JP2981463B1 - Tip support plate type steel pipe pile and method of supporting steel pipe pile with plate-like member - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To provide a steel pipe pile formed by fixing a support plate 4b perpendicular (horizontal with respect to the earth) to a lower end of a steel pipe 4a,
After rotating about the vertical axis z and penetrating into the ground, the steel plate pile is prevented from sinking by receiving earth pressure by the support plate 4b after penetrating. SOLUTION: A cutting claw 4c projecting downward is fixed to a peripheral portion of a support plate 4b. The steel pipe 4a is rotated by a rotary driving machine 1e.
When the cutting claw 4c is rotated as indicated by the circular arrow ω, the cutting claw 4c digs up the earth and sand and sinks into the ground. When the rotation is stopped, the lower surface of the support plate 4b receives an upward earth pressure,
Supports downward loads on steel pipe piles. It is difficult to guess the mechanism by which the support plate 4b descends only by looking at this diagram, but the downward excavation of the support plate 4b has been almost theoretically almost completely elucidated and experimentally confirmed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a substantially horizontal plate-like support member attached to the lower end of a steel pipe pile cast in relatively soft ground, and an upward earth pressure on the lower surface of the support plate. The present invention relates to a steel pipe pile created in such a manner as to support the steel pipe pile and prevent the settlement thereof, and a supporting method.

[0002]

2. Description of the Related Art When driving an existing pile into the ground, it is roughly classified into a method of embedding the pile in a hole dug by an earth auger and a method of applying a force to the pile to penetrate the ground. . The latter method of forcibly inserting, furthermore,
It is classified into press-fitting pile driving and "a method of rotating a pile around a vertical axis by a rotary drive and screwing it into the ground". FIG. 5 shows an operation of driving a steel pipe pile into the ground by a pile driver equipped with a rotary drive so that a steel pipe pile vertically supported on the ground is penetrated into the ground while rotating about a vertical axis z. FIG. 4 is a front view partially cut and drawn in a state where preparation is completed. The steel pipe pile 2 of this conventional example is a tip screw type, and a screw 2a of about one pitch is provided at the tip (lower end). The pile driver 1 vertically supports the reader 1c by a chassis 1b mounted on a crawler 1a.

A rotary drive 1e having a chuck 1d is:
The steel pipe pile 2 is rotationally driven around the vertical axis z and screwed into the ground while being guided up and down by the leader 1c and driven up and down. What is shown by reference numeral 1f is a sheave that acts as a crane for suspending the steel pipe pile 2 to a casting point. FIG. 6 is a schematic front view showing a state in which the conventional screw-tipped steel pipe pile of the conventional example shown in FIG. 5 is driven to rotate and penetrate into the ground. is there. Since the screw 2a of the present example is formed in a right-handed screw shape, the rotary drive 1e rotates the tip screw type steel pipe pile 2 in the direction of the circular arc arrow ω so as to be clockwise as viewed from above. The steel pipe pile is provided with a downward load by its own weight, a downward driving force provided by the vertical driving means provided in the reader 1c (FIG. 5), and a propulsion force (downward) generated by rotation of the screw 2a. It is added and penetrates into the ground.

FIGS. 7A and 7B show two examples of a known steel pipe pile made to be driven into the ground by the pile driver with a rotary drive shown in FIG. 5 described above, and FIG. (B) is a perspective view near the tip of a steel pipe pile different from that described above. Figure 7
A point 2b is provided at the lower end of the steel pipe 2c forming the main body of the steel pipe pile 2 shown in (A) so as to easily penetrate into the ground. This pointed head may be a simple conical member, or the screw 2a may be reduced to have a shape extending downward. A rectangular plate-shaped cutting blade 3a is attached to the lower end of the steel pipe 3b constituting the main body of the steel pipe pile 3 shown in FIG. 7 (B) along the plane passing through the axis of the steel pipe 3b. In order to drill an advanced pit for guiding the body part of the steel pipe pile 3 to descend, its radial length L is:
It is set to be much larger than the diameter D of the steel pipe 3b. The lower end opening of the steel pipe 3b forming the main body of the steel pipe pile 3 is closed by a bottom plate 3c.

[0005]

The force acting on a pile driven almost vertically into the ground so as to support a downward load and prevent the pile from sinking is complicated when it is strictly analyzed. In general, a. B. frictional force generated in a direction in which soil in contact with the outer peripheral surface of the pile prevents settlement of the pile; Earth pressure in the upward direction exerted on the bottom surface of the pile by the soil in contact with the bottom surface of the pile. The tip screw type steel pipe pile 2 shown in FIG. 7A is provided with a pointed head 2b on the bottom surface of the steel pipe 2c which is its main body, so that the steel pipe pile 3 shown in FIG. Compared to the bottom plate 3c forming a horizontal plane, the receiving of the earth pressure is not "perpendicular to the surface" and the earth pressure distribution is not uniform, which is not desirable.
In addition, the earth pressure received by the screw 2a from below is complicated, and it is not preferable because there is no isotropy in a state viewed from above, that is, in a plane projection. In addition, the steel pipe pile 3 of the cutting edge type shown in FIG. 7B has a small cross-sectional area in a horizontal plane passing through the bottom plate 3c. That is, although the bottom plate 3c receives the earth pressure in the upward direction almost uniformly and prevents the steel pipe pile 3 from sinking, the cutting blade 3a has a small horizontal cross-sectional area, so that the steel pipe pile 3
There are few places that contribute to the prevention of settlement. As described above, the bearing force for preventing the settlement of the pile is conceptually the sum of the earth pressure applied to the bottom surface of the pile and the friction force acting on the outer peripheral surface of the pile. As for the force, this figure (A)
There is no great difference between the tip screw type steel pipe pile 2 of (1) and the tip cutting blade type steel pipe pile 3 of (B). In the present invention, the earth pressure mainly applied to the bottom surface of the pile is examined.

[0008] FIG. 8 shows a comparison with a pillar installed on the ground in order to consider load support of a pile to which the present invention is applied. FIG. 8A shows a load applied to a pillar of an outrigger. Is a schematic view of a state in which the support is supported by a support plate, (B) is a schematic view of a state in which the support is supported by a board, and (C) is a part of a load applied to a pile driven in the ground. It is a partial sectional view of a state. For example, when supporting a large load applied to the pillar 9a of the outrigger of the construction machine, a support plate 9b is provided as shown in FIG. (The earth pressure is applied on a wide horizontal surface so as not to get into the ground.) In the case where the ground is soft and the support plate 9b is immersed in the ground, as shown in FIG. FIG. 8 (A),
The technique described above for (B) is well known and widely used. Based on the above-mentioned findings, when a horizontal support plate 12 is attached to the lower end of the steel pipe pile 11 as shown in the prototype shown in FIG.
It is easily conceivable that the settlement of one could be prevented. However, it is impossible to penetrate the steel pipe pile 11 to which the support plate 12 is attached as shown in FIG. For example, if a pit such as a well having a larger cross-sectional shape than the support plate 12 is dug, and the steel pipe pile 11 with the support plate 12 is inserted and backfilled, the steel pipe pile 11 can be driven. However, it requires a great deal of time and labor, and the construction cost is enormous, so that it cannot be economically feasible. However, even if the steel pipe pile with the support plate 12 is attached to a known vibration pile driver or a press-fitting pile driver (neither is shown), the ground which can support the pile without knowing inside the sludge is known. It is hard to imagine trying to pierce inside. In the pile driver 1 shown in FIG. 5 described above, the screw 2a is provided at the tip of the steel pipe pile 2 so that the screw 2a can be rotated and screwed into the ground. It is not considered that the steel pipe pile 11 is penetrated into the ground no matter how much the steel pipe pile 11 is rotated around the vertical axis if the support plate (FIG. 8C) is attached. The present invention has been made in view of the above circumstances, and a steel pipe pile having a horizontal support plate fixed to a lower end is rotated around a vertical axis by a pile driver equipped with a rotary drive to penetrate the ground. Accordingly, an object of the present invention is to provide a technique for supporting a steel pipe pile.

[0007]

The basic principle of the present invention created to achieve the above object will be briefly described below with reference to FIG. 3 corresponding to one embodiment. That is, a steel pipe pile formed by fixing a support plate 4b perpendicular (horizontal with respect to the earth) to the lower end of the steel pipe 4a is rotated around a vertical axis z, and penetrates into the ground. In order to prevent the steel pipe pile from sinking by receiving the earth pressure by the support plate 4b, a cutting claw 4c projecting downward is fixed to a peripheral portion of the support plate 4b. When the steel pipe 4a is rotated by the rotary drive 1e as shown by the circular arrow ω, the cutting claw 4c digs and digs the earth and sand and sinks in the ground. When the rotation is stopped, the lower surface of the support plate 4b receives an upward earth pressure to support a downward load applied to the steel pipe pile. FIG just looking at is difficult to infer the mechanism of the support plate 4b is slide into drops, but lowered excavation of the support plate 4b is real <br/> experimental manner confirmed.

Based on the above-mentioned principle, the construction of the steel pipe pile according to the first aspect of the present invention is such that a steel plate larger than the cross-sectional shape of the steel pipe is fixed at a substantially right angle so as to cover the end opening of the steel pipe. In addition, a cutting claw protruding in the direction of extension of the steel pipe is fixed near the periphery of the steel plate , and
Is almost square, or almost regular pentagonal, or
They are almost regular hexagons and the center points of these regular polygons
Is located substantially on the center line of the steel pipe, and
The number of setting nails is more than one.
Are arranged almost symmetrically . According to the invention of claim 1 described above, since the end face of the steel pipe is covered with the steel plate, when the steel pipe is penetrated into the ground, no earth and sand enter the steel pipe, and the entire area of the steel plate faces upward. The earth pressure is supported, and the effect of antagonizing the downward load of the steel pipe pile to prevent its settlement is reliably achieved. Moreover, the steel plate
The shape and the position of the cutting claw rotate about the center line of the steel pipe
Because these parts are symmetrical in the direction,
The cutting reaction force and friction resistance received from the ground when
Drag is applied symmetrically about the rotation axis. Because of this, steel
When the pipe pile is rotated and penetrated into the ground,
Driving steel pipe straight in the desired direction without any risk of occurrence
It becomes possible. Furthermore, the steel plate is almost square,
These are polygons or regular hexagons.
When the corners of the shape rotate, this polygonal steel plate
Each near the apex angle acts like a cutting blade.
However, the effects of the author, which could not have been
The support plate, which is a horizontal plate-like member,
It can descend in the ground while rotating while standing. So
Above, because the steel plate is a regular polygon,
The bearing capacity of the pipe pile is isotropic in all directions (360 degrees)
To ensure that the steel pipe pile is securely and stably supported.
Can be. Then, when the steel pipe to which the steel plate is attached is set up almost vertically and rotated around the axis, the cutting claw rotates in a circle below the steel plate and cuts the earth and sand to induce the lowering of the steel plate. I do. When the steel pipe is used in a vertical posture, the manufacturing cost is low since the steel pipe has a simple structure in which a cutting claw is provided around a steel plate fixedly covering the lower end opening of the steel pipe. In addition, when the steel pipe pile having this simple configuration is rotated, the cutting pawl excavates the advanced pit while drawing a spiral trajectory in the ground, and assists the lowering of the support plate. When the rotation of the steel pipe pile is stopped, the rotation of the cutting claw also stops and the excavation operation stops, and after the stop, the horizontal steel plate having a large area receives the earth pressure in the upward direction uniformly, and the sinking of the steel pipe pile is performed. To prevent. In order to perform the above action,
It is sufficient to use the conventional pile driver for the tip screw type steel pipe pile, does not require a new special work machine, does not require special skill, and uses the conventional screw tip steel pipe pile of the conventional example or the conventional cutting blade By treating the pile almost in the same manner as the steel pipe pile, it is possible to obtain a large supporting force which is an effect unique to the present invention.

[0009]

[0010]

According to a second aspect of the present invention, there is provided the configuration according to the first aspect.
In addition to the constituent features of the invention according to 1 , in addition to the above, the cutting claw is arranged substantially near the apex of the regular polygon, and protrudes only in the extending direction of the steel pipe, and hardly or not protrudes in the radial direction. It is characterized by. According to the invention of claim 2 described above, cutting of the advanced pit by the cutting claw is performed rationally, the steel pipe pile penetrates into the ground with less power consumption, and the steel pipe pile is prevented from sinking by the steel plate. be able to. That is, when the polygonal steel plate is rotated about a vertical axis while maintaining a horizontal posture, the vicinity of the vertex (corner) of the polygon acts as a cutting blade, and digs downward while cutting earth and sand. And when the present invention is applied and the cutting claw is arranged near the apex, the cutting action near the apex and the cutting action of the cutting claw are effectively exhibited in cooperation with each other,
The steel pipe pile can be dug down with low rotational power and can be efficiently and efficiently penetrated into the ground. further,
Since the plurality of cutting claws are arranged near the vertices of the regular polygon, the plurality of cutting claws are positioned symmetrically with respect to the rotation axis, and there is a possibility that the cutting reaction force may cause the core to run out of the rotation shaft. There is no.

According to a third aspect of the present invention, in addition to the constituent features of the first aspect of the present invention, the steel plate fixed to the steel pipe has a shape in which the cutting claws are integrally connected. It is a member cut out from a steel material having a shape, and a portion of a cutting claw is bent substantially at a right angle. According to the third aspect of the present invention described above, "the steel plate to which the cutting claw is fixed"
Can be easily and firmly configured. Especially,
The steel plate and the cutting claw are continuously integrated in the material structure, there is no material discontinuity such as welds, and there is no embrittlement structure such as the weld heat affected zone, so the highly reliable "cutting claw is fixed. Steel plate ". When the invention of claim 3 is carried out, the reinforcing rib is cut out integrally with the cutting claw from the same steel material as the plate-like steel material from which the cutting claw is cut out, or the reinforcing rib is cut out and connected integrally with the steel plate. It is also possible to cut out the rib, and it is also possible to use welding of the reinforcing rib to a steel plate or welding of the reinforcing rib to a cutting claw.

[0013]

According to a fourth aspect of the present invention, there is provided a method for supporting a lower end portion of a steel pipe pile driven by a substantially upward earth pressure in order to prevent the steel pipe pile set in the ground from sinking.
In advance, cover the lower end opening of the steel pipe pile , and make a substantially square or substantially square steel made substantially perpendicular to the steel pipe pile.
A rectangular or substantially regular hexagonal support plate is fixed and one of the three types of substantially regular polygons is fixed.
In the vicinity of the apex of the polygon, a cutting claw projecting downward is attached, and the steel pipe pile is rotated around the longitudinal center line of the steel pipe pile while maintaining the steel pipe pile in a substantially vertical posture, and After cutting the ground into the ground while spirally cutting the ground with the cutting claw and sinking to a desired depth, preventing the sinking of the steel pipe pile by the earth pressure acting substantially upward on the support plate. It is characterized by. According to the above-described method of the fourth aspect of the present invention, the support plate is fixed at right angles to the steel pipe pile (horizontally with respect to the earth) so as to cover the lower end opening of the steel pipe material. After that, even if a large downward load is applied, the load distributed on the lower surface of the support plate is supported in balance with the upward earth pressure, and the sinking is prevented. It is not easy to drive a steel pipe pile to which a shoe-shaped support plate is fixed to a predetermined depth as described above by a conventional technique, but the present invention is applied to project downward from a peripheral portion of the support plate. When the cutting claw is provided and rotated about a vertical axis, the cutting claw excavates earth and sand located below the support plate. Since at least a downward force due to its own weight is applied to the steel pipe pile with the support plate, the support plate rotates and sinks into the ground where the rotating cutting claw is dug and loosened. The above-mentioned operation of causing the steel pipe pile to penetrate into the ground while rotating about the vertical axis can be easily performed using a pile driver equipped with a known rotary driving means. Besides, the above
Since the support plate is almost a regular polygon, near its apex angle
Is rotated, the vicinity of the apex angle becomes a cutting blade.
Acts to facilitate the sinking of the support plate into the ground. Up
If the regular polygon described above is made into a hexagon or more, the shape will be close to a circle.
It becomes difficult to act as a cutting blade near the apex angle,
A hexagonal shape provides a practically meaningful cutting effect.
Can be It has a small apex angle and functions as a cutting blade
From a viewpoint alone, it is preferable to make the shape almost a regular triangle.
There is a plane when the equilateral triangular support plate is grounded horizontally
As you can see from the projected figure,
Direction (360 degrees all directions)
The support performance of steel pipe piles also lacks isotropy. From this perspective,
If it is a square or more, practically sufficient isotropy can be obtained.
As is evident from the above considerations, almost square, regular pentagon
By using a hexagonal and regular hexagonal support plate,
Cutting performance and omnidirectional isotropy of steel pipe pile bearing capacity
I can do it.

[0015]

[0016]

According to a fifth aspect of the invention, in addition to the constituent elements of the fourth aspect of the invention, a plate-like steel material is cut or punched to form a substantially regular polygonal support plate. A cutting claw of a plate-like steel material cut out or punched out by integrally connecting a cutting claw near the apex angle of the substantially regular polygon and cutting out or punching the steel material. Is bent substantially at right angles to the support plate. According to the method of the fifth aspect described above, the support plate to which the cutting claw is fixed can be formed quickly, easily, and at low cost. In addition, no material organizational boundary is formed at the connecting portion between the support plate and the cutting claw, and the crystal structure of the steel material is continuous. The risk of breakage at the boundary is small, the operation reliability is high, and the durability is excellent.

According to a sixth aspect of the present invention, in addition to the steel requirement of the fourth aspect of the invention, a plate-like steel material is cut or punched to form a substantially regular polygonal support plate. A plurality of cutting claws are formed separately from the above by a steel material, and the cutting claws are fixed by welding to the vicinity of the apex of the substantially regular polygonal support plate, or fixed by screw means such as bolts. Alternatively, it is fixed by a caulking means such as a rivet, and a reinforcing rib for preventing damage to the cutting claw is attached. According to the method of the invention of claim 6 described above, because it forms the supporting plate and the cutting claw separately, independently of one another each between the support plate and the cutting claw can be composed of any steel For example, the support plate may be made of inexpensive carbon steel for machine structure, and the cutting claw may be made of tough nickel chrome steel or chromium molybdenum steel. Also, heat treatment can be performed to increase the wear resistance of the cutting claw. Since welding is not used for the mounting work, there is no danger that the heat treatment will affect the tempering condition and the durability will be improved. obtain. Furthermore, since the cutting claw is attached to the support plate by means other than welding, if any trouble occurs before the cutting claw is driven, it is easy to attach and detach the cutting claw to replace it with a spare cutting claw. In addition, by providing the reinforcing rib on the cutting claw, the reliability of the cutting claw is further improved. Since the support plate and the cutting claw according to the present invention operate in the ground and the damage state cannot be visually observed, it is extremely significant that the material and the strength have reliability.

[0019]

FIG. 1 is an external perspective view showing one embodiment of a steel pipe pile of a tip support plate type according to the present invention, in which a part of a steel pipe is cut away. The steel pipe pile 4 of the tip support plate type of the present embodiment has a support plate 4 at one end of a steel pipe 4a and at right angles thereto.
b is fixed by welding. Although there is no distinction between the upper and lower sides of the steel pipe 4a as a material, when the support plate 4b is attached, the attached side becomes the lower end, and becomes the tip when the steel pipe pile is driven into the ground. The method of forming the support plate 4b will be described later in detail with reference to FIG. 2. However, in general, a plate-shaped steel material is cut out by fusing or the like or punched out with a press to form a substantially square plate shape. It is. As described later with reference to FIG. 3, the above-mentioned support plate is a component for receiving the earth pressure on the lower surface to prevent the steel pipe pile from sinking, and covers the end opening of the steel pipe 4 a. The cutting claws 4c are attached so as to be welded and project downward from the four corners.

FIGS. 2A and 2B are views for explaining a method of forming the support plate and the cutting claws in the embodiment shown in FIG. 1. FIG. 2A shows a support with cutting claws cut out from a plate-like steel material. A plan view depicting a state in which the plate is being processed,
(B) is a plan view of a state in which a support plate with cutting claws similar to the above is cut out from a plate-like steel material, and then the cutting claws are bent. From a plate-like steel material, a square support plate 4b integrally formed with cutting claws is cut out or punched out. However, in the present invention, "cut out or punch out" includes cutting out or cutting out. In short, all means for producing a member having a desired shape from a steel material are collectively referred to. For example, burning off with a laser beam and shaving off with a jet fluid are also included in the technical scope of the present invention. 4b is a cutting claw that has been cut out from a steel plate. When this is bent at a right angle as shown by 4c, the cutting claw 4c shown in a perspective view in FIG. 1 is formed. In the example shown in FIG. 2, the cutting claw was cut out integrally and then bent, but after the cutting claw is formed separately, it can be attached using a screw means such as a bottle or a caulking means such as a rivet. good. Also, it may be attached by welding (including forging).

The above-mentioned screw means such as a bolt includes a right-hand screw,
Regardless of the left-handed screw, it is a generic term for members that are formed with a male screw.
The term “crimping means such as rivets” is a general term for joining means involving plastic working regardless of cold working or hot working.

Reference numeral 4a 'indicated by an imaginary line is a position where a steel pipe (member 4a in FIG. 1 described above) which forms the main body of the steel pipe pile is attached. In this way, the center of the support plate formed in a square and the center of the steel pipe are made to substantially coincide. In this case, substantially matching means not intentionally causing eccentricity, and a general tolerance is allowed. Since the cores are aligned as described above, the resistance received from the soil when rotated about the center point O becomes symmetrical with respect to the center point O, and the core pile does not cause deflection of the steel pipe pile, so that accurate pile driving is possible. Become.
The cutting claw 4d is provided one by one near each apex angle of the square. As shown in FIG. 2 (B), a pair of cutting claws 5a, 5a 'may be cut out near each apex angle of the square, and may be bent like 5b, 5b' to perform welding 5c. good. As described above, when the cutting claws are arranged at each apex angle of the square, each of the plurality of cutting claws rotates while drawing the same circular arc s in the planar projection figure, and the circular arc s is substantially the same as that of the support plate 4b. Since the circumscribed circle is a square, the cutting operation without waste and without shortage is performed to sink the support plate 4b. In this case, the portion surrounded by the locus circle s where the cutting claw 4c performs the cutting operation is not cut, but the horizontal plate-like support plate 4b can sink into the ground of the non-cutting area. The mechanism will be described later with reference to FIG.

In the case of forming the above-mentioned cutting claw, various means such as "integral cutting / bending process", "separate structure / welding", and "separate structure / with bolt and caulking" have different lengths. Therefore, it can be arbitrarily selected and applied. Hereinafter, only the advantages of each will be described. There are disadvantages except for the advantages. The cutting claw that is cut out (or punched) as one piece has no material texture boundary with the main body, has a continuous crystal structure and has few material defects, and the bent part is strengthened by the work hardening phenomenon Have been. When the steel plate and the cutting claw that are separately formed are welded, each of the above-described steel plate and the cutting claw can be configured with an optimum steel type. For example, the square plate-like portion is made of carbon steel for machine structure which is inexpensive and has good weldability, and the cutting nail is made of special steel which is tough and has good weldability. The steel plate and the cutting claw, which are composed separately, are
When fixed by non-welding means such as caulking, each steel type can be arbitrarily selected, and the cutting nail can be quenched and tempered to be attached without disturbing the refining state.

The cutting claws 5b and 5b 'shown in FIG.
When a pair of cutting claws provided integrally with the apex angle interposed therebetween are bent and then welded to each other as described above, the state becomes similar to the case where the reinforcing ribs are provided, and is deformed or broken. Danger is reduced and durability is improved. Although not shown, the required reinforcing ribs can be additionally provided even when the single cutting claw 4d is bent like 4c as in the example of FIG. Providing the necessary reinforcing ribs means providing them as needed, and does not constitute a component that cannot be omitted without providing the ribs. In addition to the case where the cutting claw is formed as “integrally connected and bent” as shown in FIG. 2, that is, when the cutting claw is formed separately and attached by bolts, caulking, or welding, reinforcing ribs are provided as necessary. Can be provided. What means to form the cutting claw and whether or not to provide the reinforcing rib may be appropriately determined based on the geological structure of the ground on which the steel pipe pile is to be driven and the construction instructions.

FIG. 3 shows that the steel pipe pile of the tip support plate type according to the embodiment of FIG. 1 described above is placed in a vertical posture, attached to a rotary drive, and penetrated into the ground while rotating around a vertical axis z. FIG. Since the steel pipe 4a is vertical, the support plate 4b is horizontal. Although not shown, the steel pipe 4a may be slightly inclined with respect to the vertical line under special working conditions. Rotary drive 1e
Rotates the steel pipe 4a as shown by an arc arrow ω. Since the support plate 4b and the cutting claw 4c are fixed to the steel pipe 4a, they are rotated together in a substantially horizontal plane.

The rotary drive 1e is the same as the rotary drive 1e of the pile dry type shown in FIG. 5 (conventional example) described above, and is guided up and down by a leader 1c. It is designed to be driven up and down.
Therefore, the steel pipe pile in the state of FIG. 3 receives a downward load at least by the weight and the own weight of the rotary driving machine 1 e, and is superimposed on these gravitational loads, so that the downward driving force by the pile driver 1 is given. Since the support plate 4b and the cutting claw 4c are given a downward load while rotating in the direction of the arc arrow ω, they sink into the ground while drawing a spiral with a fine pitch. After stopping the rotation and completing the driving of the steel pipe pile, the steel pipe pile receives its own weight and the gravitational load due to the structure (not shown). It is the friction force with the soil acting on the outer peripheral surface of the steel pipe 4a and the upward earth pressure acting on the lower surface of the support plate 4b that mainly prevent the settlement of the steel pipe pile in opposition to the gravity load. . The frictional force that the steel pipe 4a constituting the steel pipe pile receives from the surrounding soil is similar or similar to that of the conventional steel pipe pile (for example, the steel pipe pile 2 and the steel pipe pile 3 shown in FIG. 7). In the example steel pipe pile (FIG. 3), since the support plate 4b having a relatively large area covering the lower end opening of the steel pipe 4a has a horizontal posture, the supporting force generated by the upward earth pressure is large. That is,
Even if the supporting earth pressure per unit area is small, the total supporting force obtained by multiplying the supporting earth pressure by the area of the supporting plate is significantly larger than that of the related art.

FIG. 4 is a view for explaining the shape of the support plate to be mounted on the tip support plate type steel pipe pile according to the present invention. FIG. 4 (A) shows an equilateral triangular support plate as a comparative example. It is a schematic plan view, (B) is a square, (C)
FIG. 3D is a bottom view of a regular pentagonal support plate, and FIG. The advantages and disadvantages when the equilateral triangular support plate 6 is configured as shown in FIG. Considering the action of only the portion of the equilateral triangular steel plate drawn by the imaginary line drawn with the solid lines, when the steel pipe fixed at the position indicated by reference numeral 4a 'rotates, the support plate of the equilateral triangle is obtained. 6
Rotates with this. Then, the corner portion 6a considered in the previous thinking experiment moves as shown by the arc arrow r, and cuts the surrounding soil. Since the circular arc arrow r is a circumscribed circle of the support plate 6 of a regular triangular shape, a range without excess and deficiency is cut because the support plate 6 is settled while rotating. Since an unnecessary operation such as cutting a portion on the outer peripheral side of the circumscribed circle of the equilateral triangle support plate 6 is not performed, the energy effect is high. High energy efficiency means that the steel pipe pile driving work is performed with high efficiency if the output of the pile driver (see FIG. 5) is the same.

A state in which a steel pipe is fixed to the center of the equilateral triangular support plate 6 shown in FIG. 4A as indicated by a virtual line 4a ', and the equilateral triangular support plate 6 is buried in the ground. In consideration of the load applied to the steel pipe, this load (that is, the load to be supported) is not always a simple static load directed vertically downward. Assuming two horizontal orthogonal axes X and Y as shown in FIG. 4 (A), there are cases where a rotational moment load is applied to the X axis and a case where a rotational moment load is applied to the Y axis. In this case, a rotational moment load about both the X and Y axes is applied in combination. Under such a load, the equilateral triangular support plate 6 is not preferable because the support performance is not isotropic. However, in the case where a steel pipe pile is driven under design conditions that do not require the isotropy of the bearing load, providing a regular triangular support plate 6 as shown in FIG. There is. In FIG. 4A, the cutting claw is not shown in order to clarify the cutting action by the corner portion 6a of the support plate 6, but the corner portion (that is, the vertex angle of the equilateral triangle) is omitted. Provision of a cutting claw protruding downward (near the paper surface in the drawing) from the vicinity 6a, the cutting claw is formed together with the corner portion 6a by an arc arrow r.
Thus, the cutting function of the corner portion and the cutting function of the cutting claw cooperate to effectively promote the sinking of the support plate 6.

Considering the isotropy of the load supporting performance described above, it can be remarkably improved by providing the square support plate 4b as shown in FIG. However, as described above, the rotational moment load applied to the steel pipe pile is often a composite load around the X-axis and around the Y-axis, and therefore, as shown in FIG. Just because the plate is symmetric with respect to the XX 'axis and also to the YY' axis does not guarantee perfect isotropy. However, in contrast to the equilateral triangle support plate 6 having three symmetry axes (not shown) in the plane figure (FIG. A), the square support plate 4b (FIG. B) has three symmetry axes (not shown). Therefore, the isotropy with respect to the combined rotational moment load is remarkably improved, and a cutting claw 4c is provided near the apex angle of the square support plate 4b. However, apart from the action of the above-mentioned cutting claw, the cutting performance near the apex angle of the regular polygonal plate-like member (for example, the portion indicated by reference numeral 6a) may be an equilateral triangle. It is the sharpest, and as the number of sides increases, such as a regular quadrilateral, a regular pentagon, or a regular hexagon, it approaches the disk, the isotropy improves, and the machinability due to the right angle decreases. An N-sided polygon is equivalent to a regular N-sided polygon.) FIG.
The regular pentagonal support plate 7 shown in FIG.
The plurality of cutting claws 7a are arranged. Further, as shown by the imaginary lines, five cutting claws 7a 'each sandwiching the apex angle.
(Only one is shown) may be provided. The regular hexagonal support plate 8 shown in FIG. 4 (D) has six cutting claws 8a arranged near the apex angle. Further, as shown by the imaginary lines, six cutting claws 8a '(only one is shown) may be provided so as to sandwich the apex angle.

In practicing the present invention, the number of the supporting plate to be formed and the number of the cutting pawls provided in the vicinity of the apex of the regular polygon, one or two, are determined. Although it may be appropriately set in consideration of the stratum structure near the steel pipe pile setting point, a square support plate 4b shown in FIG. 4B is generally suitable. The reason for this is that it has moderate isotropy and moderate apical corner cutting properties, and is highly versatile. As described above, in the case where the demand for isotropicity is moderate and it is required that the cutability due to the apex of the polygon is good, the equilateral triangle support plate 6 shown in FIG. It is also possible. (B) If a higher degree of isotropy is required than the square support plate 4b shown in the figure, the application of the regular pentagonal support plate 7 shown in the figure (C) should be considered. If a higher degree of isotropy is required, a regular hexagonal support plate 8 shown in FIG. A regular heptagon (not shown) or a polygon larger than that is not impossible, but its shape is similar to a circle, and the angle of the apex angle becomes large, so that the cutting performance by the apex part is remarkably reduced. The improvement in isotropy is small compared to the regular hexagonal support plate 8, and a practically significant difference is hardly recognized. However, as an extreme example, even if a cutting claw is attached to a circular support plate (not shown), it is within the technical scope of the present invention.

[0031]

As described above, the configuration and function of the embodiment of the present invention are clarified. According to the first aspect of the present invention, the end face of the steel pipe is covered with a steel plate. When the steel pipe is pierced, no sediment enters into the steel pipe, the entire area of the steel plate supports the upward earth pressure, and the effect of antagonizing the downward load of the steel pipe pile and preventing its sinking is surely achieved. . Then, when the steel pipe to which the steel plate is attached is set up almost vertically and rotated around the axis, the cutting claw cuts the earth and sand while rotating in a circle below the steel plate to induce the steel plate to descend. I do. And the shape of the steel plate,
And the position of the cutting claw in the rotation direction with respect to the center line of the steel pipe
Because of the symmetry, these components are
The cutting reaction force and friction resistance received from the ground when rotating
Hangs symmetrically about the rotation axis. For this reason, steel pipe piles
Core run-out occurs when penetrating into the ground while rotating
It is possible to drive the steel pipe straight in the desired direction without fear.
Will be possible. Furthermore, the steel plate is almost square, pentagonal,
Or because they are regular hexagons, these polygonal shapes
Of the polygonal steel plate when the corners of
Each of them has a similar effect to the cutting blade,
The remarkable effect that could not be expected in
The support plate, which is a
It can descend in the ground while rotating. Besides, steel
Because the plate is a regular polygon, the steel plate supports the steel pipe pile.
Power isotropic in all directions (360 degrees)
And the steel pipe pile can be reliably and stably supported.
You. In order to perform the above-described operation, a conventional screw driver for a tip screw type steel pipe pile may be used, and no new special work machine is required, and no special skill is required. By handling in substantially the same manner as a steel pipe pile or a conventional cutting edge type steel pipe pile, it is possible to obtain a large supporting force which is an effect unique to the present invention.

[0032]

[0033]

According to the second aspect of the present invention, the advanced pile is dug by the cutting claw, and the steel pipe pile penetrates into the ground with little power consumption, and the steel pipe pile is prevented from sinking by the steel plate. be able to. That is, when the polygonal steel plate is rotated about a vertical axis while maintaining a horizontal posture, the vicinity of the vertex (corner) of the polygon acts as a cutting blade, and digs downward while cutting earth and sand. And when the present invention is applied and the cutting claw is arranged near the apex, the cutting action near the apex and the cutting action of the cutting claw are effectively exhibited in cooperation with each other, and the steel pipe pile can be formed with less rotational power. By digging down, it can penetrate into the ground efficiently and with high efficiency.
Furthermore, since the plurality of cutting claws are arranged near the apex of the regular polygon, the plurality of cutting claws are positioned symmetrically with respect to the rotation axis, and the cutting reaction force causes the shaft to run out of the rotation shaft. There is no fear.

According to the third aspect of the present invention, the "steel plate to which the cutting claws are fixed" can be easily and firmly formed. Particularly, since the steel plate and the cutting claw are continuously integrated in the material structure, there is no material discontinuity such as a welded portion, and there is no embrittlement structure such as a weld heat affected zone, so the highly reliable “cutting claw” Is fixed. When the invention of claim 5 is carried out, a reinforcing rib is cut out integrally with the cutting claw from the same steel material as the plate-like steel material from which the cutting claw is cut out, or a reinforcing rib is cut out and connected integrally with the steel plate. It is also possible to cut out the rib, and it is also possible to use welding of the reinforcing rib to a steel plate or welding of the reinforcing rib to a cutting claw.

[0036]

According to the fourth aspect of the present invention, since the support plate is fixed at right angles to the steel pipe pile (horizontally with respect to the earth) so as to cover the lower end opening of the steel pipe material, the steel pipe pile is cast. After that, even if a large downward load is received, the load distributed on the lower surface of the support plate is supported in balance with the upward earth pressure, thereby preventing sinking. It is not easy to drive a steel pipe pile to which a shoe-shaped support plate is fixed to a predetermined depth as described above by a conventional technique, but the present invention is applied to project downward from a peripheral portion of the support plate. When the cutting claw is provided and rotated about a vertical axis, the cutting claw excavates earth and sand located below the support plate. The above
Since the support plate is almost a regular polygon, near its apex angle
Is rotated, the vicinity of the apex angle becomes a cutting blade.
Acts to facilitate the sinking of the support plate into the ground. Up
If the regular polygon described above is made into a hexagon or more, the shape will be close to a circle.
It becomes difficult to act as a cutting blade near the apex angle,
A hexagonal shape provides a practically meaningful cutting effect.
Can be It has a small apex angle and functions as a cutting blade
From a viewpoint alone, it is preferable to make the shape almost a regular triangle.
There is a plane when the equilateral triangular support plate is grounded horizontally
As you can see from the projected figure,
Direction (360 degrees all directions)
The support performance of steel pipe piles also lacks isotropy. From this perspective,
If it is a square or more, practically sufficient isotropy can be obtained.
As is evident from the above considerations, almost square, regular pentagon
By using a hexagonal and regular hexagonal support plate,
Cutting performance and omnidirectional isotropy of steel pipe pile bearing capacity
I can do it. Since at least a downward force due to its own weight is applied to the steel pipe pile with the support plate, the support plate rotates and sinks into the ground where the rotating cutting claw is dug and loosened. The above-mentioned operation of causing the steel pipe pile to penetrate into the ground while rotating about the vertical axis can be easily performed using a pile driver equipped with a known rotary driving means.

[0038]

[0039]

According to the fifth aspect of the present invention, the support plate to which the cutting claw is fixed can be formed quickly, easily, and at low cost. In addition, since the material structure boundary is not formed at the connecting portion between the support plate and the cutting claw, and the crystal structure of the steel material is continuous, the steel plate is strong. The risk of breakage at the boundary is small, the operation reliability is high, and the durability is excellent. According to the method of the invention of claim 6, because it forms the supporting plate and the cutting claw separately, independently of one another each between the support plate and the cutting claw can be composed of any steel, for example, the support plate Can be made of inexpensive carbon steel for machine structural use, and the cutting claws can be made of tough nickel chrome steel or chromium molybdenum steel. Also, heat treatment can be performed to increase the wear resistance of the cutting claw. Since welding is not used for the mounting work, there is no danger that the heat treatment will affect the tempering condition and the durability will be improved. obtain. Furthermore, since the cutting claw is attached to the support plate by means other than welding, if any trouble occurs before the cutting claw is driven, it is easy to attach and detach the cutting claw to replace it with a spare cutting claw. In addition, by providing the reinforcing rib on the cutting claw, the reliability of the cutting claw is further improved. Since the support plate and the cutting claw according to the present invention operate in the ground and the damage state cannot be visually observed, it is extremely significant that the material and the strength have reliability.

[Brief description of the drawings]

FIG. 1 is an external perspective view showing one embodiment of a steel pipe pile of a tip support plate type according to the present invention, in which a part of a steel pipe is cut and drawn.

FIG. 2 is a view for explaining a method of configuring a support plate and a cutting claw in the embodiment shown in FIG. 1;
(A) is a plan view depicting a state in which a support plate with a cutting claw cut out from a plate-shaped steel material is being processed, and (B) is a support plate with a cutting claw similar to the above cut out from the plate-shaped steel material. It is a top view in the state where a cutting nail is bent after cutting.

FIG. 3 shows a state in which the steel pipe pile of the tip support plate type according to the embodiment of FIG. 1 described above is mounted on a rotary drive with a vertical posture, and is penetrated into the ground while being rotated about a vertical axis z. It is a schematic diagram.

FIG. 4 is a view for explaining a shape of a support plate to be mounted on the tip support plate type steel pipe pile according to the present invention,
(A) is a schematic plan view of a regular triangular support plate as a comparative example, (B) is a square, (C) is a regular pentagon, (D) is a bottom view of a regular hexagonal support plate. It is.

FIG. 5 shows an operation of driving a steel pipe pile into the ground by a pile driver equipped with a rotary drive so that a steel pipe pile vertically supported on the ground is penetrated into the ground while rotating about a vertical axis z. FIG. 4 is a front view partially cut and drawn in a state where preparation is completed.

FIG. 6 is a schematic front view showing a state in which the tip screw type steel pipe pile of the conventional example shown in FIG. 5 described above is driven into rotation and penetrates into the ground. is there.

7A and 7B show two examples of a known steel pipe pile made to be driven into the ground by the pile driver with a rotary drive shown in FIG. 5 described above, and FIG. 7A is drawn in FIG. FIG. 3B is an enlarged view of the vicinity of the screw of the steel pipe pile, and FIG.

FIG. 8 is a diagram illustrating a load support of a pile to which the present invention is applied, in comparison with a pillar installed on the ground, wherein (A) shows a load applied to a pillar of an outrigger; (B) is a schematic diagram of a state supported by a board, and (C) is a portion of a state in which a part of a load applied to a pile driven into the ground is supported by a support plate. It is sectional drawing.

[Explanation of symbols]

Reference Signs List 1 pile driver, 1a crawler, 1b chassis, 1
c: reader, 1d: chuck, 1e: rotary drive, 2 ...
Tip screw type steel pipe pile, 2a ... screw, 2b ...
Pointed head, 2c ... steel pipe, 3 ... steel pipe pile of cutting edge type, 3a
... Cutting blade, 4 ... Steel pipe pile of tip support plate type, 4a ... Steel pipe, 4
a ': steel pipe mounting position; 4b: support plate; 4c: bent cutting claw; 4d: cutting claw cut out from a plate-like steel material; 5: support plate; 5a, 5a': cut out close to each other. A pair of cutting claws, 5b, 5b '... bent 1
A pair of cutting nails, 5c: welding for connecting the pair of cutting nails, 6: equilateral triangle support plate, 6a: equilateral triangle corner portion, 7: equilateral pentagonal support plate, 7a: cutting nail, 8 ... regular hexagonal support plate, 8a ... cutting claw, 9a ... outrigger pedestal, 9b ... support plate, 10 ... wood board, 11 ... steel pipe pile, 12 ...
A support plate attached to the lower end of the steel pipe pile.

Claims (6)

(57) [Claims] 1. A steel plate which is larger than a cross-sectional shape of a steel pipe and is fixed at substantially right angles so as to cover an end opening of the steel pipe .
At the same time, a cutting claw projecting in the direction of extension of the steel pipe is fixed near the periphery of the steel plate , and the steel plate has a substantially square or substantially pentagonal shape.
And the center point of these regular polygons is located almost on the center line of the steel pipe.
And, the number of installation of the cutting claw is a plurality, the above
A steel pipe pile of a tip support plate type, which is arranged substantially symmetrically with respect to a center line . 2. The cutting claw according to claim 1, wherein said cutting claw has a substantially regular polygonal vertex.
It is placed close to and protrudes only in the direction of extension of the steel pipe.
And project almost radially at all
2. The tip support according to claim 1, wherein the tip support is not provided.
Plate type steel pipe pile. 3. A steel sheet fixed to said steel sheet,
Cut the cutting nails from a plate-shaped steel material into a
A member that has been pulled out and the cutting claw part has been bent almost at a right angle
The tip support according to claim 1, characterized in that:
Plate-shaped steel pipe pile. 4. Preventing settlement of steel pipe piles cast in the ground
Therefore, the lower end of the steel pipe pile is supported by almost upward earth pressure.
In the holding method, the lower end opening of the steel pipe pile is covered in advance, and the steel pipe pile is
Made of steel at right angles, approximately square, or approximately five
If a rectangular or nearly regular hexagonal support plate is fixed,
In addition, any one of the three types of substantially regular polygonal support plates is used.
Near the apex of the regular polygon, insert a cutting claw that projects downward.
Mounting the steel pipe pile while maintaining the steel pipe pile in a substantially vertical position.
Rotate around the longitudinal center line and use the cutting claw to
After the ground is spirally cut into the ground and penetrated into the ground and submerged to a desired depth,
Earth pressure acting in the upward direction prevents the settlement of steel pipe piles.
The steel pipe pile is supported by a plate-shaped member .
Way. 5. A plate-shaped steel material is cut out or stamped out.
To form a substantially regular polygonal support plate, and contact a cutting claw integrally near the apex angle of the above substantially regular polygon.
Cut out or punched out the above steel material, cut out or punched out with cutting nails connected integrally
Of the cutting claw of a flat sheet of steel at a right angle to the support plate
5. The steel according to claim 4, wherein the steel is bent to
A method of supporting a pipe pile with a plate-like member. 6. A plate-shaped steel material is cut out or punched out.
And forming a substantially regular polygonal support plate, and forming a plurality of cutting claws separately from the above with a steel material, and placing the cutting claws near the apex angle of the substantially regular polygonal support plate.
Fixed by welding or by screw means such as bolts
Or by caulking means such as rivets
Reinforcing ribs to fix and prevent damage to the cutting claw
5. The method according to claim 4, wherein the step of attaching
A method of supporting a steel pipe pile with a plate-like member.