JP2015143472A - Construction method with steel tube pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a construction method with a steel tube pile with which vertical precision of a support pile is improved and operation at a high place and in water is to be unnecessary.SOLUTION: There is provided a construction method with a steel tube pile comprising: a step of installing a first steel tube pile comprising a joint on its peripheral surface; a steel tube pile installing step in which, under a state where a joint arranged on peripheral surface of a second steel tube pile is engaged with a joint on an installed first steel tube pile, the second steel tube pile is slid in longitudinal direction of the steel tube pile relative to peripheral surface of the first steel tube pile so that the steel tube pile is installed on the ground. The joint on the first steel tube pile having a T-shape section and extends from upper edge to lower edge of the steel tube pile. The joint of the second steel tube pile has a configuration capable of being engaged with the joint of the first steel tube pile.

Description

  The present invention relates to a steel pipe pile construction method capable of improving vertical accuracy of support piles and eliminating high-altitude work and underwater work in water jetty construction work.

  In a pile-type pier having a structure in which a floor slab is placed on a pile (see, for example, Patent Document 1 below), the pile itself is a bridge pier that requires strength. Therefore, when the length of a pile becomes long, it will be necessary to connect and reinforce between adjacent piles with a beam.

Usually, the connection between piles by beams is performed by welding the beams to the piles after placing the piles on the ground.
In such a conventional construction method, since the next pile is advanced in advance, it is difficult to accurately adjust the placement position of the pile, and it is difficult to ensure the vertical accuracy of the pile. Therefore, for example, after pile driving once, the direction of the pile has to be readjusted, and there is a problem that it takes time and effort.
In addition, the work of connecting the piles with beams (work to weld the beams to the piles) requires work at a high place and underwater work. there were.

In Patent Document 2, as one of the problems to reduce the joining work of the beam in water and improve the installation workability, a guide is provided on the mutually opposing surfaces of the adjacent support piles, and a high-strength fiber is provided between the guides. A construction method of a temporary pier in which a reinforcing member made of reinforced concrete is slid and inserted is disclosed.
However, since the method described in Patent Document 2 is a method in which the reinforcing member is slid between the piles after the next pile is advanced, the problem that it is difficult to ensure the vertical accuracy of the pile is still solved. Absent.

Japanese Patent No. 3043320 JP 2011-162988 A

  The present invention has been made to solve the problems of the prior art as described above, and improves the vertical accuracy of the support pile and can eliminate the work at high places and underwater work. Is to provide.

  The reference example is a grounding process for grounding a reinforcing member comprising a plurality of support members extending in parallel to each other and a connecting member that connects adjacent support members in an oblique direction and a perpendicular direction to the longitudinal direction of the support member. And the support member on the one end face side of the grounded reinforcement member and the joint provided on the outer peripheral surface of the existing first support pile are engaged with the reinforcement member in the first support pile. A reinforcing member disposing step of sliding the supporting member at a predetermined height position by sliding in the longitudinal direction of the supporting pile with respect to the outer peripheral surface, a joint provided on the outer peripheral surface of the second supporting pile, and the disposed reinforcing member In a state where the support member on the other end surface side of the member is engaged, the second support pile is slid in the longitudinal direction of the support member with respect to the other end surface of the support member, and the second support pile is And a support pile placing process for placing on the ground. Method pier construction to on.

  In the reference example, the connecting member is connected in a direction perpendicular to the longitudinal direction of the support member and connected to the connecting member arranged in parallel with each other at an interval, and connected in an oblique direction to the longitudinal direction of the support member. It is composed of a brace material provided by crossing between the connecting materials, and the brace materials are rotatably fixed to each other at the cross portion, and the length of the connecting material in the longitudinal direction is adjustable. Thus, the present invention relates to a pier construction method, wherein the reinforcing member is configured to be foldable with respect to the longitudinal direction of the support member.

  In the support pile placing step, a rod having a down-the-hole hammer and an expandable hammer bit at the lower end is inserted into the second support pile in the support pile placing step, and the hammering action of the down-the-hole hammer and the hammer bit The present invention relates to a method for constructing a pier, characterized in that a drilling hole is formed by the rotary excavation action, and then the second support pile is driven into the drilling hole.

  The invention according to claim 1 includes a step of placing a first steel pipe pile having a joint provided on the outer peripheral surface, and an outer peripheral surface of the second steel pipe pile with respect to the joint of the first steel pipe pile placed. The steel pipe pile driving step of sliding the second steel pipe pile in the longitudinal direction of the steel pipe pile with respect to the outer peripheral surface of the first steel pipe pile and placing the second steel pipe pile on the ground with the joint provided on The joint of the first steel pipe pile has a T-shaped cross section and is extended from the upper end to the lower end of the steel pipe pile, and the joint of the second steel pipe pile is the first steel pipe The present invention relates to a steel pipe pile construction method characterized by having a shape that engages with a pile joint.

  The invention according to claim 2 is characterized in that the joint of the second steel pipe pile is a long member having a hollow square cross section in which a part of a surface facing the first steel pipe pile is opened. The steel pipe pile construction method according to claim 1.

  The invention according to claim 3 is characterized in that the joint of the second steel pipe pile is a long member having a substantially C-shaped cross section in which a part of the surface facing the first steel pipe pile is opened. The steel pipe pile construction method according to claim 1.

  According to a fourth aspect of the present invention, in the steel pipe pile placing step, a rod having a down-the-hole hammer and an expandable hammer bit at the lower end is inserted into the second steel pipe pile, and the impact action of the down-the-hole hammer is performed. 4. The steel pipe pile construction method according to claim 1, wherein a drilling hole is formed by a rotary excavation action of the hammer bit and then the second steel pipe pile is driven into the drilling hole.

According to the reference example, the reinforcing member is connected to the first reinforcing member in a state where the supporting member on one end surface side of the ground reinforcing member is engaged with the joint provided on the outer peripheral surface of the existing first supporting pile. Reinforcing member placement step for sliding the supporting pile outer circumferential surface in the longitudinal direction of the supporting pile to place the reinforcing member at a predetermined height position, and the joint provided on the outer circumferential surface of the second supporting pile The second support pile is slid in the longitudinal direction of the support member with respect to the other end face of the support member while the second support pile is engaged with the support member on the other end surface side of the reinforcing member, and the second support pile is grounded. A support pile placing step for placing the second support pile on the outer peripheral surface of the reinforcing member installed on the existing first support pile, and adjusting the vertical direction separately. Good vertical accuracy of the second support pile can be obtained without doing so. Moreover, since the reinforcing member is interposed between the first support pile and the second support pile, the distance between the support piles can be made constant. And in a support pile placing process, since the depth of placement of the 2nd support pile can be determined on the basis of the upper surface of a reinforcing member, a support pile (the 1st support pile and the 2nd support pile) ) The height of the pile tips between each other can be aligned.
Further, by adopting the above slide structure, even if the support pile and the reinforcing member are not fixed by bolting, welding, or the like, fixing only in the vertical direction (for example, a stopper that supports the reinforcing member on the first support pile) It is possible to determine the position of the reinforcing member with respect to the support pile only by providing. Thereby, work at height and underwater work can be reduced, and safety can be improved.

  According to the reference example, the connecting material is connected in a direction perpendicular to the longitudinal direction of the support member and connected in a diagonal direction with respect to the longitudinal direction of the support member and the connecting material arranged in parallel with each other. It consists of a brace material provided in a cross between the adjacent connecting materials, and the brace materials are rotatably fixed to each other at the cross portion, and the length in the longitudinal direction of the connecting material is adjustable. Thus, since the reinforcing member is configured to be foldable with respect to the longitudinal direction of the support member, the reinforcing member can be operated in a folded state, thereby improving work efficiency of transportation and arrangement of the reinforcing member. Can be made.

  According to the reference example, in the support pile placing step, a rod having a down-the-hole hammer and an expandable hammer bit at the lower end is inserted into the second support pile, and the hammering action of the down-the-hole hammer and the hammer Since the excavation hole is formed by the rotary excavation action of the bit and the second support pile is driven into the excavation hole, the support pile can be reliably placed with good vertical accuracy even on a deep water bottom.

According to the present invention, the step of placing the first steel pipe pile with the joint provided on the outer peripheral surface, and the outer peripheral surface of the second steel pipe pile with respect to the joint of the first steel pipe pile placed. A steel pipe pile placing step in which the second steel pipe pile is slid in the longitudinal direction of the steel pipe pile with respect to the outer peripheral surface of the first steel pipe pile and placed on the ground with the joints engaged with each other. Since the steel pipe piles (the first steel pipe pile and the second steel pipe pile) are connected to each other, the influence of water flow and waves can be reduced.
Moreover, the favorable vertical precision of a 2nd steel pipe pile can be obtained only by sliding a 2nd steel pipe pile with respect to the existing 1st steel pipe pile outer peripheral surface, without adjusting a perpendicular direction separately. In addition, since the first steel pipe pile and the second steel pipe pile are connected with a joint interposed therebetween, the distance between the steel pipe piles can be made constant. In the steel pipe pile placing process, the depth of the second steel pipe pile can be determined based on the upper surface of the first steel pipe pile, so that the steel pipe pile (the first steel pipe pile and the first steel pipe pile) 2 steel pipe piles), the heights of the pile tips can be made uniform.

  According to the present invention, in the steel pipe pile placing step, a rod having a down-the-hole hammer and an expandable hammer bit at the lower end is inserted into the inside of the second steel pipe pile, and the hammering action of the down-the-hole hammer and the hammer Since the excavation hole is formed by the rotary excavation action of the bit, and the second steel pipe pile is driven into the excavation hole, the steel pipe pile can be reliably driven even with a deep water bottom with good vertical accuracy.

It is a figure which shows the state before construction of the pier construction method of a reference example. (A) It is a front view of a reinforcement member, (b) It is a left view of a reinforcement member. It is a figure which shows a mode that the grounded reinforcement member is suspended with a crane. It is a figure for demonstrating a reinforcement member arrangement | positioning process, (a) The state before connecting reinforcement members, (b) It is a figure which shows the state which has arrange | positioned the reinforcement member in predetermined height. It is a top view of the engaging part of a support pile and the support member of a reinforcement member. It is a top view which shows the example of a change of the engaging part of a support pile and the support member of a reinforcement member. It is a figure which shows the state which is sliding the 2nd support pile to the reinforcement member outer peripheral surface. It is a figure which shows the state which is excavating the ground by down the hole. It is a figure which shows the state which has driven the support pile. It is a figure which shows the example of a change of a reinforcement member. It is a figure which shows the state by which the reinforcement member was folded. It is a figure which shows the state which has laid the 1st steel pipe pile. It is a figure which shows the state which is sliding the 2nd steel pipe pile on the 1st steel pipe pile outer peripheral surface.

  Hereinafter, preferred embodiments of a pier construction method according to a reference example and a steel pipe pile construction method according to the present invention will be described with reference to the drawings as appropriate.

First, the pier construction method will be described.
Drawing 1 is a figure showing the state before construction of the pier construction method of a reference example.
The pier construction method according to the present invention can be used both when constructing a new pier from scratch and when constructing a pier by sequentially extending from an existing pier. Hereinafter, from the pier completion part (A) A method of constructing the pier by sequentially extending toward the pier unfinished part (B) will be described. In the figure, (W) is the water surface and (G) is the ground surface (water bottom). In addition, when constructing a new jetty from scratch, it is possible to apply a method similar to the method described below.
Hereinafter, the pier construction method according to the reference example will be described along the work process.

<1. Ground assembly process>
First, the reinforcing member is grounded.
2A is a front view of the reinforcing member, and FIG. 2B is a left side view of the reinforcing member.
The reinforcing member (1) is composed of a plurality of support members (2) extending in parallel to each other and a connecting member (3) for connecting adjacent support members in an oblique direction and a perpendicular direction to the support member longitudinal direction. The
The connecting member (3) of the reinforcing member (1) is connected in a direction perpendicular to the longitudinal direction of the supporting member (2), and connected to the connecting member (31) spaced in parallel with each other, and the supporting member ( 2) It consists of a brace material (32) that is connected obliquely to the longitudinal direction and is crossed between adjacent tie materials (31), and the tie material (31) and the brace material (32) Are integrally connected via fixing plates (33) fixed to the left and right ends of the connecting member (31), respectively.
The reinforcing member (1) is formed in a lattice shape by the support member (2) and the connecting material (31), and the number of the support members (2) is three in FIG. 2B (that is, a total of six). However, it may be two (that is, a total of four) or four (that is, a total of eight) or more.
The reinforcing member (1) may be supplied to the reinforcing member arranging step which is the next step in a state where the supporting members (2) are connected in the longitudinal direction. The support members (2) can be connected to each other by welding flanges formed on the ends of the support member (2) or by bolting.

<2. Reinforcing member placement process>
FIG. 3 is a diagram illustrating a state in which a grounded reinforcing member is suspended by a crane. FIGS. 4A and 4B are diagrams for explaining the reinforcing member arranging step, in which FIG. 4A shows a state before the reinforcing members are connected to each other, and FIG. 4B shows a state where the reinforcing members are arranged at a predetermined height. .
As shown in FIG. 3, the reinforcing member (1) assembled in the above-mentioned assembly process is suspended by a crane on the pier completed part (A), and the first support pile (4a) already installed from the upper side in FIG. ) In order. Specifically, the support member (2) on one end surface side (1a) of the ground reinforcing member (1) is engaged with a joint provided on the outer peripheral surface of the existing first support pile (4a). In this state, the reinforcing member (1) is slid in the longitudinal direction of the supporting pile (in the direction of the arrow in FIGS. 3 and 4A) with respect to the outer peripheral surface of the first supporting pile (4a), and the reinforcing member (1) is Temporarily fix the upper surface at a position where it is almost the same height as the bridge surface of the completed pier (A). The temporary fixing method is not limited. For example, it can be moved in the left-right direction in FIG. 3 or horizontally in the existing reinforcing member (11) or the first support pile (4a) of the pier completed part (A). By providing a rotatable stopper, the reinforcing member (1) can be temporarily fixed. Alternatively, the reinforcing member (1) can be temporarily fixed by suspending the reinforcing member (1) with a predetermined wire using the existing reinforcing member (11) as a reaction force.
When the first reinforcing member (1) is slid with respect to the outer peripheral surface of the first support pile (4a), the upper surface is suspended and temporarily fixed to a position where it is almost the same height as the bridge surface of the pier completed part (A), Next, the next reinforcing member (1) is suspended from the upper side in FIG. 4 along the existing first support pile (4a), and the reinforcing members (1) are connected to each other. This connection work can be performed on a scaffold provided so as to slide horizontally and extend from the bridge surface at substantially the same height as the bridge surface of the pier completed part (A). After connecting the reinforcing members, remove the temporary fixing of the lower reinforcing member (1), and then to the position where the upper surface of the upper reinforcing member (1) is almost the same height as the bridge surface of the pier completion part (A), The connected reinforcing member is suspended to temporarily fix the lower reinforcing member (1). This is repeated to arrange a desired number of reinforcing members (1).

  The final height position of the lowermost reinforcing member (1) can be determined by providing a stopper (not shown) on the first support pile (4a). ) Can be supported. Therefore, the reinforcement member (1) is suspended by the crane until the lower surface comes into contact with the stopper, the engagement between the crane and the reinforcement member is disengaged, and the crane is lifted up. ). Therefore, the method of the present invention is excellent in safety because it is not necessary to perform an aerial work or an underwater work for fixing the support pile and the reinforcing member.

  As described above, the support member (2) is configured to be slidable in the longitudinal direction of the support pile with respect to the outer peripheral surface of the existing first support pile (4a). The existing first support pile (4a) has a joint on its outer peripheral surface, and this joint engages with and supports the support member (2) on one end surface side (1a) of the reinforcing member (1). It is comprised so that a member (2) can slide to a support pile longitudinal direction with respect to the existing 1st support pile (4a) outer peripheral surface.

Hereinafter, the example of the coupling which connects a reinforcing member (1) and the 1st support pile (4a) is explained. The following example is merely an example, and the shape of the joint is not limited as long as the reinforcing member (1) can be engaged and slid with respect to the first support pile (4a).
FIG. 5 is a plan view of the engaging portion between the support pile and the support member of the reinforcing member.
The 1st support pile (4a) is equipped with the joint (5) extended in the outer peripheral surface from the upper end to the lower end of the support pile while having a T-shaped cross section. On the other hand, the supporting member (2) of the reinforcing member (1) is a long member having a hollow square cross section in which a part of the surface facing the supporting pile (4a) is opened. As shown in FIG. 5, the joint (5) is inserted into the member (2) from above the support member (2) (upper side in FIG. 4), so that the support member (2) and the existing first support are provided. The reinforcing member (1) can be suspended by the crane while sliding the reinforcing member (1) with respect to the outer peripheral surface of the first support pile (4a) in a state where the pile (4a) is engaged.
Therefore, when constructing a jetty by sequentially extending from an existing jetty, the joint (5) is fixed to the outer peripheral surface of the existing first support pile (4a) in advance. When constructing a new pier from scratch, the one with the joint (5) fixed to the outer peripheral surface of the support pile can be used as the first support pile (4a).

FIG. 6 is a plan view illustrating a modification example of the engaging portion between the support pile and the support member of the reinforcing member.
The supporting member (2) of the reinforcing member (1) is a steel pipe, and includes a joint (6) made of a steel pipe having a substantially C-shaped cross section in which a part of the surface facing the first supporting pile (4a) is opened. ing. The joint (5) of the first support pile (4a) is inserted into the joint (6) from the upper side of the support member (2) (upper side in FIG. 4), thereby supporting the reinforcing member (1) as the first support. It becomes possible to hang down with a crane, sliding with respect to a pile (4a).

<3. Support pile placing process>
Next, a new support pile is laid. In the present specification, a support pile newly placed on an existing support pile is referred to as a second support pile.
FIG. 7 is a view showing a state where the second support pile is slid on the reinforcing member.
Similarly to the first support pile (4a), the second support pile (4b) is configured to be slidable from above the reinforcement member (1) (upper side in FIG. 7) with respect to the outer peripheral surface of the reinforcement member (1). ing. Specifically, the state where the joint provided on the outer peripheral surface of the second support pile (4b) and the support member (2) on the other end surface side (1b) of the arranged reinforcing member (1) are engaged. Then, the second support pile (4b) is slid down in the support member longitudinal direction (arrow direction in FIG. 7) with respect to the other end surface (1b) of the support member (2). Thereby, as shown in FIG. 7, it suspends to the predetermined height position which the lower surface of a 2nd support pile (4b) does not contact with a water bottom (G).

Next, the ground (G) is excavated. FIG. 8 is a diagram illustrating a state where excavation is performed by down-the-hole.
A rod (9) having a down-the-hole hammer (7) and an expandable hammer bit (8) at the lower end is inserted into the second support pile (4b) suspended at a predetermined height. Then, a drilling hole is formed in the ground (G) by the striking action of the down-the-hole hammer (7) and the rotary excavation action of the hammer bit (8).
The excavated soil discharged during the formation of the excavation hole rises through the gap between the second support pile (4b) and the rod (9) by supplying high-pressure air, and the upper end of the second support pile (4b). It is accommodated in a vessel (not shown) arranged on the jetty via a discharge hose (not shown). Thereby, contamination of water is prevented. Moreover, it is possible to confirm whether or not the excavation hole has reached the planned depth (support layer) by verifying the rock block accommodated in the vessel.

  FIG. 9 is a diagram showing a state in which a support pile is driven. When the drilling hole reaches the planned depth, the second support pile (4b) is driven by a hydraulic excavator, and then the rod (9) is pulled up by a crane to complete the placement of the second support pile (4b). To do.

  The distance between the support piles is constant by the reinforcing member (1). And in the placing process of the support pile, the depth of placing the second support pile (4b) can be determined based on the upper surface of the reinforcing member (1). The height can be aligned.

  After that, the floorboard is placed between the first support pile (4a) and the second support pile (4b), and the pier is sequentially extended by repeating the above-described reinforcing material arranging step and the support pile placing step. can do. That is, the second support pile (4b) becomes the existing first support pile (4a) at the time of placement, and the reinforcing member (1) and the second support pile (4b) are sequentially arranged according to the above method. By doing so, the pier can be extended. For this reason, the second support pile (4b) includes another joint (5) for engaging and sliding the reinforcing member (1) at a position that is symmetric with respect to the axis of the support pile.

Next, a modified example of the reinforcing member (1) will be described. FIG. 10 is a view showing a modified example of the reinforcing member, and FIG. 11 is a view showing a state where the reinforcing member is folded.
The connecting member (3) of the reinforcing member (1) is connected in a direction perpendicular to the longitudinal direction of the supporting member (2), and connected to the connecting member (31) spaced in parallel with each other, and the supporting member ( 2) It consists of a brace material (32) that is connected obliquely to the longitudinal direction and is crossed between adjacent tie materials (31), and the tie material (31) and the brace material (32) Are integrally connected via fixing plates (33) fixed to the left and right ends of the connecting member (31), respectively.
The brace material (32) is rotatably fixed to each other at the cross portion, and the connecting material (31) is lengthened in the longitudinal direction (21) by an extendable length adjusting mechanism (21) such as a hydraulic cylinder. The length in the left-right direction in FIG. 10 is configured to be adjustable. Thereby, as shown in FIG. 11, the reinforcing member (1) is configured to be foldable in the longitudinal direction of the support member (2).
Thereby, since it can operate | work in the state which folded the reinforcement member (1), the work efficiency of conveyance and arrangement | positioning of a reinforcement member can be improved.

Next, the construction method of a steel pipe pile is demonstrated.
Although the method of alternately installing the support pile and the reinforcing member has been described above, the same slide arrangement method can be used for the method of continuously placing the support pile (steel pipe pile).

FIG. 12 is a view showing a state in which the first steel pipe pile is driven, and FIG. 13 is a view showing a state in which the second steel pipe pile is slid on the outer peripheral surface of the first steel pipe pile.
The 1st steel pipe pile (10a) by which the joint was provided in the outer peripheral surface is driven in the ground (water bottom). This can be performed by suspending the first steel pipe pile (10a) with a crane and using the same method (down-the-hole method) as the pier construction method described above (see FIG. 8).
Next, in a state where the joint provided on the outer peripheral surface of the second steel pipe pile (10b) is engaged with the joint of the first steel pipe pile (10a) placed, the first steel pipe pile ( 10a) The second steel pipe pile (10b) is slid from the upper side (upper side in FIG. 13) with respect to the outer peripheral surface, and the lower surface of the second steel pipe pile (10b) is in contact with the water bottom (G) as shown in FIG. Do not hang down to the specified height. As an engagement and slide mechanism of steel pipe piles, the structure similar to the above-mentioned pier construction methods, such as a joint shown in FIG. 6, can be employ | adopted, for example.

By setting it as such a method, since steel pipe piles are connected, the influence of a water flow or a wave can be reduced.
Further, the second steel pipe pile (10b) is simply inserted by sliding into the first steel pipe pile (10a), and the second steel pipe pile (10b) is not adjusted separately without adjusting the vertical direction of the second steel pipe pile (10b). Good vertical accuracy of (10b) can be obtained. Moreover, it becomes possible to make the distance between each steel pipe pile constant. And in the placing process of the steel pipe pile, the depth of placing the second steel pipe pile (10b) can be determined with reference to the upper surface of the first steel pipe pile (10a). The height of the pile tip can be aligned.

  The pier construction method according to the reference example and the steel pipe pile construction method according to the present invention can be widely used for pile-type pier construction in various places, particularly suitably used for pier construction in deep water places such as dam lakes. Is done.

DESCRIPTION OF SYMBOLS 1 Reinforcement member 2 Support member 3 Connecting material 31 Connecting material 32 Breath material 4a First support pile 4b Second support pile 5 Joint 6 Joint 7 Down the hole hammer 8 Hammer bit 9 Rod 10a First steel pipe pile 10b Second steel pipe Pile

Claims (4)

A step of placing a first steel pipe pile provided with a joint on the outer peripheral surface;
With the joint provided on the outer peripheral surface of the second steel pipe pile engaged with the joint of the first steel pipe pile placed, the second steel pipe pile is connected to the outer peripheral surface of the first steel pipe pile. The steel pipe pile placing step for sliding in the longitudinal direction of the steel pipe pile and placing on the ground,
With
The joint of the first steel pipe pile has a T-shaped cross section and extends from the upper end to the lower end of the steel pipe pile,
The steel pipe pile construction method, wherein the joint of the second steel pipe pile has a shape that engages with the joint of the first steel pipe pile.   The steel pipe pile according to claim 1, wherein the joint of the second steel pipe pile is a long member having a hollow square cross section in which a part of a surface facing the first steel pipe pile is opened. Construction method.   The steel pipe pile according to claim 1, wherein the joint of the second steel pipe pile is a long member having a substantially C-shaped cross section in which a part of a surface facing the first steel pipe pile is opened. Construction method. In the steel pipe pile placing process,
A rod having a down-the-hole hammer and an expandable hammer bit at the lower end is inserted into the inside of the second steel pipe pile, and a drilling hole is formed by the hammering action of the down-the-hole hammer and the rotary excavation action of the hammer bit, The steel pipe pile construction method according to any one of claims 1 to 3, wherein the second steel pipe pile is driven into the excavation hole.

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