JP2017115453A - Construction method for foundation pile with reinforced pile head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for reinforcing a pile head of a foundation pile capable of effectively reinforcing a pile head of a foundation pile without requiring a heavy machine in addition to a pile driver and without generating excavation surplus soil.SOLUTION: The method includes the steps of: penetrating a cylindrical casing 60 which has a removable bottom cover 63 and an inner diameter larger than an outer diameter of a foundation pile body 10 to a predetermined pile head reinforcement depth of a foundation pile and securing a space part 60a inside of the casing; removing the bottom cover from the casing, inserting the foundation pile body into the space part of the casing, and penetrating the foundation pile to a support foundation; inserting a reinforcing-bar basket 20 into an annular space 70 that is formed between the casing and the foundation pile body, and installing concrete 30 as a flowable solidification material; and pulling out the casing.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for constructing a foundation pile in which a pile head of a foundation 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 view of the above, various techniques for reinforcing the pile head have been proposed. For example, a construction method using a cylindrical casing having a diameter larger than that of a steel pipe pile has been proposed (see Patent Document 1). In this construction method, first, the cylindrical casing penetrates into the ground and then excavates the earth and sand inside the cylindrical casing, forming a space inside the cylindrical casing, and then placing a steel pipe pile in the center of this space, The steel pipe pile is rotated and penetrated into the ground, then a reinforcing bar is inserted between the outer peripheral surface of the steel pipe pile and the inner peripheral surface of the cylindrical casing, and then the outer peripheral surface of the steel pipe pile and the inner peripheral surface of the cylindrical casing are Concrete is laid in between, and then the cylindrical casing is pulled out from the ground to reinforce the pile head with reinforced concrete.

  As another construction method, a construction method using a Yatco that includes an outer frame body that expands the ground and a guide that holds the pile core of the steel pipe pile substantially in line with the rotation center of the Yatco is also proposed. (See Patent Document 2). In this construction method, the pile core of the steel pipe pile is first held approximately in line with the center of rotation of the Yatco, then the steel pipe pile is buried in the ground and the outer periphery of the steel pipe pile is expanded and excavated. The pile head of the steel pipe pile is reinforced with the ground improvement material by pulling up the Yatco and placing a ground improvement material in the expanded excavated part.

JP 2005-232694 A JP 2011-117216 A

  In the former construction method, a heavy machine (in-pipe excavator such as a crane and a hammer grab) different from the pile driving machine is required for excavation work in the casing, and there is a problem that residual excavation soil is generated. In the latter construction method, no excavated soil is generated, but reinforcing rods cannot be placed in the ground improvement material (actually, cement milk or concrete), so the improved body during an earthquake where a large bending moment acts on the pile head. There is a problem that cracks occur and a large reinforcing effect cannot be obtained.

  It is an object of the present invention to provide a foundation pile construction method that does not require a heavy machine different from a pile driver, does not generate excavation residual soil, and can effectively reinforce the pile head of the foundation pile. And

  The foundation pile construction method according to claim 1 of the present invention is a foundation pile construction method in which a reinforcing body containing a reinforcing bar is constructed on the outer periphery of the pile head of the foundation pile body to enhance the horizontal resistance of the pile head. A cylindrical casing having a detachable bottom lid and having an inner diameter larger than the outer diameter of the foundation pile body, and penetrating into the ground until the lower end of the casing reaches a predetermined lower end position of the reinforcing body. Securing a space part inside, and after removing the bottom lid from the casing, inserting the foundation pile body into the space part of the casing and penetrating the foundation pile body to a supporting ground; A step of inserting a reinforcing rod into an annular space formed between the casing and the pile head of the foundation pile body and filling the fluidized solidification material; and a step of removing the casing from the ground. It is characterized by providing.

  The foundation pile construction method according to claim 2 of the present invention is a foundation pile construction method in which a reinforcing body containing a reinforcing bar is constructed on the outer periphery of the pile head of the foundation pile body to enhance the horizontal resistance of the pile head. A step of penetrating the foundation pile body having a connection fitting fixed to a predetermined lower end position of the reinforcing body into the ground until the connection fitting is located near the ground surface, and a cylinder having an inner diameter larger than the outer diameter of the foundation pile body Covering the foundation pile body with a cylindrical casing, connecting the lower end of the casing to the connection fitting, penetrating the casing into the ground so that its head remains on the ground surface, and further extending the foundation pile body to the support ground A step of penetrating, a step of inserting a reinforcing rod into the annular space formed between the casing and the pile head of the foundation pile body, and filling the fluidized solidifying material; and removing the casing from the ground And comprising the steps of: Serial connection fitting, closes the lower end of the casing, when to penetrate the casing to ground, characterized in that to prevent the internal sediment of the casing from entering.

  The foundation pile construction method according to claim 3 of the present invention is a foundation pile construction method in which a reinforcing body containing a reinforcing bar is constructed on the outer periphery of the pile head of the foundation pile body, and the horizontal resistance of the pile head is increased. A step of penetrating the foundation pile main body with a locking piece fixed to a lower end planned position of the reinforcing body until the locking piece is located near the ground surface, and an inner diameter is larger than an outer diameter of the foundation pile main body. Cover the foundation pile body with a large cylindrical employment pile, detachably connect the lower end of the employment pile to the locking piece, and further penetrate the foundation pile body to the support ground via the employment pile. A cylindrical casing having an inner diameter larger than the outer diameter of the hiring pile, wherein an annular plate having a center hole whose inner diameter is slightly larger than the outer diameter of the hiring pile is detachably attached to a lower end portion; Cover the pile and insert the casing into the ground up to the planned lower end of the reinforcement. Removing the lower end portion of the hiring pile from the locking piece, pulling out the hiring pile from the ground, and reinforcing bars in an annular space formed between the casing and the pile head of the foundation pile body. It is characterized by comprising a step of inserting a ridge and filling with a fluidized solidifying material, and a step of removing the casing from the ground.

  The foundation pile construction method according to claim 4 of the present invention is characterized in that guide fittings having an inner diameter slightly larger than an outer diameter of the foundation pile main body are provided at a plurality of locations of the reinforcing bar rod.

  The construction method of the foundation pile according to claim 5 of the present invention is characterized in that the main reinforcement of the reinforcing bar is projected upward from the reinforced concrete construction range, and the protruding portion is embedded in the foundation concrete.

According to the present invention described in claims 1 to 3,
1. Since the reinforced portion has several times the rigidity and strength of the foundation pile body, the horizontal resistance increases, and the horizontal displacement and bending moment of the foundation pile body can be greatly reduced (a fraction).
2. Heavy machinery other than pile driver is unnecessary.
3. No excavated soil is generated.
4). The non-extruded soil penetration of the casing increases the density of the outer ground of the reinforcement, resulting in increased soil strength and increased horizontal resistance.
5. In the invention according to claim 1, in order to penetrate the casing with the bottom lid prior to penetration of the foundation pile body, in order to penetrate the foundation pile body in a state wrapped in the casing in the invention according to claim 2, Since Claim 3 penetrates the foundation pile body in the state wrapped in the hiring pile, mud soil does not adhere to the outer peripheral surface of the foundation pile body in the planned reinforcement section, and ensures the integrity of the foundation pile body and the concrete. it can.

  According to this invention of Claim 4, even if it is the underground which cannot visually confirm by attaching a guide metal fitting to a reinforcing bar rod, a foundation pile main body and a reinforcing rod rod can be arrange | positioned concentrically.

  According to this invention of Claim 5, a protrusion can be swallowed at the time of foundation concrete construction by making the main reinforcement which comprises a reinforcing steel rod protrude from the upper stage of a foundation pile. As a result, the reliability of the connection between the foundation pile and the foundation concrete is increased and the connection work can be simplified as compared with the case where a steel material for connection is separately provided.

1st Example of the construction method of the foundation pile of this invention is shown, (a) is a process which penetrates a ground until the lower end part reaches the lower end planned position of a reinforcement body, and secures a space part inside a casing. Explanatory drawing of (b) is explanatory drawing of the process of removing a bottom cover from a casing, (c) is explanatory drawing of the process of inserting a foundation pile main body into the space part of a casing, and making it penetrate into a ground, (d) is a foundation. Explanatory drawing of the process of penetrating the pile main body to the support ground, (e) is an explanatory drawing of the process of inserting the reinforcing bar rod into the annular space formed between the casing and the foundation pile main body, (f) is the annular space. FIG. 4 is an explanatory view of a process of placing concrete as a fluidized solidifying material in FIG. 3, (g) is an explanatory view of a process of pulling out a casing. The 2nd Example of the construction method of the foundation pile of this invention is shown, (a) is explanatory drawing of the process which penetrates the lower pile and middle pile (lower pile) of a foundation pile main body into a ground, (b) is a reinforcement body. Explanatory drawing of the process of making the upper pile of the foundation pile main body which fixed the connection metal fitting in the lower end planned position penetrate the ground until the connection metal fitting is located near the ground surface, (c) is the cylindrical casing on the foundation pile main body Explanatory drawing of the process which connects the lower end part of this casing with a connection metal fitting on a pile, (d) is further penetrating the foundation pile body to the support ground, penetrating the casing into the ground so that its head remains on the ground surface. (E) is an explanatory view of the step of inserting a reinforcing bar into the annular space formed between the casing and the foundation pile main body, and (f) is a fluidized solidifying material in the annular space. Explanatory drawing of the process of placing concrete, (g) is the work of pulling out the casing It is an illustration of. 3rd Example of the construction method of the foundation pile of this invention is shown, (a) is explanatory drawing of the process of penetrating the lower pile and middle pile (lower pile) of a foundation pile main body into a ground, (b) is an upper pile. Cover the foundation pile body with the inner diameter larger than the outer diameter of the foundation pile body on the foundation pile body to which the locking piece is fixed at the lower end planned position of the reinforcement, and place the lower end portion of the employment pile on the engagement pile. Explanatory diagram of the process of detachably connecting to the stop piece and penetrating the ground through the hiring pile until the locking piece is located near the ground surface, (c) further supports the foundation pile body through the hiring pile Explanatory drawing of the process of penetrating to the ground, (d) is an explanatory view of the process of covering the hiring pile with a cylindrical casing in which an annular plate having a central hole whose inner diameter is slightly larger than the hiring pile is detachably attached to the lower end portion. (E) is explanatory drawing of the process which penetrates a casing to the lower end planned position of a reinforcing body, (f) is the lower end of a hiring pile. (G) is an explanatory view of the process of inserting a reinforcing bar rod into the annular space formed between the casing and the foundation pile body, (h) Explanatory drawing of the process of placing concrete as a fluidity solidification material in annular space, (i) is explanatory drawing of the process of drawing out a casing. FIGS. 1 to 3 show an example of a casing used in the construction method of FIG. 1, wherein (a) is a plan view of a casing provided with a drilling blade at the lower end, (b) is a partial longitudinal sectional view thereof, and (c) is a lower end. The top view of the casing which provided the spiral wing | blade in the outer periphery of the part, (b) is the partial longitudinal cross-sectional view. An example of the reinforcing bar rod used for the construction method of FIG. 1 thru | or FIG. 3 is shown, (a) is a top view, (b) is the longitudinal cross-sectional view. An example of the connection metal fitting used for the construction method of Drawing 2 is shown, (a) is a top view and (b) is the longitudinal section. An example of the upper pile of the foundation pile main body used for the construction method of FIG. 3 is shown, (a) is a top view, (b) is the partial longitudinal cross-sectional view. FIG. 4 is a partial side view showing an engagement portion of an employment pile used in the construction method of FIG. 3 with a locking piece. An example of the annular plate detachably attached to the lower end part of the casing used for the construction method of FIG. 3 is shown, (a) is a plan view, and (b) is a longitudinal sectional view thereof. It is a figure which shows the foundation pile constructed | assembled by the construction method of FIG. 1 thru | or FIG. 3, (a) is a top view, (b) is the partial longitudinal cross-sectional view. FIG. 4 is a partially enlarged longitudinal sectional view showing a state in which a footing is built on a pile head of a foundation pile constructed by the construction method of FIGS. 1 to 3.

  As shown in FIGS. 10 (a) and 10 (b), the foundation pile constructed by the construction method of the first, second and third embodiments of the present invention shown in FIGS. And the reinforcement body 40 with the reinforcing bar 20 formed by placing concrete 30 as a fluidized solidifying material on the pile head 14 of the foundation pile main body 10 is provided.

  The foundation pile body 10 used in the construction method of the first, second, and third embodiments shown in FIGS. 1 to 3 is a single pipe made of a plurality of steel pipes according to the depth to the support ground. Connected at the construction site and configured to a predetermined length. The foundation pile main body 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 foundation pile body 10 is formed by connecting a lower pile 11 and an upper pile 12. As a method for penetrating the foundation pile main body 10 into the ground, there are, for example, a rotation penetrating method and a press fitting method. When adopting the rotary penetration method, for example, a blade such as a spiral wing having a screwing action is provided near the tip (lower end) of the lower pile 11. The head of the upper pile 12 (the pile head 14) is covered with the reinforcing bar rod 20, and then placed on the concrete 30 placed in the annular space 70 formed between the cylindrical casing 60 and the reinforcing bar rod 20. (See FIGS. 1 (f), 2 (f), 3 (h), 10 (a), and 10 (b)). Thereby, the pile head 14 of the foundation pile main body 10 is integrated with the reinforcement body 40 which consists of the concrete 30 containing the reinforcing bar 20, and is reinforced with high rigidity and bending strength. After the completion of the pile construction, as shown in FIG. 11, the footing 50 is built on the pile head 14 of the foundation pile body 10 and joined to the pile head 14.

  The cylindrical casing 60 used in the construction methods of the first, second, and third embodiments shown in FIGS. 1 to 3 is, for example, twice to four times the outer diameter of the foundation pile body 10. It is formed from a steel pipe having an inner diameter. The casing 60 remains with its head portion (upper end portion) exposed from the ground surface, and its lower end portion is a planned lower end position of the reinforcing body 40 (see FIGS. 10A, 10B, etc.). The axial dimension is set so as to reach the part reinforcement planned depth) and penetrate into the ground. Since the ground to which the construction method of the present invention is applied is soft ground, the casing 60 penetrates into the ground by applying a slight pushing force with a pile driving machine. As shown to (a) thru | or (d), in order to reduce the penetration resistance to the ground, you may attach the excavation blade 61 to the lower end part, and the blade | wings 62, such as a spiral blade, to the outer peripheral surface of the lower end part. A bottom cover 63 (see FIG. 1A) is detachably attached to a lower end portion of the casing 60 used in the first embodiment shown in FIG. 1 through, for example, a wire. The bottom lid 63 closes the lower end opening of the casing 60 when the casing 60 penetrates, and prevents earth and sand from entering the casing 60. The casing 60 used in the third embodiment shown in FIG. 3 has an annular plate 64 (FIG. 3) having a central hole 65 at its lower end that is slightly larger than the outer diameter of the pile 90 (see FIG. 8). 9 (a), (b)) is detachably attached. For example, when the casing 60 is rotated in one direction, the annular plate 64 is maintained in a locked state with the lower end portion of the casing 60 so as to be integrated with the casing 60 and penetrates into the ground together with the casing 60. When it is rotated in the opposite direction, the locked state with the lower end portion of the casing 60 is released and the casing 60 is detached from the casing and remains in the ground. In order to prevent intrusion of earth and sand, the difference in diameter between the inner diameter of the center hole 65 and the outer diameter of the hiring pile 90 is desirably 3 mm or less. However, the mud enters slightly from a slight gap and adheres to the outer surface of the hired pile 90.

  The rebar rod 20 used in the construction methods of the first, second, and third embodiments shown in FIGS. 1 to 3 will be described with reference to FIGS. 5 (a) and 5 (b). The reinforcing bar 20 is formed in a cylindrical bar shape from, for example, a plurality of rod-shaped main bars 21 extending in the axial direction and a ring-shaped hoop bar 22 extending in the horizontal direction. The main muscles 21 are arranged inside the hoop muscles 22 with appropriate intervals along the circumferential direction, and the hoop muscles 22 are arranged with appropriate intervals along the axial direction of the main muscles 21. Inside the reinforcing bar rod 20, guide fittings 23 for aligning the axial centers of the foundation pile main body 10 and the reinforcing bar rod 20 at appropriate locations in the axial direction (two locations at the lower end and the upper portion in FIG. 5 (b)), respectively. Is placed. The guide fitting 23 includes an annular member 24 having an inner diameter slightly larger than the outer diameter of the foundation pile main body 10, and an inner side of the hoop bar 22 for holding the annular member 24 at the center position of the reinforcing bar rod 20. And a plurality of position holding members 25 extending radially, and fixed in the reinforcing bar 20 by welding or the like. Moreover, the upper end part 21a which is a protrusion part of each main reinforcement 21 is extended and protruded from the pile head 14 of the foundation pile main body 10, and when building the footing 50 (refer FIG. 11) on the pile head 14, The foundation pile main body 10 and the footing 50 are connected by being swallowed (embedded) in the footing 50. The upper end portion 12a of the main bar 21 of the reinforcing bar 20 is rubbed into the footing 50, so that the reliability of the connection between the foundation pile and the foundation concrete is increased and the connection work is simplified as compared with the case where a separate steel material is provided. it can.

  A connection fitting 80 used in the construction method of the second embodiment shown in FIG. 2 will be described with reference to FIGS. 6 (a) and 6 (b), for example. The connection fitting 80 is an annular plate and is fixed in advance to the outer peripheral surface portion of the foundation pile main body 10 (upper pile 12), which is the lower end planned position of the reinforcing body 40, and is a central hole into which the upper pile 12 is fitted. 81. On the upper surface of the connection fitting 80, a locking member 82 that is detachably locked to the lower end portion of the casing 60 is provided. The casing 60 can be detachably coupled (connected) to the connection fitting 80 via the locking member 82.

  The upper pile 12 and the hired pile (Yatco) 90 used in the construction method of the third embodiment shown in FIG. 3 will be described with reference to FIGS. 7 (a), 7 (b) and FIG. 8, for example. The hiring pile 90 is made of a cylindrical steel pipe, and the inner diameter thereof is slightly larger than the outer diameter of the foundation pile main body 10 (upper pile 12), and is placed on the foundation pile main body 10 (upper pile 12). Two locking pieces 15 made of a rectangular steel piece are fixed to the upper pile 12 in advance by welding or the like at locations on the outer peripheral surface, which is the planned lower end position of the reinforcing body 40. The hiring pile 90 is provided with a notch portion 91 in which two lower end portions thereof are cut into an inverted L shape, and the locking piece 15 is detachably locked to the notch portion 91 so that the hiring pile is detachable. 90 is connected to the upper pile 12, and the rotational torque and pushing force acting on the hired pile 90 are transmitted to the upper pile 12.

  A construction method for a foundation pile according to a first embodiment of the present invention will be described with reference to FIGS.

  With reference to Fig.1 (a), the process of penetrating the casing 60 in the ground and ensuring the space part 60a in the casing 60 is demonstrated. A bottom cover 63 is attached in advance to the tip (lower end) of the casing 60 so as to be detachable. A wire (not shown) is used for this attachment. Specifically, the bottom lid 63 and the lower end portion of the casing 60 are connected to each other at one end portion of the wire, and the other end portion of the wire is pulled out to the head portion of the casing 60. And the casing 60 is rotated by a motor (not shown) mounted on the pile driving machine, and the lower end portion of the casing 60 is the lower end expected position (foundation) of the reinforcing body 40 (see FIGS. 10A, 10B, etc.). Penetration into the ground until the pile head reinforcement depth is reached. After this penetration, the head (upper end) of the casing 60 is exposed from the ground surface, serves as a clasp, and prevents surrounding earth and sand from dropping into the space 60 a of the casing 60.

  Next, a process of removing the bottom lid 63 will be described with reference to FIG. By pulling the other end portion of the wire that has been drawn to the head of the casing 60 with a pile driver, the connection between the casing 60 and the bottom lid 63 is released, and the bottom lid 63 is removed from the casing 60.

  Next, the process of inserting the foundation pile body 10 into the space 60a of the casing 60 and penetrating into the ground will be described with reference to FIG. The lower pile 11 of the foundation pile main body 10 is inserted into the space 60 a of the casing 60 and penetrates into the ground from the lower end opening of the casing 60.

  Next, a process of penetrating the foundation pile main body 10 until its tip reaches the supporting ground will be described with reference to FIG. When the head of the lower pile 11 is positioned near the head of the casing 60, the lower end of the upper pile 12 is connected to the head of the lower pile 11 by welding or the like, and the foundation pile main body 10 is further penetrated into the ground. . Next, when the head of the upper pile 12 is positioned near the head of the casing 60, an employment pile (not shown) made of a steel pipe having the same diameter as the foundation pile body 10 can be freely attached to and detached from the head of the upper pile 12. And the rotational force is transmitted to the foundation pile main body 10 through the hired pile, and the foundation pile main body 10 is penetrated until its tip reaches the supporting ground. After this penetration, the hired pile is removed from the head of the upper pile 12.

  Next, a process of inserting the reinforcing bar 20 into the casing 60 will be described with reference to FIG. The reinforcing bar 20 is suspended by a pile driver and inserted into an annular space 70 formed between the inner periphery of the casing 60 and the outer periphery of the upper pile 12. At this time, the upper pile 12 is inserted into the annular member 24 of the guide fitting 23. Thereby, the reinforcing bar 20 is arranged in the annular space 70 coaxially with the upper pile 12. If there is time until the concrete placement in the next step shown in FIG. 1 (f), stop the groundwater as necessary to prevent the underground water from entering the annular space 70 from the tip (lower end) of the casing 60. Water treatment (for example, treatment such as adding high-strength mortar or water glass) is performed.

  Next, the step of placing concrete will be described with reference to FIG. In order to prevent material separation of the concrete, a tremy pipe (not shown) is lowered into the annular space 70 of the casing 60, and the concrete 30 is placed in order from the bottom, and a little higher than the upper end height of the planned reinforcing body is added. To do. If necessary, tighten with a vibrator. The reinforcing bar 20 is embedded in the concrete 30 leaving the upper end portion 21 a of the main reinforcing bar 21. When the concrete 30 is placed in the annular space 70 of the casing 60, the head (upper end) of the casing 60 exposed from the ground surface plays a role of retaining soil, and the surrounding earth and sand is placed in the annular space 70. Prevent falling.

  Next, the process of removing the casing 60 from the ground will be described with reference to FIG. When the concrete placement is finished, the casing 60 is rotated and pulled out from the ground. At this time, the concrete spreads sideways by an amount corresponding to the thickness of the side wall of the casing 60, so that the upper end position of the concrete 30 is slightly lowered.

  As described above, the reinforcing body 40 made of the concrete 30 containing the reinforcing bar 20 is constructed on the pile head 14 of the foundation pile main body 10. After the completion of the pile work, the footing 50 is built on the pile head 14 of the foundation pile body 10 as shown in FIG. At this time, the upper end portion 21 a of the main reinforcement 21 protruding from the pile head 14 is squeezed into the footing 50, and the footing 50 is joined to the pile head 14.

  A construction method for a foundation pile according to a second embodiment of the present invention will be described with reference to FIGS.

  With reference to Fig.2 (a), the process of penetrating the part of the lower pile 11 among the foundation pile main bodies 10 is demonstrated. The lower pile 11 is rotated by a motor (not shown) mounted on the pile driving machine, and the lower pile 11 penetrates into the ground until its head is located on the ground surface.

  Next, a process of connecting the upper pile 12 and further penetrating the foundation pile main body 10 into the ground will be described with reference to FIG. A connection fitting 80 is fixed to the upper pile 12 at a predetermined height position on the outer peripheral surface thereof in advance. Specifically, as shown in FIG. 2 (d), when the connection fitting 80 penetrates into the ground until the head of the casing 60 is located near the ground surface, the tip of the foundation pile body 10 reaches the support ground. The upper pile 12 is fixed to the outer peripheral surface. After connecting the lower end of the upper pile 12 to the head of the lower pile 11 by welding or the like, the upper pile 12 is rotated by a motor (not shown) mounted on the pile driving machine, and the height of the connection fitting 80 is increased. The foundation pile main body 10 is penetrated into the ground until the ground surface becomes about 1 m.

  Next, a process of attaching the casing 60 on the upper pile 12 will be described with reference to FIG. The casing 60 is suspended on the upper pile 12 by a pile driver, the casing 60 is lowered so as to cover the upper pile 12 and placed on the connection fitting 80, and the lower end portion of the casing 60 is attached to the locking member 82 (FIG. 6A). , (B)) and is detachably connected to the connection fitting 80.

  Next, a process of penetrating the casing 60 into the ground and penetrating the foundation pile main body 10 until its tip reaches the supporting ground will be described with reference to FIG. When the casing 60 is rotated by a motor (not shown) mounted on the pile driving machine, the casing 60 penetrates into the ground, and the rotation of the casing 60 is transmitted to the upper pile 12 via the connection fitting 80, and the foundation pile main body 10. Penetrates further into the ground, and its tip reaches the supporting ground. At this time, the lower end portion of the casing 60 (connection fitting 80) reaches the planned lower end position (planned pile head reinforcement depth of the foundation pile) of the reinforcing body 40 (see FIGS. 10A and 10B, etc.). When the casing 60 penetrates into the ground, the connection fitting 80 closes the lower end portion of the casing 60 and prevents earth and sand from entering the casing 60. Further, the head (upper end) of the casing 60 is exposed from the ground surface, serves as a clasp, and prevents surrounding earth and sand from falling into the annular space 70.

  Next, a process of inserting the reinforcing bar 20 into the casing 60 will be described with reference to FIG. 2 (e). This process is the same as the process of FIG. 1 (e) described above. That is, in order to prevent the intrusion of groundwater when there is time until the concrete is placed in the next process shown in FIG. If necessary, a water-stopping treatment (for example, adding fast-strength mortar or water glass) is performed.

  Next, the process of placing concrete will be described with reference to FIG. 2 (f). This process is also the same as the process of FIG. 1 (f) described above. That is, a tremy pipe (not shown) is lowered into the annular space 70, and the concrete 30 is placed in order from the bottom, and a vibrator is applied and compacted as necessary.

  Next, the process of removing the casing 60 from the ground will be described with reference to FIG. When the concrete placement is finished, the connection between the lower end portion of the casing 60 and the locking member 82 of the connection fitting 80 is released (for example, reverse rotation), and then the casing 60 is rotated and pulled out from the ground. At this time, as in the case of the process of FIG. 1G, the concrete spreads sideways by an amount corresponding to the thickness of the side wall of the casing 60, so the upper end position of the concrete 30 is slightly lowered.

  As described above, the reinforcing body 40 made of the concrete 30 containing the reinforcing bar 20 is constructed on the pile head 14 of the foundation pile main body 10. After the completion of the pile construction work, a footing 50 (see FIG. 11) is built on the pile head 14 of the foundation pile body 10 in the same manner as in the first embodiment described above, and the upper end portion 21a of the main bar 21 is swallowed into the footing 50. Thus, the footing 50 is joined to the pile head 14.

  A construction method of a foundation pile according to a third embodiment of the present invention will be described with reference to FIGS.

  With reference to Fig.3 (a), the process of penetrating the part of the lower pile 11 among the foundation pile main bodies 10 is demonstrated. The lower pile 11 is rotated by a motor (not shown) mounted on the pile driving machine, and the lower end of the upper pile 12 is fixed to the head of the lower pile 11 by welding or the like in the next step shown in FIG. The foundation pile body 10 is penetrated into the ground to a height at which work can be performed on the ground surface.

  Next, with reference to FIG. 3B, the upper pile 12 portion of the foundation pile body 10 to which the locking piece 15 is fixed is connected to the lower pile 11, and the height of the locking piece 15 is higher than the ground surface. The process of making the foundation pile main body 10 penetrate until it becomes about 1 m and covering the hired pile 90 on the upper pile 12 will be described. First, after connecting the lower end of the upper pile 12 to the head of the lower pile 11 penetrated into the ground by welding or the like, the upper pile 12 is rotated by a motor (not shown) mounted on the pile driver. The foundation pile main body 10 is penetrated into the ground until the height of the stop piece 15 reaches about 1 m on the ground surface. Next, the hiring pile 90 is suspended by a pile driver and covered with the upper pile 12, and the locking piece 15 fixed to the upper pile 12 is locked to the notch 91 at the lower end of the hiring pile 90 (see FIG. 8). The hiring pile 90 is connected to the upper pile 12.

  Next, a process of penetrating the foundation pile main body 10 into the support ground will be described with reference to FIG. The hiring pile 90 is rotated by a motor (not shown) mounted on the pile driving machine, the rotational torque and pushing force of the hiring pile 90 are transmitted to the upper pile 12, and the lower end of the foundation pile body 10 reaches the supporting ground. To penetrate. At this time, the hired pile 90 penetrates into the ground together with the foundation pile main body 10, and its head remains on the ground surface. In addition, the locking piece 15 extends to the lower end planned position (scheduled depth of reinforcement of the pile head of the foundation pile) of the reinforcing body 40 (see FIGS. 10A and 10B) with the penetration of the foundation pile body 10 into the ground. Intrude.

  Next, with reference to FIG. 3 (d), the process of hiring and covering the casing 60 on the pile 90 will be described. An annular plate 64 is detachably attached to the lower end portion of the casing 60 in advance, and the head of the hiring pile 90 protruding to the ground surface in the center hole 65 (see FIGS. 9A and 9B). Insert.

  Next, with reference to FIG. 3 (e), a process of allowing the casing 60 to penetrate the ground to the planned lower end position of the reinforcing body 40 will be described. When the casing 60 is rotated by a motor (not shown) mounted on the pile driver and penetrates into the ground, the casing 60 descends along the hiring pile 90 and the annular plate 64 hits the locking piece 15. Thus, the casing 60 penetrates to the planned lower end position of the reinforcing body 40, and its head remains on the ground surface at the same height as the hired pile 90. The head portion (upper end portion) of the casing 60 remaining on the ground surface plays a role of earth retaining, and prevents surrounding earth and sand from falling into the casing 60. In the process of inserting the casing 60 into the ground, earth and sand enter through a slight gap between the center hole 65 of the annular plate 64 and the hiring pile 90 and adhere to the outer peripheral surface of the hiring pile 90.

  Next, the process of removing the hiring pile 90 will be described with reference to FIG. The hiring pile 90 is rotated clockwise or counterclockwise to unlock the notch 91 and the locking piece 15, and the hiring pile 90 is pulled up. As a result, an annular space 70 is formed between the inner periphery of the casing 60 and the outer periphery of the upper pile 12. Moreover, the earth and sand adhering to the outer peripheral surface of the hiring pile 90 is carried away with the removal of the hiring pile 90 and does not remain in the annular space portion 70.

  Next, a process of inserting the reinforcing bar 20 into the casing 60 will be described with reference to FIG. 3 (g). This process is the same as the process of FIG. 1 (e) described above. That is, when the reinforcing bar 20 is inserted into the annular space 70 and there is time until the concrete is placed in the next process shown in FIG. 3 (h), the water is stopped as necessary to prevent the intrusion of groundwater. Treatment (for example, throwing in early strong mortar or water glass) is performed.

  Next, the process of placing concrete will be described with reference to FIG. 3 (h). This process is also the same as the process of FIG. 1 (f) described above. That is, a tremy pipe (not shown) is lowered into the annular space 70, and the concrete 30 is placed in order from the bottom, and a vibrator is applied and compacted as necessary.

  Next, a process of removing the casing 60 from the ground will be described with reference to FIG. When the concrete placement is finished, the casing 60 is rotated in the direction opposite to that when penetrating into the ground, and the annular plate 64 (see FIGS. 9A and 9B) is removed from the lower end of the casing 60 and pulled out from the ground. However, since the concrete spreads laterally by an amount corresponding to the thickness of the side wall of the casing 60 at this time, the upper end position of the concrete 30 is slightly lowered. In FIG. 3I, the annular plate 64 is omitted in the drawing, but the annular plate 64 remains at the lower end of the concrete 30 containing the reinforcing bar 20 after the casing 60 is removed.

  As described above, the reinforcing body 40 made of the concrete 30 containing the reinforcing bar 20 is constructed on the pile head 14 of the foundation pile main body 10. After the completion of the pile construction work, a footing 50 (see FIG. 11) is built on the pile head 14 of the foundation pile body 10 in the same manner as in the first embodiment described above, and the upper end portion 21a of the main bar 21 is swallowed into the footing 50. Thus, the footing 50 is joined to the pile head 14.

According to the foundation pile construction method of the first, second and third embodiments described above,
The reinforcing body 40 is made of the concrete 30 containing the reinforcing bar 20 and can obtain rigidity and strength several times that of the foundation pile body 10, so that the horizontal resistance increases and the horizontal displacement amount and bending moment of the foundation pile body 10 are greatly increased. Can be reduced (by a fraction).
When the casing 60 is penetrated into the ground, in the first embodiment, the bottom lid 63 detachably attached to the lower end portion of the casing 60 prevents the earth and sand from entering the casing 60. In the second embodiment, the upper pile is used. The lower end portion of the casing 60 is detachably coupled to the connection fitting 80 fixed to 12, and the connection fitting 80 prevents earth and sand from entering the casing 60. In the third embodiment, the lower end portion of the casing 60 is attached and detached. Since the ring plate 64 that is freely attached prevents the earth and sand from entering the casing 60, it is not necessary to excavate the earth and sand in the casing 60 after the casing 60 penetrates. Is unnecessary.
Excavated soil is not generated when the casing 60 penetrates the ground.
The non-extruded soil penetration of the casing 60 increases the density of the outer ground of the reinforcing body 40. As a result, the strength of the soil increases and the horizontal resistance increases.
In the first embodiment, since the casing 60 with the bottom lid 63 penetrates into the ground before the upper pile 12 penetrates, in the second embodiment, the upper pile 12 penetrates into the ground while being wrapped in the casing 60. Therefore, in the third embodiment, since the upper pile 90 penetrates into the ground while being wrapped in the hired pile 90, no mud adheres to the outer peripheral surface of the foundation pile body 10 (upper pile 12) in the planned reinforcement section. The integrity of the foundation pile body 10 and the concrete 30 can be secured.
By attaching the guide fitting 23 to the reinforcing bar 20, the foundation pile body 10 and the reinforcing bar 20 can be arranged concentrically even in the ground where visual confirmation is not possible.
By projecting the upper end portion 21a of the main reinforcing bar 21 constituting the reinforcing bar 20 from the upper stage of the foundation pile, the projecting part can be swallowed during the construction of the foundation concrete. As a result, the reliability of the connection between the foundation pile and the foundation concrete is increased and the connection work can be simplified as compared with the case where a steel material for connection is separately provided.

  The present invention relates to the foundation pile main body 10, the reinforcing bar 20, the concrete 30 as a fluidized solid body, the casing 60, and the connection fitting 80 shown in the construction methods of the first embodiment, the second embodiment, and the third embodiment described above. It is not limited to the hiring pile 90 or the like. For example, the foundation pile main body 10 is not limited to a steel pipe pile.

  The present invention is applied when a foundation pile is constructed at a place where the ground near the pile head is soft.

DESCRIPTION OF SYMBOLS 10 Foundation pile main body 11 Lower pile 12 Upper pile 14 Pile head 15 Locking piece 20 Reinforcement rod 21 Main reinforcement 21a Upper end part 23 Guide metal fittings 30 Concrete 40 Reinforcement body 50 Footing 60 Casing 63 Bottom cover 64 Ring plate 70 Annular space part 80 Connection fitting 90 Hiring pile

Claims (5)

In the construction method of the foundation pile that builds a reinforcing body with reinforcing bars on the outer periphery of the pile head of the foundation pile body and enhances the horizontal resistance of the pile head,
A cylindrical casing having a detachable bottom cover and having an inner diameter larger than the outer diameter of the foundation pile main body is inserted into the ground until the lower end of the base reaches a predetermined position of the lower end of the reinforcing body. A process of securing a space inside,
After removing the bottom lid from the casing, inserting the foundation pile body into the space of the casing and penetrating the foundation pile body to the support ground;
Inserting a rebar rod into an annular space formed between the casing and the pile head of the foundation pile body and filling a fluidized solidifying material;
And a step of removing the casing from the ground. In the construction method of the foundation pile that builds a reinforcing body with reinforcing bars on the outer periphery of the pile head of the foundation pile body and enhances the horizontal resistance of the pile head,
A step of penetrating the foundation pile main body with a connection fitting fixed at a lower end planned position of the reinforcing body into the ground until the connection fitting is located near the ground surface;
Cover the foundation pile body with a cylindrical casing whose inner diameter is larger than the outer diameter of the foundation pile body, connect the lower end of the casing to the connection fitting, and leave the casing so that its head remains on the ground surface And the process of further penetrating the foundation pile body to the support ground,
Inserting a rebar rod into an annular space formed between the casing and the pile head of the foundation pile body and filling a fluidized solidifying material;
Removing the casing from the ground, and
The method for constructing a foundation pile according to claim 1, wherein the connection fitting closes a lower end portion of the casing and prevents the earth and sand from entering the casing when the casing is penetrated into the ground. In the construction method of the foundation pile that builds a reinforcing body with reinforcing bars on the outer periphery of the pile head of the foundation pile body and enhances the horizontal resistance of the pile head,
A step of penetrating the foundation pile main body having a locking piece fixed to a lower end planned position of the reinforcing body into the ground until the locking piece is positioned near the ground surface;
Covering the foundation pile body with a cylindrical employment pile whose inner diameter is larger than the outer diameter of the foundation pile body, removably connecting the lower end of the employment pile to the locking piece, and through the employment pile A step of further penetrating the foundation pile body to the supporting ground;
A cylindrical casing having an inner diameter that is detachably attached to the lower end portion and having a central hole whose inner diameter is slightly larger than the outer diameter of the hiring pile is covered with the hiring pile. , The step of penetrating the casing to the ground to the lower end planned position of the reinforcing body,
The lower end of the hiring pile is removed from the locking piece, the hiring pile is pulled out of the ground, and a reinforcing bar is inserted into the annular space formed between the casing and the pile head of the foundation pile body. Filling the fluidized solidifying material with,
And a step of removing the casing from the ground. In the foundation pile construction method according to any one of claims 1 to 3,
A foundation pile construction method characterized by comprising guide fittings having an inner diameter slightly larger than the outer diameter of the foundation pile main body at a plurality of locations of the reinforcing bar. In the foundation pile construction method according to any one of claims 1 to 3,
A method for constructing a foundation pile, characterized in that the main reinforcement of the reinforcing bar is projected upward from the reinforcing body construction range and the projecting portion is embedded in foundation concrete.