JP2002047647A - Steel pipe pile and executing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To install a steel pipe pile of a large diameter with a closed tip opening part in a foundation and to provide the steel pipe pile allowing displaying of original supporting capacity of the foundation and executing method therefor. SOLUTION: This is the steel pipe pile 1 with the tip part closed by a cover body 5. The cover body 5 is attachably/detachably constituted also during execution of the steel pipe pile 1. The steel pipe pile 1 is constituted as a screwing type steel pipe pile with a blade.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel pipe pile having a closed end opening and a method for constructing the same, and more particularly to a steel pipe pile effective for constructing a large-diameter concrete concrete pile and a method for constructing the same. .

[0002]

2. Description of the Related Art A steel pipe pile or a concrete pile (hereinafter referred to as a tip) which is closed by attaching a lid-like member to an opening at a tip thereof in order to prevent earth and sand from entering the inside when the steel pipe pile or the like penetrates into the ground. Some are referred to as closed piles. In addition, the construction method of this tip closed pile includes a striking method of hitting the head of the pile body and penetrating the ground, excavating a hole in advance in the ground where the pile body is installed, and installing the pile body in the hole There is a pre-boring method, or a method of rotating and burying a pile by the action of a wood screw attached to the vicinity of the tip of the pile. Further, there has been proposed an invention in which a steel pipe pile having an open end portion is dug and concrete is poured only into the end portion.

[0003] Some of the tip obstruction piles are ones to which a tipping shoe for excavation is attached and those which improve the supporting force characteristics of the tip ground by the ground, and examples thereof are shown below. JP 55
JP-A-119822 discloses a concrete pile comprising a tubular portion inserted into an opening at the tip of the concrete pile, and a flange portion connected to the lower end of the tubular portion and engaged with the lower end surface of the concrete pile. A steel pipe member for reinforcing a supporting force is described. Japanese Patent Application Laid-Open No. 55-155823 describes a pile in which an enlarged shoe having a diameter larger than that of the bladed steel pipe and having a triangular rib on the lower surface is attached to the tip of the bladed steel pipe.

Japanese Unexamined Patent Publication No. Sho 60-55119 describes a ready-made pile in which an end plate having a diameter larger than that of the pile and having a sediment rising port, a cutting edge, and the like is attached to the tip opening of the pile. Japanese Unexamined Patent Publication (Kokai) No. 62-29614 describes a ready-made pile having an anchor member fixed to a lower end portion. Further, Japanese Patent Application Laid-Open No. 9-242068 describes a cast-in-place pile having a bottom plate having an excavation blade and whose upward movement and rotation are restricted at an opening at the tip end of the steel pipe (these 5). The inventions are collectively referred to as prior art 1).

[0005] In the method of hitting a pile with a closed tip, a striking force is applied to the head of the pile with a hammer or the like, and the striking force removes the earth and sand constituting the tip of the pile and the surrounding soil of the pile in the depth direction and The pile is pierced into the ground while being compacted while being removed to the side (Prior Art 2).

[0006] In the pre-boring method of a pile with a closed tip, a hole is drilled in the ground with a drill or the like prior to the installation of the pile, and usually, the gap is filled with cement milk or the like to suppress the collapse of the geology. A pile body is erected in the gap (prior art 3).

[0007] A method of rotating and embedding a pile body by acting as a wood screw of a wing attached to the vicinity of the tip of the tip closed pile is as follows.
Some have been put to practical use for small diameter steel pipe piles. In the method of burying steel pipe piles described in Japanese Patent Publication No. 2-62848, a bottom plate is fixed to the lower surface of a steel pipe pile body, a drilling blade is provided on the bottom plate, and the bottom plate is provided on the outer peripheral surface at the lower end of the pile body. A steel pipe pile, which has a screw wing with a large wing width and almost twice as large as the outside diameter of the pile body, is projected over almost one turn and pressed into the ground while rotating so as to be screwed into soft ground. The excavation blade at the lower end excavates and softens the earth and sand at the tip of the pile body. The pile is extruded to the side of the pile and compressed, and the pile is screwed and installed in the ground without discharging (prior art 4).

In the method of burying steel pipe piles described in Japanese Patent Publication No. 4-58850, the lower end of the steel pipe pile is closed with a bottom plate having a cutting blade and a grout outlet, and the outer diameter of the steel pipe is approximately 2 mm. A steel pipe pile in which a spiral wing having a double outer diameter is fixed to the outer circumference of the lower end of the steel pipe pile in almost one turn, so that cement milk is squirted from the grout outlet during and after burial to strengthen the surrounding ground. (Prior Art 5).

Further, there is a method described in Japanese Patent Publication No. 5-517305 for digging inside a steel pipe pile having an open end and placing concrete only at the end. In this construction method, the ground is excavated, a steel pipe is erected in the hole, the support layer is excavated to the bottom, concrete is poured into the tip, and the excavated soil is buried back in the steel pipe ( Conventional technology 6).

[0010]

In each of the tip closed piles of the prior art 1, the lid-like member attached to the tip cannot be moved or removed toward the inside of the pile during construction. For this reason, it is not possible to excavate the tip of the pile body using a separate means during construction.

In the hitting method according to the prior art 2, the penetration resistance of the surrounding ground increases by the diameter of the pile when the diameter of the pile is increased, but the penetration resistance of the ground at the distal end is reduced because the tip of the pile is closed. It increases in proportion to the square of the pile diameter. Therefore, when the outer diameter is 60
With a tip block pile of 0 mm or more, it is practically impossible to penetrate the ground to a predetermined depth, in particular, punch out a hard intermediate layer and pierce the tip support layer.

Further, in the pre-boring method of the prior art 3, when the pile diameter is increased, the amount of soil due to pre-excavation increases, and the cement milk or the like which has been filled in the hole prior to the installation of the pile causes the tip blockage. With the installation of the pile body, only the volume of the pile body is discharged, and a great deal of cost is required for the treatment of the discharged soil and cement milk.

In the method of embedding a steel pipe pile having wings attached to its tip, the method according to the prior art 4 is such that the outer diameter of the steel pipe pile is 3 mm.
It is widely used in a range of less than 00 mm. This buried method can secure a relatively large tip supporting force because the tip of the steel pipe is closed by the bottom plate, but the spiral blade has a large reaction force from the ground, so the torque required for rotational penetration Not only becomes very large, but also the penetration efficiency becomes poor. According to field tests conducted by the inventors, the torque required for penetrating the support layer is 3 to 3 times the torque when penetrating soft ground.
Increase by 5 times.

For this reason, a motor having a large capacity for rotating the pile and a base machine for mounting the motor are required, and the torsional moment of the pile is increased to be larger than the thickness required for design. In many cases, a thick steel pipe is required for construction. In addition, concrete piles that are vulnerable to torsion cannot be applied. Further, the outer diameter of the steel pipe is 6
If it exceeds 00 mm, the torque required for construction becomes too large, and a special large-sized machine is required, which is not practical.

In the method of embedding a steel pipe pile according to the prior art 5, since the cement milk is jetted from the tip of the pile and mixed with the earth and sand by the spiral blade, the disturbance of the support layer ground due to the spiral blade is somewhat recovered. However, since the rotation for stirring and mixing is only in one direction of the spiral blade, sufficient stirring of earth and sand and cement milk cannot be expected. In particular, when the ground is cohesive soil,
Stirring tends to be uneven. Although the rotation torque can be slightly reduced as compared with the case where cement milk is not ejected, a large reduction in the rotation torque cannot be expected because the soil near the closed pile tip is hard to move. Further, the range of the mixing and mixing of the earth and sand is only the spiral blade portion, and only the ground support capacity corresponding to the area of the spiral blade can be expected.

In the construction method of the prior art 6, since the tip is opened, it is necessary to excavate all the earth and sand at the position where the pile is to be installed.
There is a possibility that the bearing capacity characteristics of the pile may be degraded by loosening the local board.

The present invention has been made in order to solve the above-mentioned problems, and a large-diameter steel pipe pile having a closed end opening can be installed in the ground, and the original supporting capacity of the upper ground can be improved. An object of the present invention is to provide a steel pipe pile that can be used and a method of constructing the pile.

[0018]

The steel pipe pile according to the present invention comprises:
A steel pipe pile whose tip is closed by a lid, wherein the lid is detachable even during construction of the steel pipe pile. Further, the above-mentioned steel pipe pile is constituted by a screwed steel pipe pile with wings.

Further, the method for constructing a steel pipe pile according to the present invention comprises:
A step of penetrating the steel pipe pile into the ground, and a step of extracting the lid from the steel pipe pile with the steel pipe pile remaining in the ground when the tip of the steel pipe pile reaches the support layer or the vicinity thereof, A step of inserting a drum bucket into a steel pipe pile left in the ground to excavate a support layer, and a step of extracting the drum bucket; and a step of casting concrete into the excavation part and the steel pipe pile. Things.

Further, in the above-described method for constructing a steel pipe pile, when the tip of the steel pipe pile reaches the hard ground or in the vicinity thereof before reaching the support layer, the steel pipe pile is left in the ground and the lid is left. Extracting the body from the steel pipe pile, inserting a drum bucket into the steel pipe pile remaining in the ground to excavate the hard ground, and extracting the drum bucket when the hard ground is excavated. And closing the tip opening of the steel pipe pile again with a lid.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] FIG. 1 is an explanatory sectional view of a main part of a steel pipe pile according to Embodiment 1 of the present invention.
In the figure, reference numeral 2 denotes a steel pipe constituting a steel pipe pile 1 having an open end, and an internal thread 3 is provided on an inner peripheral surface near the end. Reference numeral 5 denotes a lid for opening and closing the opening at the tip of the steel pipe 2, and a male screw 6 screwed to the female screw 3 of the steel pipe 2 is provided on the outer periphery. Reference numeral 7 denotes a rod fixed to the center of the upper surface of the lid 5.

Next, an example of a construction method of the steel pipe pile 1 configured as described above will be described with reference to FIGS. In this embodiment, the steel pipe pile 1 is installed on the ground including the soft layer S and the support layer B by the impact method. Also, as shown in FIG. 1, the steel pipe pile 1 is provided with a screw 3 with an external thread 6 of a lid 5 screwed into the screw 3 so that the tip opening is closed.

(1) First, as shown in FIG. 2 (a), the steel pipe pile 1 penetrates into the ground by a hitting method, and its tip is positioned in the support layer B as shown in FIG. 2 (b). Let it.
(2) Next, the rod 7 is attached to a drive motor mounted on a base machine or the like (not shown), and as shown in FIG. Remove from the female thread 3 and pull up. (3) Next, as shown in FIG. 2D, the drum bucket 15 is inserted into the steel pipe pile 1 and rotated to excavate the support layer.

As shown in FIG. 4, the drum bucket 15 is provided with a drum-shaped main body 16 and a lower portion provided at the bottom thereof so as to be opened and closed by an external operation. It comprises a digging blade 17 and a plurality of side digging blades 18 provided on the outer wall and deployed in the left-right direction by an external operation. 19 is a body 16 at one end
, And the other end is a rod which is attached to, for example, a drive motor mounted on a base machine and rotates.

(4) Then, as shown in FIG.
The side excavating blade 18 of the drum bucket 15 is gradually unfolded, the rod 19 is rotated, and the support layer B is excavated together with the lower excavating blade 17 to form an enlarged bottom 25, and at the same time, the main body 16 is removed from the bottom.
Take in earth and sand inside. When the excavation of the expanded bottom portion 25 is completed, the side excavation blade 18 is returned to the original position, and the drum bucket 15 is pulled out from the steel pipe pile 1. (5) The raised drum bucket 15
As shown in (f), the lower excavation blade 17 is opened near the steel pipe pile 1 or at a predetermined place, and the earth and sand 31 taken into the main body 16 is discharged to the ground. If necessary, the steel pipe pile 1 is penetrated at this time or after the later-described concrete 30 is poured in until the tip of the steel pipe pile 1 reaches the vicinity of the center of the expanded bottom portion 25.

(6) Next, as shown in FIG.
The tremy tube 14 penetrates into the steel pipe pile 1, and concrete 30 is poured into the expanded bottom portion 25 and the entire length or a predetermined height in the steel pipe pile 1 to form a steel pipe concrete pile. (7) Then, as shown in FIG.
4 is pulled out, and if necessary, earth and sand 31 are put into the steel pipe pile 1 as shown in FIG.

In the above description, the case where the drum bucket 15 is used for excavating the widened bottom portion 25 and carrying out the earth and sand is shown, but a grab bucket may be used instead of the drum bucket 15. The grab bucket 20 has a digging blade 21 that is opened and closed by an external operation, for example, as shown in FIG.
The excavating blade 21 excavates the support layer, and the excavating blade 21 is rotated in the center direction to hold the earth and sand and carry it out. In addition, the apparatus used for excavating the support layer B, forming the expanded bottom portion 25, and carrying out the earth and sand is not limited to the above-described drum bucket 15 and grab bucket 20, and other apparatuses may be used (hereinafter, referred to as "the apparatus"). These are collectively called drum buckets).

According to the construction method as described above, a large-diameter steel pipe pile can be installed at a high speed with a small amount of earth removal, and a large tip supporting force can be obtained. In the above description, the case where the expanded bottom portion 25 is formed by the drum bucket and the concrete 30 is cast in the expanded bottom portion 25 and the steel pipe pile 1 is shown, but the expanded bottom portion 25 is omitted and the steel pipe pile 1 is omitted.
The concrete 30 may be cast therein.

In the above description, the case where the steel pipe pile 1 according to the present embodiment is installed on the ground including the soft layer S and the support layer B has been described. The intermediate layer I of the ground which is harder than the soft layer S may exist between the soft layer S and the support layer B. In such a case, as shown in FIG. 6A, the steel pipe pile 1 is penetrated into the soft layer S by a percussion method in a state in which the front end opening is closed by the lid 5. Then, as shown in FIG. 6 (b), when the tip of the steel pipe pile 1 reaches the intermediate layer I or its vicinity, the rod 7 is rotated to remove the lid 5 from the steel pipe pile 1 and lift it up. .

Next, as shown in FIG. 6C, the drum bucket 15 is inserted into the steel pipe pile 1, the intermediate layer I is excavated by the lower excavation blade 17, and the steel pipe pile 1 is penetrated. Middle layer I
, The drum bucket 15 is lifted to discharge the earth and sand taken into the main body 16 to the outside. Then, as shown in FIG. 6 (d), the lid 5 is inserted into the steel pipe pile 1, attached to the distal end, and penetrates into the next soft layer S with the distal end opening closed again. Hereinafter, the work is performed by the steps after (b) described with reference to FIGS. In the case where a hard ground exists up to the support layer B following the intermediate layer I, the ground may be excavated by the drum bucket 15 without raising the drum bucket 15.

FIGS. 7 and 8 show another example of the steel pipe pile according to the present embodiment. The steel pipe pile 1 of FIG. 7 is different from the steel pipe pile 1 of FIG. It is formed in a shape and facilitates penetration into the ground. In addition, the steel pipe pile 1 of FIG. 8 has one or more inverted L-shaped key grooves 8 provided on the side wall of the drum-shaped lid 5 and a key groove formed on the inner peripheral surface near the distal end of the steel pipe 2. 8 is provided with a key 9. When closing the opening of the tip of the steel pipe pile 1, the cover 5 is lowered and the key groove 8 is fitted to the key 9, and then turned to position the key 9 at the horizontal portion of the key groove 8. Thus, the lid 5 is held at that position, and does not move in the vertical direction. When removing the lid 5 from the steel pipe 2, the lid 5 can be easily removed by rotating the lid 5 in the opposite direction and pulling it up.

According to the present embodiment, a detachable lid 5 is provided at the tip of the steel pipe pile 1 even during construction, and the steel pipe pile 1 is penetrated into the ground with the tip opening closed by the lid 5. When the tip of the pile reaches the middle layer I or the support layer B, which is a hard ground, or the vicinity thereof, the lid 5 is removed with the steel pipe pile 1 left in the ground and pulled up. By excavating by inserting the drum bucket 15 as the excavating means, the large-diameter steel pipe pile 1 can easily penetrate even on hard ground. In addition, since the excavated earth and sand is taken into the drum bucket 15 and discharged to the outside,
By casting the concrete 30 as it is without soil and sand entering the steel pipe pile 1, the steel pipe concrete pile can be easily formed. Further, the lid 5 is pulled up, the drum bucket 15 is inserted into the steel pipe pile 1, and the expanded bottom portion 25 is formed on the support layer B to form the concrete 3.
Since 0 is cast, a steel pipe concrete pile having a large tip supporting force can be formed. In this embodiment, the case where the steel pipe pile 1 is penetrated by the impact method is shown, but the steel pipe pile 1 may be penetrated by the press-fitting method.

[Second Embodiment] FIG. 9 is a cross-sectional explanatory view of a main part of a steel pipe pile according to a second embodiment of the present invention. The same parts as those of the steel pipe pile described with reference to FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. In the present embodiment, in the steel pipe pile 1 of the first embodiment shown in FIG.
1 to form a screwed steel pipe pile 10 with wings (hereinafter referred to as a winged steel pipe pile).

FIGS. 10 and 11 show an example of the wing 11 provided on the winged steel pipe pile 10. In the example of FIG. 10, the steel wings 11 a and 1 made of a fan-shaped flat plate are provided on the outer circumference near the tip of the steel pipe 2.
1b are joined at the same height position by welding and are joined together.
1. Further, the example of FIG.
A spiral blade 12 formed by cutting and bending a part of a donut-shaped steel plate is joined to the outer periphery near the front end portion by welding to form a blade 11.

An example of the wing 11 has been described with reference to FIGS. 10 and 11, but is not limited thereto.
The shape may be a polygon other than a spiral shape, or a shape obtained by dividing these into a plurality may be appropriately selected. Also, the mounting position can be set appropriately,
If necessary, a plurality of stages may be provided in the axial direction. Wing 1
It is desirable to use a steel tube 1 whose outer diameter is about 1.5 to 3.0 times the outer diameter of the steel pipe 2.

Next, an example of a method of constructing the winged steel pipe pile 10 according to the present embodiment will be described with reference to FIGS. (1) First, the pile head of the winged steel pipe pile 10 whose tip opening is closed by the lid 5 is attached to a drive motor mounted on a base machine or the like (not shown) installed on the ground. 12 (a), the steel pipe pile 10 is rotated, and is propelled by the action of a wood screw of the wing 11 to penetrate into the ground, as shown in FIG. 12 (b). It is located in or near layer B. In addition, you may make it attach a drive motor to the trunk | drum of the steel pipe pile 10 with a wing instead of a pile head.

(2) Then, the drive motor is removed from the winged steel pipe pile 10, the rod 7 of the lid 5 is attached to the drive motor, and the rod 7 is rotated to remove the lid 5 from the steel pipe 2.
It is pulled up as shown in FIG. (3) Next, as shown in FIG.
Inserts the drum bucket 15 attached to the drive motor into the winged steel pipe pile 10 and rotates to excavate the support layer B. (4) Then, as shown in FIG. 12 (e), the expanded bottom portion 25 is formed in the support layer B, and the drum bucket 15 is pulled out from the steel pipe pile 10 with wings, and as shown in FIG. The sediment taken in 15 is discharged.

(5) Next, as shown in FIG. 13 (a), the tremee pipe 14 is inserted into the steel pipe pile 10 with wings, and concrete is extended to the entire length of the expanded bottom portion 25 and the steel pipe pile 10 with wings or to a predetermined height. 30 is cast. (6) Next, as shown in FIG.
Pull up 4 to build a steel pipe concrete pile. Then, the winged steel pipe pile 10 is attached to the drive motor again and rotated, and penetrates until the tip reaches the vicinity of the center of the widened portion 25. As shown in FIG. 13C, earth and sand 31 are put into the steel pipe concrete pile 10 as necessary.

According to the above construction method, low vibration,
Large-diameter winged steel pipe pile 10 can be installed in the ground with low noise and little earth removal, and since soil does not infiltrate into the inside, concrete is poured without discharging earth and sand. To form a steel pipe concrete pile. Also, the concrete 30 cast on the wing 11 and the bottom portion 25 can provide a large tip supporting force with a small amount of concrete used. In addition, also in the present embodiment, when the intermediate layer I exists in the ground, as described in the construction method of FIG. 6 of the first embodiment, the tip of the winged steel pipe pile 10 has the intermediate layer I or When reaching the vicinity, the lid 5 is pulled up, the drum bucket 15 is inserted, the intermediate layer I is excavated, and then the lid 5 is pulled up and the lid 5 may be inserted again and attached.

FIGS. 14 and 15 show another example of the screw-in type steel pipe pile according to the present embodiment. In the example of FIG. 14, the lower surface of the lid 5 of FIG. 9 is formed in an inverted conical shape. It is. In the example of FIG. 15, one or a plurality of inverted L-shaped key grooves 8 are provided on the side wall of the drum-shaped lid 5, and the key grooves 8 are formed on the inner peripheral surface near the distal end of the steel pipe 2. The key 9 is provided correspondingly, and its operation is the same as that of the steel pipe pile described with reference to FIG.

Although the embodiment of the present invention has been described above, the lid 5 for opening and closing the tip opening of the steel pipe pile 1 or the winged steel pipe pile 10 according to the present invention is not limited to the steel pipe pile 1 or the winged steel pipe pile 10. This is for preventing earth and sand from entering the inside at the time of intrusion, so that the opening at the tip end does not have to be completely closed, and a part of the opening may be open. Further, the mechanism for attaching and detaching the lid 5 to and from the steel pipe pile 1 or the winged steel pipe pile 10 is not limited to the above-described example, and can be detached by an external operation during the construction of the steel pipe pile 1 or the winged steel pipe pile 10. Other means may be used.

Further, an excavation blade may be provided on the lower surface of the lid 5, or an injection hole for injecting water, cement milk or the like into the ground may be provided on the lid 5. Further, ribs or other convex portions may be provided on the inner or outer peripheral surface or near one of the tip portions of the steel pipe pile 1 or the winged steel pipe pile 10 to increase the adhesive force of concrete.

[0043]

EXAMPLE Next, an example of the construction method shown in FIGS. 12 and 13 using the steel pipe pile with wings of Embodiment 2 will be described. The steel pipe pile 10 with wings has a female screw 3 on the inner peripheral surface of the tip, a steel pipe 2 having an outer diameter of 1000 mm, a plate thickness of 12 mm, and a length of 31 m.
Outer diameter 1800mm, long inner diameter 1008mm,
Two donut-shaped steel plates with a short inner diameter of 1000 mm and a thickness of 40 mm
The blades 11 were configured by welding the steel blades made of the divided flat plates at the same height position and by welding.

The lid 5 was made of a drum-shaped steel material having a thickness (height) of 40 mm and having a screw 6 on the outer periphery, and a rod 7 was attached to the center of the upper surface. The ground to be constructed is a soft layer having an N value of 3 from the surface up to 23 m, 23 to 32.
Up to m, a soft layer having an N value of 7 and a support layer having an N value of 50 at a depth lower than m.

First, the lid 5 was inserted into the steel pipe 2 from the upper opening, and the rod 7 was rotated to screw the male screw 6 into the female screw 3 of the steel pipe 2 to close the opening at the tip. Next, a steel pipe pile with wings was attached to the drive motor of the base machine installed on the ground.
The pile head of No. 0 was attached, and the wing 11 was pushed down while rotating so as to be propelled through the soft layer by the wood screw action of the wing 11 and penetrated. When the tip of the pile reaches the support layer, the drive motor is detached from the winged steel pipe pile 10 and attached to the rod 7 of the lid 5, and the rod 7 is rotated to engage with the female thread 3 of the steel pipe 2. Is removed and the winged steel pipe pile 10 is left in the ground,
Was raised.

Next, the rod 19 of the drum bucket 15 is attached to the drive motor and inserted into the steel pipe pile 10 with the wing. The drum bucket 15 is rotated to excavate the support layer by the lower excavation blade 17 and to excavate the side. The blade 18 was gradually unfolded to excavate an expanded bottom 25 having a depth of 35 m from the surface and a maximum outer diameter of 2000 mm. When the excavation of the expanded bottom portion 25 was completed, the side excavation blade 18 was returned to the original state, and the drum bucket 15 was pulled up to discharge the sediment taken in the drum bucket 15.

Then, the tremy tube 14 was attached to the drive motor, concrete 30 was poured into the steel pipe pile 10 with the expanded bottom 25 and the wings, and the tremy tube 14 was pulled up. The casting height of the concrete 30 was 4 m from the bottom of the expanded bottom 25. Next, the steel pipe pile with wings 10 was attached to a drive motor and rotated, and penetrated until the tip reached the vicinity of the center of the widened part 25. As a result, the wing 11 is expanded 2
5 located.

According to the above procedure, a large-diameter winged steel pipe pile can be installed in the ground in a short time with low vibration and low noise with a small amount of earth removal, and concrete can be cast by widening the bottom. As a result, a large tip supporting force could be obtained in combination with the presence of the wing.

[0049]

The steel pipe pile according to the present invention is a steel pipe pile whose tip is closed by a lid, wherein the lid is detachable even during the construction of the steel pipe pile. Since the pile is composed of a screw-in type steel pipe pile with wings, it is possible to excavate the ground near the tip of the steel pipe pile by extracting the lid and inserting a separate excavating means inside during construction.

Further, in the method for constructing a steel pipe pile according to the present invention, the above-described step of penetrating the steel pipe pile into the ground and, when the tip of the steel pipe pile reaches the support layer or its vicinity, the steel pipe pile is placed in the ground. A step of extracting the lid from the steel pipe pile in a state where it is left behind, a step of inserting a drum bucket into the steel pipe pile left in the ground to excavate the support layer, and a step of extracting the drum bucket; Since it is constituted by the step of placing concrete in the pile, a large-diameter steel pipe pile can be installed in the ground, and a large tip support force can be obtained with less soil removal and less concrete.

In the above-described method for constructing a steel pipe pile, when the tip of the steel pipe pile reaches the hard ground or in the vicinity thereof before reaching the support layer, the steel pipe pile is left in the ground and the cover body is left. Extracting a solid ground from a steel pipe pile, inserting a drum bucket into a steel pipe pile left in the ground to excavate hard ground, and extracting a drum bucket when excavation of the hard ground is completed, And the step of closing the front end opening with the lid again. Therefore, even when the hard ground such as the intermediate layer exists before reaching the support layer, the steel pipe pile having a large diameter can be easily penetrated.

[Brief description of the drawings]

FIG. 1 is a sectional explanatory view of a steel pipe pile according to Embodiment 1 of the present invention.

FIG. 2 is an explanatory view of another construction method of the steel pipe pile of FIG.

FIG. 3 is an explanatory view of another construction method of the steel pipe pile of FIG. 1;

FIG. 4 is an explanatory view of an example of a drum bucket used in the construction method of FIGS. 2 and 3;

FIG. 5 is an explanatory diagram of an example of a grab bucket used in the construction method of FIGS. 2 and 3;

FIG. 6 is an explanatory view of still another construction method of the steel pipe pile of FIG. 1;

FIG. 7 is an explanatory sectional view of another example of the steel pipe pile according to the first embodiment.

FIG. 8 is an explanatory diagram of still another example of the steel pipe pile according to the first embodiment.

FIG. 9 is an explanatory sectional view of a winged steel pipe pile according to Embodiment 2 of the present invention.

FIG. 10 is an explanatory diagram illustrating an example of a wing according to the second embodiment.

FIG. 11 is an explanatory view showing another example of the wing of the second embodiment.

FIG. 12 is an explanatory view of another example of a method for constructing the steel pipe pile with wings of FIG. 9;

FIG. 13 is an explanatory diagram of another example of the method of constructing the steel pipe pile with wings in FIG. 9;

FIG. 14 is an explanatory diagram of another example of the steel pipe pile with wings of the second embodiment.

FIG. 15 is an explanatory view of still another example of the winged steel pipe pile according to the second embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 steel pipe pile 2 steel pipe 3 female thread 5 lid 6 male screw 8 keyway 9 key 10 winged steel pipe pile 11 wing 14 tremy pipe 15 drum bucket 20 grab bucket 25 expanded bottom 30 concrete

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshio Shinohara 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Gen Gen Mori 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Sun F-term in Honko Tube Co., Ltd. (Reference) 2D041 AA02 AA03 BA13 CA05 DA01 DB02 EB02 FA03 FA12 FA14

Claims (4)

[Claims] 1. A steel pipe pile, the tip of which is closed by a lid, wherein the lid is detachable even during construction of the steel pipe pile. 2. The steel pipe pile according to claim 1, wherein the steel pipe pile is a screwed steel pipe pile with wings. 3. The step of penetrating the steel pipe pile according to claim 1 or 2 into the ground, and when the tip of the steel pipe pile reaches the support layer or its vicinity, the steel pipe pile is left in the ground. Removing the lid from the steel pipe pile, inserting a drum bucket into the steel pipe pile left in the ground to excavate the support layer, and extracting the drum bucket; and A method for constructing a steel pipe pile, comprising a step of placing concrete in a pile. When the tip of the steel pipe pile reaches the hard ground or its vicinity before reaching the support layer, removing the lid from the steel pipe pile with the steel pipe pile remaining in the ground; A step of inserting a drum bucket into the steel pipe pile remaining in the ground to excavate the hard ground, and a step of extracting the drum bucket when the excavation of the hard ground is completed, and a tip opening of the steel pipe pile 4. The method for constructing a steel pipe pile according to claim 3, further comprising the step of closing the pipe again with a lid.