KR102288209B1 - Complex helical pile and construction method thereof, complex pile constructed thereby - Google Patents

Abstract

The present invention relates to a composite helical pile, which has a first cutting blade on the upper circumferential surface of a pile shaft having a plurality of helices on the lower outer circumferential surface to maintain a load bearing capacity in a helix section and to maximize a main surface fractional force by filling a main cutting hole with a grout material in an upper helix section, and to a construction method thereof, and a composite pile constructed thereby. The composite helical pile includes: a hollow pile shaft; helices helically coupled to the lower outer circumferential surface of the pile shaft and provided to be vertically spaced apart from each other to penetrate the ground in a non-earthing manner; a plurality of first cutting blades provided on the outer circumferential surface of the pile shaft of an upper portion of the uppermost helix at equal angles in plain view at different heights to form a main cutting hole in the ground outside the pile shaft at upper portions of the helices; an injection hole formed in the pile shaft at an upper portion of the first cutting blades; a hollow extension shaft coupled to an upper portion of the pile shaft; a second cutting blade provided on the outer circumferential surface of the extension shaft to hold the main cutting hole; and a third cutting blade provided on the outer circumferential surface of the pile shaft between the vertically neighboring helices, and forming a sub-cutting hole having a smaller diameter than that of the main cutting hole around the pile shaft.

Description

Complex helical pile and construction method thereof, and composite pile constructed thereby

In the present invention, since the first cutting blade is provided on the upper outer circumferential surface of the pile shaft having a plurality of helixes on the lower outer circumferential surface, the grout material is filled in the main cutting hole in the helix upper section while maintaining the load-bearing capacity in the helix section. A composite helical pile that can maximize

A helical pile is a steel pipe pile in which a plurality of spiral helixes are vertically spaced apart from the outer circumferential surface of a pile shaft, which is a small-diameter steel pipe with a diameter of about 50 to 120 mm.

Such a helical pile penetrates to the support layer in the ground by rotation, and a helix, which has a larger diameter than the pile shaft, is attached to the outer circumferential surface, so it can exhibit a higher bearing capacity than a steel pipe pile of the same standard.

In addition, unlike the driving method or the method of burying piles after pre-excavation of the drilling hole, it is constructed with non-embedded soil by rotational penetration, so there is less ground disturbance, less noise and vibration, and fast construction speed. Its use is increasing for facility support structures and the like.

When the distance between the upper and lower helixes exceeds three times the diameter of the helix, the helical file exerts its bearing capacity by independent helix bearing capacity by acupressure of the expanded area of the helix (FIG. 1 (a)) ).

In addition, when the distance between the upper and lower helixes is 3 times or less of the helix diameter, the ground between the upper and lower helixes is constrained and the bearing force is exerted by the frictional force on the main surface of the cylindrical support formed by the ground between the helix under the condition that it is integrally fixed with the pile. (cylindrical shearing resistance, (b) of FIG. 1).

However, when rotating the pile, the pile shaft at the top of the helix is designed without considering the frictional force of the circumferential surface of the pile shaft itself due to the influence of ground disturbance around the pile shaft.

In addition, since the conventional helical pile is constructed by non-ground rotation penetration, there is no space outside the pile shaft, and since the inside of the pile shaft is grouted after the penetration of the helical pile is completed, frictional force between the pile shaft and the surrounding ground cannot be expected.

US 20-0490633 B1

In order to solve the above problems, the present invention is to provide a composite helical pile capable of maximizing the circumferential friction force of the helix upper section while maintaining the load bearing capacity in the helix section, a construction method thereof, and a composite pile constructed thereby.

The present invention according to a preferred embodiment is a hollow pile shaft; Helixes spirally coupled to the lower outer circumferential surface of the pile shaft and provided to be vertically spaced apart from each other to penetrate the ground; A plurality of pieces are provided on the outer peripheral surface of the pile shaft of the upper helix at different heights at equal angles in plan view, and are provided so that a part of the vertical height overlaps with each other. a first cutting blade forming a main cutting hole; an injection hole formed in the pile shaft above the first cutting blade; a hollow extension shaft coupled to an upper portion of the pile shaft; a second cutting blade provided on the outer circumferential surface of the extension shaft, the protrusion width being smaller than the helix radius, and maintaining the main cutting hole; and a sub-cutting hole provided on the outer circumferential surface of the pile shaft between the helix adjacent up and down, the protruding width being smaller than the protruding width of the first and second cutting blades, and having a smaller diameter than the main cutting hole in the periphery of the pile shaft a third cutting blade forming a; It provides a composite helical file, characterized in that consisting of.

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The present invention according to another preferred embodiment relates to a construction method of the composite helical pile, comprising the steps of: (a) rotating and penetrating the composite helical pile up to the upper height of the helix so that the helix is descended without soil in the ground; and (b) main cutting the grout material through the injection hole while rotating and penetrating the composite helical file so that the helix continues to descend into the ground, and the first cutting blade cuts the ground above the helix to form a main cutting hole injecting into the hole; It provides a construction method of a composite helical pile, characterized in that consisting of.

In the present invention according to another preferred embodiment, a third cutting blade is provided on the outer circumferential surface of the pile shaft between the helixes adjacent up and down, and in step (a), the third cutting blade is a sub-cutting hole on the outside of the pile shaft between the helix. The composite helical pile is penetrated into the ground to form

The present invention according to another preferred embodiment provides a composite pile constructed by the construction method of the composite helical pile.

According to the present invention, it is possible to provide a composite helical pile having a first cutting blade on an upper outer circumferential surface of a pile shaft having a plurality of helixes spaced up and down on the lower outer circumferential surface, a construction method thereof, and a composite pile constructed thereby.

Accordingly, when the pile rotation penetrates, the first cutting blade cuts the helix upper ground and fills the grout material in the main cutting hole formed between the pile shaft and the pile shaft. By securing additional frictional force, the pile bearing capacity can be maximized.

1 is a view showing an installation state of a conventional helical pile.
Figure 2 is a perspective view showing a composite helical pile of the present invention.
Figure 3 is a view showing the installation state of the composite helical pile shown in Figure 2;
4 to 7 are plan sectional views showing various embodiments of the first cutting blade.
Figure 8 is a front view of the composite helical pile showing the position of the first cutting blade according to an embodiment.
9 is a perspective view showing an embodiment provided with a second cutting blade.
10 is a view showing an installation state of the composite helical pile shown in FIG.
11 is a perspective view showing an embodiment provided with a third cutting blade.
Fig. 12 is a view showing an installation state of the composite helical pile shown in Fig. 11;

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings and preferred embodiments.

Figure 2 is a perspective view showing a composite helical pile of the present invention, Figure 3 is a view showing an installation state of the composite helical pile shown in FIG. And Figures 4 to 7 are plan sectional views showing various embodiments of the first cutting blade.

2, 3, and the like, the present invention composite helical pile is a hollow pile shaft 21; Helix 22, which is spirally coupled to the lower outer circumferential surface of the pile shaft 21, and is provided with a plurality of vertically spaced apart helices 22 that penetrate into the ground; and a first cutting blade 23 provided on the outer peripheral surface of the pile shaft 21 on the uppermost helix 22; It is characterized in that it is composed of

An object of the present invention is to provide a composite helical pile capable of maximizing the circumferential friction force of the helix 22 upper section while maintaining the load bearing capacity in the helix 22 section, a construction method thereof, and a composite pile constructed thereby.

The present invention composite helical pile is configured to include a pile shaft 21 , a helix 22 and a first cutting blade 23 .

The pile shaft 21 has a hollow formed therein, and a high-strength steel pipe or the like can be used.

The helix 22 is spirally coupled to the lower outer circumferential surface of the pile shaft 21 and can be attached by welding.

A plurality of helix 22 are each independently provided to be vertically spaced apart from each other.

The helix 22 may preferably be provided in 2 to 5 pieces.

It is possible to resist a compressive or tensile load by acupressure on the lower or upper surface of the helix 22 .

The helix 22 may be formed as a closed ring on a planar projected area so that the outer circumferential surface of the pile shaft 21 rotates 360° or more to evenly support the ground load on the entire surface of the helix 22. .

The first cutting blade 23 is provided on the outer peripheral surface of the pile shaft 21 above the uppermost helix 22 .

The first cutting blade 23 is formed to have a protruding width smaller than the radius of the helix 22 to cut the pile shaft 21 external ground 1 above the helix 22 when the composite helical pile 2 rotates. To form a main cutting hole 11 in the ground (1). That is, the first cutting blade 23 forms a certain space between the pile shaft 21 and the ground (1).

Accordingly, the space between the main cutting hole 11 and the pile shaft 21 is filled with the grout material (G), so that frictional force on the main surface can be secured even in the upper part of the helix 22 section.

Since the first cutting blade 23 is located above the helix 22 section, in the helix 22 section, the helix 22 rotatably penetrates into the ground 1 without ground disturbance, so that the lowering of the tip support force of the helix 22 is reduced. Although there is no helix 22, it is possible to maximize the pile support by additionally securing the circumferential friction force in the upper part of the section.

In addition, since the lower helix 22 section is penetrated without ground disturbance, it is possible to exert bearing power immediately after construction, regardless of whether the upper grout material (G) is hardened. Therefore, it is possible to start the construction of the upper structure early, thereby obtaining the effect of shortening the construction period.

4 to 7, the first cutting blade 23 can be configured in various ways.

The first cutting blade 23 may have a rectangular plate shape as shown in FIG. 4 .

Alternatively, as shown in FIG. 5, the cutting edge 231 is protruded from the cutting surface, or the cutting edge 231 is attached to the end of the first cutting blade 23 as shown in FIG. 6 to increase cutting efficiency. You may.

In addition, as shown in Figure 7, the first cutting blade 23, the second cutting blade 25, or the third cutting blade 26 is formed to be inclined from the pile shaft 21 to reduce the penetration resistance when rotating. It is also possible

As shown in FIG. 2 , an injection hole 211 may be formed in the pile shaft 21 above the first cutting blade 23 .

As described above, after forming the main cutting hole 11 in the ground 1 by the first cutting blade 23, the grout material (G) in the main cutting hole 11 at the top of the ground 1 can be injected.

However, in some cases, if the grout material (G) is not properly injected into the main cutting hole 11 due to the collapse of the hollow wall, it may be difficult to secure the frictional force on the main surface.

Therefore, the present invention composite helical pile (2) is rotated and penetrated so that the first cutting blade (23) cuts the ground (1) while simultaneously injecting the grout material (G) into the first cutting blade (23) directly above the An injection hole 211 may be formed.

For smooth injection of the grout material (G), 2 to 4 injection holes 211 may be disposed on the outer peripheral surface of the pile shaft 21 at an even angle.

8 is a front view of a composite helical pile showing the position of the first cutting blade according to an embodiment.

As shown in FIG. 8 , a plurality of the first cutting blades 23 are provided with different heights at equal angles on a plane, and the adjacent first cutting blades 23 may partially overlap each other in vertical height. .

The first cutting blade 23 is formed to protrude in a direction orthogonal to the pile shaft 21 , and penetration resistance by the ground 1 may occur when the pile rotation penetrates.

Therefore, it is preferable to arrange a plurality of first cutting blades 23 at an even angle on the outer peripheral surface of the pile shaft 21 so as to prevent eccentricity due to penetration resistance during rotation and to quickly cut the ground. In particular, the first cutting blade 23 may be symmetrically arranged to prevent eccentricity during rotational penetration.

In addition, the first cutting blade 23 cuts the surrounding ground 1 while rotating downward. Therefore, the adjacent first cutting blade 23 can be configured so that a part of the vertical height overlaps each other so that the ground can be continuously cut.

In this case, more efficient ground cutting is possible during rotational penetration.

9 is a perspective view showing an embodiment provided with a second cutting blade, and FIG. 10 is a view showing an installation state of the composite helical pile shown in FIG.

9 and 10 , the hollow extension shaft 24 is coupled to the upper portion of the pile shaft 21 , and the protrusion width is greater than the radius of the helix 22 on the outer peripheral surface of the extension shaft 24 . A second cutting blade 25 which is formed small and holds the main cutting hole 11 may be provided.

When the length of the pile is long, the extension shaft 24 may be connected to the upper part of the pile shaft 21 by a joint 27 .

When the upper ground is good, the hole wall of the main cutting hole 11 is stably maintained even if the first cutting blade 23 moves downward in a state in which the main cutting hole 11 is cut by the first cutting blade 23 do. However, in the case of soft ground, if the composite helical file 2 penetrates into the lower part in a state in which the main cutting hole 11 is cut by the first cutting blade 23, the hole wall of the pre-cut main cutting hole 11 is It may collapse and the injection of the grout material (G) may not be smooth.

Therefore, the second cutting blade 25 may be formed on the outer circumferential surface of the extension shaft 24 so that the grout material G can be easily injected into the space pre-cut by the first cutting blade 23 .

A plurality of second cutting blades 25 may be provided on the outer peripheral surface of the extension shaft 24 . At this time, since the second cutting blade 25 maintains the pre-cut main cutting hole 11 to facilitate the injection of the grout material G, it is okay to increase the vertical interval than the first cutting blade 23 . do.

11 is a perspective view showing an embodiment provided with a third cutting blade, and FIG. 12 is a view showing an installation state of the composite helical pile shown in FIG.

11 and 12, on the outer peripheral surface of the pile shaft 21 between the helix 22 adjacent up and down, the protrusion width of the first cutting blade 23 and the protrusion width of the second cutting blade 25 is A third cutting blade 26 formed smaller to form a sub-cutting hole 12 having a smaller diameter than the main cutting hole 11 may be provided around the pile shaft 21 .

When the distance between the helix 22 is large, the supporting force is exerted by the supporting force at the tip of each helix 22 , but the pile shaft 21 between the helix 22 does not exert the circumferential friction force.

Therefore, the third cutting blade 26 may be provided between the upper and lower helix 22 to exert additional frictional force on the main surface even in this part. The third cutting blade 26 forms a sub-cutting hole 12 around the pile shaft 21 to form a space between the pile shaft 21 and the ground 1 between the helix 22 .

The space between the sub-cutting hole 12 and the pile shaft 21 may be filled with a grout material G to secure additional frictional force on the main surface. In this case, it can be used as a file for high load.

It is preferable that the protrusion width of the third cutting blade 26 is smaller than the protrusion width of the first cutting blade 23 and the second cutting blade 25 so as to minimize the ground disturbance in the helix 22 section. .

Accordingly, the diameter of the sub-cutting hole 12 is smaller than the diameter of the main cutting hole 11 .

A tip injection hole 212 may be formed at the tip of the pile shaft 21 to inject the grout material G into the sub-cutting hole 12 .

The method of constructing a composite helical pile of the present invention relates to a method of constructing the composite helical pile of the present invention described above.

In the method of constructing a composite helical pile of the present invention, first, (a) the composite helical pile 2 is rotated and penetrated to the upper height of the helix 22 so that the helix 22 is descended without soil in the ground.

In step (a), the composite helical pile 2 is rotated and penetrated up to the support layer using penetration equipment such as a pile driver or backhoe.

At this time, the end blade of the helix 22 cuts the ground 1 according to the rotation of the pile, and the pile is penetrated without soil.

After that, (b) the helix 22 continues to descend in the ground, and the first cutting blade 23 cuts the ground 1 above the helix 22 to form the main cutting hole 11. The grout material (G) is injected into the main cutting hole (11) through the injection hole (211) while rotating the composite helical pile (2).

That is, the composite helical pile (2) is further rotated press-fit so that the first cutting blade (23) cuts the ground (1). Even in this case, the lower helix 22 is rotated and penetrated into the ground 1 with unbaked soil and unfertilized eggs.

The grout material (G) is injected into the main cutting hole (11) together with cutting the ground (1) of the first cutting blade (23).

Here, when the extension shaft 24 provided with the second cutting blade 25 is coupled to the upper portion of the pile shaft 21 , the pile shaft 21 protrudes to the upper portion of the ground 1 by a certain length, and the joint The extension shaft 24 is connected with (27), and the penetrating equipment is connected to the upper part of the extension shaft 24 to rotate and penetrate. Then, the grout material G can be smoothly filled in the main cutting hole 11 while the main cutting hole 11 is maintained by the second cutting blade 25 .

After completing the file penetration through the steps (a) and (b), the pile tofu is arranged and finished.

On the other hand, a third cutting blade 26 is provided on the outer circumferential surface of the pile shaft 21 between the helix 22 adjacent up and down, and in step (a), the third cutting blade 26 is positioned between the helix 22. The compound helical pile 2 is penetrated into the ground 1 to form a sub-cutting hole 12 outside the pile shaft 21 of ) can be configured to be injected into

When the third cutting blade 26 is provided, the pile in which the third cutting blade 26 is formed between the helix 22 in step (a) penetrates into the ground 1 . And when the grout material (G) is injected into the main cutting hole 11 in step (b), the grout material (G) is also injected into the sub-cutting hole (12).

[Table 1] below compares the bearing capacity and settlement amount of each type of helical pile.

HP is a conventional helical pile, AHP is an embodiment in which a main cutting hole is formed in the shaft section according to the present invention and grout material is filled, AHP-R is an embodiment in which a main cutting hole is formed in the shaft section according to the present invention, and a sub-cutting hole is formed in the helix section according to the present invention. This is an embodiment in which a cutting hole is formed and each grout material is filled.

The structure calculation of each pile was calculated based on API5CGT P110, Φ114.3×7.5t, 3 helix (top Φ300mm, middle Φ2700mm, bottom Φ240mm), and the pile length was 21m.

As a result of the structural calculation, AHP and AHP-R increased by 103% and 116%, respectively, compared to the conventional helical pile, and the compressive bearing capacity increased by 109% and 115%, respectively, due to the improvement of the frictional force on the circumferential surface by external expansion grouting.

In addition, the amount of settlement decreased by 10% due to the increase of the steel wire by external grouting, and the horizontal bearing capacity was increased to 238%.

file type material load
(kN) compression bearing capacity
(kN) settlement amount
(mm) horizontal bearing capacity
(kN) calculated value ratio calculated value ratio calculated value ratio calculated value ratio HP 767.7 100% 648.7 100% 27.2 100% 27.4 100% AHP 789.8 103% 708.3 109% 24.4 90% 65.1 238% AHP-R 892.4 116% 742.8 115% 24.4 90% 65.1 238%

The present invention includes a composite pile constructed by the construction method of the composite helical pile.

The composite pile is a composite pile composed of a helical pile in which the tip support force is exerted by the helix 22 at the lower part, and a steel pipe pile in which the upper surface friction force is exerted on the outer surface of the pile shaft 21 .

1: ground
11: Main cutting hole
12: sub-cutting hole
2: Composite Helical Pile
21: pile shaft
211: injection hole
212: tip injection hole
22: Helix
23: first cutting blade
231: cutting edge
24: extension shaft
25: second cutting blade
26: third cutting blade
27: joint
G: grout material

Claims (8)

hollow pile shaft 21; Helix 22 which is spirally coupled to the lower outer circumferential surface of the pile shaft 21 and is provided with a plurality of vertically spaced apart helices 22 that penetrate into the ground; a first cutting blade 23 for forming a main cutting hole 11 in the ground 1 outside the pile shaft 21 on the helix 22; an injection hole 211 formed in the pile shaft 21 above the first cutting blade 23; a hollow extension shaft 24 coupled to an upper portion of the pile shaft 21; a second cutting blade 25 provided on the outer circumferential surface of the extension shaft 24 and having a protrusion width smaller than the radius of the helix 22 to maintain the main cutting hole 11; And a third cutting blade 26 provided on the outer peripheral surface of the pile shaft 21 between the up and down helix 22; In the composite helical file consisting of,
The first cutting blade 23 is formed to have a protruding width smaller than the radius of the helix 22, so that a plurality of the first cutting blades 23 are provided at different heights at equal angles in plan view on the outer peripheral surface of the pile shaft 21 on the uppermost helix 22. , a portion of the vertical height is provided to overlap each other,
The third cutting blade 26 has a protrusion width smaller than the protrusion width of the first cutting blade 23 and the second cutting blade 25 , so that the main cutting hole 11 is formed around the pile shaft 21 . Forming a sub-cutting hole 12 having a smaller diameter,
The first cutting blade 23, the second cutting blade 25, or the third cutting blade 26 has a cutting edge 231 protruding from the cutting surface or the cutting edge ( 231), and the first cutting blade 23, the second cutting blade 25, or the third cutting blade 26 is formed to be inclined from the pile shaft 21. Composite Helical Pile.
delete delete delete delete It relates to the construction method of the composite helical pile according to claim 1,
(a) rotationally penetrating the composite helical pile (2) up to the upper height of the helix (22) so that the helix (22) descends into the ground; and (b) the helix 22 continues to descend in the ground, and the first cutting blade 23 cuts the ground 1 above the helix 22 to form the main cutting hole 11. injecting the grout material (G) into the main cutting hole 11 through the injection hole 211 while rotating the helical pile 2; and a third cutting blade 26 is provided on the outer circumferential surface of the pile shaft 21 between the helix 22 adjacent up and down, and the third cutting blade 26 is the helix 22 in step (a). ), the composite helical pile 2 is penetrated into the ground 1 to form a sub-cutting hole 12 on the outside of the pile shaft 21 between In the construction method of the composite helical pile injected into (12),
The first cutting blade 23 is formed to have a protruding width smaller than the radius of the helix 22, so that a plurality of the first cutting blades 23 are provided at different heights at equal angles in plan view on the outer peripheral surface of the pile shaft 21 on the uppermost helix 22. , a portion of the vertical height is provided to overlap each other,
The third cutting blade 26 has a protrusion width smaller than the protrusion width of the first cutting blade 23 and the second cutting blade 25 , so that the main cutting hole 11 is formed around the pile shaft 21 . Forming a sub-cutting hole 12 having a smaller diameter,
The first cutting blade 23, the second cutting blade 25, or the third cutting blade 26 has a cutting edge 231 protruding from the cutting surface or the cutting edge ( 231), and the first cutting blade 23, the second cutting blade 25, or the third cutting blade 26 is formed to be inclined from the pile shaft 21. Construction method of composite helical pile.
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