KR101238124B1 - Rotary pile and construction method using the same - Google Patents

Abstract

PURPOSE: A rotary pile and a construction method for the same are provided to heighten skin friction force and horizontal resistance force and prevent buckling by increasing cross-sectional area and to improve the end bearing capacity by penetrating and consolidating urethane resin in the loosened ground of the front end. CONSTITUTION: A rotary file(10) comprises a plurality of steel pipes(12a,12b), at least one spiral wing(14), a removal casing(16), and a casing bottom plate(18). The steel pipes penetrate into the ground with a regular external diameter and are connected to each other in the longitudinal direction. The spiral wing is equipped on the outer circumferential surface of the lower steel pipes. The removal casing is connected to the upper side of the steel pipes. The removal casing rotates and penetrates along the steel pipes and is drawn with the injection of a grout material. The casing bottom plate is installed at the lower side of removable casing. The casing bottom closes the lower side of removable casing and delivers torque to the removable casing when the steel pipes rotates and penetrates.

Description

Rotary pile and construction method using the same

The present invention relates to a rotary pile and its construction method, and in particular, to increase the cross section of the pile, thereby improving friction and horizontal resistance, preventing buckling, and infiltrating and solidifying urethane into the loosening ground of the tip to improve tip support. Rotary files and how to build them.

Rotary piles are introduced into the ground through rotation to give tip support with friction and spiral wings. Rotary piles also have inherent strength, resisting horizontal shear forces. As such, the principal friction, tip bearing and horizontal shear resistance are important factors that the rotary pile must have to support the foundation concrete structure.

In order to increase the principal friction and horizontal shear resistance, the cross-sectional diameter of the steel pipe should be increased, but the rotary pile is made of steel pipe with a small diameter of less than 200mm ~ 300mm, so it is difficult to achieve more resistance strength. In addition, the rotary pile causes frictional expansion, which causes the hole to expand to the upper periphery during rotational penetration.

 In addition, the tip bearing capacity is dependent on the spiral wing, which causes the strata to loosen the strata during rotational penetration, resulting in excessive initial settlement upon load loading on the rotary pile. Therefore, if the settlement of the rotary pile exceeds the limit (for example, 1 inch), even if the bearing capacity of the steel pipe with high yield strength and high tensile strength is high, it cannot be used as a foundation pile.

In addition, the rotary pile has a small bearing capacity of about 50 to 60 tons, so that the load is increased when the load (or design load) is larger than 100 tons, for example, thereby increasing the additional construction cost.

Background art of the present invention is Korean Patent Registration No. 10-0686697, there is a support pile that serves both tension and compression. It is a pile embedded in the ground connected to a heavy-duty rotary output end, such as an earth drill or auger, a hollow pipe having a predetermined length, and forms an inclined sharp portion at its tip, and is connected to the rotary output end at its rear end. It is provided with a circular long main pipe having a connecting flange, wherein the outer circumferential surface of the main pipe is characterized in that it is provided with one or more swivel blades spirally rotated.

However, the background art has a disadvantage in that the size of the diameter cross section of the main pipe is limited so that the principal surface friction and the horizontal shear resistance cannot be increased. In addition, because the tip bearing capacity depends only on the rotor blades, there is a problem that settlement occurs under load due to the loose ground.

Korea Patent Registration No. 10-1011583 Korea Patent Registration No. 10-0566068

The present invention provides a rotary pile and its construction method to improve the end bearing capacity by increasing the cross section of the pile to increase friction and horizontal resistance and to prevent buckling, and to penetrate and solidify the urethane resin into the loose ground of the tip. There is a purpose.

Rotary file according to a preferred embodiment of the present invention,

A plurality of steel pipes having the same outer diameter and interconnected in the longitudinal direction according to the penetration depth and penetrated into the strata;

At least one spiral wing provided on at least an outer circumferential surface of the lower steel pipe;

Removed and removed after being inserted into the outer diameter of the upper steel pipe with an inner diameter larger than the outer diameter of the steel pipe to form a gap for filling the grout material between the steel pipe and the ground cavity wall around the pipe. Casing for; And

It is fixed to the steel pipe is characterized in that it comprises a casing bottom plate for closing the lower surface of the removal casing and at the same time to transmit the rotational force of the steel pipe to the removal casing.

In addition, the casing bottom plate is circular, its outer diameter is characterized in that it is configured to be the same or smaller than the outer diameter of the spiral blade.

In addition, between the casing bottom plate and the removal casing is characterized in that the coupling projection and the coupling groove is further provided with a male and female coupling with each other.

In addition, mutually adjacent steel pipes are characterized in that they have at least a pair of additional metal plates whose ends are overlapped on the outer circumferential surface close to the joint surface side, and are welded to the entire joint surface after the cross sections are butted together.

In addition, the connection part of mutually adjacent steel pipes,

Forming a cylindrical coupling formed by forcibly expanding or separately installing one end portion, forming a bolt insertion hole in the coupling, and simultaneously forming a screw hole in the steel pipe portion inserted into the coupling;

It is characterized in that the joint bolt is screwed to the screw hole after being inserted into the bolt insertion hole so that the joint bolt does not protrude to the inner diameter of the steel pipe located inside.

In addition, the urethane backflow prevention plate which is introduced into the interior of the steel pipe to form a urethane injection chamber and having a urethane inlet through the center;

A urethane injection pipe having an outer diameter smaller than the inner diameter of the steel pipe and connected to the urethane inlet of the urethane check valve by screw connection;

The urethane injected through the urethane injection pipe is characterized in that it further comprises one or more urethane discharge holes penetrated through the steel pipe to be discharged to the outside of the steel pipe.

In addition, the outer ring of the urethane backflow prevention plate is characterized in that the O-ring in close contact with the inner surface of the steel pipe is further installed.

According to a preferred embodiment of the present invention, a method of constructing a rotary pile may include: connecting a lower steel pipe to a rotation axis of a drilling equipment and rotating the pipe to a predetermined depth perpendicular to the ground floor to connect the upper steel pipe; Inserting the casing bottom plate into the upper side steel pipe and then joining by welding; Coupling the removal casing to the casing bottom plate using a coupling groove formed at a lower end of the removal casing and a coupling protrusion protruding from an upper surface of the casing bottom plate; Intruding the upper steel pipe together with the lower steel pipe to induce the removal casing into the strata; Filling the grout material around the upper steel pipe by injecting the grout material into the inside of the removal casing while drawing the removal casing upward; Inserting the tip of the urethane injection pipe into the urethane inlet of the urethane backflow prevention plate and inserting the steel pipe into the steel pipe after the steel pipe is rotated into the strata; And connecting the upper part of the urethane injection pipe with the urethane injector and forcibly injecting urethane to discharge the urethane discharge hole formed in the lower side steel pipe to penetrate and solidify the surrounding ground.

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According to the present invention, the grout material is filled into the main surface of the upper steel pipe, so that the cross section of the pile is increased, the main surface friction force and the horizontal resistance force are increased, and the thin equipment is reduced to prevent buckling. In addition, urethane resin penetrates and solidifies into the loosening ground around the tip of the lower steel pipe, thereby greatly improving the tip bearing capacity.

The following drawings, which are attached in this specification, illustrate the preferred embodiments of the present invention, and together with the detailed description thereof, serve to further understand the technical spirit of the present invention. It should not be construed as limited.
1 is an overall assembly state of the rotary pile according to the present invention.
2 is an exploded view of FIG. 1;
Figure 3 is an exploded view of the connection of the removal casing and casing bottom plate applied to the present invention.
4A to 4C are various connection state diagrams of adjacent steel pipes.
5 is a construction sequence diagram of a rotary file according to the present invention.
Figure 6 is a construction flowchart showing the filling process of the additional urethane resin according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the accompanying drawings, but the present invention is not limited thereto.

≪ Embodiment 1 >

The first embodiment according to the present invention extends the cross-sectional size of the pile to increase the principal friction and horizontal shear resistance, and provides a rotary pile (10) to prevent buckling by reducing fine equipment (ratio of the length to the cross section). do.

1 and 2, the rotary pile 10 includes a plurality of long steel pipes 12a and 12b having the same outer diameter and interconnected in the longitudinal direction along the penetration depth to penetrate into the strata. This embodiment is composed of two steel pipes (12a, 12b) but the number can be increased or decreased depending on the length and penetration depth of the individual steel pipe. The steel pipes 12a and 12b have a small diameter hollow cross section with an outer diameter of 200 mm to 300 mm or less.

At least one spiral wing 14 is provided on the outer circumferential surface of the lower side steel pipe 12a. The lower side steel pipe 12a may be configured to be closed with an inclined surface as in this embodiment as the tip is closed. The spiral wing 14 forms a spiral to help intrusion of the strata and exerts a tip bearing force after construction. In the present embodiment, three spiral blades 14 are installed at three locations at a predetermined interval from the lower side of the steel pipe 12a, but the present invention is not particularly limited to the number of installations thereof. In addition, of course, the spiral wing may be additionally installed on the upper side steel pipe (12b).

It is connected to the upper side steel pipe (12b) is a rotational penetration is made with the steel pipes (12a, 12b) is provided with a removal casing 16 which is drawn out when the grout material is injected. The removal casing 16 is inserted into the outer diameter portion of the upper steel pipe 12b with an inner diameter larger than that of the steel pipe 12a or 12b in the form of a long pipe. The removal casing 16 is rotated through the plurality of steel pipes 12a and 12b and then removed while being drawn for filling of grout material between the upper soil layer void wall and the steel pipe 12b. The grout material may be cement milk (cement + water) or cement mortar (cement + sand + water) or concrete (cement + sand + water + aggregate). The removal casing 16 has a suitable length such that the top of the removal casing 16 is rotated together with the steel pipe and protrudes a predetermined height from the ground surface. The removal casing 16 may be made of the same material as the steel pipe, for example, as a metal material.

The bottom surface of the removal casing 16 is provided with a casing bottom plate 18. The casing bottom plate 18 has a disc shape and closes the lower surface of the removal casing 16 and simultaneously transmits the rotational force to the removal casing 16 when the steel pipe 12b is rotated in the pipe. The casing bottom plate 18 is made of metal. The casing bottom plate 18 is directly joined to and fixed to the steel pipe 12b by welding. At this time, the outer diameter of the casing bottom plate 18 is configured to be the same or smaller than the outer diameter of the spiral blade (14).

The removal casing 16 is installed on the casing bottom plate 18 so as to be coupled and detached. That is, between the casing bottom plate 18 and the removal casing 16 is coupled and separated through the coupling protrusion 182 and the coupling groove 162 which are engaged and released with each other. Coupling protrusion 182 and the coupling groove 162 is composed of a pair each facing each other. In the present embodiment, the coupling groove 162 has a vertical long hole 162 along the longitudinal direction of the steel pipe and a horizontal long hole 162 communicating in a direction perpendicular to the vertical long hole 162a. Therefore, the coupling protrusion 182 is fitted to the vertical long hole 162a of the coupling groove 162 and then rotates the removal casing 16 in one direction to be coupled to the vertical long hole 162a. In this state, when the removal casing 16 is rotated in the reverse direction, the coupling protrusion 182 exits the horizontal hole 162, and then, when the removal casing 16 is removed, the coupling protrusion 182 is removed from the vertical hole 162a. The detachable casing 16 is separated from the casing bottom plate 18 by being detachable.

The construction method of the rotary file 10 configured as described above will be described with reference to FIG. 5.

First, the lower side steel pipe 12a is connected to the rotary shaft of the drilling equipment (for example, auger, earth drill, etc.) from the top, and then rotated vertically to the ground layer (Fig. 5 (a)).

Next, the upper steel pipe 12b is connected immediately before the lower steel pipe 12a is completely inserted. In this case, the upper steel pipe 12b and the lower steel pipe 12a are directly connected to each other by welding the surfaces in contact with each other or through a cylindrical coupling 122.

Then, the casing bottom plate 18 is inserted into the upper steel pipe 12b as shown in Figs. 1 and 5 (b) and then joined by welding. This process can be omitted if the casing bottom plate 18 is already installed in the upper steel pipe 12b.

Then, the removal casing 16 is coupled to the casing bottom plate 18 as shown in FIG. The coupling method is performed by inserting the coupling groove 162 formed on the lower side of the removal casing 16 into the coupling protrusion 182 of the casing bottom plate 18.

Then, as shown in FIG. 5 (C), the upper side steel pipe 12b is connected to the rotary shaft of the drilling equipment again, and then rotated vertically to the ground layer. Therefore, the removal casing 16 is guided by rotational penetration of the steel pipes 12a and 12b and introduced into the strata together. In this way, penetration of the rotary pile 10 is completed while leaving the head of the upper steel pipe 12b a predetermined section.

Then, as shown in FIG. 5 (d), the grout material 50 is drawn between the inside of the removal casing 16, that is, the upper steel pipe 12b and the removal casing 16 while drawing the removal casing 16 upward. ). The grout material may be cement milk, cement mortar or concrete already presented. The grout material is filled around the upper steel pipe 12b through the lower portion of the removal casing 16 being drawn out.

Therefore, as shown in Fig. 5 (e), the grout material is filled to a predetermined thickness around the upper side steel pipe 12b, and the cross section of the pile is increased. As a result, the main surface frictional force of the upper steel pipe 12b is increased to improve the bearing force in the axial direction, and the small equipment representing the ratio of the length to the cross section can be reduced to prevent buckling, and the horizontal shear resistance is improved by increasing the cross section.

The removal casing 16 is removed here is recycled during the construction of the rotary pile is an economical construction method.

≪ Embodiment 2 >

On the other hand, the second embodiment according to the present invention is a technique that can be additionally tightened with urethane resin to prevent tip settlement of the rotary pile 10 and at the same time increase the bearing capacity.

1 and 2 further comprises one or more urethane discharge holes 125 penetrated through the urethane backflow prevention plate 20, the urethane injection pipe 22 and the lower side steel pipe 12a.

The urethane backflow preventing plate 20 is introduced into the steel pipes 12a and 12b to form a urethane injection chamber in which the volume is changed, and has a urethane inlet 20a penetrated at the center thereof. The urethane backflow prevention plate 20 is in the form of a disc having a constant thickness, the diameter of which is equal to or smaller than the inner diameter of the steel pipe. At this time, it is preferable that an O-ring 24 made of rubber or silicon is installed to maintain airtightness between the urethane backflow prevention plate 20 and the steel pipe. The O-ring 24 is fitted into an annular groove 201 formed on the outer circumferential surface of the urethane backflow prevention plate 20.

The urethane injection pipe 22 is drawn into the steel pipe with an outer diameter smaller than that of the steel pipe 12a or 12b and is connected to the urethane inlet 20a of the urethane backflow prevention plate 20 by screwing. Urethane injection pipe 22 may be configured to be connected to each other in plurality or more depending on the depth of intake. In this case, the connection method may be welding, screwing, coupling, or the like.

The urethane discharge holes 125 are penetrated through the lower side steel pipe 12a so that urethane injected through the urethane injection pipe 22 is discharged to the outside of the steel pipe, and a plurality of urethane discharge holes 125 are formed at the same height and have a predetermined interval in the height direction. Can be formed.

On the other hand, it is preferable to have the following structure so that the urethane backflow prevention plate 20 can easily pass through the inside of the connecting portion of the steel pipe (12a and 12b).

In other words, mutually adjacent steel pipes 12a and 12b have at least one pair of additional metal plates 15 and 15 which are overlapped at both ends on the outer circumferential surface near the joining surface side thereof, and the cross sections are butted together, and can be welded all around the joint surface. have.

In addition, the steel pipes 12a and 12b constitute the expansion portion 12b-1 forcibly expanding the inner diameter of either portion as shown in FIGS. 4B and 4C or constitute a separate cylindrical coupling 122, and the expansion portion At the same time as the bolt insertion hole 122a is formed in the 12b-1 or the coupling 122, the screw hole 123 is formed in the portion of the steel pipe 12a into which the coupling 122 is inserted. And it is inserted into the bolt insertion hole (122a) by screwing the joint bolt 13 to the screw hole 123 is configured so that the joint bolt 13 does not protrude into the inner diameter of the steel pipe (12a) located inside.

The construction method using the rotary file 10 will be described.

First, as shown in the first embodiment, the steel pipes 12a and 12b are rotated into the strata, and then the urethane backflow preventing plate 20 and the urethane injection pipe 22 are connected to the steel pipes 12a and 12b as shown in FIG. Insert into. At this time, the urethane injection pipe 22 is screwed into the urethane backflow prevention plate 20 is drawn in the assembled state. When the urethane backflow prevention plate 20 reaches a predetermined depth, a urethane injection chamber is formed under the urethane backflow prevention plate 20.

Next, the upper part of the urethane injection pipe 22 is connected with a known urethane injector 100 and then urethane resin (cement milk or chemical liquid) is pressurized. The injected urethane resin is discharged through the urethane discharge hole 125 of the lower side steel pipe 12a and penetrates into the surrounding ground (Fig. 6 (b). At this time, the urethane resin is fine particles, so that fine pores in the layer having clay particles are present. Therefore, the strength is increased to the hard layer 200 where the ground around the pile tip is solidified by the spiral blades 14, thereby further increasing the tip bearing force.

In this way, the urethane resin injected through the urethane injection pipe 22 solidifies the ground layer around the tip of the rotary pile 10 and increases its strength to improve the bearing capacity. Therefore, even if the principal friction is reduced, the tip bearing capacity is increased, and thus the number of heads of steel pipes can be reduced, thereby reducing the construction cost.

In addition, it is possible to secure the construction stability of the loading structure by suppressing the initial settlement due to the ground loosening of the tip of the rotary pile, and economical construction is possible because the inherent high strength of the steel pipe is exhibited.

The second embodiment is constructed in parallel with the first embodiment, but may be constructed independently.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the above teachings. will be. The invention is not limited by these variations and modifications, but is limited only by the claims appended hereto.

12a, 12b: steel pipe
125: urethane discharge hole
13: joint bolt
14: spiral wing
16: removal casing
162: coupling groove
18: Casing Bottom Plate
182: engaging projection
122: coupling
122a: bolt insertion hole
123: screwdriver
20: urethane check valve
22: urethane injection pipe

Claims (9)

A plurality of steel pipes 12a and 12b having the same outer diameter and interconnected in the longitudinal direction according to the penetration depth to penetrate into the strata;
At least one spiral wing 14 provided on at least an outer circumferential surface of the lower side steel pipe 12a;
Inserted into the outer diameter of the upper steel pipe 12b with an inner diameter larger than the outer diameter of the steel pipe 12a or 12b to form a gap for filling grout material between the upper steel pipe 12b and the ground void wall around the upper steel pipe 12b. A removal casing 16 inserted into the plurality of steel pipes 12a and 12b and then drawn out;
A casing bottom plate 18 fixed to the upper steel pipe 12b to close the lower surface of the removal casing 16 and to transmit the rotational force of the upper steel pipe 12b to the removal casing 16;
A urethane backflow prevention plate 20 having a urethane inlet 20a penetrated into the center of the steel pipes 12a and 12b to form a urethane injection chamber;
A urethane injection pipe 22 having an outer diameter smaller than the inner diameter of the steel pipes 12a and 12b and screwed into the urethane inlet 20a of the urethane backflow prevention plate 20 by screwing; And
Rotary pile, characterized in that the urethane injected through the urethane injection pipe 22 includes at least one urethane discharge hole 125 penetrated through the lower steel pipe 12a so as to be discharged to the outside of the lower steel pipe 12a. . The method of claim 1,
The casing bottom plate (18) is circular, its outer diameter is characterized in that the rotary file is configured to be smaller than or equal to the outer diameter of the spiral wing (14). The method of claim 1,
Rotary casing, characterized in that between the casing bottom plate 18 and the removal casing 16 is further provided with a coupling projection 182 and the coupling groove 162 is coupled to and released from each other by a male and female. The method of claim 1,
The mutually adjacent steel pipes 12a and 12b have at least one pair of additional metal plates 15 and 15 having both ends overlapped on the outer circumferential surface close to the joining surface side thereof, and after the cross sections are butted together, the joints are welded all around the joint surface. Rotary files. The method of claim 1,
In the connection part of mutually adjacent steel pipes 12a and 12b,
A cylindrical coupling 122 formed by forcibly expanding or separately installing one end portion is formed, and the bolt insertion hole 122a is formed in the coupling 122 and inserted into the coupling 122 at the same time. Forming a screw hole 123 in the steel pipe portion;
After being inserted into the bolt insertion hole 122a by screwing the joint bolt 13 to the screw hole 123 is configured so that the joint bolt 13 does not protrude to the inner diameter of the steel pipe 12a located inside. Featuring Rotary Files. delete The method of claim 1,
Rotary file, characterized in that the O-ring (24) in close contact with the inner surface of the steel pipe is further installed on the outer peripheral surface of the urethane backflow prevention plate (20). Connecting the lower steel pipe (12a) to the rotary shaft of the drilling equipment, and then vertically penetrating the ground layer to a predetermined depth, and then connecting the upper steel pipe (12b);
Inserting the casing bottom plate 18 into the upper steel pipe 12b and joining by welding;
The removal casing 16 is coupled to the casing bottom plate 18 by using the coupling groove 162 formed at the bottom of the removal casing 16 and the coupling protrusion 182 protruding from the upper surface of the casing bottom plate 18. Making a step;
Rotationally injecting the upper steel pipe 12b together with the lower steel pipe 12a to induce the removal casing 16 to penetrate into the strata;
Filling the grout material around the upper side steel pipe 12b by injecting grout material into the removal casing 16 while drawing the removal casing 16 upward;
After the steel pipes (12a, 12b) is rotated through the strata, the front end of the urethane injection pipe 22 is coupled to the urethane inlet (20a) of the urethane backflow prevention plate 20 and inserted into the steel pipe (12a, 12b); And
The upper part of the urethane injection pipe 22 is connected to the urethane injector 100 and then urethane is forcibly injected into the urethane discharge hole 125 formed on the lower steel pipe 12b to penetrate and solidify the surrounding ground. Construction method of a rotary file, characterized in that the construction including the step; delete

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