JP2007231552A - Construction method of foundation pile using recycled electric pole - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a foundation pile, by arranging a recycled electric pole in the ground, without disturbing the surrounding ground to the foundation ground including the ground of an N value of 3 or less, by using a characteristic of the recycled electric pole having a taper-off shape toward the tip. <P>SOLUTION: This construction method of the foundation pile by the recycled electric pole includes a process of pressing the recycled electric pole 10 put in an inverted state in the ground 12 of the N value or 3 or less of the foundation ground 11 including the ground 12 of the N value of 3 or less, by using press-in heavy machinery 13 without excavating and forming a guide hole in advance. The recycled electric pole is a precast reinforced concrete electric pole. When there is the ground 22 harder than this ground 12 above the ground 12 of the N value or 3 or less, after precedently excavating the guide hole of an inner diameter smaller than a minimum outer diameter of the recycled electric pole 10 in the harder ground 22, the recycled electric pole 10 is pressed in toward the ground 12 of the N value of 3 or less. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for constructing foundation piles using recycled utility poles, and more particularly to a method for installing foundation piles using recycled utility poles on foundation ground including ground having an N value of 3 or less.

  In recent years, many electric poles have been removed and treated as industrial waste, etc., for example, due to redevelopment of urban areas and road widening work, etc., so that such electric poles can be effectively used as recycled products Various methods have been developed. For example, in the case of a power pole made of precast reinforced concrete, it is taken over by a demolition contractor, etc., and separated and disassembled into a concrete part and a reinforcing bar, and then the reinforcing bar is reused as iron scrap, or the aggregate obtained from the concrete part is recycled aggregate The method of reusing as is generally adopted.

Also, precast reinforced concrete utility poles are embedded with a number of reinforcing bars to improve the tensile strength so that they do not bend or deform against the moment force caused by strong winds, etc., loaded in an upright installation state. Since it has a strong structure, a method has been developed in which a recycled power pole having such a strong structure is installed in the ground and effectively used as a foundation pile of a building (for example, Patent Document 1, Patent Document 2).
JP-A-9-71932 JP 2002-256550 A

  However, in the method of effectively using these recycled power poles as the foundation pile of the building, using a heavy machine for drilling such as an earth auger, an insertion hole for inserting the pile and a guide hole for driving the pile are provided. After excavation and formation in advance, piles are inserted and the surroundings are solidified with sentiment milk, etc., or piles are driven in, so especially in the foundation ground where soft layer with N value of 3 or less continues. In the case of construction, the surrounding ground tends to be disturbed during excavation using heavy machinery for digging. In addition, when injecting sentiment milk or the like around the pile, hexavalent chromium or the like is eluted in the surrounding ground, which may cause environmental problems.

  The present invention has been made paying attention to such a conventional problem, and utilizes the characteristics of a recycled power pole having a shape tapered toward the tip, and includes a foundation including a ground having an N value of 3 or less. Recycling poles can be installed underground without disturbing the surrounding ground, and sufficient piles can be effectively obtained without using sentiment milk. The purpose is to provide.

  The present invention uses a press-fitting heavy machine without forming a guide hole in advance for a recycle power pole that is in an inverted state with respect to a ground having an N value of 3 or less and a ground having an N value of 3 or less. The above-mentioned purpose is achieved by providing a method for constructing foundation piles using recycled electric poles including a step of press-fitting.

  And according to the construction method of the foundation pile by the recycling electric pole of this invention, it is preferable that the said recycling electric pole is an electric pole made from a precast reinforced concrete.

  Moreover, according to the construction method of the foundation pile by the recycling utility pole of this invention, when there exists a harder ground above this above the ground where the N value is 3 or less, the hard ground is less than the minimum outer diameter of the recycled utility pole. After the excavation of a guide hole having a small inner diameter, the recycled power pole can be pressed into the ground having an N value of 3 or less.

  Furthermore, according to the construction method of the foundation pile by the recycling electric pole of the present invention, a tip metal fitting provided with a displacement plate member is attached to the lower end of the recycling electric pole in an inverted state, while the tip metal fitting pushes the boulder away. It is preferable to press-fit a recycling utility pole.

  Furthermore, according to the construction method of the foundation pile using the recycled electric pole of the present invention, the steel pile having a function of preventing relative rotation with the press-fitting construction jig of the press-fitting heavy machine at the upper end of the recycled electric pole in an inverted state. A capping member is welded and fixed to a reinforcing bar of the recycling electric pole, and the recycling electric pole is press-fitted in a state where the press fitting jig is attached to the upper end portion of the recycling electric pole with the steel capping member interposed. It is preferable to do.

  According to the construction method of the foundation pile by the recycling electric pole of the present invention, using the characteristics of the recycling electric pole having a shape tapered toward the tip, the foundation ground including the ground having an N value of 3 or less, A recycling utility pole can be installed in the ground without disturbing the surrounding ground, and a sufficient supporting force can be obtained effectively without using sentiment milk or the like.

  As shown in FIG. 1, the construction method of the foundation pile by the recycling utility pole which concerns on preferable one Embodiment of this invention WHEREIN: As the recycling utility pole 10, Preferably the power pole made from precast reinforced concrete (henceforth "PC concrete utility pole") is N value. Pile driving equipped with a press-fitting mechanism, which is known as a heavy machine for placing, for example, steel pipe piles and PC concrete piles, on a foundation ground 11 in which a soft ground 12 having a thickness of 3 or less continues as a soft layer over a considerable depth from the ground surface It is adopted when it is effectively used as a foundation pile of a building by press-fitting installation using the machine 13.

  That is, the construction method of the foundation pile by the recycling utility pole of this embodiment is a construction method of the foundation pile for installing the foundation pile by the recycling utility pole 10 on the foundation ground 11 including the ground 12 having an N value of 3 or less. , Including a step of press-fitting the recycled power pole 10 in an inverted state with respect to the ground 12 having an N value of 3 or less using a pile driving machine 13 as a press-fitting heavy machine without excavating and forming a guide hole in advance. .

  In the present embodiment, the PC concrete utility pole as the recycled utility pole 10 is a utility pole that has become unnecessary or replaced due to, for example, redevelopment of an urban area, road widening work, or the like. Moreover, the PC concrete electric pole 10 is manufactured as a precast concrete product in a factory or the like, and when installed in an upright state as an electric pole, even if a moment force due to a strong wind or the like is applied, no bending or deformation occurs. Thus, it has a strong structure in which a large number of reinforcing bars for improving the tensile strength are embedded. Therefore, the PC concrete utility pole 10 can be diverted as a foundation pile without adding many modifications in the state when removed.

  Furthermore, when the PC concrete utility pole 10 is installed in an upright state and a moment force is applied, the base portion receives a larger bending load than the tip portion, so that such a load is efficiently supported. Therefore, the outer diameter of the root portion is large, the outer diameter gradually decreases toward the tip portion, and the outer peripheral surface has a cylindrical shape with a tapered shape (a truncated conical cylinder shape). Yes. In the present embodiment, while utilizing the characteristics of the recycled power pole 10 having a shape tapered toward the tip, the recycled power pole 10 is efficiently installed on the soft ground 12 and sufficient supporting force as a friction pile is provided. To be obtained.

  In this embodiment, the PC concrete utility pole 10 has a cylindrical shape with an outer diameter of the base portion of 200 to 250 mm, an outer diameter of the tip portion of 120 to 140 mm, and a length of 6 to 8 m, and tapers in a tapered shape. The outer peripheral surface having an axial gradient of 1/100 to 1/75 can be used. Moreover, it is preferable to use a thing whose gradient of the axial direction of an outer peripheral surface is 1/75 or 1/100.

  And in this embodiment, after carrying in such a PC concrete utility pole as the recycling utility pole 10 in the building construction site of a building, as shown to Fig.2 (a), installation of a foundation pile using the pile driving machine 13 is shown. In the position, it is built upside down with the tapered tip facing vertically downward. After that, as shown in FIG. 2 (b), the pile foundation 13 is used to appropriately rotate the built-in PC concrete utility pole 10, while applying a pressure input of, for example, about 7t to 8t to As shown in FIG. 1, the foundation pile made of the recycled power pole 10 is embedded and installed in the foundation ground 11 by press-fitting into the soft ground 12 having an N value of 3 or less to a predetermined depth.

  Here, since the cylindrical PC concrete electric pole 10 has a through hole 10a (see FIG. 3A) formed on the inner side, with the end fitting 14 that closes the lower end of the through hole 10a being attached, It is preferable to perform an operation of press-fitting the PC concrete utility pole 10. In this embodiment, as shown in FIG. 3A, a tip metal fitting 14 having a displacement plate member 15 is attached to the lower end of the PC concrete utility pole 10 in an inverted state, and the PC concrete utility pole 10 is attached to the foundation ground 11. Even if there is a boulder or the like that hinders the press-fitting of the PC concrete, for example, while the PC concrete utility pole 10 is rotated, the PC concrete utility pole 10 is press-fitted while pushing away the boulder or the like by the displacement plate member 15 of the tip metal fitting 14. Can be done.

  That is, the tip metal fitting 14 is divided into a hollow interior of a cylindrical sleeve portion 14a whose inner peripheral surface is the same tapered shape as the tip portion of the PC concrete utility pole 10, and the upper portion thereof is divided up and down by the partition plate 14b, and the upper portion thereof is the PC concrete utility pole 10. The front end fitting portion is fixed by welding or the like with the front end portion of the PC concrete power pole 10 fitted into the front end fitting portion. The cylindrical sleeve portion 14a below the partition plate 14b has a substantially rectangular displacement plate member 15 that crosses the center of the cylindrical sleeve portion 14a in the diametrical direction and protrudes further downward than the cylindrical sleeve portion 14a. It is fixed and attached by etc. By rotating the displacement plate member 15 with the rotation of the PC concrete utility pole 10 during press-fitting, the PC concrete utility pole 10 is moved substantially vertically while pushing away the rolling stones existing in the foundation ground 11 radially outward. In this state, it is possible to continue press-fitting.

  Moreover, in this embodiment, although the press-fitting work jig | tool 16 of the pile driving machine 13 is mounted | worn with the upper end part of the PC concrete electric pole 10 made into the inverted state, press-fitting work is performed, Preferably FIG. ) And (b), a steel capping member 17 having a function of preventing relative rotation with the press fitting jig 16 is welded to the reinforcing bar 10b of the PC concrete utility pole 10 at the upper end of the PC concrete utility pole 10. The PC concrete electric pole 10 is press-fitted in a state where the press-fitting jig 16 is attached to the upper end portion of the PC concrete electric pole 10 with the steel capping member 17 interposed therebetween.

  That is, the steel capping member 17 includes an annular plate-shaped annular plate portion 17a disposed on the upper end surface surrounding the periphery of the upper end opening of the through hole 10a of the PC concrete utility pole 10 in an inverted state, and this circle. It consists of a cylindrical insertion sleeve portion 17b provided projecting downward from the inner edge of the ring plate portion 17a. While inserting the insertion sleeve 17b into the upper portion of the through hole 10a and placing the annular plate portion 17a on the upper end surface of the PC concrete electric pole 10, the annular plate portion 17a is attached to the reinforcing bar 10b exposed on the upper end surface. By welding, the steel capping member 17 is firmly fixed to the upper end of the PC concrete utility pole 10. In addition, a pair of anti-rotation ribs 18 are provided on the upper surface of the annular plate portion 17a so as to protrude upward at positions opposed to each other in the diameter direction. These anti-rotation ribs 18 are provided across the hollow interior of the press fitting jig 16 when the press fitting jig 16 of the pile driving machine 13 is mounted so as to cover the upper end portion of the PC concrete electric pole 10. The end surface abutting plate 19 is inserted and disposed in a locking slit 19a formed to extend in the diameter direction. Accordingly, when the PC concrete electric pole 10 is rotated and pressed into the foundation ground 11 by the pile driving machine 13, the PC concrete electric pole 10 is relatively rotated with respect to the press fitting jig 19, and the rotational force is not transmitted. It can be effectively avoided.

  The steel capping member 17 is preferably provided with a closing plate 17c covering the lower end opening of the insertion sleeve portion 17b. By covering the lower end opening of the insertion sleeve portion 17b and providing the closing plate 17c, as shown in FIG. 5, after the PC concrete utility pole 10 is press-fitted to a predetermined depth, the foundation crushed stone 20 is applied to the ground surface of the foundation ground 11. , When placing concrete bars 21 such as cloth foundations, solid foundations, and footing foundations by placing reinforcing bars, formwork, etc., avoid placing the cast concrete falling into the through holes 10a of the PC concrete utility pole 10 Is possible.

  In the present embodiment, as described above, the PC concrete utility pole 10 built at the foundation pile installation position is press-fitted from the ground surface toward the soft ground 12 to a predetermined depth using the pile driving machine 13. The PC concrete utility pole 10 will be effectively used as the foundation pile 13, but according to the construction method of the foundation pile by the recycled utility pole of this embodiment, the shape tapered toward the tip is used. Efficiently utilizing the features of the recycling utility pole 10 provided, the PC concrete utility pole 10 can be installed in the ground without disturbing the surrounding ground with respect to the foundation ground 11 including the soft ground 12 having an N value of 3 or less, Sufficient support force can be effectively obtained without using sentiment milk or the like.

  That is, according to the present embodiment, the PC concrete utility pole 10 as a recycling utility pole has a cylindrical shape whose outer peripheral surface is tapered in a tapered shape, and a wedge-like inverted shape with the tip end side of the taper facing downward. In this state, the pile driver does not rotate as needed, but press-fits the soft ground 12 having an N value of 3 or less without digging a guide hole in advance to disturb the surrounding ground. 13 can be used to press fit smoothly. In addition, as the PC concrete utility pole 10 is press-fitted, the outer surface of the PC concrete utility pole 10 is in close contact with the surrounding ground while pushing the surrounding ground in a tapered wedge shape, A considerable frictional force can be secured. Further, since the PC concrete utility pole 10 is in close contact with the surrounding ground, it is not necessary to inject sentiment milk or the like around the PC concrete utility pole 10, and there is no possibility of causing environmental problems. Accordingly, the tapered shape of the PC concrete utility pole 10 can increase the supporting force as a friction pile and improve the settlement of buildings.

  Moreover, according to this embodiment, since the PC concrete utility pole 10 as a recycling utility pole is installed in the foundation ground 11 by the press-fitting with the pile driving machine 13, for example, the pushing force at the time of construction of press-fit work or after completion | finish of press-fit work Can be measured as management data, and the support capacity of the foundation pile by the PC concrete utility pole 10 can be confirmed or the support capacity can be estimated from the management data.

  In the present embodiment, the support force of the PC concrete utility pole 10 immediately after the PC concrete utility pole 10 of the above embodiment is press-fitted by the pile driving machine 13 and the average outer diameter of the PC concrete utility pole 10 are converted as the pile diameter. As a result of comparing the support force of the PC pile immediately after the straight PC pile is press-fitted with the pile driving machine 13, for example, as shown in FIG. 7, the outer peripheral surface of the PC of this embodiment is tapered. It was confirmed that the concrete electric pole 10 can obtain a supporting force of about 2 to 2.5 times that of a conventional straight PC pile.

  FIG. 6 shows that the foundation ground 11 into which the PC concrete utility pole 10 is press-fitted becomes, for example, a soft ground 12 having an N value of 3 or less, and a harder ground than this, and a ground 22 tightened by embankment or embedding of the surface layer portion. The construction method in the case of 11 will be described. According to the present embodiment, as shown in FIG. 6, when there is a harder ground 22 above the soft ground 12 having an N value of 3 or less, preferably the hard ground 22 has a maximum of the PC concrete utility pole 10. As an inner diameter smaller than the outer diameter (preferably an inner diameter smaller than the outer diameter of the central portion of the PC concrete utility pole 10), for example, a guide hole having an inner diameter of 60 to 70% of the outer diameter of the root portion is used. After the previous excavation using the auger 23, by pressing the PC concrete utility pole 10 toward the soft ground 12 having an N value of 3 or less, the same effect as that obtained when the hard ground 22 is not provided can be obtained. Become.

  The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, the recycled power pole does not necessarily need to be a PC concrete power pole, and may be a wooden power pole or the like having a tapered outer peripheral surface. Moreover, the guide hole excavated in advance on the hard ground can be formed with an inner diameter smaller than the minimum outer diameter of the lower end portion of the PC concrete utility pole.

It is a side view explaining the situation which press-fits a recycling electric pole by the construction method of the foundation pile by the recycling electric pole which concerns on preferable one Embodiment of this embodiment. (A), (b) is the schematic side view explaining the process of pressing-in a recycling electric pole with the construction method of the foundation pile by the recycling electric pole which concerns on preferable one Embodiment of this embodiment. (A) is a fragmentary sectional view in the state where the tip metal fitting was attached to the lower end of the recycling electric pole, and (b) is a perspective view of the tip metal fitting. (A) is a fragmentary sectional view in the state where a press-fitting construction jig and a steel capping member are attached to the upper end of the recycling electric pole, and (b) is an exploded perspective view of (a). It is sectional drawing explaining the state which formed the foundation concrete in the ground surface of the foundation ground which injected the recycling electric pole. It is a schematic side view explaining the construction method when there is a harder ground above the ground with an N value of 3 or less. It is a chart which compares and shows the supporting force by the recycling electric pole which the outer peripheral surface became the taper shape of taper, and the supporting force by the conventional straight-shaped PC pile.

Explanation of symbols

10 PC concrete utility pole (recycled utility pole)
10a PC concrete utility pole through hole 10b PC concrete utility pole rebar 11 Foundation ground 12 Soft ground (N-value of 3 or less)
13 Pile driver (Pressure press heavy machine)
14 End fitting 14a Cylindrical sleeve portion 14b of the end fitting End metal partition plate 15 Push-off plate member 16 Press fitting jig 17 Steel capping member 17a Annular plate portion 17b of steel capping member Insert sleeve portion of steel capping member 18 Anti-rotation rib 19 End surface contact plate 19a End surface contact plate locking slit 20 Foundation crushed stone 21 Base concrete 22 Hard ground 23 Auger

Claims (5)

  A process of press-fitting a recycle utility pole in an inverted state to a ground including an N value of 3 or less using a press-fitting heavy machine without previously excavating a guide hole with respect to the ground having an N value of 3 or less. Construction method of foundation pile by recycled electric pole including   The construction method of the foundation pile by the recycled electric pole according to claim 1, wherein the recycled electric pole is an electric pole made of precast reinforced concrete.   In the case where there is a harder ground above the ground where the N value is 3 or less, the N value is 3 or less after excavating a guide hole having an inner diameter smaller than the maximum outer diameter of the recycled power pole in the hard ground. The construction method of the foundation pile by the recycling electric pole of Claim 1 or 2 which press-fits the said recycling electric pole toward the ground of the.   The recycling according to any one of claims 1 to 3, wherein a tip metal fitting provided with a displacement plate member is attached to a lower end of the recycling electric pole in an inverted state, and the recycling electric pole is press-fitted while pushing a rolling stone with the tip fitting. Construction method of foundation pile by electric pole. A steel capping member having a function of preventing relative rotation with the press-fitting construction jig of the press-fitting heavy machine is fixed to the upper end of the recycled power pole in an inverted state by welding to the rebar of the recycled power pole, The pile of the foundation pile by the recycling electric pole according to any one of claims 1 to 4, wherein the recycling electric pole is press-fitted in a state where the press fitting jig is attached to the upper end portion of the recycling electric pole with the steel capping member interposed. Construction method.

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