JP2013124509A - Pile head treatment method and charge holder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pile head treatment method capable of more reducing labor and time required for construction than a conventional pile head treatment method in which a horizontal circular plate of the same size as a pile diameter is previously installed, and to provide a charge holder.SOLUTION: A pile head treatment method is a construction method for pile head treatment of a cast-in-place concrete pile. A plurality of charge holders 10 each having a charge space formed inside and a horizontal crushing part 12 provided on the bottom side and extending in the longitudinal direction are prepared. The horizontal crushing part has a first plate part extending in the horizontal direction and a second plate part overlapping with the first plate part to form a horizontal joint part communicating with the charge space. A support member 24 for supporting the charge holder at the horizontal crushing part is horizontally provided at a place corresponding to a pile top end, the charge holder is installed in the vertical direction of the pile such that the horizontal crushing part is mounted on the support member, and a kinetic crushing agent charged in the charge space is ignited after concrete placing. Thereby, a horizontal crushed face is formed in concrete of a pile head part above the pile top end and the pile head part is crushed by a crushing force spurting out from the horizontal joint part.

Description

  The present invention relates to a pile head processing method for a cast-in-place concrete pile and a charge holder used for the method.

The following are known as conventional methods for pile head treatment of cast-in-place concrete piles.
(1) Lifting method This is a method that uses a manual crusher to hang up the pile head and manually handle the generated concrete. Noise and vibration are significant and greatly affect the surrounding environment. In addition, there is a problem in the construction method, such as damaging the reinforcing bars of the pile head during the work.

(2) Static crushing agent This is a construction method in which the concrete of the pile head is subdivided and processed by the expansion action of a crushing agent inserted in a sheath tube or the like previously installed on the pile head (for example, see Patent Documents 1 and 2). However, since it is post-construction, it is difficult for the crushing agent to act moderately, and the horizontal surface is difficult to be constructed, and as a result, the amount of the finishing by human power tends to increase.

(3) Vertical crushing method using dynamic crushing agent A dynamic crushing agent is installed in the vertical direction of the pile head, the pile head is subdivided in the vertical direction by dynamic crushing, and accompanied by a suspension operation by a manual crusher. A method of treating the generated concrete glass has been proposed (see, for example, Patent Documents 3 and 4). In the conventional dynamic crushing method, it is necessary to form a horizontal plane after vertical splitting by vertical fracture method or to install a horizontal circular plate having the same dimensions as the pile diameter in advance.

  The horizontal circular plate installed in the above-mentioned conventional pile head processing method by dynamic crushing will be described. As shown in FIGS. 10 (a) and 10 (b), after assembling the pile reinforcement bar with the plurality of pile main bars 410 and the plurality of shear reinforcement bars 420, the ground is placed on the upper part of the pile bar bar corresponding to the pile head processing unit 310. A horizontal circular plate 340 having a diameter substantially the same as the pile diameter is installed in a set, a plurality of simple charge holders 210 are installed, and concrete is placed. Thereafter, a high-energy substance is loaded inside the simple charge holder 210, and a shock wave or expansion gas due to detonation or deflagration acts on the butting portion of the simple charge holder 210, and a vertical crack develops, causing a fracture surface. And the shock wave or the expanding gas reaches the horizontal circular plate 340, and the boundary between the horizontal circular plate 340 and the concrete on the upper side thereof is peeled, thereby controlling the crack propagation along the horizontal direction. In this way, the concrete can be crushed without damaging the pile body in the pile head processing section 310.

JP 9-280800 A JP 2002-285550 A Japanese Patent Publication No. 8-12040 Japanese Patent No. 4245614

  Pile head treatment works in urban areas need to be reduced as much as possible to avoid anxiety and discomfort in the vicinity as well as noise and vibration generated within specified limits. For that purpose, it is desirable to avoid as much as possible the lifting work by the crusher, and therefore, the application of a static crushing agent or a dynamic crushing agent is a prerequisite. On the other hand, as described above, since the crushing agent insertion is a subsequent operation and the influence of the sheath tube mounting and concrete placement, which are the preceding operations, is large, the former cannot be said to have high accuracy of crushing. From the surface and process aspects, it can be judged that the dynamic crushing is more effective.

  In the dynamic crushing method, the current method is to load a high-energy substance in the vertical direction and place a horizontal circular plate between the pile head and the pile body, but after crushing, According to the finished mold, the finish will be increased. In the current dynamic crushing method, the horizontal control of the crushing effect depends exclusively on the horizontal circular plate, but the installation process of this horizontal circular plate is required, and it takes time and effort for that.

  In view of the problems of the prior art as described above, the present invention can reduce the labor and time required for construction compared to a conventional pile head processing method in which a horizontal circular plate having the same size as the pile diameter is installed in advance. An object is to provide a pile head processing method and a charge holder.

  In order to achieve the above object, the pile head processing method according to the present embodiment is a pile head processing method for performing the pile head processing of cast-in-place concrete piles, and is provided on the bottom side and the charge space formed inside. A plurality of charge holders having a horizontal crushing portion and extending in the longitudinal direction, wherein the horizontal crushing portion overlaps the first plate portion and the first plate portion and communicates with the charge space. A second plate portion that forms a horizontal alignment portion, and a support member for supporting the charge holder at the horizontal crushing portion is provided in a horizontal direction at a position corresponding to the top of the pile, and the charge holder is Installed in the vertical direction of the pile so that the horizontal crushing part is placed on the support member, and after laying the concrete, the dynamic crushing agent loaded in the charge space is ignited to eject from the horizontal alignment part Said by crushing force From crest to form a horizontal fracture surface concrete pile head portion of the upper, characterized in that for breaking the pile head portion.

  According to this pile head processing method, when the charge holder having the horizontal crushing part on the bottom side is installed on the support member provided at the top of the pile, the horizontal crushing part is located near the top of the pile, and the first plate of the horizontal crushing part Since a horizontal crushing surface can be formed from the top of the pile to the top of the pile head by the crushing force ejected from the horizontal alignment part between the part and the second plate part, a horizontal circular plate having the same dimensions as the conventional pile diameter Can be omitted, and the charging holder can be installed more easily than the conventional horizontal circular plate.

  In the pile head processing method, the charge holder has a vertical crushing portion extending in a longitudinal direction, the vertical crushing portion is installed so as to be positioned in the vertical direction of the pile, and the vertical crushing is performed when the crushing agent is ignited. It is preferable to crush the pile head part by forming a crushing surface on the concrete of the pile head part by crushing force ejected from the part. Thereby, a pile head part can be crushed in the perpendicular direction.

  Moreover, it is preferable to comprise the said charge holder so that the ejection direction of the crushing force from the said horizontal alignment part and the ejection direction of the crushing force from the said vertical crushing part may become a substantially identical direction. The pile head portion can be efficiently crushed by combining the horizontal crushing and the vertical crushing.

  In addition, the first plate portion and the second plate portion may be configured such that the entire planar shape is rectangular, and the charge holder has an opening communicating with the charge space in the horizontal crushing portion. preferable.

  Moreover, it is preferable that the said 2nd board part is comprised by the flat plate, or the part facing the said opening part is bend | folded.

  Further, a tremey pipe for placing concrete in the center of the pile is arranged in a vertical direction, a plurality of pile main bars are arranged to extend in the vertical direction of the pile, and surround the plurality of pile main bars It is preferable that a ring-shaped shear reinforcement is arranged, and the support member is arranged so that the plurality of charge holders can be installed around the tremy tube using the shear reinforcement. Thereby, a some charge holder can be easily installed in a pile head part.

  The charge holder according to the present embodiment is used in the above-described pile head processing method.

  According to this charge holder, when installed on the support member, the horizontal crushing portion on the bottom side is located near the top of the pile, and from the horizontal alignment portion between the first plate portion and the second plate portion of the horizontal crushing portion. Since the horizontal crushing surface can be formed from the top of the pile to the top of the pile head by the crushing force to be ejected, it is possible to omit the circular plate of the same size as the conventional pile diameter and to install the charge holder conventionally This is easier than the case of arranging a circular plate.

  According to the pile head processing method and charge holder of the present invention, it is possible to reduce the labor and time required for construction compared to the conventional pile head processing method in which a horizontal circular plate having the same dimension as the pile diameter is previously installed. is there.

It is a front view of the charge holder by this embodiment. It is a top view of the vertical crushing part of the charge holder of FIG. It is the upper side figure (a) and principal part front view (b) of the charge holder of FIG. In order to demonstrate the pile head processing method by this embodiment, it is a top view which shows the example of arrangement | positioning of the reinforcing bar and charge holder in the pile top end of the pile reinforcement rod before concrete placement. FIG. 5 is a view of one charge holder of FIG. It is the figure which looked at the whole reinforcing bar and charge holder of FIG. 4 from direction VI. It is a flowchart for demonstrating the construction process of the concrete pile by this embodiment. It is the figure which saw through the inside of a charge holder in order to demonstrate the state which loaded the dynamic crushing agent etc. in the charge holder after concrete placement in this embodiment. It is a principal part front view similar to FIG.3 (b) which shows another example of the charge holder 10 by this embodiment. It is the top view (a) and sectional drawing which show arrangement | positioning of the pile reinforcement, the charge holder, and a horizontal circular board in the conventional pile head processing method.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

<Charge holder>
First, the charge holder which can be used for the pile head processing method of this embodiment is demonstrated with reference to FIGS.

  FIG. 1 is a front view of a charge holder according to the present embodiment. FIG. 2 is a top view of the vertical crushing part of the charge holder of FIG. FIG. 3 is a top view (a) and a main part front view (b) of the charge holder of FIG.

  As shown in FIG. 1, the charge holder 10 includes a vertical crushing portion 11 that is elongated in the longitudinal direction and a horizontal crushing portion 12 that is provided at the bottom of the vertical crushing portion 11 so as to spread in the horizontal direction. Is provided. The vertical crushing part 11 is comprised from a pair of bending steel plate 11a, 11b which bent the steel plate like FIG.

  As shown in FIG. 2, the bent steel plates 11 a and 11 b are bent at the tops at, for example, 120 ° and the same side, the end portions 11 c and 11 d are abutted with each other to form a substantially rhombus shape in a plane, and the vertical crushing portion 11. Configure. Specifically, for example, the folded steel plates 11a and 11b are formed into a cylindrical shape by winding them around the folded steel plates 11a and 11b using an adhesive tape such as a gum tape. At this time, an abutting portion SL1 extending in the vertical direction is formed at the end portion 11d of the bent steel plates 11a and 11b, and an abutting portion SL2 extending in the vertical direction is formed at the end portion 11c.

  As shown in FIG. 3A, a charging space SP is formed on the substantially rhombus-shaped inner surface of the vertical crushing portion 11, and a cylindrical dynamic crushing agent HA is inserted and loaded into the charging space SP. Can do. When the dynamic crushing agent is ignited, the expansion pressure of the combustion gas acts on the abutting portions SL1 and SL2 extending in the vertical direction of the vertical crushing portion 11, and the crack is advanced.

  As shown in FIGS. 3 (a) and 3 (b), the horizontal crushing portion 12 includes a first steel plate portion 13 configured in a rectangular shape so as to expand in the horizontal direction with respect to the vertical crushing portion 11, and a first steel plate portion 13. And an overlapping second steel plate part 14.

  As shown in FIGS. 3A and 3B, the lower end portion of the bent steel plate 11b of the vertical crushing portion 11 is along an inclined side connecting the point a on the top portion 11f and the bottom end b of the end portion 11c. Similarly, it is cut along an inclined side connecting the point a on the top portion 11f and the bottom end c of the other end portion 11d to form an opening AP having an angle of 120 °, for example, by both sides. In addition, an opening is formed by cutting in the same manner at the lower end of the bent steel plate 11a of the vertical crushing portion 11.

  The 1st steel plate part 13 of the horizontal crushing part 12 is bend | folded so that the edge | side where the opening part AP was cut | disconnected as FIG.3 (b). At this time, an opening (not shown) is formed in the first steel plate portion 13 so that the opening AP communicates with the charging space SP. The bent steel plates 11a and 11b and the first steel plate portion 13 are joined by welding, for example.

  A flat plate-like second steel plate portion 14 configured to match the planar shape of the first steel plate portion 13 is placed on the bottom surface of the first steel plate portion 13 to form a horizontal alignment portion 15 having a gap between both surfaces. To do. Thereby, the charge space SP, the opening AP, and the horizontal alignment portion 15 communicate with each other. Specifically, the first steel plate portion 13 and the second steel plate portion 14 are integrated by winding an adhesive tape such as a gum tape, for example. At this time, the gap between the long sides d and e of the first steel plate portion 13 and the second steel plate portion 14 and the opening AP (also the opening on the bent steel plate 11a side) in FIG. The adhesive tapes such as these are overlapped and closed, and the short sides f and g are similarly closed. In this way, by closing the periphery of the leveling portion 15 and the opening AP with a gummed tape or the like, moisture in the concrete is prevented from entering the inside of the charge holder 10 when placing the concrete. Note that the gum tape and the like are broken by the expansion pressure of the combustion gas during the pile head treatment.

  When the dynamic crushing agent loaded in the charge space SP is ignited, the short side f of the horizontal alignment portion 15 extending mainly in the horizontal direction between the first steel plate portion 13 and the second steel plate portion 14 of the horizontal crushing portion 12. , G causes the expansion pressure of the combustion gas to act and cause cracks to propagate in the horizontal direction. That is, the horizontal crushing portion 12 of the charge holder 10 is configured in a rectangular shape in plan view as shown in FIG. 3A, but in the rectangular longitudinal gap (short sides f, g). The crack propagation action is very large with respect to the crack propagation action in the gap (long side d, e) in the short direction, and a horizontal crack is developed in the short side direction. In addition, the expansion gas pressure also acts on the horizontal alignment portion 15 on the short side f, g side, so that an effective horizontal fracture surface can be formed also on the long side d, e side.

  By making the opening AP at the bottom of the charge holder 10 into a wedge-shaped cavity cross section as shown in FIG. 3B and FIG. 8 described later, the effect of concentrating the working direction of the expansion pressure can be obtained. Thereby, the expansion pressure of the combustion gas in the opening AP acts on the leveling portion 15 of the horizontal crushing portion 12 and the gas enters the gap of the leveling portion 15 protruding from the opening AP, The fracture surface in the horizontal direction is efficiently formed. Moreover, the space with the opening AP at the bottom of the charge holder 10 becomes a space for generating a horizontal fracture surface, and the filled combustion gas enters the gap of the horizontal alignment part 15 and opens the gap. Can create and propagate cracks in the planned direction.

  Further, as shown in FIG. 3A, the direction of the butting portion SL1 extending in the vertical direction of the vertical crushing portion 11 and the direction of the short side f of the horizontal matching portion 15 extending in the horizontal direction of the horizontal crushing portion 12 are the same. Facing the direction. Similarly, the direction of the butted portion SL2 and the direction of the short side g are in the same direction. Thereby, the ejection direction of the crushing force from the horizontal alignment part 15 of the horizontal crushing part 12 and the ejection direction of the crushing force from the vertical crushing part 11 become substantially the same direction.

  In addition, although the bending steel plates 11a and 11b and the 1st steel plate parts 13 and 14 of the charge holder 10 can use a 1.6 mm-thick zinc steel plate, for example, it is not limited to this.

<Pile head processing method>
Next, the pile head processing method by this embodiment using the charge holder 10 of FIGS. 1-3 is demonstrated with reference to FIGS.

  FIG. 4 is a top view showing an example of arrangement of reinforcing bars and charge holders at the pile top end of the pile reinforcement rod before placing concrete in order to explain the pile head processing method according to the present embodiment. FIG. 5 is a view of one charge holder of FIG. FIG. 6 is a view of the entire reinforcing bar and charge holder of FIG. 4 as seen from the direction VI.

  As shown in FIG. 4, in order to place a cast-in-place concrete pile P indicated by a broken line, a plurality of pile main bars 21 extending in the longitudinal direction of the pile P are arranged on the circumference in a substantially equal interval, The pile reinforcing bar 22 is assembled by arranging the ring-shaped shear reinforcing bar 22 so as to surround the main pile bar 21. A plurality of shear reinforcement bars 22 are arranged at substantially equal intervals in the longitudinal direction of the pile P. In addition, a tremmy pipe TM is disposed in the approximate center of the upper surface of the pile bar for placing concrete.

  As shown in FIG. 6, the plurality of pile main bars 21 are arranged so as to protrude from the pile top end UP of the concrete pile P, and an extra-banking portion YM (shown by a one-dot chain line) is formed beyond the pile top end UP when placing concrete. It arrange | positions so that it may protrude also from this extra peak YU.

  As shown in FIG. 4 to FIG. 6, the support member 24 for installing the charge holder 10 is stretched over the shear reinforcement bars 22 near the pile top end UP and fixed horizontally, L-shaped steels 27, 27 disposed on the reinforcing bars 25, 26 and horizontally fixed, and flat steels 28, 28 spanned between the L-shaped steels 27, 27 and fixed horizontally. . As the reinforcing bars 25 and 26, for example, those having the same diameter as the pile main reinforcing bars 21 can be used.

  As shown in FIGS. 4 to 6, L-shaped steels 27, 27 along the reinforcing bars 25, 26 arranged in parallel to each other, and flat steel 28, which is stretched in parallel between the L-shaped steels 27, 27, 28 is horizontally attached to a position where the tremy tube TM is displaced, and has a substantially square shape in plan view. The four charge holders 10 are installed by disposing the charge holders 10 at substantially the center in the longitudinal direction of the L-shaped steels 27 and 27 and the flat steels 28 and 28, respectively.

  In the circular plane of FIG. 4, the charge holder 10 faces the butting portion SL1 of the vertical crushing portion 11 facing the same direction and the short side f of the horizontal crushing portion 15 of the horizontal crushing portion 12 facing radially outward r. Position and arrange so that. As a result, the butted portion SL2 and the short side g are arranged to face the radially inward r ′.

  Next, the cast-in-place concrete pile construction steps S01 to S11 performed using the pile reinforcing bar shown in FIGS. 4 to 6 will be described with reference to FIGS. FIG. 7 is a flowchart for explaining a concrete pile construction process according to this embodiment. FIG. 8 is a perspective view of the inside of the charge holder in order to explain a state in which a dynamic crushing agent or the like is loaded in the charge holder after the concrete is placed in the present embodiment.

  As shown in FIG. 4 to FIG. 6, pile reinforcing bars are assembled to form a pile reinforcing rod (S01). Next, as shown in FIGS. 4 to 6, the four charge holders 10 are attached so as to extend vertically upward from the pile top end UP of the piling bar (S02). Thereafter, the horizontal mounting position and level of the charge holder 10 are adjusted. Next, a pile reinforcement rod (pile reinforcement) is built in the pile construction position (S03), and then concrete is laid through the tremy pipe TM. After the concrete has hardened, the pile head surface of the concrete is exposed by excavation work (S05), and the columnar dynamic crushing agent HA is inserted into the charging space SP of FIG. Then, it is loaded (S06). When placing concrete, the Tremy tube TM is placed at the center of the pile diameter, and the work is performed with care so as not to shift the horizontal position and level of the charge holder 10. In addition, after pulling the concrete, when pulling out the Tremy tube TM, work is performed with care so as not to contact the horizontal crushing portion 12 of the charge holder 10.

  As shown in FIG. 8, the dynamic crushing agent HA is inserted from the upper part of the charging holder 10 into the charging space SP, and the paper cylinder 34 is attached to the lower part, and the front end of the paper cylinder 34 is the horizontal crushing part at the bottom of the holder. It is located on 12 second steel plate portions 14. As a result, the lower part of the dynamic crushing agent HA is in a volume decoupling state (providing a gap), and the combustion gas generated by ignition can exert an expansion pressure on the horizontal crushing part 12. Moreover, the foaming polystyrene 31 and sand (or powder) 32 are arrange | positioned at the upper part of the dynamic crushing agent HA, and the charge space SP was tamped by the cement-type early strong material 33 being arrange | positioned at the upper part. It becomes a sealed state and prevents ejection of the combustion gas from the upper end of the charging space SP of the combustion gas of the dynamic crushing agent HA. Further, a leg 35 for igniting the dynamic crushing agent HA is led out from the upper part of the charge holder 10.

  Next, the surplus portion YM corresponding to the pile head portion is crushed by passing an electric current through the leg 35 and igniting the dynamic crushing agent HA (S07). As a result, it is possible to remove the surplus portion YM where impurities and the like are likely to be mixed just before the concrete placement is finished. Next, the crushed concrete glass is removed (S08), the finish is suspended (S09), the pile rebar is reworked (S10), and the state of the pile top and the pile rebar after the suspension is inspected (S11). If there is no abnormality, finish the construction, and rework if necessary.

  As the dynamic crushing agent HA, various known crushing agents can be used, for example, cupric oxide, aluminum, magnesium sulfate heptahydrate as a main component, and those in a cylindrical cartridge are used. When ignited, a thermite reaction generates a high-temperature and high-pressure steam together with a vigorous redox reaction, and the generated expansion pressure is used. In addition, a unit in which a barrel and an igniter each having a gas generating agent such as bromate as a main component can be used, and when ignited in a sealed state, a high-temperature and high-pressure gas is generated.

  In the crushing step (S07), the dynamic crushing agent HA loaded in the charge holder 10 is ignited so that the crushing force due to the expansion pressure generated by the combustion gas extends mainly in the horizontal direction of the horizontal crushing unit 12. By spraying from the short sides f and g of the mating portion 15, a crack is generated in the horizontal direction in the concrete of the surplus portion YM (pile head portion) and propagates, thereby forming a horizontal crushing surface simultaneously with crushing. The extra portion YM is mainly crushed in the horizontal direction.

  In addition, when the dynamic crushing agent HA is ignited, the crushing force due to the expansion pressure generated by the combustion gas is ejected from the abutting portions SL1 and SL2 extending in the vertical direction of the vertical crushing portion 11 so that the concrete at the pile head portion is mainly vertical. Crush in the direction. That is, as previously disclosed in Patent Document 4 by the present applicant, the shock wave or the expansion wave is reflected on the inner wall of the approximately rhombus-shaped charging space SP, and the reflection shock wave or the reflection expansion wave is shown in FIG. Thus, the stronger the concentration effect is, the closer to the abutting portions SL1 and SL2, the more the concentration effect is further increased by approaching the abutting portions SL1 and SL2. The crack progresses and the crack progresses in the vertical direction as a whole.

  As described above, according to the pile head processing method of the present embodiment, the charging holder 10 to which the dynamic crushing agent is attached includes the horizontal crushing portion 12 on the bottom side, and the supporting member is provided with the charging holder 10 at the top of the pile. If it installs in 24, since the horizontal crushing part 12 is located near a pile top end, arrangement | positioning of the charge holder 10 will become easy.

  Further, by providing the horizontal crushing portion 12 of the charge holder 10 with a horizontal alignment portion 15 extending in the horizontal direction by the first steel plate portion 13 and the second steel plate portion 14, the crushing direction is controlled in the horizontal direction, and the first Since the long sides of the first steel plate portion 13 and the second steel plate portion 14 extend in the horizontal direction, the directivity in the horizontal direction during crushing can be enhanced. Thereby, the horizontal dynamic crushing effect by the crushing agent can be maximized and optimized, and the horizontal dynamic crushing effect can be made more efficient. Moreover, the horizontal circular board (FIG. 10) of the same dimension as a conventional pile diameter can be abbreviate | omitted.

  Therefore, in the pile head crushing work of a cast-in-place concrete pile that requires labor and time for construction, the horizontal crushing surface is formed simultaneously with crushing by applying the charge holder 10 having the horizontal crushing part 12 according to this embodiment. Therefore, it is possible to form a horizontal plane after longitudinal division by crushing using the conventional vertical fracture method, or to install a horizontal circular plate 340 having the same dimensions as the pile diameter in FIGS. 10 (a) and 10 (b) in advance. Compared with the mechanical crushing method, it is possible to greatly reduce the labor and time required for construction.

  Next, another example of the charge holder 10 according to the present embodiment will be described with reference to FIG. FIG. 9 is a front view of an essential part similar to FIG. 3B, showing another example of the charge holder 10 according to the present embodiment.

  9A, the second steel plate portion 14A of the horizontal crushing portion 12 is symmetrical in the horizontal direction with the two sides forming the opening AP (FIG. 3B) at the lower end portion of the vertical crushing portion 11. The point which has the shape chevron part 16 is different from FIG.3 (b), and is the structure similar to the charge holder 10 of FIGS. 1-3 except this. On the bottom side of the charge holder 10A, an opening AP 'having a cross-sectional area approximately twice that of the opening AP in FIG. 3B is formed.

  In order to install the charging holder 10A of FIG. 9, the reinforcing bars 25 and 26, the L-shaped steels 27 and 27, and the flat steels 28 and 28 of the support member 24 of FIG. It can be installed with support. The space with the opening AP ′ in FIG. 9 becomes a space for generating a horizontal fracture surface, and the filled combustion gas enters the gap of the horizontal alignment portion 15 to create an action of opening the gap in the planned direction. Cracks can be propagated.

  As described above, the modes for carrying out the present invention have been described. However, the present invention is not limited to these, and various modifications can be made within the scope of the technical idea of the present invention. For example, as the dynamic crushing agent and crusher, those other than those exemplified can be used.

  Moreover, although the vertical crushing part 11 of the charge holder of the present embodiment is configured by combining two bent steel plates, it is not limited to this and may have other configurations.

  In the present embodiment, four charge holders are arranged. However, the present invention is not limited to this, and may be five or more, or may be three.

  Moreover, although the pile reinforcement bar | burr of this embodiment is a pile head fixed type in which the pile main reinforcement is extended by the fixed part upward like FIG. 6, this invention is not limited to this, For example, a pile main reinforcement is It can also be applied to a pile head semi-fixed type that does not extend upward (see FIG. 10B).

  Moreover, in the charge holder 10 of the present embodiment, the apex angle of the opening AP is 120 ° and the base angle is 30 ° as shown in FIG. 3B and FIG. May be.

DESCRIPTION OF SYMBOLS 10,10A Charge holder 11 Vertical crushing part 12 Horizontal crushing part 13 1st steel plate part 14, 14A 2nd steel plate part 15 Horizontal alignment part 21 Pile main reinforcement 22 Shear reinforcement reinforcement 24 Support member 25, 26 Reinforcement 27 L-shaped steel 28 Flat steel HA Crushing agent P Concrete pile SP Charging space SL1, SL2 Butting part TM Tremy pipe UP Pile top YM Extra part (pile head part)

Claims (7)

A pile head treatment method for pile head treatment of cast-in-place concrete piles,
A plurality of charging holders having a charging space formed inside and a horizontal crushing portion provided on the bottom side and extending in the longitudinal direction,
The horizontal crushing portion has a first plate portion that extends in the horizontal direction, and a second plate portion that forms a horizontal alignment portion that overlaps the first plate portion and communicates with the charging space,
A support member for supporting the charge holder at the horizontal crushing portion is provided in a horizontal direction at a location corresponding to the top of the pile,
The charge holder is installed in the vertical direction of the pile so that the horizontal crushing part is placed on the support member,
After laying the concrete, by igniting the dynamic crushing agent loaded in the charge space, the crushing force is ejected from the leveling part to form a crushing surface on the concrete at the top of the pile head from the top of the pile. Pile head processing method characterized by crushing the pile head part. The charge holder has a vertical crushing portion extending in the longitudinal direction, and the vertical crushing portion is installed so as to be positioned in the vertical direction of the pile,
The pile head processing according to claim 1, wherein a crushing surface is formed on the concrete of the pile head portion by crushing force ejected from the vertical crushing portion when the crushing agent is ignited to crush the pile head portion. Construction method.   The said charge holder is comprised so that the ejection direction of the crushing force from the said horizontal alignment part and the ejection direction of the crushing force from the said vertical crushing part may become a substantially the same direction. The described pile head processing method. The first plate portion and the second plate portion are configured with a rectangular planar shape as a whole,
The pile head processing method according to any one of claims 1 to 3, wherein the charge holder has an opening communicating with the charge space in the horizontal crushing part.   The pile head processing method according to claim 4, wherein the second plate portion is configured as a flat plate, or a portion facing the opening is bent. Tremy pipes for concrete placement are arranged in the vertical direction in the center of the pile,
A plurality of pile main bars are arranged so as to extend in the vertical direction of the pile, and a ring-shaped shear reinforcement bar is arranged so as to surround the plurality of pile main bars,
The pile according to any one of claims 1 to 5, wherein the support member is arranged so that the plurality of charge holders can be installed around the tremy tube using the shear reinforcement. Head treatment method.   The charge holder used for the pile head processing method of any one of Claims 1 thru | or 6.

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