JP4473400B2 - Foundation of construction and construction method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a foundation structure for supporting various structures such as a steel tower that supports an overhead transmission line.
[0002]
[Prior art]
As a foundation structure for supporting a pillar base such as a steel tower on a natural ground, a foundation pile such as that shown in FIG. 13 is conventionally known. First, a foundation structure 100A shown in FIG. 1 (A) includes a foundation pile 102 made of a steel pile or cast-in-place concrete pile placed on a natural ground G, and a footing made of concrete combined with the pile head 102a. The column base 101 is constructed on the footing 103. One or a plurality of foundation piles 102 are usually placed vertically per footing 103.
[0003]
In addition, the foundation structure 100B shown in FIG. 13B is constructed by vertically constructing a foundation pile 102 made of a large-diameter cast-in-place concrete pile on the natural ground G and embedding the lower end portion of the column base 101 in the pile head. Are combined. The foundation pile 102 is placed in a vertical frame portion 102b formed of reinforced concrete and a steel pipe 102c extending from the head so as to be exposed on the natural ground G, and reinforces and protects the lower portion of the column base 101. It consists of column part 102d.
[0004]
[Problems to be solved by the invention]
By the way, in recent years, for example, in the case of a transmission tower, in order to compensate for an increase in the amount of slack in the transmission line due to an increase in the weight of the transmission line accompanying an increase in power demand, it is necessary to increase the support height of the transmission line. For this reason, the height of the steel tower tends to increase. As a result, the weight of the steel tower increases, and it is required to improve the supporting force of the foundation structure that supports the tower. However, according to the prior art shown in FIG. 13 above, it is necessary to increase the area of the footing 103 or increase the diameter of the foundation pile 102 in order to improve the supporting force of the foundation structure. In addition to the high construction cost, there was a problem that land with a large area had to be secured.
[0005]
Also, since large construction machines are required to construct large-diameter foundation piles, for example, in the case of steel towers built on mountain slopes, the cutting area for securing the construction machinery can be increased. The temporary construction of the scaffolding has also become a major issue, and construction difficulties and construction costs have increased.
[0006]
The present invention has been made in view of the above-described problems, and a main technical problem thereof is to provide a foundation structure that has a large proof strength against a load of a structure and that can be easily constructed.
[0007]
[Means for Solving the Problems]
As means for effectively solving the above technical problem, the foundation of the structure according to the present invention is laid on the bottom of the foundation material integrally provided at the bottom of the pillar of the structure , An iron plate having a larger area than the axial projection area of the base material and a pile head were joined to the base material, and were placed in the direction parallel to the pillars to the ground through a base pile insertion hole established in the iron plate One or a plurality of foundation piles or pile heads are connected to the foundation material, and are driven to the ground via the foundation pile insertion holes in a direction opened at an equal angle around the extension line of the axis of the column. And a plurality of foundation piles. In other words, by placing the foundation pile in the direction parallel to the column or in the direction opened at an equal angle around the axis of the column, only the axial force of the load of the structure is supported, and footing etc. Since it is not constructed, the construction becomes easy and the construction area can be reduced.
[0008]
In the present invention, the foundation material is provided in advance integrally with a lower portion of the column and extends in the axial direction of the column, and is previously provided integrally with the lower portion of the column and the rib and the axis of the column. It can be set as the structure which consists of a main body flange which makes a surface orthogonal to, and a coupling member group which couple | bonds the pile head of a foundation pile with the said main body flange.
[0009]
Further, the construction method of the foundation of the structure according to the present invention includes a step of integrally providing a foundation material provided with a coupling means with a pile head at a lower part of the column, and an axial direction of the foundation material at a planned construction position on the ground. A step of laying a steel plate having a foundation pile insertion hole having a larger area than the projected area , and an axis of the pillar from the planned construction position of the column on the ground into the ground through the foundation pile insertion hole of the iron plate A step of placing a plurality of foundation piles in a direction parallel to the center or a direction opened at an equal angle around the planned angle of building the pillar, and building the column at a planned construction position on the ground, It comprises the step of coupling the foundation material provided integrally therewith to the pile head of the foundation pile protruding from the foundation pile insertion hole of the iron plate via the coupling means .
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, a preferred embodiment of the foundation of the structure according to the present invention will be described with reference to FIGS. First, FIG. 1 schematically shows the basic structure of the present invention together with a part of a power tower constructed thereon. Reference numeral 10 in the figure is a tower base of the tower, and 20 is this pillar base 10. The foundation material which consists of steel materials etc. which were joined to the lower end of No. 1 and 30 is a foundation pile which pile head 30a was combined with the foundation material 20, and was laid in the direction parallel to the column base 10 to the natural ground G. .
[0011]
The base material 20 is a steel plate integrally joined to the lower outer periphery of the column base 10 in a feather shape by welding at a predetermined interval in the circumferential direction (90 ° interval in the illustrated example) so as to form a planar shape passing through the axis. A plurality of ribs 21, a square body flange 22 made of a steel plate integrally joined to the lower outer periphery of the column base 10 by welding so as to form a plane perpendicular to the axis thereof, and the ribs 21. The coupling member group 23 provided in the said main body flange 22 is provided in the area | region divided into four. Each rib 21 has a lower end that reaches the lower end position of the column base 10 and is joined to the main body flange 22 at right angles. Moreover, these members which comprise the base material 20 are rust-prevented by plating or painting or spraying after construction.
[0012]
The foundation material 20 is for connecting the lower part of the column base 10 and the pile head of the foundation pile 30 and for transmitting the load of the steel tower from the column base 10 to the natural ground G and the foundation pile 30. . Further, the column base 10 of the steel tower is built so as to make a predetermined inclination angle with respect to the horizontal plane, but the foundation pile 30 is placed so as to be parallel to the column base 10. It becomes the structure where the bending stress by the load of a steel tower is hard to act between the foundation pile 30 and the foundation pile 30, and the outstanding proof stress with respect to a load is obtained.
[0013]
Further, as shown in FIG. 10 described later, an iron plate 4 having a larger area than that of the main body flange 22 can be laid on the lower surface of the base material 20 so that a larger load can be supported.
[0014]
On the other hand, as the foundation pile 30, a relatively small diameter (for example, 300 mm or less) having a known structure and a high proof stress is preferably used. That is, as shown in FIG. 3, the foundation pile 30 is inserted to the lower end depth of the soft layer G <b> 1 in the natural ground G, and the head is inserted into the main body flange 22 of the foundation material 20 via the coupling member group 23. The steel pipe 31 and the inner periphery of the steel pipe 31 are inserted, the lower end reaches into the solid support layer G2 below the soft layer G1, and the head is connected to the main body flange 22 respectively. 23, a deformed rebar 32 as a core material connected through 23, and a grout 33 as a solidified material filled between the steel pipe 31 and the natural ground G and the deformed rebar 32. The grout 33 is diffused in the form of a pedestal on the lower side of the steel pipe 31 (in the support layer G2), and a part of the grout 33 wraps around the outer peripheral side of the steel pipe 31 to form the drilling surface of the natural ground G Has been established.
[0015]
As shown in FIG. 4 to FIG. 6, various coupling structures of the base material 20 and the foundation pile 30 are illustrated, and the base flange 20 of the base material 20 is divided into four areas by the ribs 21. A coupling hole 22a through which the steel pipe 31 of the pile 30 can be inserted with appropriate play is provided.
[0016]
Among these, in the example shown in FIG. 4, the coupling member group 23 is steel that is fixed to the outer periphery in the vicinity of the head of the steel pipe 31 in the foundation pile 30 by welding or the like so as to be positioned below the main body flange 22. A lower flange 231 made of steel, an upper flange 232 made of steel fixed by welding or the like to the outer periphery of the head of the steel pipe 31 protruding from the coupling hole 22a to the upper side of the main body flange 22, and an upper portion of the upper flange 232 And a steel bearing plate 234 that holds the pile head of the foundation pile 30 with the upper flange 232 sandwiched between the main body flange 22 and the plurality of screw members 233. A screw hole 234a is formed at the center of the support plate 234, and the head of the deformed reinforcing bar 32 in the foundation pile 30 is screwed into the screw hole 234a so that it is coupled to the support plate 234. It has become.
[0017]
Further, in the example shown in FIG. 5, the coupling member group 23 is made of steel fixed by welding or the like to the outer periphery in the vicinity of the head portion of the steel pipe 31 in the foundation pile 30 so as to be positioned below the main body flange 22. The lower flange 231 and the head of the steel pipe 31 protruding from the coupling hole 22a to the upper side of the main body flange 22 are disposed so that the outer peripheral lower surface is in contact with the main body flange 22, and the main body flange is welded or the like. A pair of nuts that join the head of the deformed reinforcing bar 32 in the foundation pile 30 to the inserted state into a steel supporting cap 235 fixed to the steel 22 and a reinforcing bar insertion hole 235a opened at the upper center of the supporting cap 235. 236, 236.
[0018]
Further, in the example shown in FIG. 6, the coupling member group 23 is made of steel that is fixed to the outer periphery in the vicinity of the head portion of the steel pipe 31 in the foundation pile 30 by welding or the like so as to be positioned below the main body flange 22. A lower flange 231, a steel upper flange 232 fixed by welding or the like to the outer periphery of the head of the steel pipe 31 protruding from the coupling hole 22 a to the upper side of the main body flange 22, and on the upper flange 232 A steel bearing plate 234 that presses the pile head of the foundation pile 30 with the upper flange 232 sandwiched between the main body flange 22 by a plurality of bolts 237, and is opened at the center of the bearing plate 234 The rebar insertion hole 234b is composed of a pair of nuts 236 and 236 for coupling the head of the deformed rebar 32 in the foundation pile 30 in an inserted state.
[0019]
Next, the construction procedure in the case of constructing the steel tower that employs the above-mentioned foundation structure on a sloped area in a mountainous area will be described with reference to FIGS.
[0020]
First, as shown in FIG. 7, the cut of the slope 1 of the natural ground G and the construction of the scaffold 2 are performed. That is, the slope 1 of the natural ground G on which the foundation of the steel tower is constructed is cut to form a cut surface 1a having a slope perpendicular to the inclination angle of the column base 10, and the temporary construction constructed on the lower slope thereof The earth material 3 generated by the cut is filled with the scaffold 2 so as to have a height continuous with the cut surface 1a. In the present invention, since the footing 103 as in the prior art shown in FIG. 13 is not constructed, the cut surface 1a may have a relatively small area.
[0021]
Next, as shown in FIG. 8, the iron plate 4 is laid at the foundation construction position on the cut surface 1 a formed by cutting. This iron plate 4 has a larger area than the axial projection area of the column base 10 shown in FIGS. 2 and 3, in other words, the area of the main body flange 22, and each coupling hole 22 a of the main body flange 22. Correspondingly, since the foundation pile insertion hole 4a through which the steel pipe 31 of each foundation pile 30 can be inserted with appropriate play is opened, the placement location of the foundation pile 30 can be easily determined.
[0022]
Next, as shown in FIG. 9, by the construction machine 5, the direction perpendicular to the cut surface 1 a toward the ground pile G from the foundation pile insertion hole 4 a of the iron plate 4, in other words, the cutting Pile driving is performed in a direction parallel to the axis of the column base 10 of the steel tower built on the soil surface 1a. As described above, since the foundation pile 30 has a relatively small diameter, the pile can be driven by the small construction machine 5. For this reason, the area of the temporary scaffold 2 and embankment can also be made small.
[0023]
In the placing work of each foundation pile 30, as is well known, first, boring (casing digging) is performed using a casing having a diameter larger than the steel pipe 31 of the foundation pile 30, and the support layer in the natural ground G A drilling hole reaching G2 is formed. At that time, the steel pipe 31 is inserted together with the casing to the support layer G2 of the natural ground G in accordance with the boring. When the hole is formed, the steel pipe 31 is left in the ground G and only the casing is pulled out. Next, the deformed rebar 32 is inserted into the steel pipe 31, and a device for press-fitting the grout 33 is attached to the deformed rebar 32 and is inserted together. When the insertion is completed, using this press-fitting device, the grout 33 is press-fitted into the drilling hole, and the steel pipe 31 is pulled up to a predetermined height accordingly. When the grout 33 is sufficiently filled, the steel pipe 31 is inserted again, and the grout 33 is also press-fitted at the same time. The grout 33 is diffused in a pedestal shape below the steel pipe 31 by the applied pressure at this time.
[0024]
When the foundation pile 30 has been driven, the column base 10 is built on the iron plate 4 as shown in FIG. The column base 10 is carried into the site and built in advance in a state where the rib 21 and the main body flange 22 in the coupling member group 20 are integrally joined to each other by welding or the like. Moreover, the lower flange 231 which is a part of the coupling member group 23 is joined to the upper end of the steel pipe 31 of the foundation pile 30 by welding or the like in advance as shown in FIGS.
[0025]
When the column base 10 is built, the pile heads of the foundation piles 30 protruding from the foundation pile insertion holes 4a of the steel plate 4 on the natural ground G are inserted into the coupling holes 22a of the main body flange 22 joined to the lower part thereof. This is coupled by the coupling member group 23 in the manner shown in FIGS. 3 to 5. Thereafter, if necessary, after applying a rust prevention process by painting or spraying, the earth material 3 is buried on the cut surface 1a.
[0026]
In the embodiment described above, the foundation pile 30 is driven in parallel with the axis of the column base 10, that is, the foundation piles 30 are parallel to each other. However, FIG. 11 shows another embodiment of the present invention. As described above, it is also possible to drive them in directions that are opened at equal angles around the extension line of the axis O of the column base 10.
[0027]
In this case, as shown in the perspective view of FIG. 12, the main body flange 22 of the foundation material 20 is such that the region divided by the ribs 21 forms a surface orthogonal to the placement direction of each foundation pile 30. It is provided in an inclined state. Thereby, the load from the column base 10 can be transmitted to the axial direction of each foundation pile 30.
[0028]
In addition, as the foundation pile 30 used in this invention, what can be couple | bonded with the foundation material 20 and exhibits required proof stress should just be.
[0029]
【The invention's effect】
According to the foundation structure according to the present invention, the foundation pile is driven in a direction parallel to the column, or in a direction opened at an equal angle around the axis of the column, thereby obtaining a high yield strength against the load of the structure. . In addition, since the footing and foundation piles are connected using foundation materials without constructing footings, the construction area is reduced, so it is possible to construct with small construction machines, so construction on mountainous slopes is easy. Therefore, the construction period can be shortened and the construction cost can be reduced.
[Brief description of the drawings]
FIG. 1 is an explanatory view schematically showing a foundation structure according to an embodiment of the present invention, together with a part of a power tower constructed thereon.
FIG. 2 is a perspective view showing a schematic configuration of a base material in the embodiment.
FIG. 3 is a cross-sectional view showing a schematic configuration of a foundation pile in the embodiment.
FIG. 4 is a cross-sectional view of an essential part showing an example of a connection structure between a foundation material and a foundation pile in the embodiment.
FIG. 5 is a cross-sectional view of an essential part showing another example of a connecting structure of a foundation material and a foundation pile in the embodiment.
FIG. 6 is a cross-sectional view of an essential part showing another example of a connecting structure of a foundation material and a foundation pile in the embodiment.
FIG. 7 is an explanatory diagram schematically showing a cut and scaffold construction state in the construction of a structure that employs the foundation structure according to the embodiment.
FIG. 8 is an explanatory diagram showing a state in which an iron plate is laid on a cut surface in the construction of a structure that employs the foundation structure according to the embodiment.
FIG. 9 is an explanatory view showing a pile driving operation in the construction of a structure employing the foundation structure according to the embodiment.
FIG. 10 is an explanatory diagram schematically showing a coupling state between a pile head of a foundation pile and a column base in the construction of a structure adopting the foundation structure according to the embodiment.
FIG. 11 is a perspective view showing a schematic configuration of a base material according to another embodiment of the present invention.
FIG. 12 is an explanatory diagram schematically showing a foundation structure according to another embodiment of the present invention, together with a part of a power tower constructed thereon.
FIG. 13 is an explanatory view showing a basic structure according to the prior art.
[Explanation of symbols]
10 column base 20 foundation material 21 rib 22 main body flange 23 coupling member group 30 foundation pile

Claims (4)

A base material integrally provided at the bottom of the pillar of the structure;
An iron plate that is laid on the lower surface of the foundation material and has a larger area than the axial projection area of the foundation material;
A pile head is coupled to the foundation material, and one or a plurality of foundation piles driven in a direction parallel to the column to the ground through a foundation pile insertion hole established in the iron plate ,
The foundation of a structure characterized by consisting of A base material integrally provided at the bottom of the pillar of the structure;
An iron plate that is laid on the lower surface of the foundation material and has a larger area than the axial projection area of the foundation material;
A plurality of pile heads are connected to the foundation material, and are driven to the ground through the foundation pile insertion holes established in the iron plate in a direction opened at an equal angle around the extension line of the axis of the column. Foundation piles,
The foundation of a structure characterized by consisting of The basic material is
A plurality of ribs integrally provided in advance in the lower part of the pillar and extending in the axial direction of the pillar;
A main body flange which is provided integrally with the lower portion of the column and the rib in advance and forms a surface perpendicular to the axis of the column;
A coupling member group for coupling the pile head of the foundation pile to the main body flange;
The foundation of the construct according to claim 1 or 2, characterized in that it consists of: A step of integrally providing a base material provided with a coupling means with a pile head at the bottom of the pillar;
Laying an iron plate having an area larger than the axial projection area of the foundation material and having a foundation pile insertion hole opened at a planned construction position on the ground; and
From the planned construction position of the pillar on the ground, it opened at an equal angle around the direction parallel to the axis of the pillar or the planned construction angle of the pillar into the ground via the foundation pile insertion hole of the iron plate A process of placing a plurality of foundation piles in the direction;
The pillar is built at a planned construction position on the ground, and the base member integrally provided at the lower portion thereof is connected to the pile head of the foundation pile protruding from the foundation pile insertion hole of the iron plate. A step of joining through ,
The construction method of the foundation of the structure characterized by consisting of.

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