JPH0624420Y2 - Multi-blade steel pipe pile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a multi-blade steel pipe pile that is rotationally buried in the ground without vibration.

(Prior art) Conventionally, in order to bury a pile in the ground without vibration, a buried hole is excavated by a spiral auger, the hole is filled with an injection liquid such as semet milk, and then a deformed pile with knots is inserted. I am trying to do it. However, in such a construction method, the state of formation around the buried pile is columnar, and there is a problem that the supporting force due to the original unevenness of the deformed pile cannot be utilized. Therefore, in recent years, it has been practiced to form a continuous spiral blade over the entire length and bury the concrete spiral pile in the ground while rotating it.

(Problems to be solved by the invention) However, in the method of burying the spiral pile, not only is the manufacturing of the pile very expensive and the price becomes high, but also when it is buried in the ground as the pile diameter increases, It takes time to discharge and compress the volume of piles of sand, and it is more difficult to bury it in hard ground.In addition, the volume of soil excavated by the continuous spiral over the entire length of the piles replaces the piles and replaces them on the ground. As a result, the frictional force is reduced and it is difficult to dispose of a large amount of earth and sand and cement milk that have been left on the ground. It has the drawback.

The present invention solves the drawbacks of the conventional foundation piles as described above, and can easily and stably bury the piles in the ground by a simple method of rotational propulsion, and at the same time, support pressure of the wing portion and the periphery of the piles can be achieved. It is intended to provide a multi-blade steel pipe pile having a large supporting force and a pulling-out force by combining the above friction, the effect similar to the tip closing by the spiral blade inside the pile and the bearing support force of the external spiral blade at the tip.

(Means for Solving the Problems) Next, the structure of the present invention will be described with reference to the drawings corresponding to the embodiments. In the present invention, the drilling blades 4 and 4 are provided at the lower end of the steel pipe pile body 1 in a protruding manner. Then, the inner spiral blade 2 extending almost one turn is projected inside the tip of the pile, and on the outer peripheral surface of the pile main body,
Almost vertically over the entire length, evenly spaced,
Each of them is characterized in that an external spiral blade having an outer diameter two to three times larger than the outer diameter of the steel pipe pile main body is provided so as to project almost one turn. Further, in the above-mentioned structure, two inner spiral blades extending substantially one turn are provided inside the tip of the pile, and the lower end positions of the inner spiral blades are protruded from each other by about half a turn.

(Operation) The multi-blade steel pipe pile of the present invention is configured as described above, and at the time of construction, a rotary drive cap (not shown) is coupled to the upper end of the pile 1 and the pile is rotated so as to be screwed. , The soil at the tip of the pile is excavated and softened and fluidized by the drilling blade at the bottom of the pile, and almost half of the sediment flows into the inside of the pile 1 by the spiral blades 2 inside the tip of the pile, and the other soil is spread on the outer surface of the pile 1. The outer spiral blades 3a that flow out to consolidate the surrounding sediment and project at equal intervals on the outer peripheral surface of the pile 1 bite into the surrounding sediment and rotate and propel the sediment as a reaction force, and further the upper spiral blade. The rotational propulsive force increases due to the cuts into the sand and sand of 3b to 3d, and the steel pipe piles are efficiently rotationally buried in the soil without discharge. The multi-blade steel pipe pile buried in this way has the same effect as the bearing pressure of the large number of large-diameter outer spiral blades 3a to 3d and the inner spiral blade 2, the surface friction force of the pile, and the tip closing by the pile inner spiral blade. A large supporting force, a pulling-out force, and a horizontal resistance force, which are combined with the supporting force for supporting the pile tip end with the external tip spiral blade, will be exhibited.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

In the figure, 1 is a steel pipe pile main body, and a plurality of excavating blades 4, 4 are provided at the lower end of the pile main body at intervals in the circumferential direction so as to project downward, and in the tip portion of the pile main body 1. On the circumference,
The internal spiral blade 2 is provided so as to extend over almost one turn. Then, outside the lower end of the pile main body 1, an external spiral blade 3a having a large wingspan is provided so as to project along the peripheral surface. The spiral blade 3a has an outer diameter that is 2 to 3 times the outer diameter of the pile body 1, and is continuously formed over almost one turn. Further, the pitch 1 of the outer spiral blade 3a is a small pitch of about 1/4 of the outer diameter of the spiral blade 3a. The pile body 1 has the spiral wing 3 over its entire length.
External spiral blades 3b, 3c ... Similar to a are provided at a predetermined equal distance above and below, respectively. The distance between the spiral blades 3a, 3b, ...
It is preferable to set the length to a multiple of.

In the illustrated embodiment, one pile body 1 is provided with four external spiral blades 3a to 3d, but the number of these spiral blades can be appropriately increased or decreased. When the burying depth of the steel pipe pile becomes long, another pile body 1 is connected to this steel pipe pile by welding or a screw type joint and used.

In burying the steel pipe pile of the present invention, as shown in FIG. 4, a rotary pushing drive device (not shown) is attached to the upper end of the pile body 1, and the pile body 1 is rotated into the ground by the drive. Push it in. As a result, the earth and sand a at the tip of the pile is softened by excavation by the action of the excavating blade 4 at the lower end and fluidized, and almost half of it flows into the inside of the pile body 1 from the lower end,
The spiral blades 2 provided inside the piles send them upward, and other excavated earth and sand flow out to the outside of the pile body 1 to consolidate the surrounding earth and sand.

Then, the external spiral blade 3a, which has a large wing width and has a short pitch, which projects from the outer peripheral surface of the pile main body 1, bites into the excavated earth and sand a and the ground b, rotationally propels the soil composition as a reaction force, and flows. The earth and sand a on the outside of the piled pile body 1 is pushed to the side surface of the pile, and the steel pipe pile is twisted into the ground while being compressed. In this case, the propulsion length per one rotation of the steel pipe pile is almost equal to the length of the pitch 1 of the outer spiral blade 3a. As the steel pipe piles are promoted and settled, the outer spiral blades 3b to 3d provided above also bite into the ground b one after another and are similarly rotated and propelled. In this case, those spiral wings 3
Since b to 3d are on the spiral axis mark c continuous with the spiral blade 3a at the lower end, the bite into the ground b is good, and the rotational propulsion is facilitated.

Therefore, in the steel pipe pile of the present invention, the outer spiral blades 3a-3
Since the piles will be settled by the rotation propulsion of d, the piles will be buried without soil discharge, and the ground around the piles will be compacted.

5 and 6 show another embodiment of the present invention.
The structure of the internal spiral blade 2 is different from that of the above-described embodiment. That is, similar to the internal spiral blade 2 in the above-described embodiment, two internal spiral blades 2a and 2b are provided on the inner peripheral surface of the lower end portion of the pile main body 1 so as to extend almost one turn. Then, as shown in FIGS. 6 (a) and 6 (b), the two inner spiral blades 2a, 2b are arranged so that their lower end positions are different from each other by about half a turn and are opposed to the circumferential surface. Spiral wings 2
a and 2b are provided so as to project in a shape intersecting in an x shape when viewed from the side. By providing such internal spiral blades 2a and 2b, both internal spiral blades 2
Since the lower ends of a and 2b bite simultaneously from the positions facing each other on the circumferential surface, the effect of transporting the inflowing sand and sand is greatly improved.

(Effect of the Invention) As described above, in the steel pipe pile of the present invention, the excavating blade is projected from the lower end of the steel pipe pile body, and the internal spiral blade extending over almost one turn is projected inside the tip of the pile. A configuration in which outer spiral blades having an outer diameter of 2 to 3 times the outer diameter of the steel pipe pile main body are provided on the outer peripheral surface over substantially the entire length thereof at equal distances in the vertical direction so as to protrude from the outer peripheral surface. Therefore, by excavating the earth and sand with an excavating blade, softening, fluidizing and biting the external spiral blade into the earth and sand and the ground, just by rotating the pile with a slight pressing force, it is possible to bury it without discharging soil, In particular, the excavated earth and sand flows into the pile body without clogging due to the internal spiral blades protruding from the inside of the tip of the pile body. Sediment flows out of the pile body to consolidate surrounding sediment Will be. Therefore, it is possible to easily and efficiently carry out construction on hard ground. Moreover, since the spiral blade has a simple structure in which a plurality of spiral blades are provided in several places at intervals, it can be manufactured at low cost. In addition, since the external spiral blades are wide and are provided in multiple numbers, not only a large supporting force corresponding to the total area of the inner and outer spiral blades can be obtained, but also the presence of the internal spiral blades makes it unlike the cement milk method. However, the pile tip blockage due to the injection of cement milk and the pile tip blockage effect similar to the pile with the bottom plate closed at the tip will be exhibited. A large bearing capacity for supporting the tip of the pile will be obtained. In this way, it exhibits an excellent effect on both the easiness of burying the pile and the bearing capacity, and can be widely applied from soft ground to hard ground.

Further, the two internal spiral blades protruding from the pile body have a better effect of conveying the sand and sand that have flowed into the pile body.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of the steel pipe pile of the present invention, FIG. 2 is an enlarged vertical sectional view of the lower part thereof, FIG. 3 is a bottom view of the same, FIG. 4 is an explanatory view of a buried state, and FIG. Is an enlarged vertical sectional view of an essential part showing another embodiment, and FIGS. 6 (a) and 6 (b) are perspective views showing two internal spiral blades of the same embodiment separately. 1 ... pile main body, 2, 2a, 2b ... internal spiral blade 3a-3d ... external spiral blade, 4 ... excavating blade

Claims (2)

[Scope of utility model registration request] 1. A steel pipe pile main body is provided with a digging blade at the lower end thereof, and an internal spiral blade extending almost one turn is provided inside the tip of the pile, and the outer peripheral surface of the pile main body is provided over substantially the entire length thereof.
A large number of outer spiral blades having an outer diameter of 2 to 3 times the outer diameter of the pile main body and having a pitch of approximately 1/4 of the outer diameter and extending over approximately one turn are used as pitch multiple lengths of the outer spiral blades. A multi-blade steel pipe pile, characterized in that it is projected at equal intervals. 2. A utility model registration claim according to claim 1, wherein two inner spiral blades extending substantially one turn inside the tip of the pile are projectingly provided with their lower end positions being different from each other by about half a turn.
Multi-blade steel pipe pile described in paragraph.