JP7335842B2 - Pile head processing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a pile head treatment method for performing pile head treatment on cast-in-place concrete piles.

As a method of crushing the pile head of cast-in-place concrete piles, the pile head reinforcement is horizontally fractured at a predetermined position with a dynamic crushing agent, and the fractured pile head reinforcement is integrated with the pre-installed suspension base. A method of lifting and moving is known (see Patent Document 1). At that time, it is necessary to cut the edges of the reinforcing bars and concrete by attaching reinforcing bar covers and void materials to each main bar. In reality, the pile head surplus is usually more than 1m in diameter and about 80 to 100cm in height. It is sufficient if it can be installed on the ground, but usually, after the horizontal break, the pile head surplus is cut into pieces of about 15 to 2 cm in size before being transported out. Patent documents 2 and 3, for example, propose a method of splitting and crushing the pile head reinforcement after horizontal breaking.

Japanese Patent Application Laid-Open No. 2018-76650 Japanese Patent Application Laid-Open No. 2019-167690 Japanese Patent Application Laid-Open No. 2019-120095

As described above, conventionally, after the pile head reinforcement portion is horizontally broken, the pile head reinforcement portion after the horizontal break is crushed into small pieces. The entire process of processing is lengthened, and the evacuation time of other workers at the time of crushing is also lengthened, which adversely affects the entire construction period. Therefore, if the horizontal breaking of the pile head reinforcement portion and the breaking of the pile head reinforcement portion into small pieces can be performed almost simultaneously, the number of times of crushing is only one, and the above problem can be solved.

Focusing on the method of creating the charge hole for the dynamic crushing agent and the method of horizontal breaking and splitting of the pile head reinforcement part, the various conventional pile head processing methods, including pre-construction and post-construction, are described below. ,think about.
(1) Chipping method This method uses a manual crusher to manually chip off the excess pile head and dispose of the generated concrete debris.・The vibration is remarkable, and it greatly affects the surrounding environment. There are also construction problems, such as damage to the reinforcing bars of pile heads during work.

(2) Seriyama method This method is relatively effective for medium-sized piles with a pile diameter of 1,200 to 1,600 mm. This is a construction method that horizontally fractures the pile head reinforcement by driving the cracks around the entire circumference of the pile. It requires a certain amount of labor and time, but the certainty is relatively high for a simple construction method. However, in areas where the pile diameter exceeds 2,000 mm, the number of pre-drilled points increases, and the cutting accuracy drops significantly. In addition, when the pile head reinforcement portion is to be divided into small pieces on site, the above-mentioned chipping method must be applied after all.

(3) Crushing method using static crushing agent This is a construction method in which the concrete at the pile head is broken into small pieces by the expanding action of a crushing agent inserted into a sheath pipe or the like installed at the pile head in advance. In this construction method, the preparatory work for the pre-construction is the arrangement and fixing of the sheath pipe, and the static crushing agent is added as the post-construction. In addition, since it is difficult to form a suitable horizontal surface, there is a tendency for a large amount of manual finishing to be carried out.

(4) Horizontal and vertical breaking method for dynamic crushing by vertical pipe type horizontal fins and charge holder method Vertical pipe (cross section: angle steel butt) type horizontal fins (flat steel 2 layers) are attached during pile reinforcement assembly Four charge holders are placed inside the main reinforcement of the pile on the outer circumference of the pile and sealed. At the same time as the pile head reinforcement is horizontally broken by mechanical crushing, gas pressure is ejected vertically and radially from the vertical pipe joint, and the pile is vertically divided into four parts. Although this method does not require any particular time or effort, it has the same drawbacks as (3), such as the need to install related equipment before pile construction, and the difficulty of fixing the charge holder. be done. In addition, it is necessary to close the upper part of the holder with fast-hardening mortar, which requires about one hour of hardening time. In addition, the vertical tube type charge holder is expensive, and it is the most expensive pile head processing method. In addition, since the crushing force in the vertical direction is directed toward the outer circumference, the influence on the pile body is not eliminated, such as the main reinforcing bars of the pile opening outward.

(5) Horizontal breaking with dynamic crushing agent + small split crushing method In this construction method, a dynamic crushing agent is charged by the horizontal hole method, which is a post-construction method, and after horizontal breaking of the pile head excess banking, the additional banking In this method, oblique direction holes (upper and lower) are provided in the part to further subdivide the pile head reinforcement part. Since the required work is divided into horizontal breaking and breaking into small pieces (diagonally up and down), it takes time to drill holes and charges in various places, so significant improvements are required.

(6) Batch crushing method for pile head excess reinforcement A small amount of explosive (explosive cord) crushes the concrete into human-head-sized pieces. The crushing agent used for horizontal breaking does not generate shock waves, so it does not damage the pile itself. Therefore, it is necessary to constrain the outer periphery. In addition, the explosives for small splitting are said to be charged using a vertical pipe (φ22mm) and a spiral CD pipe (φ22mm), but both are installed in the previous construction, and problems such as clogging and deformation occur. is concerned.

Pile head treatment work in urban areas must not only keep noise and vibrations within specified limits, but also reduce them as much as possible so as not to cause anxiety or discomfort to the surrounding area. For that reason, it is desirable to avoid chipping work with a crusher as much as possible. Therefore, the application of a static crushing agent that makes a slight noise when crushing, or a dynamic crushing agent that is high level but only makes an instantaneous noise is applied. It is a prerequisite. On the other hand, in the crushing method using static crushing agents, as mentioned above, inserting the crushing agent is a follow-up work, and the preceding work, such as sheath pipe installation and concrete placement, is greatly affected by damage, deformation, and displacement. Therefore, it cannot be said that the accuracy of crushing is necessarily high, and it can be judged that dynamic crushing is more effective from the viewpoint of environment and workability.

As a current construction method that applies dynamic crushing, 4 to 6 charge holders with horizontal fins (two layers of flat steel) of the vertical pipe (cross section: butt steel angle steel) method are evenly placed inside the main reinforcement of the pile around the circumference of the pile. After the pile head is exposed after the pile construction and excavation work, the dynamic crushing agent is inserted into the charge holder, and the pile head reinforcement is simultaneously broken horizontally and vertically by dynamic crushing by remote control. There is a way. However, since most of the preparation for the charge is done during the assembling of the pile rebar, the work until the pile head is exposed may damage the equipment for the charge, bend the pile rebar, and cause the pile head to be left after crushing. Various obstacles have occurred, such as the pile cannot be lifted. In addition, when the charging hole is vertical, it is necessary to restrain the upper end of the charged crushing agent with a solidifying material in order to function effectively. However, since it took about one hour to harden, the amount of work per day was limited.

Based on the post-construction method where the charge preparation is performed after the pile head is exposed, the charge preparation is performed by a simple method that does not require time, and the pile head excess reinforcement can be broken horizontally reliably by dynamic crushing. Furthermore, as a method of subdividing the pile head reinforcement part, there is a vertical crushing method by horizontal fracture + diagonal hole (upper and lower) by the above-mentioned horizontal hole method, but this is also a horizontal fracture of the pile head reinforcement part and the pile head after fracture The subdivision of the reinforcement portion is a separate process, and the dynamic crushing is performed twice, which takes nearly twice as long.

In view of the problems of the prior art as described above, the present invention provides a pile head processing method that can reliably perform horizontal breaking and small splitting of the pile head reinforcement portion almost simultaneously using a dynamic crushing agent. With the goal.

A pile head treatment method for achieving the above object is a pile head treatment method for performing pile head treatment on cast-in-place concrete piles,
A step of arranging a plurality of horizontal sheath pipes perpendicular to the pile axis direction and having the same height position relative to the top of the pile when assembling the pile reinforcing bars of the concrete pile; A step of arranging obliquely upward with respect to the perpendicular direction to the pile axis from a position corresponding to the outer peripheral surface of the pile head at the height position, and a step of placing concrete at a predetermined position where the pile reinforcing bar is installed; In the concrete pile, a plurality of horizontal charge holes formed in the horizontal direction by the plurality of horizontal sheath tubes and a plurality of oblique charge holes formed obliquely upward with respect to the horizontal direction by the plurality of oblique sheath tubes are charged respectively. A step of charging a chemical material, and a step of horizontally breaking and splitting the pile head surplus portion of the pile head by a dynamic crushing agent in the charged charging material,
The plurality of oblique sheath tubes are provided in the same number as the plurality of horizontal sheath tubes so that each horizontal projected position overlaps each horizontal position of the plurality of horizontal sheath tubes.

According to this pile head treatment method, a charge material is charged into each of a plurality of horizontal charge holes formed horizontally in the pile head and a plurality of oblique charge holes formed diagonally upward with respect to the horizontal direction. After that, for example, the leg wires extending from the igniter of the charge material are connected in series with a plurality of horizontal charge holes and diagonal charge holes, respectively, and wired so that electric conduction is performed in order from the horizontal direction to the diagonal direction. By doing so, after the pile head reinforcement is horizontally fractured by the charging material in the multiple horizontal charging holes, the pile head reinforcement is reduced by the charging material in the multiple diagonal charging holes immediately after that. Can be split and crushed. In this way, by dynamic crushing, it is possible to break and crush the pile head surplus portion from horizontal breakage to small split breakage almost simultaneously and reliably.

In the above pile head processing method, it is preferable that the plurality of horizontal charge holes and the plurality of oblique charge holes have the same openings on the outer peripheral surface of the pile head. This allows charging material into the horizontal and oblique charge holes from a common opening.

Moreover, it is preferable that the horizontal sheath tube and the oblique sheath tube are integrally formed in advance. This facilitates the process of arranging the horizontal sheath tube and the oblique sheath tube.

Also, a portion of the plurality of horizontal charging holes are formed to form a portion of the radial arrangement of the pile center, and at least the same number of horizontal charging holes as the plurality of horizontal charging holes forming the remainder of the radial arrangement. It is preferable that the holes are formed symmetrically with respect to a predetermined pile diameter direction.

Also, the plurality of horizontal charge holes may be formed in a radial arrangement around the center of the pile.

Further, it is preferable that the breaking into small pieces at the plurality of oblique charging holes is slightly delayed from the horizontal breaking at the plurality of horizontal charging holes. Such a slight delay can be achieved, for example, by connecting the legs extending from the igniter of each charge in series first for a plurality of horizontal charge holes and then for a plurality of oblique charge holes in series. It can be realized by connecting with the leg wire connected to the blasting bus, making the whole in series, and wiring so that the current from the blasting bus is directed from the horizontal charging hole to the diagonal charging hole. In addition, it is preferable to adjust the length of the horizontal sheath pipe and the diagonal sheath pipe so that the horizontal sheath pipe and the diagonal sheath pipe do not interfere with the tremie pipe arranged at the center of the pile in the concrete placing step.

ADVANTAGE OF THE INVENTION According to this invention, the pile head processing construction method which can implement the horizontal fracture|rupture and subdivision crushing of a pile head reinforcement part substantially simultaneously and reliably by dynamic crushing can be provided.

FIG. 1( a ) is a plan view of the main part in which the pile reinforcing bars and the pile head are seen through from above to explain the pile head reinforcement portion of the concrete pile in this embodiment, and the pile head in FIG. 1( a ) is seen through from the direction Z. FIG. 10B is a side view of the essential part. Fig. 1(a) is an elevational cross-sectional view of a main part taken along line II-II of Fig. 1(a). It is an elevational cross-sectional view which shows roughly the charge material used for the pile head processing construction method by this embodiment. 4 is a flowchart for explaining main steps S01 to S13 of the pile head treatment method for cast-in-place concrete piles according to the present embodiment. FIG. 3 is a plan view of the main part similar to FIG. 1(a) showing another example in which the total number of horizontal charging holes and oblique charging holes is eight; FIG. 1B is a plan view of the essential parts similar to FIG.

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated using drawing. FIG. 1 is a plan view (a) of the main part of the pile reinforcement and the pile head seen through from above to explain the pile head reinforcement portion of the concrete pile in this embodiment, and the pile head of FIG. It is the principal part side view (b) seen through from Z. FIG. FIG. 2 is an elevational cross-sectional view of the essential part taken along line II-II in FIG. 1(a).

First, the cast-in-place concrete pile and pile reinforcing bars in this embodiment will be described with reference to FIG. As shown in FIGS. 1(a) and 1(b), the pile reinforcing bars for constructing the cast-in-place concrete pile 10 are composed of a predetermined number of pile main reinforcements 11 extending in the pile axial direction of the concrete pile 10 on the circumference when viewed from above. , and ring-shaped shear reinforcements 12 are arranged so as to surround a predetermined number of pile main reinforcements 11 . A predetermined number of shear reinforcing bars 12 are arranged at equal intervals in the pile axis direction of the concrete pile 10, as shown in FIG. 1(b).

As shown in FIGS. 1(a) and 1(b), the concrete pile 10 is formed by pouring concrete after a pile reinforcing bar is installed at a predetermined position. located above.

Next, in the pile head processing method according to this embodiment, the pile head surplus portion 21 of the concrete pile 10 is horizontally broken by the horizontal breaking method of the horizontal hole method and the small split breaking method of the oblique hole method. An oblique charge hole for crushing into small pieces will be described.

In FIGS. 1(a) and 1(b), the total number of horizontal charge holes for horizontal breaking of the pile head reinforcement portion 21 is nine, and the total number of oblique charge holes for splitting the pile head reinforcement portion 21 into small pieces. are the same number of nine. A plurality of horizontal charging holes 31-39 are provided perpendicular to the pile axis and at the same height relative to the pile crest 22. As shown in FIG.

As shown in FIG. 1(a), the horizontal charging holes 31, 36, 37 are arranged radially around the pile center P, and the horizontal charging holes 32-35, 38, 39 are arranged non-radially. A plurality of horizontal charging holes 37 , 38 , 39 shorter than the horizontal charging holes 31 , 36 are located at intermediate positions between the horizontal charging holes 31 , 36 . The horizontal charge hole 37 is located intermediate the horizontal charge holes 31 and 36 and on the predetermined pile diametrical axis r. The horizontal charging holes 32-35, 38, 39 are provided parallel to the horizontal charging holes 31, 36, respectively.

That is, horizontal charging holes 32 and 33 are parallel and substantially parallel to horizontal charging hole 31; likewise horizontal charging holes 34 and 35 are parallel and substantially parallel to horizontal charging hole 36; is. Also, the horizontal charge holes 33, 32, 38 and 34, 35, 39 are line-symmetrical with respect to a predetermined pile diameter direction axis r. Further, the innermost portions of the horizontal charging holes 32 and 33 and the innermost portions of the horizontal charging holes 34 and 35 are arranged so as to deviate from the pile center P. Also, the length of each horizontal sheath tube corresponding to the horizontal charge holes 31 and 36 is adjusted so as not to interfere with the tremie tube T used when placing concrete.

Specific positions, lengths and diameters of the horizontal charging holes 31 to 39 and the oblique charging holes 41 to 49 in this example will be described.

On the outer peripheral surface of the piles of the horizontal charging holes 38, 31, 32, 33, the pile circumference between the horizontal charging holes 38 and 31, the pile circumference between the horizontal charging holes 31 and 32, and the horizontal The positions of the pile outer peripheral surfaces of the horizontal charging holes 38, 31, 32, and 33 are set so that the peripheral length of the pile between the charging holes 32 and 33 is substantially the same. The position of the pile outer peripheral surface is similarly set for the horizontal charge holes 39, 36, 35, and 34 as well. Therefore, the spacing between horizontal charging holes 38 and 31, the spacing between horizontal charging holes 31 and 32, and the spacing between horizontal charging holes 32 and 33 are substantially the same. there is The horizontal charge holes 39, 36, 35 and 34 are similarly spaced substantially the same.

As indicated by broken lines in FIG. 1(a), the horizontal cross-sectional area of the pile plane is divided into a plurality of regions C, D, E, F, G, H, and I with respect to the pile diametrical axis r. Regions C and I, D and H, E and G are each symmetrical about the pile diameter axis r, and region F is the remainder of regions C-E and G-I. Regions C to E correspond to horizontal charging holes 33, 32 and 31, regions G to I correspond to horizontal charging holes 36, 35 and 34, and region F corresponds to horizontal charging holes 37 to 39. Each of the regions C, D, E, F, G, H, and I is defined by the division line indicated by the dashed line at the intermediate position between the charge hole and the adjacent charge hole, the predetermined pile diametrical axis r, and the outer circumference of the pile. defined.

The horizontal charging holes 32 in region D are formed substantially centrally and parallel to the dashed demarcation lines on both sides defining region D. As shown in FIG. The horizontal charging holes 31 in the region E are formed substantially in the center and parallel to the dashed demarcation lines defining the region E on both sides. The horizontal charge hole 33 in the area C is almost parallel to the division line indicated by the broken line defining the area C, and the concrete is damaged when the concrete pile 10 is horizontally broken at the top end 22 of the concrete pile 10 (Fig. 1(b)). are placed in such a way that they do not exist. The horizontal charge holes 35, 36, 34 are similarly arranged. The horizontal charge hole 37 in region F is positioned on the pile diametrical axis r, and the charge holes 38,39 are arranged generally parallel to the horizontal charge holes 31,36, as described above.

In FIG. 1(a), the horizontal charge holes 33, 32, 31 each share a portion of the horizontal fracture of the pile, and the areas of regions C, D, and E are the shared fracture cross-sectional areas. Similarly, the horizontal charge holes 34, 35, 36 each share a portion of the horizontal breakage of the pile, and the areas of regions I, H, G are the respective share breakage areas. Also, the horizontal charging holes 37 to 39 each share a portion of the horizontal fracture of the pile, and the area of region F is the shared fracture area.

The areas of each of the regions C, D, E, F, G, H, and I are calculated, and the charging amount of the dynamic crushing agent is determined according to the calculated area. , 37, 39, 36, 35 and 34 are set to lengths corresponding to the charge amount. In this way, since the charging amount of the dynamic crushing agent required for each charging hole is determined from the shared fracture area of each of the regions C to I, the required charging amount of the dynamic crushing agent can be accommodated. At least one of the length and diameter of each charge hole is adjusted.

Also, as shown in FIGS. 1(a), 1(b) and 2, the oblique charge holes 41 to 49 are positioned at the same height as the horizontal charge holes 31 to 39 and correspond to the outer peripheral surface of the pile head. It is provided diagonally upward from the position with respect to the direction orthogonal to the pile axis. Each of the oblique charging holes 41-49 is formed so that its horizontal projection position overlaps with each horizontal position of the horizontal charging holes 31-39. The openings of the horizontal charging holes 31 to 39 and the openings of the oblique charging holes 41 to 49 in the pile head outer peripheral surface 20a are common.

The plurality of horizontal charging holes 31-39 and the plurality of diagonal charging holes 41-49 are formed by arranging horizontal sheath pipes and diagonal sheath pipes in the pile head 20 and embedding them in concrete. The horizontal sheath tubes of the horizontal charging holes 31-39 and the oblique sheath tubes of the oblique charging holes 41-49 are integrally formed of, for example, a plastic tube so that their openings are common. That is, as shown in FIG. 2, the horizontal sheath tube of the horizontal charging hole 31 and the oblique sheath tube of the oblique charging hole 41 are integrally constructed so as to have a common opening 59. The tube is inclined at an angle .theta. The angle θ is determined by the relationship between the pile diameter and the height of all pile head reinforcements. That is, the angle θ is determined so that the upper end of the oblique charge hole 41 is buried in the pile head reinforcement portion by at least 50 mm. The opening 59 is exposed on the pile head outer peripheral surface 20a after the concrete is poured, and the charging material can be inserted. The horizontal sheath tube of the other horizontal charging hole and the oblique sheath tube of the other oblique charging hole are integrally constructed so as to have a common opening, respectively, as in FIG.

The horizontal sheath tube length L1 of the horizontal charging hole 31 in FIG. 2 and the oblique sheath tube length L2 of the oblique charging hole 41 have the following relationship.
L1 = L2 cos θ
The angle θ between the oblique charging hole 41 and the horizontal charging hole 31 can be set to, for example, 30°, but is not limited to this. Other angles may be used as long as they are buried more than 50 mm.

FIG. 3 is a cross-sectional elevational view schematically showing the charging material used in the pile head processing method according to this embodiment. As shown in FIG. 3, a dynamic crushing agent 61 and an igniter 62 are arranged in the charge material 60 . That is, the propellant material 60 contains a granular dynamic crushing agent 61 and an igniter 62 in a flexible vinyl tube 63, and plastic plugs 65a and 65a are provided at both ends of the vinyl tube 63. After 65b is fitted, sealing members 66a and 66b stop water and are sealed. A leg wire 64 extends from the igniter 62 to the outside.

As the dynamic crushing agent 61, various known crushing agents can be used, for example, those containing cupric oxide, aluminum, and magnesium sulfate heptahydrate as main components can be used. High-temperature, high-pressure steam is generated with the reduction reaction, and the generated expansion pressure is used as a crushing force. In addition, it is also possible to use an integrated cartridge containing a gas generating agent such as bromate as a main ingredient and an igniter.

In addition, the charging amount of the dynamic crushing agent 61 used in the horizontal charging holes 31 to 39 is based on the shared breaking area shared by each horizontal charging hole 31 to 39 with respect to the horizontal cross-sectional area of the pile that breaks horizontally. is set. That is, the charging material 60 charged in each of the horizontal charging holes 31 to 39 participates in the horizontal fracture of the pile according to the charging amount of the dynamic crushing agent 41 therein, and part of the horizontal fracture of the pile. However, by setting the charge amount of the dynamic crushing agent 61 in the charge material 60 so that the shared breaking area for each horizontal charge hole is equal, for example, horizontal breaking of the pile is carried out efficiently. can. At least one of the length and diameter of each horizontal charge hole 31-39 is adjusted based on the required charge of dynamic fragmentation agent 61 in the charge material 60 . In FIG. 1, the diameter of each of the horizontal charging holes 31 to 39 is fixed, and the required charging amount of the dynamic crushing agent 61 is adjusted by adjusting the length. In the horizontal charging holes 37 to 39, although the configuration is the same as that of FIG. material is inserted.

In addition, the amount of charge of the dynamic crushing agent 61 for crushing into small pieces used in the oblique charge holes 41 to 49 is set for each oblique charge with respect to the vertical cross-sectional area of the pile head excess reinforcement portion 21 to be crushed into small pieces. It is set based on the shared fracture area shared by the holes 41 to 49 . At least one of the length and diameter of each oblique charge hole 41-49 is adjusted based on the required charge of dynamic fragmentation agent 61 in the charge material 60. FIG. In FIG. 1, the required charge amount of the dynamic crushing agent 61 is adjusted by setting the diameter of each of the oblique charging holes 41 to 49 constant and adjusting the length.

As described above, stable crushing can be expected by setting the amount of charge based on the shared area of each of the horizontal charge holes 31-39 and each of the oblique charge holes 41-49. In this case ^, the target fracture surfaces for the amount of charge are, in FIGS. × (pile diameter/2) ² × (1/cos ² θ)) × 4], and the area of the oblique fracture surface is [π × (pile diameter/2) ² × (1/cos ² θ)]. Become.

Next, main steps S01 to S13 of the pile head treatment method for cast-in-place concrete piles according to the present embodiment will be described with reference to the flowchart of FIG. First, as shown in FIGS. 1(a) and 1(b), pile reinforcing bars are assembled from a predetermined number of pile main reinforcements 11 and a predetermined number of shear reinforcements 12 (S01).

Horizontal sheath tubes and oblique sheath tubes for horizontal charging holes 31 to 39 and diagonal charging holes 41 to 49 in FIGS. 1(a) and 1(b) and FIG. 2 are prepared (S02). Both sheath tubes consist of an integrated plastic tube with a horizontal charge hole 31 and an oblique charge hole 41 as shown in FIG.

As shown in FIGS. 1(a) and 1(b), a pair of lightweight steel materials 51 and 52 are placed as a pre-construction for assembling the pile reinforcing bars, and each sheath pipe made of an integrated plastic pipe as shown in FIG. are supported by lightweight steel materials 51 and 52 (S03). Each sheath tube is fixed by a pair of lightweight steel members 51 and 52 and is in a stable supported state.

Next, the pile reinforcing bars are erected at the pile installation position, and after adjusting the positions of the horizontal charging holes 31 to 39 and the oblique charging holes 41 to 49 with sheath tubes, concrete is poured into the pile reinforcing bars through the tremie tubes T. Then, pile construction is performed (S04).

Next, earthwork and excavation are performed (S05), the pile head 20 of the concrete pile 10 in FIG. (For example, the opening 59 in FIG. 2) is exposed (S06). Each sheath tube becomes a horizontal charge hole 31-39 and an oblique charge hole 41-49, and each common opening thereof becomes a charge material insertion port.

Next, as shown in FIG. 3, the dynamic crushing agent 61 and the igniter 62 are stuffed in the vinyl tube 63 to prepare the charged material 60, and the charged material 60 is inserted into the horizontal charging holes 31 to 39 at an angle. It is inserted into the charging holes 41 to 49 so as to reach the deep end from each opening (S07).

Next, after each leg wire 64 connected to the igniter 62 of the charge material 60 is taken out of the horizontal charge holes 31 to 39 and the oblique charge holes 41 to 49, the remaining fillers such as sand are removed. The gap is filled and each opening (for example, opening 59 in FIG. 2) is sealed (S08).

Next, the leg wires 64 of the igniters 62 of the respective explosive materials 60 taken out from the diagonal charging holes 41 to 49 are wired so as to be connected in series, and in the horizontal charging holes 31 to 39 The leg wires 64 of the igniters 62 of the propellant materials 60 taken out from the outlet are wired so as to be connected in series (S09).

Next, an explosion-proof sheet (not shown) is wrapped around the entire pile head reinforcement portion 21 shown in FIGS. The oblique charge holes 41 to 49 for crushing the pile head reinforcement portion 21 into small pieces are contained within the pile head reinforcement portion 21, and their ends are not exposed to the outside. There is no need for an upward ejection prevention means for constraining the upper portion of the charge holder with a hardening material such as quick-hardening mortar, and explosion-proof curing with an explosion-proof sheet is sufficient.

Next, the wiring connecting the leg wires 64 of the igniter 62 of the charge material 60 was extended from the blaster (not shown) so as to form a horizontal charge hole series leg wire from the oblique charge hole series leg wire. It is connected to a blasting bus (not shown) (S11).

Next, each igniter 42 is ignited by remote control using a blaster, and each dynamic crushing agent 61 in the horizontal charging holes 31 to 39 is ignited in advance by serial wiring, thereby igniting the horizontal charging hole 31. ~ 39, the crushing force of each dynamic crushing agent 61 horizontally breaks the pile head surplus portion 21 of the pile head 20 in FIG. By igniting each dynamic crushing agent 61 in 49, the pile head reinforcement portion 21 is ignited by the crushing force of each dynamic crushing agent 61 in the oblique charging holes 41 to 49 slightly later than the horizontal fracture. It is crushed into small pieces (S12).

That is, the cracks due to the crushing forces generated by the respective dynamic crushing agents 61 in the horizontal charge holes 31 to 39 almost simultaneously move toward the other closest horizontal charge hole, which is another source of crushing force. The pile head reinforcement portion 21 is horizontally fractured by the cracks propagating in four radial directions and connecting to each other. In addition, since the cracks due to the crushing forces generated almost simultaneously by the respective dynamic crushing agents 61 in the oblique charging holes 41 to 49 move toward the nearest other charging hole that is another source of the crushing force, the oblique charging The hole and the cracks from the horizontal charging hole at the horizontal projection position of the hole are connected to each other, and the cracks from the adjacent oblique charging holes are connected to each other, whereby the pile head surplus portion 21 is broken into small pieces.

Next, the small pieces of the pile head reinforcement portion 21 that have been horizontally broken and broken into small pieces are carried out from the construction site (S13).

According to the pile head processing method of the present embodiment, the plurality of horizontal charging holes 31 to 39 formed in the horizontal direction in the pile head 20 and the plurality of diagonal charging holes 41 formed diagonally upward with respect to the horizontal direction . The pile head reinforcement portion 21 is horizontally broken by the chemical material 60, and preferably, the pile head reinforcement portion 21 is split into small pieces by the charging material 60 in the plurality of oblique charging holes 41 to 49 with a slight delay from this horizontal breaking. Can be crushed. In this manner, the dynamic crushing agent 61 can reliably perform horizontal breaking and small splitting of the pile head reinforcement portion 21 almost simultaneously.

Compared to the conventional method of horizontally breaking the pile head reinforcement portion and then splitting and crushing the pile head reinforcement portion after horizontal breaking, the horizontal breakage of the pile head reinforcement portion 21 and the small size of the pile head reinforcement portion 21 are reduced. Since splitting and crushing can be performed almost simultaneously, the number of crushing is only one, and the entire process of pile head treatment can be shortened. It can reduce the impact on the surface and improve construction efficiency.

In addition, in the pile head treatment of the concrete pile 10, the horizontal charging hole and the diagonal charging hole are replaced with the sheath pipe, and the pre-construction for installing the sheath pipe is performed when the pile reinforcing bars are assembled, and the post-construction after concrete casting is charged. By using only the wiring and ignition method, horizontal charge holes and diagonal charge holes are formed at positions corresponding to the sheath pipes, and there is no need to drill charge holes in the concrete pile. Work efficiency is greatly improved compared to the construction method with

In addition, as shown in FIG. 1(a), even when the concrete pile 10 is positioned at the corner CR formed by the boundary lines B1 and B2 of the construction area, all the charging holes 31 to 39 and 41 to 49 are 3 can be inserted without interfering with obstacles such as outer walls existing on boundary lines B1 and B2. Therefore, the arrangement of the charging holes 31 to 39 and 41 to 49 as shown in FIG. 1(a) is applicable regardless of the construction position of concrete piles within the construction area.

In addition, in FIGS. 1(a) and 1(b), the total number of horizontal charging holes and oblique charging holes is nine, respectively, but the present embodiment is not limited to this. The horizontal charging hole 37 and the oblique charging hole 47 may be omitted, and the total number of each may be eight.

Next, FIG. 5 shows another example in which the total number of horizontal charging holes and oblique charging holes is eight. As shown in FIG. 5, among the horizontal charging holes 71 to 78, horizontal charging holes 73, 74, 77, and 78 are radially arranged around the pile center P, and the same number of charging holes as the remaining radially arranged charging holes are arranged. A plurality of horizontal charging holes 71, 72, 75, 76 are non-radially arranged. The non-radially arranged horizontal charging holes 71, 72 are arranged substantially parallel to the horizontal charging hole 73 and are spaced equally between adjacent horizontal charging holes. Similarly, the non-radially arranged horizontal charging holes 75, 76 are arranged generally parallel to the horizontal charging hole 77 and with equal spacing between adjacent charging holes. Also, the horizontal charge holes 71, 72 and 75, 76 are line-symmetrical with respect to a predetermined pile diameter direction axis r. Further, the innermost portions of the horizontal charging holes 71 and 72 and the innermost portions of the horizontal charging holes 75 and 76 are arranged so as to deviate from the pile center P. The length of each horizontal sheath pipe corresponding to the radially arranged horizontal charge holes 73, 74, 77, 78 of the pile center P is adjusted so as not to interfere with the tremie pipe used when placing concrete. ing.

In addition, diagonal charging holes 81 to 88 are provided corresponding to the horizontal charging holes 71 to 88 in the same manner as in FIG. 1(b) and FIG. Each of the horizontal charging holes 71-88 is positioned at the horizontal projection position of each of the oblique charging holes 81-88. The horizontal charging holes 71 to 88 and the oblique charging holes 81 to 88 are integrally formed of a plastic tube or the like so that the horizontal sheath tube and the oblique sheath tube have a common opening, as in FIG. be.

As in the case of FIG. 1, the charging amount of the dynamic crushing agent 61 of the charging material 60 is the shared breaking area of each of the horizontal charging holes 71 to 78 with respect to the horizontal cross-sectional area of the horizontally broken pile. Also, it is set based on the shared breaking sectional area that each of the oblique charging holes 81 to 88 shares with respect to the vertical sectional area of the pile head reinforcement portion 21 to be broken into small pieces.

According to the example of FIG. 5, horizontal crushing and splitting of the pile head reinforcement portion 21 can be performed in the same manner as in FIGS. Further, even when the concrete pile 10 is positioned at the corner CR formed by the boundary lines B1 and B2 as in FIG. Material 60 can be inserted.

Next, FIG. 6 shows yet another example in which all the horizontal charge holes are radially arranged around the pile center. As shown in FIG. 6, all (eight) horizontal charging holes 91 to 98 are radially arranged around the pile center P. As shown in FIG. The length of each horizontal sheath pipe corresponding to the horizontal charging holes 91 to 98 is adjusted so as not to interfere with the tremie pipe used when placing concrete. Further, diagonal charging holes 101 to 108 are provided corresponding to the horizontal charging holes 91 to 98 in the same manner as in FIG. 1(b) and FIG. Horizontal charging holes 91 to 98 are positioned at the horizontal projection positions of the oblique charging holes 101 to 108, respectively. Each of the horizontal charging holes 91 to 98 and each of the oblique charging holes 101 to 108 is integrally constructed of a plastic tube or the like so that the horizontal sheath tube and the oblique sheath tube have a common opening, as in FIG. be. According to the example of FIG. 6, horizontal crushing and splitting of the pile head reinforcement portion 21 can be performed in the same manner as in FIGS.

Although the embodiments for carrying out the present invention have been described above, the present invention is not limited to these, and various modifications are possible within the scope of the technical idea of the present invention. For example, in FIGS. 1, 5, and 6, the number of each of the horizontal charging holes and the oblique charging holes is 8 to 9, but the present invention is not limited to this, depending on the pile diameter and the like. Of course, it can be increased or decreased as appropriate. In other words, the number of charging holes is determined in advance by testing the dynamic crushing agent capacity per square meter with respect to the cross-sectional area, and the number is determined by assuming the range that will be cut by the gas pressure during crushing. It varies depending on the pile diameter and the diameter of the charge hole.

In addition, the depth of the charge stuffed into each charge hole is about 40% of the length of the charge hole, similar to the charge length ratio of the horizontal hole method. It is preferable to adjust the diameter of 63 . In this case, the length of the propellant material also includes the igniter.

Further, the charging amount of each oblique charging hole for crushing into small pieces in the pile head reinforcement portion 21 may be determined, for example, by the sharing breaking volume, in addition to being determined by the sharing breaking cross-sectional area. good.

According to the present invention, in pile head processing of cast-in-place concrete piles, it is possible to omit drilling, which is the post-processing that takes the most time, and to perform horizontal breaking and small splitting of the pile head reinforcement portion almost simultaneously. Therefore, the time is greatly reduced, and the entire process of pile head treatment can be shortened by more than 50%. In addition, since manpower and work period required for drilling are not required, significant cost reduction can be achieved.

10 Concrete pile 11 Pile main reinforcement 12 Shear reinforcement 20 Pile head 20a Pile head outer peripheral surface 21 Pile head surplus 22 Pile top 31-39 Horizontal charge holes 41-49 Diagonal charge holes 51, 52 Pair of lightweight members 59 Opening 60 charging material 61 dynamic crushing agent 62 igniter 63 vinyl tube 64 leg lines 71-78, 91-98 horizontal charging holes 81-88, 101-108 oblique charging holes

Claims (6)

A pile head treatment method for treating the pile head of a cast-in-place concrete pile,
A step of arranging a plurality of horizontal sheath pipes perpendicular to the pile axis direction and having the same height position relative to the top of the pile when assembling the pile reinforcing bars of the concrete pile;
a step of arranging a plurality of oblique sheath pipes at the same height position at the time of assembly from a position corresponding to the outer peripheral surface of the pile head toward an obliquely upward direction with respect to the perpendicular direction to the pile axis;
A step of placing concrete at a predetermined position where the pile reinforcing bars are installed;
In the concrete pile, a plurality of horizontal charge holes formed in the horizontal direction by the plurality of horizontal sheath tubes and a plurality of oblique charge holes formed obliquely upward with respect to the horizontal direction by the plurality of oblique sheath tubes are charged respectively. a step of loading the medicinal material;
horizontally breaking and splitting the pile head reinforcement portion of the pile head by a dynamic crushing agent in the loaded charging material,
The pile head processing method, wherein the plurality of oblique sheath pipes are provided in the same number as the plurality of horizontal sheath pipes so that each horizontal projected position overlaps each horizontal position of the plurality of horizontal sheath pipes. The pile head processing method according to claim 1, wherein the openings of the plurality of horizontal charging holes and the openings of the plurality of oblique charging holes are aligned on the outer peripheral surface of the pile head. The pile head processing method according to claim 1 or 2, wherein the horizontal sheath pipe and the oblique sheath pipe are integrally formed in advance. a portion of the plurality of horizontal charge holes are formed to form a portion of a radial arrangement about the pile center;
The pile head treatment according to any one of claims 1 to 3, wherein at least the same number of horizontal charging holes as the rest of the radially arranged horizontal charging holes are formed line-symmetrically with respect to a predetermined pile diameter direction. Construction method. The pile head processing method according to any one of claims 1 to 3, wherein the plurality of horizontal charging holes are formed so as to form a radial arrangement around the center of the pile. 6. The pile head processing method according to any one of claims 1 to 5, wherein the breaking into small pieces at the plurality of oblique charging holes is slightly delayed from the horizontal breaking at the plurality of horizontal charging holes.

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