JPH0639783B2 - Oval steel pipe pile driving method and apparatus - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method and apparatus for driving an oval steel pipe pile,
In particular, the present invention relates to a method and an apparatus for driving an oval steel pipe pile while forming the steel pipe pile into an elliptical shape by a rolling device.

(Prior Art) Steel pipes, steel pipe sheet piles, steel pipe piles (hereinafter,
Because of its strong bearing capacity and economic efficiency, steel pipe piles are not only used as permanent structures such as revetment bridge construction, but also as temporary structures or support piles such as mountain retaining and deadline construction that cannot be covered with steel sheet piles. Is also widely used.

Due to the circular cross section, these steel pipe piles can exhibit uniform strength against external force in any direction. Such lack of directionality, on the contrary, means that a large strength cannot be exhibited in a specific stress direction, which is not very preferable for use in which the stress direction is specified.

On the other hand, since the steel pipe piles have good workability as described above, they are sometimes used as mountain retaining walls.However, when using steel pipe piles as mountain retaining walls, steel pipes of a predetermined length are continuously driven. When the soil is installed and excavated by excavating the soil on one side, the earth pressure of the soil on the other side is received by the surface of each steel pipe to prevent the soil from collapsing.

The size (diameter, wall thickness) of the steel pipe pile used for such retaining wall is calculated by design conditions such as earth pressure distribution, rooting length, and number of truss beams, and the soil per unit width of retaining wall. It is calculated based on bending stress and shear stress in the pressure direction.

(Problems to be solved by the invention) By the way, there are cases where the thickness of the retaining pipe, that is, the diameter of the steel pipe pile cannot be set large due to the site restrictions. In such a case, the diameter of the steel pipe pile is allowed. The thickness of the retaining wall must be less than the thickness of the retaining wall.

In such a mountain retaining wall whose thickness in the earth pressure direction is limited, the bending strength may be insufficient even if the shear strength can be secured for a predetermined amount of steel used.

Therefore, in order to obtain a predetermined bending strength per unit width of the retaining wall, increase the cross-sectional area of the steel material per unit width,
That is, it is necessary to increase the thickness of the steel material, the amount of the steel material used increases, and a large problem occurs in terms of economy.

In addition, steel pipe piles with the same size are often used in consideration of workability, but in this case, the size of the steel pipe pile is calculated in the earth pressure direction per unit width calculated based on the above design conditions. A size that can simultaneously satisfy the maximum values of bending stress and shear stress is used, and it may be overdesigned depending on the site.

However, in such a case, if the cross-sectional shape of the steel pipe pile in use is changed to ensure the minimum necessary bending strength, and if the surface that contacts the soil per steel pipe pile can be expanded, Pile materials can be used effectively and waste is eliminated.

When constructing a mountain retaining wall using a conventional elliptical steel pipe pile, the elliptical steel pipe pile was formed in a place away from the casting site and was transported to the casting site. Therefore, in order to prepare a little more than the required amount of piles at the site, the amount of steel used is bulky, which is uneconomical, and the space for stocking steel pipe piles must be prepared. There was a point.

The present invention has been made in order to solve such a problem, while forming a required amount of elliptical steel pipe piles at a setting site by attaching a forming device for elliptical steel pipe piles to a pile press-in / pull-out machine. An object of the present invention is to provide a method and apparatus for driving an oval steel pipe pile that can be driven.

(Means for Solving Problems) In order to achieve the above object, the present invention has a pile press-fitting / pulling machine fixed on a support made of existing piles, etc., and is attached to the pile press-fitting / pulling machine and is vertically movable. After sandwiching the steel pipe pile in the pile holder, the tip of the steel pipe pile is brought into contact with a rolling device that is provided below the pile holder and forms a steel pipe pile in an elliptical shape, and the pile holder is lowered. A steel pipe pile is formed into an elliptical shape while being driven into the ground, and a pile holder formed in the front part of the pile press-fitting / pulling machine so as to be vertically movable via an arm, and the pile holder. A rolling device having a rolling means for forming the sandwiched steel pipe pile into an elliptical shape is provided below the pile holder.

(Operation) A rolling device for forming an elliptical steel pipe pile is provided below the pile holder mounted vertically movable on the pile press-in / pull-out machine, and the pile holder holding the steel pipe pile is moved downward to move the elliptical steel pipe pile. Since this pile can be driven into the ground while forming, it is not necessary to carry a ready-made elliptical steel pipe pile to the driving site and work efficiency is good.

(Embodiment) Next, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 to 3 are views showing a steel pipe pile in which the cross section of the steel pipe main body is formed into an arbitrary elliptical shape.

The steel pipe piles 1, 2, 3 have short sides S, S1, S2 and long sides L, L1, L2, respectively, and are formed from circular steel pipe main bodies of the same size with the same diameter and wall thickness.

Such a steel pipe pile having an elliptical cross section can give directionality to the bending strength. For example, in the steel pipe pile 1, the short side S is the basis for earth pressure in the direction of the long side L. However, the bending strength in this direction can be made larger than that of the base circular steel pipe pile.

In this way, the steel pipe piles 1, 2, and 3 can be selected to be the optimum ones for use by changing the short sides S, S1, S2 and the long sides L, L1, L2.

FIG. 4 to FIG. 9 are diagrams showing a retaining wall constructed with an elliptic steel pipe pile formed by the method and apparatus for placing an elliptic steel pipe pile according to the present invention.

FIG. 4 shows a first form of the mountain retaining wall to be constructed, in which the short sides S of the oval steel pipe piles 1 are arranged in the earth pressure direction P so that the steel pipe piles 1 are adjacent to each other.

In the mountain retaining wall 4 arranged in this way, compared with the mountain retaining wall 51 formed by adjoining circular steel pipes 50 having the same diameter S as the short side S as shown in FIG. It is possible to obtain a large bending strength, and it is possible to set a small steel material cross section per unit width.

In addition, as shown in FIG. 13, a mountain retaining wall using a circular steel pipe of the same size with a diameter ψ may have excessive strength depending on the part to be used. By forming an elliptical shape and arranging it like the mountain retaining wall 4, the long side L becomes larger than the diameter ψ of the circular steel pipe, but the earth pressure receiving area increases, instead of decreasing the bending strength per piece. As a result, less pile material is needed and the economy is improved. By arbitrarily forming the elliptical shape of the elliptical steel pipe pile 1 in this manner, the bending strength with respect to the earth pressure P and the earth pressure receiving area can be set to an optimum combination.

FIG. 5 is a diagram showing a second form of the Yamadome wall to be constructed.
In this mountain retaining wall 5, the long sides L of the elliptical steel pipe piles 1 are arranged in the earth pressure direction P so as to be adjacent to each other. The mountain retaining wall uses circular steel pipes of the same size, and the strength depends on the part to be used. It can be applied where there is a shortage.

FIG. 6 is a view showing a third form of the Yamadome wall to be constructed.
In this mountain retaining wall 6, the long side L of the steel pipe pile 1 is inclined with respect to the earth pressure receiving surface by an angle α, and the size of the steel pipe pile 1 and the short side S and the long side L are constant and the angle α is set. By arbitrarily setting, the bending strength with respect to the earth pressure P and the earth pressure receiving area can be set to an optimum combination.

FIG. 7 is a view showing a fourth form of the Yamadome wall to be constructed.
Since the steel pipe piles 1a and 1b at the corners of the mountain retaining wall 7 are in contact with each other at the surface of the earth pressure directions Pa and Pb at 45 ° and compete with each other, high strength is obtained.

FIG. 8 is a view showing a fifth form of the Yamadome wall to be constructed.
In this mountain retaining wall 8, a circular steel pipe pile 9 having a diameter ψ before being formed into an ellipse is used together with an elliptical steel pipe pile 1 having a short side S and a long side L to be used as a support pile or the like of a building. .

FIG. 9 is a diagram showing a sixth form of the Yamadome wall to be constructed.
The male portion 10 is provided at a portion of the mountain retaining wall 9 where the steel pipe piles 1 are adjacent to each other.
A section 10 including a and a female portion 10b is provided.

When constructing a mountain retaining wall, those shown in each of the above-mentioned modes are appropriately combined.

Next, one embodiment of the method for placing an elliptic steel pipe pile and the apparatus therefor according to the present invention will be described.

FIG. 10 is a view showing a device for press-fitting a circular steel pipe while forming it into an elliptical shape. Reference numeral 11 in the drawing is a pile press-fitting / pulling-out machine for the steel pipe pile 12, and the pile press-fitting / pulling-out machine 11 is fixed to a support body 15 by a clamp 14 formed at a lower portion of a base 13, and a mast standing on the base 13. An arm 19 having a chuck 18 at its tip is attached to the 16 via a reader 17 so as to be vertically slidable. Mast 16 and arm 1
A hydraulic device 20 is provided between the steel pipe pile 9 and the pipe 9, and when the steel pipe pile 12 is held by the chuck 18 and the arm 19 is moved downward, the steel pipe pile 12 is pressed into the ground.

As shown in FIG. 11, the chuck has an annular frame 22.
Fluid pressure cylinders 23, 24, 25, 26 are disposed inside the holding cylinders, and holding plates 23a, 24a, 25 provided at the tips thereof.
The steel pipe pile 12 is held via a and 26a.

On the other hand, the chuck 18 is attached to the base 13 via the connector 27.
A roller rolling device 28 is supported below the roller rolling device 28. As shown in FIG.
It is composed of two parallel rollers 30 and 31 which are fixed to each other at an adjustable distance. By pressing the steel pipe pile 12 between the rollers 30 and 31 from above, a pressing force is applied from both sides of the steel pipe pile 12 to form an elliptical cross section.

Therefore, when press-fitting the steel pipe 12 into the ground, first, the cylinders 23 to 26 of the chuck 18 are moved with the arm 19 of the pile press-fitting / extracting machine 11 fixed at a predetermined position by the clamp 14 being moved to the uppermost part. Shorten and insert the circular steel pipe pile 12 into the chuck 18 to bring the tip of the steel pipe pile 12 into contact with the upper end of the roller rolling device 28, and then extend the cylinders 23 to 26 to tighten the chuck 18 and clamp the steel pipe pile 12. To do.

Next, the distance S between the rollers 30 and 31 of the roller rolling device 28 is set to be smaller than the diameter ψ of the steel pipe pile 12, and the arm 1
When 9 is moved downward, the steel pipe pile 12 is press-fitted into the roller rolling device 28 to form the elliptical portion 12b of the short side S, and after passing through this, it is press-fitted into the ground to construct the elliptical steel pipe pile 1.

In the above construction apparatus, the roller rolling apparatus 28 as a forming machine and the pile press-fitting / pulling-out machine 11 as a placing apparatus are integrally configured. However, the forming machine is provided separately from the placing apparatus. It may be removable. Further, as shown in FIG. 14, the roller rolling machine 28 can be configured integrally with the chuck 18. A vibro hammer or a striking device may be used as the driving device in addition to the press-fitting device.

The modified cross section of the steel pipe pile 12 is not limited to an ellipse,
The forming machine is not limited to the roller type, and may be, for example, a chuck type to intermittently form an ellipse. In this case,
Using the chuck 18 of the pile punching / pulling machine 11, the chuck 1
It is also possible to drive the steel pipe pile 2 while deforming the steel pipe pile 2 into a deformed shape by the holding plates 23a to 26a of No. 8.

(Effects of the Invention) Since the present invention is configured as described above, it is possible to immediately drive an elliptical steel pipe pile having directionality in bending strength while forming it at a casting site. It is economical because there is no need to prepare extra and the amount of steel used does not increase, and it is not necessary to transport the elliptical pile formed at a location away from the site, thus improving work efficiency.

[Brief description of drawings]

1 to 3 are plan views showing a steel pipe pile whose cross section is formed in an arbitrary elliptical shape, and FIGS. 4 to 9 are first to sixth forms of a retaining wall constructed by the elliptical steel pipe pile. And FIG. 10 is a side view showing an apparatus for press-fitting a circular steel pipe as an embodiment of the present invention while forming it into an elliptical shape,
11 is a sectional view taken along line XI-XI of FIG. 10, and FIG.
XII-XII sectional view of the figure, FIG. 13 is a plan view showing a mountain retaining wall using a conventional circular steel pipe pile, and FIG. 14 is press-fitting while forming a circular steel pipe which is an embodiment of the present invention into an elliptical shape. It is a side view which shows the other example of an apparatus. 1.2.3 …… Oval steel pipe pile 11 …… Pile press-in / pull-out machine

Claims (2)

[Claims] 1. A pile press-fitting / pulling machine is fixed on a support made of an existing pile, and the steel pipe pile is inserted into a vertically movable pile holder mounted on the pile press-fitting / pulling machine. , The steel pipe pile provided below the pile holder is brought into contact with the upper end of a rolling device for forming an elliptical shape, then the steel pipe pile is sandwiched by the pile holder, and then the pile holder is moved downward. A method for placing an oval steel pipe pile, in which a steel pipe pile is formed into an elliptical shape and placed in the ground. 2. Rolling having a pile holder formed vertically in the front of the pile press-in / pull-out machine via an arm, and rolling means for forming a steel pipe pile sandwiched by the pile holder into an elliptical shape. An oval steel pipe pile placing device provided with a device below the pile holder.