JP5557503B2 - Steel pipe pile insertion method - Google Patents

Description

The present invention relates to the insertion how suitable steel pipe pile in hard ground.

  Conventionally, when a building such as a house is constructed on a site having a low ground strength, a pile foundation is provided at the lower part of the building so that the building can be firmly supported. When construction is performed in a residential area or the like, since noise and vibration to the surroundings become a problem, steel pipe piles with spiral wings attached to the surroundings are used as pile foundations (see, for example, Patent Document 1). According to this steel pipe pile, the noise and vibration at the time of construction can be suppressed by rotationally pressing the steel pipe pile into the ground.

Japanese Patent No. 2592079

  Here, in order to obtain sufficient supporting force by the steel pipe pile, the lower end of the steel pipe pile must be inserted into the support layer. When the support layer is hard or there are obstacles in the ground, even when steel pipe piles with spiral wings are installed around the steel pipe as described above, when the lower end is inserted into the support layer, It is necessary to apply rotational torque to the steel pipe pile, and a large rotary press-fitting machine must be used, which is not suitable for construction in a narrow site.

  In addition, it is possible to excavate a hole that reaches the support layer in advance and insert a steel pipe pile into this hole, but a large excavator is required to excavate a solid ground, Not suitable for construction in narrow sites.

  This invention is made | formed in view of said problem, and is providing the insertion method of the steel pipe pile applicable even if it is a site | part with a narrow and strong ground.

The steel pipe pile insertion method of the present invention is a method of inserting a steel pipe pile into the ground, and the hole agitation step of agitating the ground by injecting cement milk and rotating the excavating bit while vibrating, A steel pipe insertion step for inserting the steel pipe while vibrating and rotating the hole-stirred portion, the steel pipe is provided with an annular annular portion protruding from the outer periphery above the lower end of the steel pipe, and the ground is A support layer is provided below, and in the steel pipe insertion step, the annular portion is brought into contact with an upper portion of the support layer or embedded in the support layer, and a portion below the annular portion of the steel pipe is provided. And projecting from the hole-stirred portion and press-fitting into the support layer.
The above-mentioned “stirring the ground by drilling cement milk and rotating the excavating bit while vibrating” means that the cement milk is sprayed on the ground and the ground is stirred for drilling, and the ground This includes the case where the excavated soil and the cement milk are stirred while the cement milk is sprayed after the agitation.

In the steel pipe pile insertion method described above, in the hole agitation step, the ground may be agitated while spraying cement milk .

Also, in the above steel pipe pile insertion method, the steel pipe may be provided with a plurality of annular portions.

  According to the present invention, since the excavation hole is formed by excavating the ground by rotating the excavation bit while applying an oscillating force, even a small excavator has a strong ground or an obstacle in the ground. Since the excavation hole can be formed in a certain ground and the steel pipe is inserted into the excavation hole, the steel pipe can be inserted even with a small press-fitting device. Since it can be constructed with such a small apparatus, the steel pipe pile can be inserted even in a site where the ground is narrow and the ground is strong or there is an obstacle in the ground.

It is a figure which shows a press fit apparatus, (A) shows the state at the time of excavating the ground, (B) shows the state at the time of press-fitting a steel pipe pile. The detailed structure of a drill bit is shown, (A) is a front view, (B) is a side view, (C) is a top view. It is a figure which shows the steel pipe pile used by this embodiment, (A) is a front view, (B) is a look-up figure. It is a figure (the 1) for demonstrating the insertion method of the steel pipe pile of this embodiment. It is a figure (the 2) for demonstrating the insertion method of the steel pipe pile of this embodiment. It is a figure (the 3) for demonstrating the insertion method of the steel pipe pile of this embodiment. It is a figure (the 4) for demonstrating the insertion method of the steel pipe pile of this embodiment. It is a figure which shows the friction pile constructed | assembled by the insertion method of the steel pipe pile of this invention.

Hereinafter, an embodiment of a steel pipe pile insertion method of the present invention will be described in detail with reference to the drawings. In the present embodiment, for example, a case where construction is performed in a narrow site such as a platform of an existing railway station will be described.
First, the press-fitting device used in the steel pipe pile insertion method of this embodiment will be described. FIG. 1 is a diagram showing a press-fitting device 10, (A) shows a state when excavating the ground, and (B) shows a state when press-fitting a steel pipe pile 100. As shown in the figure, the press-fitting device 10 includes a moving mechanism 20 composed of a caterpillar, a pedestal portion 30 placed on the moving mechanism 20, a guide portion 40 supported by the pedestal portion 30 so as to extend vertically, and a guide. The vibration apparatus 50 attached to the part 40, the rod 70 connected to the vibration apparatus 50, and the rotation apparatus 60 which rotates the rod 70 are provided.

The vibration generating device 50 is a device that transmits a vibration generating force generated by rotating an eccentric weight to the rod 70, for example. The vibration force transmitted to the rod 70 only needs to include at least one component in the vertical direction or the horizontal direction, but when the vibration generator 50 is used, both components are included. The vibration generating device 50 is movable along the guide portion 40 together with the rod 70 and the rotating device 60.
The rotating device 60 is a device that applies a rotational force about the axis to the rod 70.

  As shown in FIG. 1 (A), when excavating the ground, a drill bit 80 is attached to the tip of the rod 70 of the vibration generator 50, and from the tip of the drill bit 80 through the inside of the rod 70 from the outside. A cement milk supply device 90 for discharging the cement milk is connected.

  2A and 2B show a detailed configuration of the excavation bit 80, where FIG. 2A is a front view, FIG. 2B is a side view, and FIG. As shown in the drawing, the excavation bit 80 includes a shaft portion 81 connected to the rod 70, a drill blade main body 83 attached to the tip of the shaft portion 81 so as to extend laterally, and a drill blade main body 83. A bit 84 attached, a plurality of stirring blades 82 connected to the shaft portion 81 so as to extend toward the outer periphery, and a bit 85 attached to the tip of the shaft portion 81 are provided. The cement milk supplied through the rod 70 by the cement milk supply device 90 is discharged from the tip of the shaft portion 81.

  The press-fitting device 10 rotates the excavation bit 80 through the rod 70 by the rotation device 60 in a state where the excavation bit 80 is attached to the tip of the rod 70, and thereby the ground by the bit 84 attached to the excavation blade body 83. Can be excavated. Further, the cement milk is sprayed into the excavation hole by the cement milk supply device 90, and the excavation bit 80 rotates so that the agitating blade 82 mixes and agitates the cement milk and the excavated soil to form a soil cement. Can do.

  Further, as shown in FIG. 1 (B), an attachment 95 is attached to the tip of the rod 70 when the steel pipe pile 100 is press-fitted. The attachment 95 can be attached to and detached from the tip of the rod 70 and can hold the upper portion of the steel pipe pile 100 coaxially with the rod 70.

  Drawing 3 is a figure showing steel pipe pile 100 used by this embodiment, (A) is a front view and (B) is a bottom view. As shown in the figure, the steel pipe pile 100 includes a cylindrical steel pipe pile main body 105 and an annular annular portion 120 attached to the lower end of the steel pipe pile main body 105 along the outer periphery. Moreover, the steel pipe pile main body 105 is formed by connecting a plurality of steel pipes 110.

Drawing 4A-Drawing 4D are figures for explaining the insertion method of steel pipe pile 100 of this embodiment.
This embodiment demonstrates the case where the steel pipe pile 100 is press-fit in the ground 1 provided with the support layer 3 with high intensity | strength in the lower part.
First, as shown in FIG. 4A, the excavation bit 80 is attached to the tip of the rod 70 of the press-fitting device 10, and the cement milk supply device 90 is connected to the press-fitting device 10. Then, while rotating the excavation bit 80 through the rod 70 by the rotating device 60 at a speed of 20 to 60 revolutions per minute, the ground 1 is excavated until the lower end reaches the upper part of the support layer 3 to form the excavation hole 4. To do. At this time, for example, a vibration force of about 20 to 50 Hz is applied to the excavation bit 80 through the rod 70 by the vibration generator 50. Thereby, since the excavation bit 80 excavates the ground by the rotational force and the vibration force, the cutting efficiency of the excavation bit 80 is improved. In addition, because the excavation force is transmitted from the excavation bit 80 to the ground 1, large gravel and rock in the ground 1 move due to vibration, and there are obstacles such as solidified bodies such as gravel and concrete in the ground. Even if there is, excavation can be done easily.

  In parallel with the excavation work, cement milk is injected into the excavation hole 4 through the inside of the rod 70 by the cement milk supply device 90. Cement milk is sprayed from the tip of the rod 70 to the ground 1 below the excavation bit 80 and an exciter force is transmitted from the excavation bit 80, so that the ground 1 vibrates in a state containing cement milk. Since it is liquefied and softened, it can be easily cut by the excavation bit 80. Thus, according to the press-fitting device 10, the excavation efficiency of the excavation hole 4 is improved by applying the excitation force by the vibration generation device 50.

  Then, the soil and sand cut by the excavation bit 80 and the cement milk sprayed from the tip of the rod 70 are agitated by the agitating blade 82 to form a soil cement in the excavation hole 4.

  Next, as shown in FIG. 4B, the excavation bit 80 and the cement milk supply device 90 are removed from the press-fitting device 10. Then, an attachment 95 is connected to the tip of the rod 70, and the lowermost steel pipe 110 constituting the steel pipe pile 100 is attached to the attachment 95. Then, the lowermost steel pipe 110 is press-fitted into the excavation hole 4 filled with the soil cement 5 by the press-fitting device 10.

  Furthermore, the steel pipe 110 is newly connected to the upper part of the press-fitted steel pipe 110, and the connected steel pipe 110 is press-fitted. At this time, vibration is applied to the steel pipe 110 by the vibration generator 50 of the press-fitting device 10, and rotation is applied via the rod 70 by the rotating device 60. Thereby, since the soil cement around the steel pipe 110 is liquefied, the steel pipe 110 can be smoothly press-fitted.

Next, as shown in FIG. 4C, after the lower end of the steel pipe pile 100 reaches the upper portion of the support layer 3, the steel pipe pile 100 is further press-fitted until the annular portion 120 reaches the upper portion of the support layer 3. At this time, in order to insert a portion below the annular portion 120 of the steel pipe 110 into the support layer 3, it is necessary to press-fit the steel pipe pile 100 while excavating the sand of the support layer 3 with the bit 120 at the lower end of the steel pipe pile 100. . On the other hand, by applying the vertical vibration by the vibration generator 50 and press-fitting the steel pipe 110 while applying the rotational force by the rotating device 60, the excavation efficiency is the same as in the case of excavating the ground 1 by the excavating bit 80. In order to improve, the strong support layer 3 can be excavated by the excavation bit 80 provided in the lower part of the steel pipe 110.
4D, after the steel pipe pile 100 is press-fitted until the annular portion 120 reaches the upper part of the support layer 3, the soil cement 5 filled in the excavation hole 4 is cured, so that The press-fitting work is completed.

  According to the steel pipe pile 100 thus press-fitted, the annular portion 120 abuts on the upper portion of the support layer 3, so that the vertical load acting on the steel pipe pile main body 105 acts on the lower end of the steel pipe pile main body 105. In addition to the supporting pressure and the peripheral surface frictional force of the steel pipe pile main body 105, the annular portion 120 is resisted by the supporting pressure acting from the support layer 3. For this reason, the support force of the steel pipe pile 100 improves.

  As described above, according to the present embodiment, the excavation hole 4 is formed in advance and the excavation hole 4 is formed even in a site where the ground is solid and the ground is obstructed. Since the steel pipe pile 100 is inserted therein, the steel pipe pile 100 can be press-fitted without a large press-fitting device.

  Further, when the excavation hole 4 is formed, the excavation bit 80 is rotated, and the ground 1 is excavated while applying the vibration force to the excavation bit 80 by the vibration exciter 50. Even in a site where the ground is strong or there are obstacles in the ground, the ground can be easily excavated. For this reason, it is possible to press-fit steel pipe piles even in a narrow site where the ground is solid or there are obstacles in the ground.

  Further, when the steel pipe pile 100 is inserted, it is necessary to press-fit the steel pipe pile 100 so that the annular portion 120 reaches the upper portion of the support layer 3. By applying a rotational force with the device 60, the steel pipe pile 100 can be smoothly inserted in the same manner as when the excavation hole 4 is formed.

  Moreover, since the steel pipe pile 100 was embedded so that the annular part 120 was in contact with the upper part of the support layer 3 using a steel pipe pile 100 provided with an annular part 120 around the steel pipe pile body 105, FIG. In (B), the area of the annular portion 120 indicated by hatching becomes the support area, and the support force as the support pile can be improved.

In this embodiment, when the steel pipe pile 100 is press-fitted, the rotational force and the excitation force are applied. However, the present invention is not limited to this, and only the rotation force or the excitation force may be applied. It is also possible to press-fit without applying the rotational force and the vibration force.
Further, in this embodiment, the excavation bit 80 is rotated while vibrating the cement milk by the ground improvement device 10 and the excavation hole 5 is formed in the ground. However, the present invention is not limited to this, and excavation is performed while injecting water. After the bit 80 is rotated while being vibrated and the ground is ground to a predetermined depth, cement milk is injected into the excavated soil while the excavating bit 80 is pulled up, and the excavating bit 80 is rotated to rotate the excavated soil and cement milk. It is good also as stirring.

  In the present embodiment, the steel pipe pile 100 having the annular portion 120 attached to the periphery thereof is used. However, the present invention is not limited to this, and one having a spiral wing attached may be used. Any steel pipe provided with a protruding portion protruding toward the outer periphery may be used. Furthermore, you may use the steel pipe pile to which the annular part and spiral wing are not attached. Moreover, although the steel pipe pile main body 105 used what the some steel pipe 110 was connected as the steel pipe pile 100, it is not restricted to this, You may use an integral thing.

  In the present embodiment, the excavation hole is formed such that the lower end reaches the upper part of the support layer 3. However, the present invention is not limited to this, and the lower end may not reach the support layer 3, The lower end may reach the inside of the support layer 3.

Moreover, in this embodiment, although the case where the steel pipe pile 100 was press-fit in the ground 1 provided with the support layer 3 was demonstrated, this invention is applicable not only to this but to any ground.
For example, as shown in FIG. 5, when the support layer is very deep, after excavating the ground to form cement milk 5 in the excavation hole 4 as in the above embodiment, the excavation hole 5 A steel pipe pile 230 having a plurality of annular portions 210 attached around the steel pipe pile main body 220 is inserted therein. And the friction pile 200 can be constructed | assembled because the cement milk 5 hardens | cures. In such a case, the steel pipe pile body 220 may be composed of a plurality of steel pipes. When the steel pipe pile main body 220 is constituted by a plurality of steel pipes, an annular part 210 may be provided at the end of each steel pipe.

DESCRIPTION OF SYMBOLS 1 Ground 3 Support layer 4 Drilling hole 5 Soil cement 10 Press-fitting device 20 Moving mechanism 30 Base part 40 Guide part 50 Exciting device 60 Rotating device 70 Rod 80 Drilling bit 90 Cement milk supply device 95 Attachment 100 Steel pipe pile 105 Steel pipe pile main body 110 Steel pipe 120 Annular part 130 Bit 200 Friction pile

Claims (3)

A method of inserting a steel pipe pile into the ground,
Drilling agitation step of agitating the ground by jetting cement milk and rotating the excavating bit while vibrating,
A steel pipe insertion step of inserting the steel pipe into the agitated portion while vibrating and rotating the steel pipe,
The steel pipe is provided with an annular annular portion protruding from the outer periphery above the lower end of the steel pipe,
The ground includes a support layer below,
In the steel pipe insertion step, the annular part is brought into contact with the upper part of the support layer or embedded in the support layer, and the part below the annular part of the steel pipe is subjected to the drilling and stirring. The steel pipe pile insertion method characterized by making it protrude from and press-fitting in the said support layer. A steel pipe pile insertion method according to claim 1,
In the drilling stirring step,
A method for inserting steel pipe piles, wherein the ground is drilled and agitated while spraying cement milk. A steel pipe pile insertion method according to claim 1 or 2 ,
The steel pipe is provided with a plurality of the annular portions, and the steel pipe insertion method is characterized in that:

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