JP2014009440A - Mortar injected steel pipe pile and burying attachment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steel pipe pile, which is used for reinforcing the ground or a foundation of a structure and modifying an inclination of an existing foundation and can be pressed into the ground while injecting mortar therein, capable of being easily constructed, achieving a large reinforcement effect and reducing a manufacturing cost.SOLUTION: A steel pipe pile 10 comprises: a cylindrical main body 1; a first helical blade 21 which is arranged close to a tip 1A (a lower edge when constructed) of the main body and used for screwing; a second helical blade 22 which is arranged at a posterior portion of the main body with a helical pitch smaller than that of the first helical blade; discharge holes 11 which are arranged inside a region of the first helical blade; and a bead section 23 which is arranged between the first helical blade and the second helical blade and wound in an opposite helical direction thereto.

Description

  The present invention relates to a steel pipe pile that can be used to reinforce the ground or foundation of a building or to correct the inclination of an existing foundation, and particularly relates to a steel pipe pile that can be embedded by injecting mortar or the like. Further, the present invention relates to an attachment for making it possible to use a general earth auger or the like when pressing and embedding such a mortar-injected steel pipe pile while rotating.

  In Japan, a large number of houses and small-scale structures have been built on soft ground where liquefaction can occur due to earthquakes without burying piles. Therefore, earthquake countermeasure methods applicable to these have been strongly demanded. On the other hand, houses and small buildings often tilt when the ground and foundation are not strong enough or after an earthquake. Therefore, there has been a strong demand for a construction method that can regenerate housing and small-scale buildings without excessive burden.

  The steel pipe pile described in Patent Document 1 is provided with a pair of jet nozzles that protrude downward in a nozzle shape on an end plate (bottom plate) that closes the tip, and a spiral blade plate (spiral wing) on the side of the steel pipe. ). In particular, the spiral blade plate is configured such that the diameter increases as the distance from the tip increases, and the pitch (that is, the inclination angle of the blade plate) is constant. Further, one trapezoidal plate (excavation blade) that extends vertically downward protrudes from the end plate (bottom plate).

  In the steel pipe pile described in Patent Document 2, the tip is formed in a taper shape like the tip of a bullet, a mortar spout is provided on the tapered surface, and a spiral blade plate (spiral blade) is provided only near the tip. It is provided. Then, a threaded portion is provided at the rear end of the steel pipe pile, and a cylindrical steel pipe having the same diameter as that of the steel pipe pile is added using a connecting pipe having a larger diameter than the steel pipe pile (female short pipe 1c). Further, press-fitting is performed. On the other hand, Patent Documents 3 to 4 describe a method of driving a reinforcing pile and reinforcing the ground of an existing house or correcting the inclination.

  Although the demand for this type of steel pipe pile is very strong as described above, the steel pipe piles of Patent Documents 1 and 2 capable of injecting mortar and the like are generally not commercially available. The reason for this is presumed that the practical usability is poor and the cost of forming the spiral blade plate and the tip is relatively high.

Patent 3372627 (JP 07-189249) JP 11-093163 JP2009-185603 JP2011-163073

  The present invention has been made in view of the above problems, and aims to provide a mortar-injectable steel pipe pile that is easy to construct, has a large reinforcing effect, and can reduce manufacturing costs. In addition, the present invention intends to provide an attachment that makes it possible to bury the steel pipe pile using a general earth auger or the like.

  The mortar-injectable steel pipe pile of the present invention includes a cylindrical main body, a first spiral blade plate for screwing provided near the tip of the main body (lower end during construction), and a first spiral blade. A second spiral blade provided on the rear side of the main body at a smaller pitch than the plate, a discharge hole provided in the region of the first spiral blade, the first spiral blade, and the second It is characterized by comprising a bead portion provided in a spiral shape opposite to these in the middle of the spiral blade plate.

  The attachment of the present invention is fitted to a cylindrical cast member in which a female screw portion for connecting to a male screw portion for connection with a boring rod in a water swivel is formed on the inner surface side, and an outer peripheral surface of the cylindrical cast member. A short steel pipe member having a threaded portion to be screwed to a threaded portion provided on the inner surface of the root end portion (upper end portion at the time of construction) of the steel pipe pile, and a cylindrical cast member and a short steel pipe member And a knock pin for fastening the two to each other.

  The steel pipe pile of the present invention is easy to construct, has a large reinforcing effect, and can reduce manufacturing costs. Moreover, if the attachment of this invention is used, it will become possible to embed a steel pipe pile using a general earth auger.

It is the external appearance perspective view which looked at the steel pipe pile of one Example from the side. It is sectional drawing along the axis line about the steel pipe pile of FIG. It is a photograph which shows the front-end | tip part of the steel pipe pile of FIG. The state is shown before the discharge hole is provided. It is sectional drawing along the axis line about the attachment of one Example. The water swivel is shown schematically.

  The preferable Example of the steel pipe pile of this invention is described using FIGS. As shown in FIGS. 1 and 2, the steel pipe pile 10 includes a main body 1 made of a cylindrical steel pipe, and first and second plates provided by welding a spirally wound plate material to the outer peripheral surface of the main body 1. The spiral blades 21 and 22, a bead portion 23 provided by winding and welding round steel bars in a spiral shape at an intermediate position between them, and a tip (lower end in the figure) 1A portion of the main body 1 It consists of a disc-shaped end plate 12 to be closed, and excavation plates 13 and 14 provided by welding a triangular plate material to the lower surface of the end plate 12.

  A pair of discharge ports 11 for injecting the mortar liquid 46 into the surrounding earth and sand is provided in the arrangement region of the first spiral blade 21 in the main body 1. In particular, it is provided at the central location (location corresponding to the axially equally divided point) of the arrangement region or at a location close to this. On the other hand, a threaded portion 15 for connecting an attachment 3 described later is provided on the inner surface of the main body 1 in the vicinity of the root end (upper end in the figure) 1B.

  The first spiral blade 21 is slightly spaced from the tip 1A of the main body 1 and is provided in the vicinity thereof to help screw the steel pipe pile 10 into the ground. The second spiral blade plate 22 is provided far behind the first spiral blade plate 21 and at a pitch P2 smaller than the pitch P1 of the first spiral blade plate 21. That is, the inclination of the blade is increased. The first and second spiral blades 21 and 22 are both provided in the direction of the right-handed spiral. This corresponds to the existing earth auger drilling screw being provided in a right-handed spiral.

  The second spiral blade 22 plays a role of compressing and hardening the earth and sand into which the first spiral blade 21 is screwed and the mortar liquid 46 is injected. That is, it plays a role of pushing air contained in the earth and sand upward. As a result, the density of the mortar soil obtained after hardening of the mortar liquid is improved, and the strength of a kind of mortar pile formed using the steel pipe pile 10 as a core part is improved. Moreover, the adhesiveness with the surrounding ground is also improved by making a part of mortar liquid spread further to the circumference | surroundings.

  The bead portion 23 is provided along a left-handed screw spiral whose spiral direction is opposite to that of the first and second spiral blades 21 and 22. Therefore, when the steel pipe pile 10 is screwed in, it plays the role which stirs the earth and sand containing mortar liquid. By stirring in this way, large bubbles in the earth and sand are crushed, and earth and sand compression by the second spiral blade plate 22 is performed more smoothly. Since the bead part 23 is a reverse spiral, even if the protrusion dimension from the outer peripheral surface of the steel pipe main body 1 is small, a desired stirring effect can be realized. In addition, since it is only necessary to bend and use round steel bars for reinforcing bars, an increase in manufacturing costs can be minimized.

  In a preferred embodiment, the first and second spiral blades 21 and 22 both have a constant outer diameter D2 and are equal to each other. In a preferred embodiment, the outer diameter D2 is 1.3 to 3 times, preferably 1.7 to 2.2 times the outer diameter D1 of the steel pipe body 1. Further, the first and second spiral blades 21 and 22 each have a protruding angle from the steel pipe body 1 of 80 to 90 degrees. That is, when a plate material having the same width is used, the dimension protruding in the radial direction is set to be substantially maximum.

  In a preferred embodiment, the first and second spiral blades 21 and 22 are both in the range of 0.5 to 1.5 rounds, particularly preferably in the range of 0.8 to 1.2 rounds. It is provided so that it may extend over. In the illustrated example, it extends over one round (360 degrees). When it is provided for about one turn, the first and second spiral blades 21 and 22 can be provided by bending and welding a ring-shaped steel plate or a C-shaped steel plate.

  In a preferred embodiment, the pitch P1 of the first spiral blade plate 21 is 0.5 to 2 times, preferably 0.8 to 1.5 times the outer diameter D1 of the steel pipe body 1. The distance L1 from the tip 1A of the steel pipe main body 1 to the axially equal dividing point in the region of the first spiral blade 21 is 0.5 to 3 times the outer diameter D1 of the steel pipe main body 1, preferably 1 0.0 to 2.0 times. On the other hand, in a preferred embodiment, the pitch P2 of the second spiral blade plate 21 is 0.3 to 0.8 times, preferably 0.4 to 0.6 times the pitch P1 of the first spiral blade plate 21. It is. Further, the distance L2 from the tip 1A of the steel pipe main body 1 to the axially equal dividing point in the region of the second spiral blade 22 is 3 to 30 times, preferably 10 to 20 times the distance L1. .

  In a preferred embodiment, the bead portion 23 is provided for 0.5 to 3 turns, preferably 0.8 to 1.5 weeks. Moreover, the outer diameter of the round steel which makes the bead part 23 is 0.03-0.2 times of the outer diameter D1 of the steel pipe main body 1, Preferably it is 0.05-0.1 times. The round steel forming the bead portion 23 may have an elliptical shape or a polygonal shape in addition to a circular cross section. Moreover, although the thing with an unevenness | corrugation in the surface which is used for the reinforcing bars for concrete is preferable, the thing without an unevenness | corrugation on the surface can also be used. On the other hand, the distance L3 from the tip 1A of the steel pipe main body 1 to the axially equal dividing point in the region of the bead portion 23 is 0.3 to 0.8 times, particularly 0.4 to 0.6, the above-mentioned distance L2. Can be set to double.

  In a preferred embodiment, the discharge port 11 for injecting the mortar liquid into the earth and sand has an axial position located at an axial equal dividing point in the region of the first spiral blade 21 and has a diameter of, for example, 5 ~ 20 mm. In a preferred embodiment, the threaded portion 16 provided in the vicinity of the root end 1B of the steel pipe body 1 is provided so as to cut out a cylindrical steel pipe into a tapered shape. That is, it forms a tapered threaded portion that expands toward the base side (upper side in the figure). The wall thickness of the steel pipe body 1 is preferably 3 to 20 mm, more preferably 4 to 15 mm.

  In a preferred embodiment, the excavation plates 13 and 14 provided at the tip of the steel pipe pile 1 are provided by combining triangular plates so as to form a cross when viewed from the tip side. In the illustrated example, the first excavation plate 13 provided in the left-right direction of FIG. 1 (direction perpendicular to the paper surface of FIG. 2) is composed of a substantially equilateral triangular plate, and is combined vertically therewith. The two excavation plates 14 are welded from both sides of the first excavation plate 13 and form an equilateral triangle when viewed from the side. In the illustrated example, the projecting dimension of the first excavation plate 13 is larger than the projecting dimension of the second excavation plate 14. In the photograph of FIG. 3, the excavation plates 13 and 14 have a rectangular portion with a small projecting dimension at the base of the triangle.

  Next, a specific example of the dimension configuration will be described. In one specific example, the total length L0 of the steel pipe body 1 is 4 m (4000 mm), the outer diameter D1 of the steel pipe body 1 is 89.1 mm, the wall thickness is 5 mm, the above-mentioned distance L1 is 150 mm, the above-mentioned distance L2 is 3000 mm, and the above-mentioned distance L3 is 1600 mm, the pitch P1 of the first spiral blade 21 is 100 mm, the pitch P2 of the second spiral blade 22 is 50 mm, the diameter of the round steel forming the bead portion 23 is 10 mm, and the first excavation plate 13 Projecting dimension is 100 mm, the projecting dimension of the second excavation plate 13 is 70 mm, and the axial dimension of the root end threaded portion 16 is 60 mm. In another specific example, the outer diameter D1 of the steel pipe main body 1 is 115 mm and the wall thickness is 6 mm, and the other dimensions are the same as the one specific example.

  Below, the attachment 3 for mounting | wearing said steel pipe pile 10 to the water swivel for earth augers is demonstrated. The attachment 3 includes a cylindrical cast member 31, a short steel pipe member 32 fitted to the outer surface, and a knock pin 33 for fastening them together. On the inner surface of the cylindrical casting member 31, a female screw portion 34 for connecting to a male screw portion 43 at the lower end of the cylindrical rotating portion 41 of the water swivel 4 is formed. In the example shown in the figure, these screw portions 43 and 34 are rope screws (the cross section of the screw thread is substantially sinusoidal). Moreover, the outer surface threaded part 35 for screwing together with the root end threaded part 16 of the steel pipe pile 10 is formed in the outer surface of the short steel pipe member 32. Further, the cylindrical cast member 31 and the short steel pipe member 32 are provided with a recessed portion for pushing and connecting the knock pin 33 in a region corresponding to the outer surface threaded portion 35. The water swivel 4 includes a fixed portion 42 connected to the tip of the arm of the construction machine. On the outer surface side of the columnar or polygonal columnar portion between the fixed portion 42 and the male screw portion 43, a rotation driving device 45 that drives by hydraulic pressure or a motor is disposed. In other words, the steel pipe pile 10 is driven to rotate through the cylindrical rotating portion 41 and the attachment 3 by the rotation driving device 45. At this time, the mortar liquid 46 is pushed into the steel pipe pile 10 through the hose connected to the fixed portion 42 of the water swivel 4.

  If such an attachment is used, the steel pipe pile 10 can be embedded while injecting mortar liquid using a small boring device such as an earth auger of various sizes. That is, the attachment 3 can be connected to a normally used backhoe and a rotary drive device and a water swivel, and construction can be performed using a variable capacity type grout pump as appropriate. In particular, since it can be set in a very small boring machine having a height of 1.5 meters, for example, it is possible to embed the steel pipe pile 10 in a narrow place or an existing general house. it can. For this reason, it is possible to simultaneously perform inclination correction and ground support of a house inclined due to an earthquake or the like.

  In addition, it can be made to be the same as that of a longer steel pipe pile by adding a steel pipe to the root end part of said steel pipe pile 10. FIG. That is, if the same steel pipe as that used to obtain the steel pipe main body 1 is used and threaded portions are provided at the tip and the base end, the steel pipes can be sequentially added. Thus, even when the stable ground is at a deep position, the steel pipe pile 10 can reach the stable ground. For example, when building a house with a floor area of 30 tsubo on soft ground where liquefaction is a concern, about 20 steel pipe piles 10 will be constructed while injecting mortar, in accordance with the position of the pillar, before foundation striking. It is possible to implement earthquake countermeasures at a minimum cost.

1 Main body of steel pipe pile (steel pipe) 10 Steel pipe pile 11 Discharge hole
12 End plate 13, 14 Excavation plate 15 Root end threaded part
21 First spiral blade 22 Second spiral blade 23 Bead part
3 Attachment 31 Cylindrical cast member 32 Short steel pipe member
33 Knock pin 34 Female thread 35 External thread cut
4 Water swivel 41 Cylindrical rotating part 42 Fixed part 43 Male screw part
45 Rotation drive 46 Mortar liquid

Claims (5)

A cylindrical body;
A first spiral blade for screwing provided near the tip of the main body;
A second spiral blade provided on the rear side of the main body at a smaller pitch than the first spiral blade;
A steel pipe pile comprising discharge holes provided in the region of the first spiral blade.   The steel pipe pile according to claim 1, further comprising a bead portion provided in a spiral shape opposite to the first spiral blade plate and the second spiral blade plate.   The steel pipe pile according to claim 1 or 2, wherein the pitch of the spiral in the second spiral blade is 0.3 to 0.8 times the pitch of the spiral in the first spiral blade. . A cylindrical body;
A helical blade for screwing provided near the tip of the main body;
Behind the screw-like spiral blade, a bead portion provided in a spiral direction opposite to this,
A steel pipe pile comprising discharge holes provided in an area of a spiral blade for screwing. A cylindrical cast member formed on the inner surface side with a female screw portion for connecting to a male screw portion for connection with a boring rod in a water swivel,
A short steel pipe member fitted to the outer peripheral surface of this cylindrical cast member, and having a threaded portion for threading a threaded portion provided on the inner surface of the root end portion of the steel pipe pile on the outer surface;
An attachment comprising a knock pin for fastening a cylindrical cast member and a short steel pipe member to each other.