JP7277743B2 - Prefabricated pile holding device and foundation pile construction method - Google Patents

Description

The present disclosure relates to prefabricated pile retention devices and foundation pile construction methods.

Some foundation piles are constructed by a pre-boring method in which a pile hole is excavated using a pile driver, a hardening material such as cement milk is injected into the pile hole, and a prefabricated pile is further submerged. In order to place the pile head of the prefabricated pile deeper than the ground surface, a support rod may be used to hold the prefabricated pile in the pile hole until the hardening material solidifies. At this time, fixtures are attached to the support rods, and the fixtures are arranged on bases arranged to sandwich the support rods. (See Patent Document 1).

JP-A-6-146278

The fixture disclosed in Patent Document 1 is fixed to the support rod by mutually fastening two fixing pieces with bolts. There is a risk that the fixture may slip on the support rod depending on the load of the prefabricated pile.
In view of the above circumstances, an object of at least one embodiment of the present invention is to provide a prefabricated pile holding device capable of reliably holding a prefabricated pile at a predetermined depth in a pre-boring method, and a foundation pile construction method using the same. to do.

(1) A prefabricated pile holding device according to at least one embodiment of the present invention,
In a holding device for a ready-made pile sunk in a pile hole,
a pile engaging portion that can be engaged with the ready-made pile;
a shaft portion connected to the pile engaging portion;
a fixture that can be fitted onto the shaft;
a girder member arranged to traverse the pile hole;
a height adjuster disposed between the fixture and the beam member;
with
A plurality of recesses are provided in the shaft portion at intervals in the axial direction of the shaft portion,
A protrusion provided on the fixture or an engagement pin inserted through the fixture can be selectively engaged with any one of the plurality of recesses.

According to the configuration (1) above, the fixture is fixed to the shaft in the axial direction of the shaft by engaging the projection of the fixture or the engaging pin with the recess of the shaft. Therefore, the fixture is restricted from slipping on the shaft, and the prefabricated pile can be reliably held at a predetermined depth.

(2) In some embodiments, in the above configuration (1),
The fixture is
two halves;
a first connecting pin that pivotally connects one side of the two half members in the circumferential direction to each other;
including.
According to the above configuration (2), since the two half-split members are connected by the first connecting pin, the fixture can be easily attached to the shaft.

(3) In some embodiments, in the above configuration (2),
The fixture is
It further includes a second connecting pin arranged in the axial direction of the shaft portion and connecting the other sides of the two half-split members to each other in the circumferential direction.
According to the above configuration (3), since the other end sides of the two half-split members are connected by the second connecting pin arranged in the axial direction of the shaft, the fixture can be easily attached to the shaft.

(4) In some embodiments, in any one of the above configurations (1) to (3),
The height adjuster is a hydraulic journal jack.
According to the above configuration (4), by using a hydraulic journal jack, the height and inclination of the fixture can be easily adjusted, and the ready-made pile can be set vertically and reliably at a predetermined depth. .

(5) A foundation pile construction method according to at least one embodiment of the present invention,
An excavation step of excavating a pile hole;
a solidification material injection step of injecting a solidification material into the pile hole;
A prefabricated pile embedding step of submerging a prefabricated pile into the pile hole after the solidifying material injection step;
a holding step of holding the ready-made pile in the pile hole until the solidifying material solidifies;
with
In the holding step, the ready-made pile is held using the ready-made pile holding device according to any one of the configurations (1) to (4).

According to the above configuration (5), the fixture is fixed to the shaft in the axial direction of the shaft by engaging the projection of the fixture or the engaging pin with the recess of the shaft. Therefore, the fixture is restricted from slipping on the shaft, and the prefabricated pile can be reliably held. As a result, the prefabricated pile can be reliably installed at a predetermined depth.

According to at least one embodiment of the present invention, a prefabricated pile holding device capable of reliably holding a prefabricated pile at a predetermined depth in a pre-boring method and a foundation pile construction method using the same are provided.

1 is a diagram schematically showing a prefabricated pile holding device according to an embodiment of the present invention together with a prefabricated pile; FIG. FIG. 4 is a plan view schematically showing a holding device; FIG. 4 is a schematic side view of part of the holding device; FIG. 4 is a schematic perspective view of part of the holding device; It is a front view which shows a fixture roughly. It is a perspective view which shows a fixture roughly. It is a flow chart which shows a schematic procedure of a foundation pile construction method concerning one embodiment of the present invention. It is a figure which shows the schematic structure of the foundation pile constructed|assembled by the foundation pile construction method mentioned above. It is a top view which shows the schematic structure of the fixture which concerns on other embodiment of this invention, (a) has shown the closed state, (b) has shown the open state. FIG. 10 is a front view showing a schematic configuration of the fixture of FIG. 9; FIG. 5 is a plan view showing a schematic configuration of a fixture according to another embodiment of the present invention; FIG. 10 is a front view schematically showing a fixture according to another embodiment of the present invention together with part of the shaft;

Several embodiments of the present invention will now be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention, and are merely illustrative examples. do not have.

FIG. 1 is a diagram schematically showing a prefabricated pile holding device (hereinafter simply referred to as a holding device) 1 together with a prefabricated pile 3 according to an embodiment of the present invention. FIG. 2 is a plan view schematically showing the holding device 1. FIG. FIG. 3 is a schematic side view of part of the holding device 1 . FIG. 4 is a perspective view schematically showing part of the holding device 1. FIG.

As shown in FIGS. 1 and 2, the holding device 1 holds the prefabricated pile 3 sunk in the pile hole 5 until the solidifying material 6 poured into the pile hole 5 solidifies. The holding device 1 includes a stake engagement portion 7 , a shaft portion 9 , a fixture 11 , a beam member 13 and a height adjuster 15 .

The pile engaging portion 7 can be engaged with the ready-made pile 3 . For example, the pile engaging portion 7 has a cylindrical shape, and the peripheral wall of the pile engaging portion 7 is provided with an L-shaped engaging groove 7a when viewed from the front. The pile head of the prefabricated pile 3 is provided with a protrusion 3a to be inserted into the engagement groove 7a so as to protrude radially from the pile head. After the protrusion 3a is inserted into the vertical portion of the engagement groove 7a for a predetermined length in the axial direction of the prefabricated pile 3, the prefabricated pile 3 is rotated relative to the pile engaging portion 7, so that the protrusion 3a moves into the engagement groove. It enters the horizontal portion of 7a, and the ready-made pile 3 and the pile engaging portion 7 are engaged in the vertical direction. From this state, by rotating the ready-made pile 3 in the opposite direction relative to the pile engaging portion 7, the vertical engagement between the ready-made pile 3 and the pile engaging portion 7 can be released.

The shaft portion 9 continues to the pile engaging portion 7 and is arranged coaxially above the ready-made pile 3 . The shaft portion 9 may be separable from the pile engaging portion 7, or may be integrated therewith.
The fixture 11 can be fitted onto and fixed to the shaft portion 9 . A configuration of the fixture 11 will be described later.

The girder members 13 are arranged so as to sandwich the shaft portion 9 so as to traverse the pile hole 5 . Preferably, on the ground surface, for example, a U-shaped base 17 in plan view is installed so as to surround the opening of the pile hole 5, and two girder members 13 are installed on the base 17 so as to sandwich the shaft portion 9. be done. The girder member 13 may also be U-shaped in plan view. In this case, the base 17 and the girder member 13 are arranged in a parallelepiped shape in plan view.
A height adjuster 15 is arranged between the fixture 11 and the beam member 13 . For example, two height adjusters 15 are arranged one each on the two beam members 13 and arranged on both sides of the shank 9 .

Here, FIG. 3 is a front view schematically showing the pile engaging portion 7, the shaft portion 9 and the fixture 11. As shown in FIG. FIG. 4 is a perspective view schematically showing the pile engaging portion 7, the shaft portion 9 and the fixture 11. As shown in FIG. FIG. 5 is a front view schematically showing the fixture 11. FIG. FIG. 6 is a perspective view schematically showing the fixture 11. FIG.
As shown in FIGS. 3 to 6, in this embodiment, the outer peripheral surface of the shaft portion 9 is provided with a plurality of recesses 19 spaced apart in the axial direction of the shaft portion 9 . For example, the shaft portion 9 has a cylindrical shape, and each recess 19 is formed by a circumferential groove 19a.

One or more protrusions 21 are provided on the inner peripheral surface of the fixture 11 . The convex portion 21 is configured by, for example, a ridge 21 a extending in the circumferential direction of the fixture 11 . The protrusion 21 protrudes radially inward from the inner peripheral surface of the fixture 11 , and enters one of the plurality of recesses 19 in a state in which the inner peripheral surface of the fixture 11 is close to the outer peripheral surface of the shaft section 9 . and selectively engageable.

According to the above configuration, the fixing tool 11 is fixed to the shaft part 9 in the axial direction of the shaft part 9 by engaging the convex part 21 of the fixing tool 11 with the concave part 19 of the shaft part 9 . Therefore, the fixture 11 is restricted from slipping on the shaft 9, and the prefabricated pile 3 can be reliably held at a predetermined depth.
Further, by adjusting the height and inclination of the fixture 11 with the height adjuster 15, the ready-made pile 3 can be reliably held vertically at a predetermined depth.

In some embodiments, the cross-sectional shape of the circumferential groove 19a is trapezoidal (see FIG. 3). By making the cross-sectional shape of the circumferential groove 19a trapezoidal, it is possible to facilitate engagement with the ridge 21a.

In some embodiments, a plurality of protrusions 21a may be provided spaced apart in the axial direction of the fixture 11 (see FIGS. 5 and 6). By providing a plurality of protrusions 21a, the fixture 11 can be more reliably engaged with the shaft. The cross-sectional shape of the ridge 21a may be trapezoidal, rectangular, or the like.

In some embodiments, fixture 11 is made up of two halves 23, as shown in FIGS. Each half-split member 23 includes a semi-cylindrical portion 25 arranged along the outer peripheral surface of the shaft portion 9 , a flange portion 27 protruding radially outward from one end of the semi-cylindrical portion 25 in the axial direction, and a circumference of the semi-cylindrical portion 25 . Ears 29 protrude radially outward from the directional side edges. The inner peripheral surface of the semi-cylindrical portion 25 is provided with, for example, two ridges 21a extending in the circumferential direction. The ear portion 29 is provided with through holes through which bolts 31 are inserted, and the two half members 23 are connected to each other by a plurality of bolts 31 and fixed to the shaft portion 9 .
3 and 5, the half-split member 23 on the right side is shown in cross section.

According to the above configuration, the fixture 11 is composed of two half-split members 23, and each half-split member 23 can be moved separately. Therefore, one worker does not need to move the two half-split members 23 at the same time, and each half-split member 23 can be easily moved.

In some embodiments, fixture 11 includes reinforcing ribs 33 that reinforce between semi-cylindrical portion 25 and flange portion 27, and reinforcing ribs 35 that reinforce between semi-cylindrical portion 25 and ear portion 29. more ready.
According to the above configuration, the reinforcement by the reinforcing ribs 33 and 35 can increase the rigidity of the fixture 11, and the prefabricated pile 3 can be reliably held at a predetermined height.

In some embodiments, height adjuster 15 is a hydraulic journal jack 15a, as shown in FIG. The journal jack 15 a is arranged between the beam member 13 and the flange portion 27 .
According to the above configuration, by using the hydraulic journal jack 15a as the height adjuster 15, the height and inclination of the fixture 11 can be easily adjusted, and the ready-made pile 3 can be set vertically and reliably. can be done.

FIG. 7 is a flow chart showing a schematic procedure of a foundation pile construction method according to one embodiment of the present invention.
As shown in FIG. 7, the foundation pile construction method includes an excavation step S1, a solidifying material injection step S3, a ready-made pile embedding step S5, and a holding step S7.
In the excavation step S1, the pile hole 5 is excavated using, for example, a pile driver. A pile driver includes a leader, an auger motor attached to the leader so as to be vertically movable, and an auger drill connected to the auger motor.
In the hardening material injection step S3, a hardening material 6 such as cement milk is injected into the pile hole 5. As shown in FIG. The solidifying material injection step S3 is performed in parallel with the excavation step S1 or after the excavation step S1.

In the prefabricated pile burying step S5, the prefabricated pile 3 is sunk in the pile hole 5 after the solidifying material injection step S3. For example, in the prefabricated pile burying step S5, a holding tool called a yatko composed of the pile engaging portion 7 and the shaft portion 9 is connected to the pile driver, and the readymade pile 3 is engaged with the yatko. The ready-made pile 3 is inserted to a predetermined depth by a pile driver and a jack. At this time, the ready-made pile 3 is inserted into the pile hole 5 while rotating the yattco with a pile driver as needed.

In the holding step S7, the ready-made pile 3 in the pile hole 5 is held until the hardening material 6 is solidified (until the required strength is exhibited). In the holding step S7, the ready-made pile 3 is held using the holding device 1 described above. After solidification of the solidification material 6, the foundation pile is constructed by removing the holding device 1. FIG.

According to the foundation pile construction method described above, in the holding step S7, the protrusion 21 of the fixture 11 is engaged with the recess 19 of the shaft 9, so that the fixture 11 moves along the axial direction of the shaft 9. 9. Therefore, the fixture 11 is restricted from slipping on the shaft 9, and the prefabricated pile 3 can be reliably held at a predetermined depth. As a result, the prefabricated pile 3 can be reliably installed at a predetermined depth.

FIG. 8 is a diagram showing a schematic configuration of the foundation pile 40 constructed by the foundation pile construction method described above. As shown in FIG. 8 , the foundation pile 40 includes a pile hole 5 , a hardening material 6 and a ready-made pile 3 .

The pile hole 5 is excavated using, for example, a pile driver.
The solidification material 6 is injected into the pile hole 5 and solidified. and the liquid 6b. The foot protection liquid 6a and the pile perimeter liquid 6b are composed of, for example, cement milk or soil cement obtained by mixing cement milk and excavated soil.
The lower end of the prefabricated pile 3 is surrounded by a foot protection portion 42a formed by solidifying the foot protection liquid 6a, and the upper end of the prefabricated pile 3 is formed by solidifying the pile peripheral liquid 6b. It is surrounded by the surface portion 42b.

The ready-made pile 3 may be a single pile or a connected pile. Moreover, the type of the prefabricated pile 3 is not particularly limited, and may be a PC pile (prestressed concrete pile), an SC pile (concrete pile with outer shell steel pipe), a steel pipe pile, or the like. In the case of connecting piles, enlarged head piles may be used as upper piles.

In some embodiments, as shown in FIG. 8, the excavation diameter (diameter) De of the pile hole 5 is constant from the entrance of the pile hole 5 to the bottom of the pile hole 5, and the outer diameter of the prefabricated pile 3 1 time or more and 2 times or less of the reference excavation diameter Ds set according to
When the ready-made pile 3 is a knotted pile having a shaft portion 44a and a knot portion 44b protruding radially outward from the shaft portion 44a, the reference excavation diameter Ds is the outer diameter of the knot portion 44b located in the foot protection portion 42a. Although it is a value obtained by adding 0.05 m to Don (Ds=Don+0.05), when the outer diameter Don is 0.44 m, the reference excavation diameter Ds is set to 0.5 m (Ds=0.5). On the other hand, when the ready-made pile 3 is a straight pile, the standard excavation diameter Ds is a value obtained by adding 0.05 m to the outer diameter of the straight pile.

In constructing the foundation pile 40 having the above configuration, since the prefabricated pile 3 is held by the holding device 1 until the solidification material 6 is solidified, the prefabricated pile 3 can be reliably held vertically by the holding device 1 at a predetermined depth. can. As a result, in the foundation pile 40 having the above configuration, even if the excavation diameter De of the pile hole 5 is 1 to 2 times the reference excavation diameter Ds set according to the outer diameter of the ready-made pile 3, A ready-made pile 3 is installed vertically at a predetermined depth.

In some embodiments, the excavation diameter De is preferably set to 1.5 times or more and 2 times or less of the reference excavation diameter Ds. According to the foundation pile construction method described above, even if the excavation diameter De is 1.5 to 2 times the standard excavation diameter Ds and the prefabricated pile 3 tends to tilt before the solidifying material 6 solidifies, Since the prefabricated pile 3 is held by the holding device 1 until the solidifying material 6 is solidified, the prefabricated pile 3 can be reliably held vertically at a predetermined depth.

In some embodiments, the distance from the lower end of the prefabricated pile 3 to the bottom of the pile hole 5 (the length of the expanded foot protection part under the pile) _LL is set to 0 m or more and 2 m or less, preferably 0.5 m or more and 2 m or less. set, more preferably 1 m or more and 2 m or less. According to the foundation pile construction method described above, the length of the under-pile expanded foot protection portion L _L is 0.5 m or more and 2 m or less, and the prefabricated pile 3 tends to sink or tilt before the solidification material 6 solidifies. Also, since the prefabricated pile 3 is held by the holding device 1 until the solidifying material 6 is solidified, the prefabricated pile 3 can be reliably held vertically at a predetermined depth.
In some embodiments, the length from the lower end of the prefabricated pile 3 to the upper end of the foot protection portion 42a (on-pile foot protection portion length) is about 2 m.

FIG. 9 is a plan view showing a schematic configuration of a fixture 50 according to another embodiment of the present invention, where (a) shows the closed state and (b) shows the open state. FIG. 10 is a front view showing a schematic configuration of the fixture. It should be noted that the same or similar configurations as those of the above-described embodiment will be given the same names or reference numerals, and description thereof will be omitted or simplified.
As shown in FIGS. 9(a), (b) and 10, the fixture 50 is configured such that one side of the half member 23 in the circumferential direction is mutually connected via a connecting pin (first connecting pin) 52 . It differs from the fixture 11 in that it is connected. In the fixture 50 , one side of the two half-split members 23 in the circumferential direction is connected to each other by a connecting pin 52 so as to be able to swing with each other.

Specifically, in each half-split member 23 , a sleeve portion 54 for inserting the connecting pin 52 is integrally provided on one side edge of the semi-cylindrical portion 25 in the circumferential direction. The sleeve portions 54 of the two half-split members 23 are arranged alternately in the axial direction of the semi-cylindrical portion 25 so that the connecting pin 52 can be inserted therethrough. In addition, in this embodiment, the connecting pin 52 is configured with a bolt and a nut so that the connecting pin 52 does not come off.

According to the above configuration, since the two half-split members 23 are connected by the connecting pin 52 , the fixture 50 can be easily attached to the shaft portion 9 . That is, if the two half-split members 23 are separate bodies, the two half-split members 23 must be moved and attached to the shaft portion 9 respectively, which is complicated. If the two half-split members 23 are connected as possible, they can be moved simultaneously and easily attached to the shaft portion 9 . The same is true vice versa, and the fixture 50 can be easily removed from the shaft portion 9 .

FIG. 11 is a plan view showing a schematic configuration of a fixture 60 according to another embodiment of the invention. As shown in FIG. 11 , the fixture 50 is connected to the half member 23 on the other side in the circumferential direction via a connecting pin (second connecting pin) 62 . is different from For this reason, sleeve portions 54 are integrally provided on both sides in the circumferential direction of the half member 23 of the fixture 60 .

According to the above configuration, the other ends of the two half-split members 23 are connected by the second connecting pin 62 arranged along the axial direction of the shaft portion 9. Therefore, when fastening the ear portion 29 with the bolt 31, In comparison, the fixture 60 can be easily attached to the shaft portion 9 . Further, if the second connecting pin 62 does not drop from the sleeve portion 54, there is no need to provide a retainer for the second connecting pin 62. FIG. From this point as well, the fixture 60 can be easily attached to the shaft portion 9 and vice versa, and the fixture 60 can be easily removed from the shaft portion 9 .

FIG. 12 is a front view schematically showing a fixture 70 according to another embodiment of the invention together with part of the shaft 9. As shown in FIG. As shown in FIG. 12, the fixture 70 has a cylindrical portion 72 and a flange portion 74 integrally provided on one end side of the cylindrical portion 72 in the axial direction and protruding radially outward. there is A through hole 76 is provided in the cylindrical portion 72 in the tangential direction, and an engaging pin 78 can be inserted into the through hole 76 . An engaging pin 78 inserted into the through hole 76 can selectively engage with any one of the recesses 19 .
According to the above configuration, the fixing member 70 is fixed to the shaft portion 9 in the axial direction of the shaft portion 9 by engaging the engaging pin 78 inserted through the fixing member 70 with the concave portion 19 of the shaft portion 9 . be. Therefore, the fixture 70 is restricted from slipping on the shaft 9, and the prefabricated pile 3 can be reliably held at a predetermined depth.

In some embodiments, fixture 70 has hanger 80 . By hanging a wire on the hanging metal fitting 80, the fixture 70 can be easily moved.

Finally, the present invention is not limited to the above-described embodiments, and includes modifications of the above-described embodiments and modes in which these modes are combined as appropriate.
For example, in the above-described embodiment, the shaft portion 9 has a cylindrical shape, and the fixtures 11, 50, 60, and 70 also have a cylindrical shape as a whole, but the shaft portion 9 has a rectangular tube shape. Correspondingly, the fixtures 11, 50, 60, 70 may also have a rectangular tubular shape as a whole. Alternatively, the shaft portion 9 may partially have a rectangular tubular shape in the region where the recessed portion 19 is provided. The cross-sectional shape of the prismatic shape may be quadrangular, hexagonal, octagonal, or the like.

Further, in the above-described embodiment, the concave portion 19 is the circumferential groove 19a, but may be a tangential groove extending in the tangential direction of the shaft portion 9. FIG. If the shaft portion 9 has a rectangular tubular shape, the recessed portion 19 may be a groove parallel to the side surface of the shaft portion 9 .
Furthermore, when inserting the engaging pin 78 into the fixture as in the fixture 70, the concave portion 19 is not limited to a groove shape, and may be a through hole passing through the shaft portion 9 so as to traverse. good.
Furthermore, the number of protrusions 21 provided on fixtures 11, 50, and 60 and the number of engagement pins 78 for fixture 70 are not particularly limited.

1 Prefabricated pile holding device 3 Prefabricated pile 3a Projection 5 Pile hole 6 Hardening material 6a Foot protection liquid 6b Pile surrounding liquid 7 Pile engagement part 7a Engagement groove 9 Shaft part 11, 50, 60, 70 Fixing tool 13 Girder member 15 Height adjuster 15a Journal jack 17 Base 19 Concave part 19a Circumferential groove 21 Protruding part 21a Ridge 23 Half split member 25 Semi-cylindrical part 27 Flange part 29 Ear part 31 Bolts 33, 35 Reinforcement rib 40 Foundation pile 42a Foot protection part 42b Pile peripheral surface portion 44a Shaft portion 44b Node portion 52 Connecting pin (first connecting pin)
54 sleeve portion 62 connecting pin (second connecting pin)
72 Cylindrical portion 74 Flange portion 76 Through hole 78 Engagement pin 80 Hanging metal fitting

Claims (5)

In a holding device for a ready-made pile sunk in a pile hole,
a pile engaging portion that can be engaged with the ready-made pile;
a shaft portion connected to the pile engaging portion;
a fixture that can be fitted onto the shaft;
a girder member arranged to traverse the pile hole;
a height adjuster disposed between the fixture and the beam member;
with
A plurality of recesses are provided in the shaft portion at intervals in the axial direction of the shaft portion,
A ready-made pile holding device, wherein a projection provided on the fixture or an engagement pin inserted through the fixture can be selectively engaged with any one of the plurality of recesses. The fixture is
two halves;
a first connecting pin that pivotally connects one side of the two half members in the circumferential direction to each other;
The prefabricated pile retaining device according to claim 1, characterized by comprising: The fixture is
3. The ready-made product according to claim 2, further comprising a second connecting pin disposed along the axial direction of the shaft portion and connecting the other sides of the two half members in the circumferential direction. Pile holding device. 4. The prefabricated pile holding device according to any one of claims 1 to 3, wherein the height adjuster is a hydraulic journal jack. An excavation step of excavating a pile hole;
a solidification material injection step of injecting a solidification material into the pile hole;
A prefabricated pile embedding step of submerging a prefabricated pile into the pile hole after the solidifying material injection step;
a holding step of holding the ready-made pile in the pile hole until the solidifying material solidifies;
with
A method for constructing a foundation pile, wherein in the holding step, the prefabricated pile is held by using the prefabricated pile holding device according to any one of claims 1 to 4.

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