JP2017101521A - Method for constructing steel pipe pile having reinforced pile head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for constructing a steel pipe pile, capable of reliably reinforcing the pile head of a steel pipe pile.SOLUTION: The method comprises the steps of: penetrating a steel pipe pile 10 the ground; inserting the head of a lower pile remaining on the ground surface into the central hole of a first circular ring plate 30 and the central hole of a second circular ring plate 21, such that the head of the lower pile is covered with the first circular ring plate and an outer pipe 20; allowing the outer pipe, together with the first circular ring plate, to penetrate the ground along the lower pile, such that the head of the outer pipe remains on the ground surface, connecting the head of the outer pipe to a first temporary pile 80 in a detachable state, and allowing the outer pipe, together with the first circular ring plate, to further penetrate the ground to a predetermined depth along the lower pile; connecting the head of the lower pile to an upper pile 12, allowing the steel pipe pile to penetrate the ground, and then connecting a second temporary pile 90 to the head of the upper pile in a detachable state, and allowing the steel pipe pile to further penetrate the ground to a predetermined depth, such that the head of the upper pile is located in a space part 40; and filling the space part 40 between the inner periphery of the outer pipe and the outer periphery of the upper pile with a flowable solidification material, such that an antislipping member 14 is embedded in the flowable solidification material to form a reinforcement body 50.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for constructing a steel pipe pile in which a pile head portion of the steel pipe pile serving as a foundation of an upper structure is reinforced.

  In the Great Hanshin-Awaji Earthquake and the Great East Japan Earthquake, there were accidents such as the foundation piles of buildings were damaged by the great earthquake force, and the buildings collapsed or tilted. According to surveys by various organizations, it has been found that most of these accidents were caused by pile head damage. The cause is that the strength of the pile head (including the vicinity of the top of the pile and the joint between the pile head and the footing) is insufficient, or that the seismic force is higher than expected in the design.

  On the other hand, various pile construction methods have been developed in recent years, and many pile construction methods having a greater vertical support force than before have been developed. However, since the horizontal load also increases in proportion to the vertical load acting on the pile, it may not be able to cope with a large bending moment of the pile head by design. As a result, the large vertical bearing force of the foundation pile may not be used effectively. It has been found that this tendency is particularly strong when the ground near the pile head is soft.

  In order to solve the above problems, various proposals have been made on the reinforcing technique of the pile head. As a typical example, a steel pipe pile having protrusions on the outer surface is penetrated to a predetermined depth, and then an outer pipe having a flange or a drilling blade attached to the lower end is covered and rotated to a predetermined position (Patent) Reference 1). The protrusion disturbs and softens the ground around the steel pipe pile and facilitates penetration of the outer pipe into the ground. Further, in the type in which the flange is attached, it is shown that the flange prevents intrusion of earth and sand and mortar or the like is injected into the resulting space. Moreover, after driving a steel pipe pile into the ground, an outer pipe is inserted and driven, and grout is injected between the two (see Patent Document 2). FIG. 1 of Patent Document 2 shows a method of preventing the intrusion of earth and sand by bending the lower end of the outer pipe to reduce the diameter to the outer diameter of the steel pipe pile.

  In both cases, an outer pipe is arranged on the head of the steel pipe pile to make the pile head a double pipe structure, and mortar and grout are filled between them.

JP 2009-30372 A JP 2010-248811 A

  There are four issues to be solved that are common to the former and the latter. The first issue is hiring piles (commonly known as “Yatoko”). Usually, since the height of the steel pipe pile head is set below (for example, 2 m below) the construction ground surface, an employment pile is required for both the penetration of the steel pipe pile and the penetration of the outer pipe. Normally, the outer diameter of the hiring pile for steel pipe piles is the same as that of the steel pipe piles due to the convenience of the pile driver, but in order to connect with the steel pipe pile head, for example, as shown in FIG. A cylindrical portion having a diameter larger than the diameter of the steel pipe pile is fixed to the pipe. A rotating bracket fixed near the head of the outer surface of the steel pipe pile is fitted into the groove processed on the inner surface of the cylindrical portion and the two are connected to each other, so that rotational force and pushing force are transmitted from the hired pile to the steel pipe pile.

  By the way, if the hiring pile is removed immediately after the penetration of the steel pipe pile, the flange and the reduced diameter portion at the lower end of the outer pipe cannot be inserted into the steel pipe pile head. For this reason, hiring piles for steel pipe piles must remain connected until the outer pipe penetrates or is filled with mortar or grout. However, if there are protrusions such as the above-mentioned cylinder part on the outer surface of the hired pile, the outer pipe cannot pass through this part because it is larger than the inner diameter of the flange or reduced diameter part, and the outer pipe can be penetrated. Absent. In this regard, the former Japanese Patent Application Laid-Open No. 2009-30372 describes in paragraph No. 0013 that “when the position of the head of the pile is deeper than the ground surface, an employment pile (so-called“ yatoko ”)” is used to penetrate the pile. However, in order to sink the outer pipe to the same depth, it is possible to leave this hired pile in the ground and use a different hired pile for the outer pipe. No specific configuration is disclosed for hiring piles used in Also, with regard to the latter Japanese Patent Application Laid-Open No. 2010-248811, paragraph No. 0010 states that “the construction of the double pipe type pile head structure is first driven into the ground and then the steel pipe pile 11 at the head. Although there is a description that “the outer pipe 12 is inserted and driven in”, the specific configuration of the employment pile that is also used for the penetration of the steel pipe pile is not disclosed. That is, in both the former and the latter, there is no specific mention about inserting the outer pipe into the steel pipe pile head through the hired pile, and how the outer pipe is inserted into the steel pipe pile head and penetrated. It is unknown.

  The second problem is that mud adheres to the outer surface of the steel pipe pile even if the outer pipe can be inserted into the steel pipe pile head through the hired pile. If the inner diameter of the flange or reduced diameter part of the outer pipe is set slightly larger than the outer diameter of the steel pipe pile, most of the mud adhering to the outer surface of the steel pipe pile will be removed, and the gap between the outer surface of the steel pipe pile and the inner face of the outer pipe will be removed. There should be room for filling mortar and grout. However, in actuality, in the field test conducted by the present inventors, even if the diameter difference between the inner diameter of the flange or the reduced diameter portion of the outer pipe and the outer diameter of the steel pipe pile is 1 mm, mud is slightly It has been found that it penetrates through a large gap and adheres to the outer surface of the steel pipe pile. Since the outer pipe penetrates without being discharged, the volume of earth and sand is compressed, and very high pressure is generated in the sand near the lower end of the outer pipe. As a result, the mud enters the space even from a slight gap and adheres to the outer surface of the steel pipe pile. According to the test by the present inventors, it has been found that mud having a thickness of about 2 mm to 5 mm adheres in a spiral shape. Even if this space is filled with mortar or grout with the mud soil attached, the frictional force with the steel pipe pile is greatly reduced, so the pile head reinforcement effect has to be reduced.

  The third problem is that there is no slip prevention mechanism in the steel pipe pile of the double pipe reinforcement part, so when vertical force or bending moment acts on the double pipe part, the steel pipe and filler (mortar, grout, concrete, etc.) Deviation occurs at the boundary and the synthesizing action of both is impaired. As a result, the strength and rigidity of the double pipe portion are reduced.

  The fourth problem is the former method for constructing a double-pipe pile head structure, but it is impossible to cope with the case where the support layer position is shallower than the planned depth. Projections are provided in advance at the position corresponding to the depth of the lower end of the outer pipe of the steel pipe pile for the purpose of softening the ground or as a positioning material for the lower end of the outer pipe. As a result, the outer pipe cannot be installed to a predetermined depth, and the length of the double pipe portion is shortened. This becomes a fatal defect as a pile.

  The fifth problem is a connecting member for connecting the pile driver, the pile and the outer pipe. Although the former and the latter are not touched on this, it is very troublesome to construct a double-pipe structure pile while exchanging the two connecting members as before, and the construction work efficiency is reduced.

  The present invention enables the steel pipe pile and the outer pipe to rotate and penetrate into the ground to reliably reinforce the pile head of the steel pipe pile, and also supports the case where the ground support layer position is shallower than the planned depth. An object of the present invention is to provide a method for constructing a steel pipe pile, in which construction work efficiency using a pile driver is not reduced.

  In the construction method of the steel pipe pile according to claim 1 of the present invention, an outer pipe having an inner diameter shorter than the steel pipe pile and larger than the outer diameter of the steel pipe pile is installed on the upper outer periphery of the steel pipe pile, A method for constructing a steel pipe pile, in which a space formed between an upper outer periphery and an inner periphery of the outer pipe is filled with a fluidized solidifying material to form a reinforcing body, and the horizontal resistance force is increased. The steel pipe pile is composed of a plurality of steel pipes, a lower steel pipe and an upper steel pipe, and a detent member for increasing adhesion to the reinforcing body is fixed to the outer periphery of the upper steel pipe located in the space portion, A first annular plate having a center hole with an inner diameter slightly larger than the outer diameter of the steel pipe and slidable along the lower steel pipe is prepared, and at the lower end of the outer pipe, the upper steel pipe A second annular plate having a center hole with an inner diameter through which a portion to which the slip prevention member is fixed can pass; And the following steps, the step of penetrating the steel pipe pile into the ground so that the head of the lower steel pipe remains on the ground surface, and the center of the first annular plate in the lower steel pipe remaining on the ground surface A step of inserting a hole and then a central hole of the second annular plate to cover the head of the lower steel tube with the first annular plate and the outer tube; and Along with the ring plate, the outer pipe head remains on the ground surface so as to penetrate the ground along the lower steel pipe, and then the first employed pile is removably connected to the outer pipe head remaining on the ground surface. A step of penetrating the outer pipe together with the first annular plate to a predetermined depth along the lower steel pipe so that a head of the outer pipe is located in the ground; and connecting the upper steel pipe to the head of the lower steel pipe The steel pipe pile penetrates into the ground, and then the second hiring pile can be attached to and detached from the head of the upper steel pipe Connecting the steel pipe pile to a predetermined depth so that the head is located in the space and the steel pipe pile reaches the support layer of the ground, and the inner circumference of the outer pipe and the upper steel pipe Filling the fluidized solidifying material into the space formed between the outer periphery and filling the fluidized solidifying material in the fluidized solidifying material to form the reinforcing body. To do.

  The construction method of the steel pipe pile according to claim 2 of the present invention is a connecting member applicable to both the connection between the steel pipe pile and the pile driving machine and the connection between the outer pipe and the pile driving machine, A first tubular connection comprising a first tubular connection for a steel pipe pile that is detachably connected to the head of the pile, and a second tubular connection for the outer pipe that is detachably connected to the head of the outer pipe. The axial length of the part is formed longer than the second cylindrical connecting part, and the connecting member is used for the step of rotating the steel pipe pile into the ground and the step of rotating the outer pipe into the ground. Features.

  According to the first aspect of the present invention, in order to allow the outer pipe to penetrate into the ground prior to penetrating the upper steel pipe of the steel pipe pile, for example, as shown in FIG. Hire piles that are commonly used in the past and that have protrusions such as a connecting portion can be employed. Moreover, the 1st ring board and the 2nd ring board are used, and the inner diameter of the center hole of the 1st ring board located in the outer side of the lower end part of an outer pipe is the outside of a steel pipe pile (lower steel pipe). Since the diameter is set to be slightly larger than the diameter, earth and sand do not enter between the steel pipe pile and the outer pipe, and the space portion can be ensured reliably. Moreover, since the upper steel pipe is penetrated into the space in the outer pipe after the outer pipe has penetrated into the ground, mud does not adhere to the planned reinforcement section (portion embedded in the reinforcement body) of the upper steel pipe. Moreover, since the slip prevention member is being fixed to the reinforcement planned area of an upper steel pipe, the synthetic effect of a steel pipe pile and a reinforcement body can be anticipated reliably. Moreover, it can respond to the case where the support layer of the ground is lower or higher than the planned depth. That is, the center hole of the second annular plate is an inner diameter through which the upper steel pipe of the portion to which the slip prevention member is fixed can pass, and the first annular plate is slidable along the lower steel pipe. Is deeper than the expected depth, the second annular plate 21 is passed through the lower part of the stopper member 14 and an insufficient length (with a stopper) is added to the upper end of the upper steel pipe. In the case where it is feared that the depth of the support layer is shallower than planned, it can be dealt with by fixing the slip preventing member to a position deeper than the planned reinforcing section in advance.

  In addition, according to the present invention as set forth in claim 2, it is possible to construct a double-pipe structure pile with a single connecting member, that is, when the steel pipe pile is rotated and penetrated into the ground, and the outer pipe is rotated and penetrated into the ground. In this case, it is possible to save the trouble of exchanging the connecting member for connecting the pile driving machine and the steel pipe pile and the connecting member for connecting the outer tube, improving the work efficiency and shortening the construction time.

An example of the construction method of the steel pipe pile of the present invention is shown, (a) is an explanatory view of the process of rotating and penetrating the steel pipe pile into the ground so that the head of the lower steel pipe (lower pile) remains on the ground surface, (b) Is a process of covering the head of the lower pile with the first annular plate and the outer steel pipe through the central hole of the first annular plate and the central hole of the second annular plate provided at the lower end of the outer pipe (outer steel pipe) (C) is an explanatory view of the process of rotating the outer shell steel pipe into the ground so that its head remains on the ground surface by a pile driving machine, and then connecting the first hiring pile to the head remaining on the ground surface , (D) is a step of rotating the outer steel pipe through the first hiring pile further to the ground to a predetermined depth, and then connecting the upper steel pipe (upper pile) with the stopper member fixed to the head of the lower pile. Explanatory drawing, (e) shows the steel pipe pile until the upper pile is located in the outer shell steel pipe by rotating the steel pipe pile into the ground and then connecting the second hired pile to the head of the upper pile. Further, an explanatory diagram of the process of rotating and penetrating into the ground to a predetermined depth, (f) is an explanatory diagram of a process of filling the space between the inner surface of the outer shell steel pipe and the outer surface of the upper pile with a fluidized solidifying material, (g) It is explanatory drawing of the process of removing a 1st hiring pile from the head of an outer shell steel pipe. It is a side view of the upper pile used for the construction method of FIG. An example of the outer shell steel pipe used for the construction method of Drawing 1 is shown, (a) is a top view of an outer shell steel pipe, and (b) is the longitudinal section. An example of the connection member which connects a pile driving machine, a steel pipe pile, and an outer shell steel pipe used for the construction method of FIG. 1 is shown, (a) is a side view, (b) is a side surface when connected to a steel pipe pile. FIG. It is the longitudinal cross-sectional view which a part of steel pipe pile by which the pile head was reinforced by the construction method shown in FIG. 1 was abbreviate | omitted. FIG. 4 is a partial longitudinal sectional view of a conventionally employed hire pile.

  As shown in FIG. 5, the steel pipe pile constructed by the construction method of the steel pipe pile of the present embodiment shown in FIGS. 1 (a) to 1 (g) includes a steel pipe pile 10, an outer shell steel pipe 20 as an outer pipe, a first one. A reinforcing body 50 made of concrete as a fluidized solidified material is provided in the space 40 between the annular plate 30 and the upper part (upper pile 12) of the steel pipe pile 10 and the outer shell steel pipe 20.

  The said steel pipe pile 10 is comprised by the predetermined length according to the depth to the support layer of a ground by connecting a plurality of single pipes (steel pipe) at a construction site. The steel pipe pile 10 is called a lower pile, a middle pile, and an upper pile from the bottom to the pile head. When the pile length is short, the middle pile is unnecessary, so for convenience, the middle pile is called the lower pile together with the lower pile. In this embodiment, the steel pipe pile 10 is formed by connecting a lower pile 11 as a lower steel pipe and an upper pile 12 as an upper steel pipe. The lower pile 11 is provided with a spiral wing 13 having a screwing action in the vicinity of its tip (lower end), and when the rotational force is applied to the head, the lower pile 11 rotates and penetrates into the ground. On the outer periphery of the upper pile 12, there is a displacement preventing member 14 that bites into the reinforcing body 50 over the entire length or a part of the upper pile 12 and firmly attaches the upper pile 12 (the pile head of the steel pipe pile 10) to the reinforcing body 50. It is fixed in advance by welding or the like. The slip preventing member 14 is made of a linear steel material such as a reinforcing bar or a round steel having a diameter of about 10 mm, and is formed by being wound around the outer periphery of the upper pile 12 in an annular shape or a spiral shape. The slip-preventing member 14 is usually attached to the planned reinforcement range by the double pipe (the outer steel pipe 20 and the pile head of the steel pipe pile 10), but the depth of the ground support layer is shallower than the planned depth. Considering that there is a case, as shown in FIG. 2, it is extended and attached to a position deeper than the planned reinforcement range. Near the upper end of the upper pile 12, a rotating metal fitting (iron piece) 15 (see FIG. 2) for transmitting rotational force is fixed by welding or the like. As shown in FIG. 5, the upper pile 12 of the steel pipe pile 10 is embedded in the concrete placed in the space 40 between the outer shell steel pipe 20 and the steel pipe pile 10, concrete (reinforcing body 50). , And the outer shell steel pipe 20 are integrated and reinforced with high rigidity and bending strength. After the completion of the pile work, a footing 60 is built on the upper pile 12 (pile head) and joined to the upper pile 12 (pile head).

  As shown in FIG. 5, the first annular plate 30 is formed such that the inner diameter of the center hole 31 is slightly larger than the outer diameter of the steel pipe pile 10. Although it is desirable that the difference in diameter between the inner diameter of the center hole 31 and the outer diameter of the steel pipe pile 10 is as small as possible, it is set to about 1 mm to 3 mm in consideration of the manufacturing dimensional accuracy of both. The first annular plate 30 can slide in the axial direction and the circumferential direction on the outer periphery of the lower pile 11 through the center hole 31. The first annular plate 30 is in close contact with the second annular plate 21 (see FIGS. 3A and 3B) of the outer shell steel pipe 20 when the outer shell steel pipe 20 is penetrated into the ground. The earth and sand are prevented from entering the inside of the outer shell steel pipe 20 (in the space portion 40 which is a concrete placement space).

  The outer shell steel pipe 20 has an outer diameter larger than the outer diameter of the steel pipe pile 10 and has an axial length shorter than the length of the upper pile 12 of the steel pipe pile 10. Although the actual dimension of the outer shell steel pipe 20 is determined by design calculation, the outer diameter is set to about 1.5 to 2.5 times that of the steel pipe pile 10. As shown in FIGS. 3A and 3B, a second annular plate 21 is fixed to the lower end portion of the outer shell steel pipe 20 by welding or the like. The inner diameter of the center hole 22 of the second annular plate 21 is set to be slightly larger than the outer diameter of the stopper member 14 so that the stopper member 14 can pass through the center hole 22 without any trouble. The second annular plate 21 has a function of preventing intrusion of earth and sand into the space 40 in cooperation with the first annular plate 30. Near the upper end of the outer shell steel pipe 20, a rotating metal fitting (iron piece) 23 for transmitting rotational force is fixed by welding or the like.

The steel pipe pile 10 (lower pile 11 and upper pile 12) and the outer shell steel pipe 20 are rotationally penetrated into the ground by a pile driving machine. At this time, the connection between the steel pipe pile 10 and the pile driving machine and the outer shell steel pipe 20 and A connecting member (commonly referred to as “cap”) 70 shown in FIG. 4 is used for connection with the pile driver. The connecting member 70 is configured to be compatible with both of the two types of diameters of the steel pipe pile 10 and the outer shell steel pipe 20. That is, on the lower surface of the disk-shaped base portion 71, two types of diameters of the first cylindrical connecting portion 72 for the steel pipe pile and the second cylindrical connecting portion 73 for the outer shell steel pipe are provided concentrically. The first and second cylindrical connecting portions 72 and 73 are provided with groove processing portions 72a and 73a, and the rotary fitting 15 attached to the head portions of the steel pipe pile 10 and the outer shell steel pipe 20 at the groove processing portions 72a and 73a. , 23 are connected by fitting. The axial length of the first cylindrical connecting portion 72 is set longer than that of the second cylindrical connecting portion 73. For this reason, the worker can visually confirm the connected state (the rotary fittings 15 and 23 are fitted in the predetermined positions of the groove processing portions 72a and 73a). The connecting member 70 eliminates the need to use two types of caps for connecting the steel pipe pile 10 and the pile driving machine and for connecting the outer shell steel pipe 20 and the pile driving machine. It is possible to improve the construction work efficiency.
Next, the construction method of the steel pipe pile of a present Example is demonstrated with reference to Fig.1 (a) thru | or (g).

  With reference to Fig.1 (a), the rotation penetration process of the steel pipe pile 10 is demonstrated. The connecting member 70 is attached to the pile driving machine, and the lower pile 11 is connected to the first cylindrical connecting portion 72 of the connecting member 70 (see FIG. 4B), thereby connecting the lower pile 11 to the pile driving machine. To do. The lower pile 11 is rotated by a motor (not shown) mounted on the pile driving machine, and the steel pipe pile 10 is penetrated into the ground to the position where the head of the lower pile 11 remains on the ground surface by the screwing action of the spiral blade 13.

  Next, a process of inserting the outer shell steel pipe 20 through the head of the lower pile 11 will be described with reference to FIG. Prior to the construction of the outer shell steel pipe 20, the first annular plate 30 is attached by inserting the center hole 31 of the first annular plate 30 into the head of the lower pile 11. This work may be performed when the medium pile is built. Next, the outer shell steel pipe 20 is attached by inserting the center hole 22 of the second annular plate 21 of the outer shell steel pipe 20 into the head of the lower pile 11.

  Next, referring to FIG. 1 (c), the process of rotating the outer steel pipe 20 into the ground so that its head remains on the ground, and then connecting the first hired pile 80 to the head remaining on the ground will be described. To do. First, a motor (not shown) mounted on the pile driving machine by connecting the head portion of the outer steel pipe 20 to the second cylindrical connecting portion 73 of the connecting member 70 (see FIGS. 4A and 4B). The outer shell steel pipe 20 is rotated by the above, and the outer shell steel pipe 20 is penetrated into the ground until the head remains on the ground surface. Next, the head of the outer shell steel pipe 20 is removed from the cylindrical connecting portion 73, and the first hired pile 80 made of a steel pipe having the same diameter as the outer shell steel pipe 20 and an axial length shorter than the outer shell steel pipe 20 is removed. It is connected to the head of the shell steel pipe 20. Next, the head of the first hired pile 80 is connected to the second cylindrical connecting portion 73.

  Next, referring to FIG. 1 (d), the outer steel pipe 20 is further rotated into the ground to a predetermined depth via the first hiring pile 80, and then the slip prevention member 14 is fixed to the head of the lower pile 11. The process of building (connecting) the pile 12 will be described. Rotation is transmitted from the motor of the pile driver to the outer shell steel pipe 20 through the first hired pile 80, and the outer shell steel pipe 20 is penetrated until its head sinks into the ground (until a predetermined depth of the ground is reached). Since the ground to which the present invention is applied is soft ground, the outer steel pipe 20 penetrates into the ground by applying a slight pushing force with a pile driving machine. When it is difficult to penetrate, a drilling blade or the like may be attached to the outer surface of the lower end of the outer shell steel pipe 20. When the outer steel pipe 20 is penetrated to a predetermined depth of the ground, the first hired pile 80 remains in the vicinity of the ground surface (in a state of protruding on the ground) and plays a role of earth retaining, Is prevented from falling into the outer shell steel pipe 20. For this reason, the 1st hiring pile 80 is not removed from the head of the outer shell steel pipe 20 until the concrete placement is finished. When the outer shell steel pipe 20 is penetrated into the ground, the first annular plate 30 that slides along the outer periphery of the lower pile 11 descends in close contact with the second annular plate 21 at the lower end of the outer shell steel pipe 20. . Since the inner diameter of the first annular plate 30 is set to be slightly larger than the outer diameter of the lower pile 11, the earth and sand are removed from the gap between the first annular plate 30 and the lower pile 11 by the second annular plate 21. Intrusion into the outer shell steel pipe 20 through the center hole 22 is prevented. By penetrating the outer steel pipe 20 to a predetermined depth in the ground, a space is formed between the outer peripheral surface of the steel pipe pile 10 and the inner peripheral surface of the outer steel pipe 20, but mud is attached to the inner surface of the outer steel pipe 20. Never do. However, since the outer shell steel pipe 20 penetrates without discharging the earth and sand to the ground, high pressure is generated in the earth and sand near the lower end of the outer shell steel pipe 20, and the gap between the first annular plate 30 and the lower pile 11 is increased. The earth and sand may enter from a slight gap, and the mud may be thinly attached (about 2 mm to 5 mm in thickness) on the outer peripheral surface of the lower pile 11. The lower pile 11 has a head protruding from the head of the first hired pile 80. The head portion of the lower pile 11 is removed from the first cylindrical connecting portion 72 of the connecting member 70, and the lower end portion of the upper pile 12 is fixedly connected to the head portion of the lower pile 11 by welding or the like. A slip-preventing member 14 is fixed in advance in a planned reinforcement section of the upper pile 12 (see FIG. 2).

  Next, referring to FIG. 1 (e), the steel pipe pile 10 is rotated and penetrated into the ground, and then the second hired pile 90 is connected to the head of the upper pile 12, and the steel pipe pile 10 is further moved to a predetermined depth (upper pile). The process of rotating and penetrating into the ground until the steel pipe pile 10 reaches the supporting ground) will be described. First, the head of the upper pile 12 is attached to the first cylindrical connecting portion 72 of the connecting member 70, and the upper pile 12 is connected to the pile driving machine via the first cylindrical connecting portion 72. The steel pipe pile 10 is rotated with a pile driving machine and penetrates to the middle of the ground. When the head of the upper pile 12 has moved to the vicinity of the head of the first hired pile 80, the head of the upper pile 12 is removed from the first cylindrical connecting portion 72, for example, the same configuration as the conventional example as shown in FIG. A cylindrical connecting portion 91 provided at the lower end of the second hired pile 90 is connected to the head of the upper pile 12. The head of the second hired pile 90 is attached to the first cylindrical connecting portion 72, and the second hired pile 90 is connected to the pile driver through the first cylindrical connecting portion 72. The steel pipe pile 10 is further rotated through the second hired pile 90 and penetrates to a predetermined depth of the ground (the upper pile 12 is accommodated in the outer steel pipe 20 and the steel pipe pile 10 reaches the supporting ground). When the penetration is finished, the second hire pile 90 may be removed. Since the planned reinforcement section of the upper pile 11 (see FIG. 2) descends in the space of the outer shell steel pipe 20, mud does not adhere to its outer peripheral surface. Moreover, when the upper pile 12 has the slip prevention member 14 below the planned reinforcement section, the slip prevention member 14 can pass through the center hole 22 of the second annular plate 21 without any trouble. As the lower portion of the stopper member 14 passes through the center hole 22 of the second annular plate 21, the first annular plate 30 that is in close contact with the second annular plate 21 is positioned at the outermost portion of the stopper member 14. It is pushed by the lower part and moves away from the second annular plate 21 together with the lowermost part (lowers). For this reason, construction can be performed even when the support layer is deeper than the planned depth. In this case, an extension pipe with a detent member 14 is connected to the head of the upper pile 12.

  Next, the step of placing concrete will be described with reference to FIG. Concrete is placed in a space portion 40 formed between the outer periphery of the upper pile 12 and the inner periphery of the outer shell steel pipe 20 to embed the upper pile 12 and the stopper member 14 in the concrete. Since the first hired pile 80 and the outer shell steel pipe 20 play a role of retaining earth, the surrounding earth and sand are not mixed with concrete. In order to prevent material separation of the concrete, it is preferable to use a tremy tube (not shown). When the placed concrete is cured, a reinforcing body 50 is formed. When the slip prevention member 14 bites into the reinforcing body 50, the upper pile 12, the reinforcing body 50, and the outer shell steel pipe 20 are firmly integrated. Is done. In addition, if it is troublesome to place concrete for each pile, a plurality of piles may be put together to place concrete.

  Next, the process of removing the first hired pile 80 will be described with reference to FIG. When the placement of the concrete into the space 40 is finished and the reinforcing body 50 is formed, the first hired pile 80 is removed from the head of the outer steel pipe 20. Construction of the steel pipe pile 10 is completed by removing the first hired pile 80.

  After the completion of the pile construction, as shown in FIG. 5, the footing 60 is built on the pile head of the steel pipe pile 10 (the head of the upper pile 12), and the pile head of the steel pipe pile 10 (the head of the upper pile 12) Be joined.

  According to the construction method of the steel pipe pile of this embodiment, the outer steel pipe 20 is penetrated into the ground prior to the penetration of the upper pile 12 of the steel pipe pile 10, and therefore, for example, FIG. The 2nd hire pile 90 which has the cylindrical connection part 91 in the lower end part of the same structure as what is generally used conventionally can be employ | adopted. Moreover, the 1st annular plate 30 and the 2nd annular plate 21 are used, and the inner diameter of the center hole 31 of the 1st annular plate 30 located in the outer side of the lower end part of the outer shell steel pipe 20 is a steel pipe pile. 10 (lower pile 11) is set slightly larger than the outer diameter, and the first annular plate 30 is a second annular ring at the lower end of the outer shell steel pipe 20 in the process of rotating the outer shell steel pipe 20 into the ground. Since it adheres to the plate 21, earth and sand do not enter the outer shell steel pipe 20 from between the lower pile 11 and the outer shell steel pipe 20, and a space can be ensured reliably. Moreover, since the upper pile 12 is penetrated in the space part of the outer shell steel pipe 20, mud does not adhere to the planned reinforcement section (portion embedded in the concrete) of the upper pile 12. Moreover, since the slip prevention member 14 is being fixed to the reinforcement plan area of the upper pile 12, the synthetic | combination effect of the steel pipe pile 10 and the reinforcement body 50 can be anticipated reliably. Furthermore, it is possible to deal with both cases where the support layer of the pile is lower and higher than the planned depth. That is, the second annular plate 21 is set so that the inner diameter of the center hole 22 is larger than the outer diameter of the portion of the upper pile 12 to which the displacement preventing member 14 is fixed, and the first annular plate 30 is Since it is pushed by the lowermost step part and can move together with the lowermost step portion (see FIG. 1 (e)), when the support layer is deeper than the planned depth, the second annular plate 21 has a lower portion of the detent member 14 below. If you are concerned that the depth of the support layer is shallower than planned by passing the part and adding the missing length (with a slip stopper) to the upper end of the upper pile 12, it is possible to prevent slippage in advance. This can be dealt with by fixing the member 14 to a position deeper than the planned reinforcement section.

  Further, once the connecting member 70 is attached to the pile driving machine, the heads of the lower pile 11, the upper pile 12, and the second hired pile 90 are attached to and detached from the first cylindrical connecting portion 72, or the second cylindrical connecting portion 73. It is only necessary to attach and detach the outer shell steel pipe 20 and the head of the first hired pile 80, and it is not necessary to remove the connecting member 70 from the pile driving machine to replace the connecting member 70 during the construction work. The labor for replacing the member 70 can be saved, the construction work efficiency can be improved, and the construction time can be greatly shortened.

  Further, the rotation penetration of the outer shell steel pipe 20 into the ground is performed without soil removal, and the sand around the outer shell steel pipe 20 is compressed in the lateral direction and the downward direction, the density is increased, and the horizontal resistance of the ground is increased.

  In the present embodiment, a case is shown in which a linear steel material is wound around the outer peripheral surface of the upper pile 12 in an annular shape or a spiral shape, and the displacement preventing member 14 is fixed. However, the present invention is not limited to this. The upper pile 12 may be fixed with an appropriate interval in the axial direction.

  The present invention is applied when a steel pipe pile is constructed in a place where the ground near the pile head is soft.

DESCRIPTION OF SYMBOLS 10 Steel pipe pile 11 Lower pile 12 Upper pile 14 Detachment member 20 Outer shell steel pipe (outer pipe)
21 2nd ring plate 22 Center hole 30 1st ring plate 32 Center hole 40 Space part 50 Reinforcement body 60 Footing 70 Connection member 72,73 Cylindrical connection part 80 1st employment pile 90 2nd employment pile

Claims (2)

An outer pipe having an inner diameter shorter than the outer diameter of the steel pipe pile and larger than the outer diameter of the steel pipe pile is installed on the upper outer circumference of the steel pipe pile, and then formed between the upper outer circumference of the steel pipe pile and the inner circumference of the outer pipe. It is a construction method of a steel pipe pile that fills a space with a fluidized solidifying material and forms a reinforcing body to enhance horizontal resistance force,
The steel pipe pile is composed of a plurality of steel pipes of a lower steel pipe and an upper steel pipe, and a detent member for increasing the adhesion to the reinforcing body is fixed to the outer periphery of the upper steel pipe located in the space portion,
A first annular plate having a center hole with an inner diameter slightly larger than the outer diameter of the lower steel pipe and slidable along the lower steel pipe is prepared,
At the lower end of the outer tube, a second annular plate having a central hole with an inner diameter through which a portion of the upper steel tube to which the slip prevention member is fixed is passed, is fixed.
The following steps,
Intruding the steel pipe pile into the ground so that the head of the lower steel pipe remains on the ground surface;
The central hole of the first annular plate is inserted into the lower steel pipe remaining on the ground surface, and then the central hole of the second annular plate is inserted, and the first annular ring is inserted into the head of the lower steel pipe. Covering the plate and the outer tube;
The outer pipe and the first annular plate are inserted into the ground along the lower steel pipe so that the head of the outer pipe remains on the ground surface, and then the first hired pile is placed on the head of the outer pipe remaining on the ground surface. And detachably connecting the outer tube to the predetermined depth along the lower steel pipe together with the first annular plate so that the head of the outer tube is located in the ground,
The upper steel pipe is connected to the head of the lower steel pipe, the steel pipe pile is penetrated into the ground, and then a second hiring pile is detachably connected to the head of the upper steel pipe, and the head is connected to the space portion. A step of penetrating the steel pipe pile to a predetermined depth so that the steel pipe pile reaches a support layer of the ground,
The space formed between the inner circumference of the outer pipe and the outer circumference of the upper steel pipe is filled with the fluidized solidifying material, and the stiffening member is buried in the fluidized solidified material, and the reinforcing body is formed. And a step of forming the steel pipe pile construction method. In the construction method of the steel pipe pile according to claim 1,
A connecting member applicable to both the connection between the steel pipe pile and the pile driving machine and the connection between the outer pipe and the pile driving machine, wherein the first steel pipe pile is detachably connected to the head of the steel pipe pile. A cylindrical connecting portion and a second cylindrical connection for the outer tube that is detachably connected to the head portion of the outer tube, and the axial length of the first cylindrical connecting portion is longer than that of the second cylindrical connecting portion. The construction method of the steel pipe pile characterized by using the formed said connection member for the process of penetrating the steel pipe pile into the ground and the process of penetrating the outer pipe into the ground.