the work space 10, the concrete 37 is placed in the work space 10, and the head of the cast-in-place concrete pile 26 and the portal support 6 are integrated. It is illustrated.
[0049]
When the gate-type support body 6 is configured in the ground 5 below the existing roadbed surface 3 by the above process, the ready-made pile 9 and the cast-in-place concrete pile 26 are ready-made piles as seen in the plan view of FIG. A cast-in-place concrete pile 26 is installed inside the gate-type support 6 at the same time as 9 is installed along the both side walls 7, 7 of the gate-type support 6.
[0050]
As a result, the foundation structure 1 is configured integrally with the gate-type support 6, the ready-made pile 9 and the cast-in-place concrete pile 26, and when the ready-made pile 9 forms a work space for the cast-in-place concrete pile, the existing road After the formation of cast-in-place concrete piles, the structure of the cast-in-place concrete piles 26 is supported together with the structure of the cast-in-place concrete piles 26. It is decided by balance.
[0051]
Accordingly, the foundation structure 1 reliably prevents the gate-type support 6 from sinking by the action of the ready-made pile 9 and the cast-in-place concrete pile 26 without requiring conventional construction means such as ground improvement. Since the foundation structure 1 supports the structure on the existing roadbed surface by the pre-made pile 9 and the cast-in-place concrete pile 26, the scale of the cast-in-place concrete pile such as the pile diameter and the number of piles can be increased. The total cost is reduced by reducing the cost compared to the conventional one.
[0052]
The process shown in FIGS. 12 and 13 is to complete a foundation structure and replace it with a new girder, and is constructed by a method similar to the conventional method.
[0053]
FIG. 12 shows a step of removing the shaft, and thereafter, a construction girder 27 is installed on the existing roadbed surface 3 so as not to affect the railway bridge 4. FIG. 13 shows a state in which a new support state is formed with respect to the railway bridge 4, and it is installed horizontally between the foundation structures 1 and 1 installed on both sides of the railway bridge 4. The new girder 28 is replaced by a construction method, a carrier construction method, or the like.
[0054]
As described above, the construction method of the foundation structure for supporting the structure on the existing roadbed surface according to the present invention comprises the gate-type support body embedded in the horizontal direction in the ground below the existing roadbed surface, The process of forming a work space at the lower end of the side wall of the body, the process of press-fitting a plurality of ready-made piles in the vertical direction from the work space to the lower ground, and filling the work space of the lower end of the side wall of the portal support with concrete The process of integrating the gate-type support and the ready-made pile, the process of forming a work space between the both side walls of the gate-type support, the process of constructing a cast-in-place concrete pile in the vertical direction of the lower ground from the work space, and the gate Since the work space of the mold support is filled with concrete and the gate support and cast-in-place concrete piles are joined together, there is no need for ground improvement work, and mortar eruption, ground uplift and roadbed surface Suppress the settlement of the support mechanism , And applying a substructure safely and accurately.
[0055]
As described above, the present invention has been described in detail on the basis of the embodiment. However, the foundation structure and the construction method according to the present invention are not limited to the above embodiment, and the form of the portal support or It goes without saying that various modifications can be made to the specific construction method and the like without departing from the spirit of the present invention.
[0056]
【The invention's effect】
  The foundation structure that supports the structure on the existing roadbed surface according to claim 1 is configured in the ground below the existing roadbed surface, and supports the structure on the existing roadbed surface.BecauseThe gate-type support body installed between the side walls of the gate-type support body buried in the ground below the existing roadbed surface and the plurality of pre-made piles and the gate-type support body arranged at the lower end of the side wall of the gate-type support body. From cast-in-place concrete piles that are united withThe cast-in-place concrete pile is composed of concrete filled in the space formed between the two side walls of the gate-type support, and is united with the gate-type support.Since it is comprised, combined with the support by the ready-made pile arrange | positioned at the side wall lower end part of the gate-type support body, it has the following effects by making a ground improvement construction unnecessary.
1. Construction can be done without loosening the ground.
2. Does not cause mortar outbursts and ground uplifts like ground improvement.
3. Construction can be performed with high accuracy by suppressing the settlement of the existing roadbed surface.
4). The ready-made piles prevent settlement of the existing roadbed surface until the work space is formed, and after the cast-in-place concrete piles are formed, the structures on the existing roadbed surface are supported together and the pile diameter, number of piles, etc. Can be reduced.
5. The overall cost of the foundation structure can be reduced.
6). The strength of the foundation structure can be secured.
[0057]
The foundation structure for supporting the structure on the existing roadbed surface according to the invention described in claim 2 is the foundation structure according to claim 1, wherein the gate-type support is embedded in the ground below the existing roadbed surface. In addition to the above-described effects, it has the effect of improving the durability of the foundation structure.
[0058]
The foundation structure supporting the structure on the existing roadbed surface according to claim 3 is the foundation structure according to claim 1 or 2, wherein the filled concrete tubular steel pipe is perpendicular to the tubular steel pipe axis. In addition to the above effects, it is possible to transmit horizontal force in the direction and is rigidly connected to the upper end of a prefabricated pile buried in the vertical direction of the ground at the lower end of the side wall of the portal support. It has the effect of suppressing the amount of settlement of the foundation structure and ensuring stability.
[0060]
  Claim 4Method of construction of foundation structure supporting structure on existing roadbed surface which is invention described inBelow the existing roadbedA process for forming a work space at the lower end of the side wall of the gate support, and forming a plurality of ready-made piles in the vertical direction from the work space to the lower ground. Process, filling the work space at the lower end of the side wall of the gate-type support body with concrete, integrating the gate-type support body and the ready-made pile, forming the work space between both side walls of the gate-type support body, Because it consists of the process of building cast-in-place concrete piles in the vertical direction of the lower ground from the work space, and the process of filling the work space of the gate-type support body with concrete and integrally joining the gate-type support body and the cast-in-place concrete pile. Combined with the support by the ready-made piles arranged at the lower end of the side wall of the gate-type support body, the following effects are achieved by making the ground improvement work unnecessary.
1. Construction can be done without loosening the ground.
2. Does not cause mortar outbursts and ground uplifts like ground improvement.
3. It is possible to confirm the bearing capacity of the ready-made piles at the current position in advance, and to form a state that does not sink when constructing the work space by excavating the inside of the portal support.
4). By measuring the amount of settlement, construction can be performed while confirming the construction state so that the portal support does not sink even if an unexpected state occurs.
5. Construction can be performed with high accuracy by suppressing the settlement of the existing roadbed surface.
6). The ready-made piles prevent settlement of the existing roadbed surface until the work space is formed, and after the cast-in-place concrete piles are formed, the structures on the existing roadbed surface are supported together and the pile diameter, number of piles, etc. Can be reduced.
7). The overall cost of the foundation structure can be reduced.
8). The construction period can be shortened.
[0061]
  Claim 5The construction method of the foundation structure that supports the structure on the existing roadbed surface that is the invention described inClaim 4In the construction method of the foundation structure described in the above, the ceiling and the ceiling of the gate-shaped support body, in which the work space formed at the gate-shaped support body and the lower end portion of the side wall is filled with a tubular steel pipe made of filled concrete in the horizontal direction. In addition to the above effects, the subsidence is characterized by comprising a working space formed on the side wall of the portal-type support body formed by embedding a filled concrete tubular steel pipe vertically from the side and the lower end of the side wall. There is an effect that can maintain a stable construction state while suppressing.
[0062]
  Claim 6The construction method of the foundation structure that supports the structure on the existing roadbed surface that is the invention described inClaim 4 or 5In the construction method of the foundation structure described in 1., the ready-made piles divided by using the jack device arranged on the upper surface of the work space formed at the lower end of the side wall are press-fitted in the vertical direction toward the lower ground in order while adding Therefore, in addition to the above-described effects, the present invention has the effect of smoothly and reliably constructing the ready-made piles while avoiding the settlement of the foundation structure.
[0063]
  Claim 7The construction method of the foundation structure that supports the structure on the existing roadbed surface that is the invention described inClaims 4 to 6In the construction method of the foundation structure according to any one of the above, the step of forming a work space between both side walls of the gate-type support is calculated by calculating the amount of subsidence at the ceiling of the gate-type support made of filled concrete tubular steel pipe. Since it is characterized by excavating the internal ground of the portal support while measuring, in addition to the above effects, the subsidence of the foundation structure is suppressed and stable support of the structure on the existing roadbed surface is provided. Has the effect of ensuring.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment in which a foundation structure for supporting a structure on an existing roadbed surface according to the present invention is applied to a bridge for a track.
[Figure 2] Cross-sectional view of the shaft built in the ground below the existing roadbed surface
[Fig. 3] A cross-sectional view below the existing roadbed to construct a portal support
FIG. 4 is a diagram showing an embodiment in which a cylindrical hollow steel pipe is pulled from a shaft on the arrival side
FIG. 5 shows an embodiment of filling concrete after embedding a cylindrical hollow steel pipe
FIG. 6 is a process diagram for constructing a ready-made pile from the work space formed at the lower end of the side wall of the portal support.
FIG. 7 is a cross-sectional view showing a state in which the gate-type support body and the ready-made pile are integrated.
FIG. 8 is a process diagram for forming a work space inside the portal support.
[Fig. 9] Process diagram for placing cast-in-place concrete piles inside the portal support
FIG. 10 is a process diagram for filling concrete inside a portal support.
[Fig. 11] Installation plan view of ready-made piles on the portal support
[Figure 12] Process diagram for installing work girders between foundation structures
[Fig. 13] Process diagram for bridging a new girder between foundation structures
[Fig. 14] Cross-sectional view of conventional construction of foundation structure
[Explanation of symbols]
1 foundation structure, 2 road, 3 existing roadbed surface, 4 bridge for railway,
5 Ground, 6 Gate-type support body, 7 Side wall, 8 Lower end, 9 Ready-made pile,
10 working space, 11 filled concrete tubular steel pipe, 12 ceiling part,
13 shafts, 14 chemical injection, 15 cylindrical hollow steel pipe, 16 working space,
17 PC steel strand, 17 'traction device, 18 drilling device,
19 concrete, 20 jacking equipment, 21 ready-made piles, 22 lids,
23 Fixing mechanism 24 Cover material 25 Filled concrete
26 Cast-in-place concrete piles, 27 construction girders, 28 new girders,
30 substructure, 31 tubular steel pipe, 32 concrete,
33 ground improvement, 34 working space, 35 lower ground,
36 concrete piles, 37 concrete,

Claims (7)

A base structure that is configured in the ground below the existing roadbed surface and supports a structure on the existing roadbed surface, and is embedded in the ground below the existing roadbed surface, and the gate-type support body The cast-in-place concrete is composed of a plurality of ready-made piles arranged at the lower end of the side wall of the door and a cast-in-place concrete pile installed between both side walls of the gate-type support and integrally coupled to the gate-type support. The pile is a concrete structure that supports the structure on the existing roadbed surface, which is concretely connected to the gate-type support with concrete filled in the space formed between both side walls of the gate-type support .   2. A foundation for supporting a structure on an existing roadbed surface according to claim 1, wherein the gate-type support is formed by joining cylindrical steel pipes made of filled concrete embedded in the ground below the existing roadbed surface. Structure.   Filled concrete tubular steel pipe enables transmission of horizontal force in the direction perpendicular to the tubular steel pipe axis, and rigidly joins the upper end of a prefabricated pile buried in the vertical direction of the ground at the lower end of the side wall of the portal support The foundation structure which supports the structure on the existing roadbed surface of Claim 1 or 2 characterized by the above-mentioned. A step of forming a gate-type support body embedded horizontally in the ground below the existing roadbed surface, and forming a work space at the lower end of the side wall of the gate-type support body, vertically extending from the work space toward the lower ground A step of press-fitting a plurality of ready-made piles, a step of filling the work space at the lower end of the side wall of the gate-type support body with concrete, and integrating the gate-type support body and the ready-made piles; A step of forming a work space in between, a step of constructing a cast-in-place concrete pile from the work space in the vertical direction of the lower ground, and filling the work space of the gate-type support with concrete to form a gate-type support and cast-in-place concrete A construction method for a foundation structure that supports a structure on an existing roadbed surface characterized by comprising a step of integrally joining a pile. The work space formed at the gate-type support and the lower end of the side wall is the ceiling of the portal-type support formed by embedding a filled concrete tubular steel pipe in the horizontal direction, and the filled concrete tubular steel pipe is vertically extended from the ceiling. 5. A foundation for supporting a structure on an existing roadbed surface according to claim 4 , comprising a side wall of a gate-type support body embedded in a direction and a work space formed at a lower end portion of the side wall. Construction method of structure. The press-fitting of the ready-made pile in the vertical direction toward the lower ground is sequentially performed while adding the ready-made pile divided using the jack device arranged on the upper surface of the work space formed at the lower end of the side wall. The construction method of the foundation structure which supports the structure on the existing roadbed surface of Claim 4 or 5 . The process of forming a work space between both side walls of the portal support is to excavate the internal ground of the portal support while measuring the amount of settlement at the ceiling of the portal support made of filled concrete tubular steel pipe The construction method of the foundation structure which supports the structure on the existing roadbed surface in any one of Claims 4 thru | or 6 characterized by these.

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