JP6504388B2 - Penetration method of penetration pile and penetration pile - Google Patents

Description

  The present invention relates to a penetration pile and a penetration method of the penetration pile.

  In the field of civil engineering and architecture, construction of foundations to support structures and structures is carried out. As a foundation which supports a structure or a work, there are, for example, a construction in which concrete is cast at a site and a construction, and a construction in which a ready-made pile is penetrated into a ground and constructed. When placing concrete, excavated soil is generated and it takes time for curing after placing concrete, so it takes time from the start of construction to the start of operation. Therefore, in recent years, piles capable of suppressing excavated soil, shortening construction time, and enabling early start of service are widely used, and those with various improvements have been proposed (see, for example, patent documents 1-3) ).

JP, 2006-283424, A Patent No. 3593070 Japanese Patent Application Laid-Open No. 9-287139

  One type of pile that supports a structure or a work is a pile with a spiral blade. Although various piles have been proposed as piles provided with spiral blades, for example, in the case of a pile provided with spiral blades used as a foundation of various structures such as a high-rise building or an artificial island, A method is adopted in which the ground is penetrated while applying pressure and rotational force. However, in the case of adopting this construction method, a rotary penetrator is required. However, the rotary penetrator is a large-scale device and expensive, and has a problem that it takes time for construction. In addition, if a pile with a spiral blade is penetrated into the ground while rotating the pile, a large torsional force acts on the pile. For example, in the case of a steel pipe pile, it is necessary to take measures such as increasing the thickness of the steel pipe. It may be

  Then, this application makes it a subject to provide the penetration method of the penetration pile and penetration pile which can penetrate into a ground, without applying rotational force to a pile, although it is a pile provided with a helical part.

  In order to solve the above-mentioned subject, in the present invention, among the outer peripheral surfaces of a rod-like pile main body having a tapered pile tip which gradually reduces its diameter toward the penetration direction, the outer peripheral surface of at least part or all of the pile tip If the reaction force from the ground when the pile body portion penetrates the ground is received, the spiral surface is provided to convert the reaction force into the rotational force of the pile body portion.

  In detail, it is a pile used as a foundation of a structure, and it has at least the rod-like pile main body having a tapered pile tip which gradually reduces its diameter toward the penetration direction, and at least the outer peripheral surface of the pile main body It is helically formed along the outer peripheral surface of a part or all of the tip end of the pile, and when the pile main body receives a reaction from the ground when it penetrates into the ground, the reaction is used to rotate the pile main body And a helical portion having a helical surface that converts to a force, and when the pile head of the pile is struck or pressed in a penetration direction, it penetrates the ground while autonomously rotating.

The penetration pile according to the present embodiment has high penetration because it has a tapered shape in which the tip end of the pile is gradually reduced in diameter in the penetration direction. And the helical part which received the reaction force from the ground at the time of hitting or pressing the pile head of a pile rotates the whole pile. Therefore, the impact force or pressing force applied to the pile is relatively small as compared to a pile whose tip is not tapered, and moreover, it penetrates into the ground while autonomously rotating without applying rotational force to the pile. . Therefore, with this penetration pile, for example, even if the support layer is a little deep from the ground surface, the penetration pile can be easily made to reach the support layer, and even if a rotational force is not applied to the pile, It is possible to embed in the support layer a helical portion that exhibits support in the direction of penetration and pull-out resistance.

  The pile main body further includes a constant axis having a constant axis diameter, and the spiral portion is an outer peripheral surface of a part or all of the pile tip end, or the entire outer circumference of the pile tip end It is preferable that a spiral shape is formed along the outer peripheral surface of the surface and part or all of the constant shaft portion. If there is a fixed shaft with a fixed shaft diameter, simply increase or decrease the length of the fixed shaft, or connect an extended shaft such as a steel pipe to the fixed shaft and lengthen the length of the fixed shaft. The overall length of the penetration pile can be made appropriate. For the extension shaft, metal such as steel or concrete can be used, and it may be a hollow rod (pipe) or a solid rod.

  Moreover, it is preferable that the said helical part is helically formed by the same pitch along the central axis of the said pile main-body part. Since the helical portion has the same pitch along the central axis of the pile main body, it is easy to spirally advance in the ground without scraping the surrounding ground.

  Further, it is preferable that the pile tip end portion gradually reduce in diameter toward the penetration direction such that the outer peripheral surface of the pile tip end portion has an inclination angle of 10 degrees or less with respect to the central axis of the pile main body portion . If the diameter is gradually reduced in the penetration direction so that the outer peripheral surface of the pile tip has an inclination angle of 10 degrees or less with respect to the central axis of the pile main body, the ground will be roughly any ground It is possible to penetrate the ground while pushing the soil laterally against the penetration direction without scraping the ground.

  Moreover, it is preferable that the said helical part is formed by the pitch 1.3 times or more of the maximum value of the diameter of the said helical part. If the helical portion is formed at a pitch of 1.3 times or more of the maximum value of the diameter, the amount of penetration per one rotation from the initial stage of penetration to the end of penetration is approximately the same amount of penetration as the pitch.

  Moreover, it is preferable that the said helical part is formed in at least 2 rounds or more in the outer peripheral surface of the said pile front-end | tip part. If the number of turns of the helical portion is smaller than two, the force to rotate the pile main portion, the supporting force in the penetration direction, and the pullout resistance are small, and it is considered that the performance of the pile is not efficiently exhibited.

  Further, it is preferable that the penetration pile is connected to the structure in a state in which the pile head can not rotate around at least a central axis of the pile main body in a state of being penetrated into the ground. By connecting the pile head and the structure so that the penetrating pile does not rotate, the helical pile does not rotate even if pressure or pulling force acts on the penetrating pile thereafter, so that the supporting strength in the direction of penetration that is stronger by the spiral and Pull resistance is exhibited.

  The present invention can also be grasped from the aspect of the method. The present invention may be, for example, a penetration method of penetrating the penetration pile into the ground while striking or pressing the pile head of the penetration pile in a penetration direction of the penetration pile.

  In the case of the penetration pile and the penetration method of the penetration pile, when the pile head of the penetration pile is hit or pressed in the penetration direction, it is possible to penetrate the ground while rotating autonomously.

FIG. 1 is a view showing a penetration pile according to the embodiment. FIG. 2 is a view showing a penetration pile according to a modification of the present embodiment. FIG. 3: is the figure which showed the penetration pile which concerns on the comparative example used by this experiment. FIG. 4 is a graph showing the relationship between the penetration amount per rotation and the depth for each of the example and the comparative example. FIG. 5 is a graph showing experimental results of the relationship between the amount of penetration per rotation and the depth for several examples in which the pitch of the spiral portion is changed.

  Hereinafter, embodiments of the present invention will be described. Note that the embodiment described below is an aspect of the present invention, and does not limit the technical scope of the present invention.

Embodiment
FIG. 1 is a view showing a penetration pile according to the embodiment. The penetration pile 1 which concerns on this embodiment is a penetration pile used as a foundation of a structure, and is provided with the pile main-body part 2 and the spiral part 3. As shown in FIG. The pile main body portion 2 is a rod-like portion having a tapered pile tip end portion 2a whose diameter gradually decreases in the penetration direction and a constant shaft portion 2b whose axis diameter is constant, and the pile head 4 of the penetration pile 1 penetrates It is hit or pressed in the direction. Further, the spiral portion 3 is formed in a spiral shape along the outer peripheral surface of the pile main body portion 2, and when receiving a reaction force from the ground when the pile main body portion 2 penetrates the ground, the reaction force is used as the pile main body portion It has a helical surface 3a that converts it into a rotational force of two.

  Since the pile tip 2a has a tapered shape that gradually reduces in diameter in the penetration direction, when the pile head 4 of the penetration pile 1 is hit or pressed, the pile tip 2a penetrates the soil that constitutes the ground. While pushing away to the side of the direction, it is possible to penetrate the ground without scraping the surrounding ground. Depending on the properties of the ground into which the penetration pile 1 is driven, the material of the penetration pile 1, and the type of structure supported by the penetration pile 1, for example, the outer peripheral surface of the pile tip 2a of the pile tip 2a If the diameter is gradually reduced in the direction of penetration so that the inclination angle is 10 degrees or less with respect to the central axis, the soil is penetrated in the direction of penetration without scraping the surrounding ground, regardless of the nature of the ground. It can penetrate the ground while pushing it to the side.

  The helical portion 3 receives the reaction force from the ground when the pile head 4 of the penetration pile is hit or pressed, and the penetration surface 1a converts the reaction force into rotational force of the pile main body portion 2 to make the penetration pile 1 Rotate. In addition, the helical portion 3 exerts a supporting force in the penetration direction and a pullout resistance force in the penetrated state. Therefore, the spiral portion 3 has a strength that does not cause plastic deformation even when receiving the reaction force from the ground when the pile head 4 of the penetration pile 1 is hit. Moreover, the spiral part 3 has the number of turns of the extent to which the pile main-body part 2 rotates. The strength of the spiral portion 3 is controlled by the thickness, shape, material and the like of the spiral portion 3. Therefore, for example, the thickness of the spiral portion 3 is the magnitude of the force for striking or pressing the pile head 4 of the penetration pile 1, the material of the penetration pile 1, the property of the ground, and the outer peripheral surface of the pile main body 2 It is appropriately determined in consideration of various factors such as the length to the outer edge, the pitch of the spiral portion 3, the ratio of the number of turns of the spiral portion 3 to the total length of the pile body 2, and the like. In addition, the number of turns of the spiral portion 3 depends on the nature of the ground, the length from the outer peripheral surface of the pile main portion 2 to the outer edge of the spiral surface 3a, etc. It is considered to be effective.

As the spiral portion 3 goes from the upper end side to the lower end side of the pile main body portion 2, the length from the outer peripheral surface of the pile main body portion 2 to the outer edge of the spiral surface 3a gradually increases, and the outer diameter of the spiral surface 3a becomes constant (See the range indicated by reference numeral 3M in FIG. 1). Also, for the lower end portion of the pile main body portion 2, the length from the outer peripheral surface of the pile main body portion 2 to the outer edge of the spiral surface 3a gradually becomes shorter toward the penetration direction so that the spiral portion 3 can easily enter the ground. (See the range indicated by reference numeral 3S in FIG. 1). The length from the outer peripheral surface of the pile main body 2 to the outer edge of the spiral surface 3a gradually becomes longer as going from the pile head 4 side to the lower end side of the pile main body 2 among the parts of the spiral part 3 The portion where the outer diameter is constant will be hereinafter referred to as the main spiral portion 3M. Further, in each portion of the spiral portion 3, a portion in which the outer diameter of the spiral surface 3a is gradually reduced as it goes in the penetration direction is hereinafter referred to as a distal end spiral portion 3S.

  For example, the penetration pile 1 may be a relatively small one used for foundations such as solar panels, fences and signs, or a size that can be used for foundations of various structures such as high-rise buildings or artificial islands, It can be used as the basis of these structures. The penetration pile 1 may be manufactured, for example, by combining and welding a steel pipe or a steel plate, or the pile main body 2 and the spiral portion 3 may be integrally manufactured by casting. In this case, it may be manufactured by casting a steel pipe or a steel plate. Furthermore, it may be made of concrete or resin. The penetration pile 1 is penetrated into various grounds and exerts a supporting force to support the structure as a foundation of the structure, and exerts a pulling resistance that can withstand even a strong wind or an earthquake.

  The penetration pile 1 according to the present embodiment can penetrate into the ground by striking or pressing the pile head 4 of the penetration pile 1 by various methods such as striking, vibro, and pressing. At the initial stage of penetration, in which the penetration pile 1 is hardly embedded, the tip spiral portion 3S whose diameter gradually reduces in the direction of penetration is gradually buried in the ground to strike or press the pile head 4 of the penetration pile 1 The helical portion 3 receiving the reaction force from the ground at the time of starting to gradually exert the rotational force for rotating the penetration pile 1. Then, after the tip spiral portion 3S is buried in the ground, the main spiral portion 3M starts to be buried in the ground. The tip spiral portion 3S and the main spiral portion 3M receive a reaction force from the ground, so that a sufficient rotational force to rotate the pile main body 2 can be obtained. Therefore, the pile main body 2 is sufficiently rotated by being buried in the ground. be able to.

  In the case of the penetration pile 1 according to the present embodiment, if the pile head 4 of the penetration pile 1 is hit or pressed by various methods such as hitting, vibro, pressing method, the pile is rotated because it penetrates the ground while rotating autonomously. There is no need to use a rotary penetrator that penetrates the ground while pressing and rotating the That is, if it is penetration pile 1 concerning this embodiment, since it is not necessary to use a large-scale rotary penetration machine, improvement of construction nature and reduction of cost are possible. Further, by connecting the pile head 4 and the structure so that the penetration pile 1 does not rotate, the autonomous rotation is hindered even if a pressing force or pulling out force acts on the penetration pile 1 thereafter, and the spiral portion 3 can exert strong supporting force in the pressing direction and pullout resistance.

  In addition, since the pile tip 1 according to the present embodiment has a tapered shape in which the tip end 2a of the pile is gradually reduced in diameter in the penetration direction, the pile 1 has high penetration. Therefore, the impact force or the pressing force applied to the pile may be relatively small as compared to a pile whose tip is not tapered. Therefore, for example, in the case of the penetration pile 1 according to the present embodiment, the penetration pile 1 can easily reach the support layer even if the support layer is a little deep from the ground surface.

  By the way, as FIG. 1 shows, the helical part 3 is helically formed by the same pitch along the central axis of the pile main-body part 2. As shown in FIG. If helical portion 3 is formed in a spiral shape at the same pitch along the central axis of pile body portion 2, when penetrating penetrating pile 1 into the ground, helical portion 3 does not scrape the surrounding ground and is within the ground It is easy to push in a spiral. However, the helical portion 3 is not limited to one formed at the completely same pitch along the central axis of the pile main body portion 2. For example, the pitch near the tip is slightly different from that of the other portion It is also good.

  Moreover, although pile main-body part 2 which has fixed axis part 2b with fixed axis diameter was illustrated by FIG. 1, penetration pile 1 which concerns on this embodiment is limited to what has fixed axis part 2b. It is not a thing. In the penetration pile 1, most of the pile main body 2 is gradually reduced in diameter in the penetration direction, and the constant shaft 2b may be omitted.

Moreover, although the helical part 3 spirally formed along the outer peripheral surface of the pile front-end part 2a and the outer peripheral surface of the fixed axial part 2b was illustrated by FIG. 1, the penetration pile 1 which concerns on this embodiment is It is not limited to such a form. The spiral portion 3 may be formed only on all or part of the outer peripheral surface of the pile tip 2a, and the outer peripheral surface of the fixed shaft 2b may be omitted.

  FIG. 2 is a view showing a penetration pile according to a modification of the present embodiment. In the modified example of the present embodiment, the helical portion 3 has a constant length (extension width) from the outer peripheral surface of the pile main portion 2 to the outer edge of the helical surface 3 a from the upper end side to the lower end side of the pile main portion 2 (See the range indicated by reference numeral 3M 'in FIG. 2). Moreover, about the lower end part of pile main part 2, the length (protrusion width) from the outer peripheral surface of pile main part 2 to the outer edge of spiral surface 3a is in the penetration direction so that spiral part 3 can easily enter the ground. It becomes gradually smaller as it goes (see the range indicated by reference numeral 3S 'in FIG. 2). Among the portions of the spiral portion 3, a portion from the outer peripheral surface of the pile main portion 2 to the outer edge of the spiral surface 3a from the upper end side to the lower end side of the pile main body portion 2 (extension width) is constant Hereinafter, the main spiral portion 3M 'will be called. Further, in each portion of the spiral portion 3, a portion where the length (extension width) from the outer peripheral surface of the pile main body 2 to the outer edge of the spiral surface 3a gradually decreases in the penetration direction I will call it 3S '.

  The penetration pile 1 which concerns on the modification of this embodiment can be penetrated in the ground by striking or pressing the pile head 4 with various construction methods, such as an impact, a vibro, and a pressing construction method. At the initial stage of penetration, in which the penetration pile 1 is hardly embedded, the tip spiral portion 3S 'of which the length (extension width) to the outer edge of the spiral surface 3a gradually decreases in the penetration direction is gradually buried in the ground The helical portion 3 receiving the reaction force from the ground when the pile head 4 of the penetration pile 1 is hit or pressed starts to gradually exert rotational force to rotate the pile main body portion 2. Then, after the tip spiral portion 3S 'is buried in the ground, the main spiral portion 3M' starts to be buried in the ground. When the tip helical portion 3S 'and the main helical portion 3M' receive a reaction force from the ground, a sufficient rotational force for rotating the pile main body 2 can be obtained. Therefore, the pile main body 2 is sufficiently filled by being buried in the ground. It can be rotated. According to the modification of the present embodiment, since the length (extension width) from the outer peripheral surface of the pile main body 2 to the outer edge of the spiral portion 3a is constant, it is possible to suppress breakage or the like of the spiral portion 3a. it can.

<Experimental result>
The effect of the penetration pile 1 according to the present embodiment was verified by an experiment, and the result is shown below.

  FIG. 3: is the figure which showed the penetration pile which concerns on the comparative example used by this experiment. The penetration pile 101 which concerns on a comparative example is equipped with the pile main-body part 102 and the spiral part 103 similarly to the penetration pile 1 which concerns on embodiment. However, the pile main body portion 102 of the penetration pile 101 according to the comparative example does not have a tapered pile tip portion that gradually reduces in diameter in the penetration direction, and a constant outer diameter from the pile head 104 in the penetration direction Is a member formed of a cylindrical or cylindrical constant shaft portion 102b. Therefore, also in the helical portion 103 formed in a helical shape so as to surround the outer peripheral surface of the pile main body portion 102, the length from the outer peripheral surface of the pile main body portion 102 to the outer edge of the helical surface 103a is from the pile head 104 to the penetration pile 101 It is constant up to the tip of the

  FIG. 4 is a graph showing the relationship between the penetration amount per rotation and the depth for each of the example and the comparative example. The penetration test was carried out with the pitch of the helical portions 3 and 103 being 30 mm and the ground conditions being the same in both the example and the comparative example.

As apparent from the graph of FIG. 4, the penetration pile 1 according to the example has a helical portion per revolution from the start of the penetration at a shallow depth (about 70 mm depth) to the end of the penetration. It is almost constant at the same 30 mm as the pitch of 3. On the other hand, in the penetration pile 101 according to the comparative example, the amount of penetration per one rotation is extremely large at the beginning of penetration, and the amount of penetration per one rotation decreases as the end of penetration is approached. In both of the penetration pile 1 according to the embodiment and the penetration pile 101 according to the comparative example, since the pitch of the helical portions 3 and 103 is constant at 30 mm, in the ideal penetration state, the penetration depth and rotation amount of the pile are the helical portions 3 , And 103 in accordance with the pitch. However, in the penetration pile 101 according to the comparative example, the penetration amount per one rotation is not constant. Therefore, in the penetration pile 101 which concerns on a comparative example, since it is thought that the surrounding ground is scraped down during penetration, it is guessed that sufficient supporting force from the ground is not obtained.

  FIG. 5: is the graph which showed the experimental result of the relationship between the amount of penetrations per rotation, and the depth about several Examples from which the pitch of the helical part 3 of the penetration pile which concerns on this embodiment differs. The graph in FIG. 5A is an experimental result in the case where the pitch of the spiral portion 3 when the outer diameter of the main spiral portion 3M is D is 1.1 times D. Moreover, the graph of FIG. 5 (B) is an experimental result at the time of making the pitch of the spiral part 3 into 1.25 times D. The graph in FIG. 5C is an experimental result in the case where the pitch of the spiral portion 3 is 1.3 times D. The graph of FIG. 5D is an experimental result in the case where the pitch of the spiral portion 3 is 1.4 times D. As can be seen by comparing the graphs of (A) to (B) in FIG. 5, when the pitch of the spiral portion 3 is 1.1 or 1.25 times D, the depth at the beginning of the penetration is shallow The amount of penetration per rotation from (the depth of about 70 mm) to the end of penetration varies as compared to 30 mm of the pitch. On the other hand, as can be seen by comparing the graphs from (C) to (D) in FIG. 5, when the pitch of the spiral portion 3 is 1.3 or 1.4 times D, the depth at the beginning of the penetration start is The amount of penetration per revolution from the shallow stage (about 70 mm in depth) to the end of penetration is generally along the 30 mm of the pitch. Therefore, according to this experimental result, if the helical portion 3 is formed at a pitch of 1.3 times or more of the maximum value of the diameter of the helical portion 3, penetration per one rotation from the beginning of the penetration to the end of the penetration It can be seen that the amount can be sized roughly along the pitch.

1, 101 · · Penetration pile 2, 102 · · Pile body portion 2a · · · Pile tip portion 2b, 102b · · · Constant shaft portion 4 104 · · Pile head 3, 103 · · Helical portion 3M, 3M '· · Main Spiral portion 3S, 3S '· · · Tip spiral portion 3a, 103a · · · Spiral surface

Claims (6)

A pile that is penetrated into the ground by impact or pressure without applying rotational force, and is used as a foundation of a structure,
A rod-like pile main body having a tapered pile tip which gradually reduces its diameter toward the penetration direction;
Of the outer peripheral surface of the pile main body, it is formed in a spiral along at least a part or all of the outer peripheral surface of the tapered pile tip, and the reaction force from the ground when the pile main body penetrates into the ground And a helical portion having a helical surface that converts the reaction force into a rotational force of the pile main body when receiving the
The spiral portion, the so that the length from the center axis of the pile body portion to an outer edge of the helical surface is a constant toward the penetration direction, the outer edge of the helical surface from the outer peripheral surface of the pile tip of the tapered The main spiral portion, the length of which gradually increases in the penetration direction ,
It is a tip spiral portion formed on the side of the main spiral portion in the penetration direction so as to be continuous with the main spiral portion, and the length from the central axis of the pile main portion to the outer edge of the spiral surface is in the penetration direction as gradually Tsugichijimi径 towards, and a progressively shorter becomes distal helix length from the outer circumferential surface to the outer edge of the helical surface is toward the penetration direction of the pile end portion of the tapered,
The helical portion extends from the tip helical portion to the main helical portion at the same pitch along the central axis of the pile main portion and a length from the central axis of the pile main portion to the outer edge of the helical surface Is formed at a pitch of at least 1.3 times the maximum value of
If the pile head of the pile is struck or pressed in the direction of penetration without applying rotational force to the pile, the amount of penetration per one rotation penetrates the ground while rotating autonomously at a size along the pitch. Penetration pile. The pile main body further includes a constant axis portion having a constant axis diameter,
The helical portion is helical along the outer peripheral surface of part or all of the tapered pile tip, or the entire outer peripheral surface of the tapered pile tip and the outer peripheral surface of part or all of the constant shaft. Is formed in
The penetration pile according to claim 1. The tapered pile tip portion is gradually reduced in diameter toward the penetration direction such that the outer peripheral surface of the tapered pile tip portion has an inclination angle of 10 degrees or less with respect to the central axis of the pile body portion.
The penetration pile according to claim 1 or 2 . The spiral portion is formed at least two turns or more on the outer peripheral surface of the tapered pile tip portion.
The penetration pile according to any one of claims 1 to 3 . The penetration pile is connected to the structure in a state in which the pile head can not rotate around at least a central axis of the pile main body in a state of being penetrated into the ground.
The penetration pile according to any one of claims 1 to 4 . The penetration pile is made to penetrate the ground while striking or pressing the pile head of the penetration pile according to any one of claims 1 to 5 in the penetration direction of the penetration pile,
Penetration method of penetration pile.