WO2018221781A1

WO2018221781A1 - Pile and construction method therefor

Info

Publication number: WO2018221781A1
Application number: PCT/KR2017/006844
Authority: WO
Inventors: 신주호
Original assignee: 한국전력공사
Priority date: 2017-05-31
Filing date: 2017-06-28
Publication date: 2018-12-06
Also published as: KR20180131042A

Abstract

The present invention relates to a pile, which comprises: an outer pipe provided in a bored hole formed in the ground; an inner pipe provided inside the outer pipe; a stiffener disposed in the inner pipe, and extending over the entire length of at least the inner pipe; and a grout injected and cured between the outer pipe and the inner pipe and between the inner pipe and the stiffener, thereby having improved resistance performance against a vertical force and a bending stress.

Description

Pile and construction method

The present invention relates to a pile such as a micropile and the like, as well as a vertical support force, and a horizontal resistance.

A micropile is a general term for piles having a diameter of 300 mm or less, and these micropiles are widely used for various applications such as construction of pile foundations of structures, seismic reinforcement of existing structures, ground reinforcement, slope stabilization, and the like. In particular, ground grouting can also be done in parallel, and because of the use of small equipment, there is an advantage in that it is easy to construct even in a narrow place or a limited area.

However, the micropile is relatively smaller in diameter than other piles and has excellent resistance to compressive and tensile loads acting in the vertical direction. However, the micropile has a very weak structural property due to its small horizontal shear surface.

Therefore, there is a situation in which it is required to add a horizontal resistance force to the micropile. This means that when using a micropile, a plurality of micropiles are used as one pile group. When the strength of the micropile, especially the vertical bearing force and the horizontal resistance force are improved, the required number of micropiles is increased. This is because the construction period can be shortened, construction costs can be reduced, and environmental load can be reduced.

For reference, the prior art related to the present invention is Korean Patent Publication No. 1332848.

Accordingly, the present invention has a main object to provide a pile and a construction method for improving the vertical bearing and horizontal resistance.

Pile according to the invention, the outer tube is installed in the drilling hole formed in the ground; An inner tube installed in the outer tube; A reinforcement disposed in the inner tube and extending over at least the entire length of the inner tube; And grout injected and cured between the outer tube and the inner tube and between the inner tube and the reinforcing material.

Pile construction method according to the invention, forming a hole in the ground; Installing an outer tube in the drilling hole; Installing an inner tube in the outer tube; Inserting a reinforcing material into the inner tube; And injecting and curing the grout into the inner tube so that the reinforcing material is embedded.

According to the present invention as described above, it is possible to sufficiently support the upper load with a large bearing capacity and to obtain a pile having improved resistance to horizontal force and bending stress.

As a result, the number of piles to be installed can be reduced, so that the construction period can be shortened, construction costs can be reduced, and environmental load can be achieved.

1 is a cross-sectional view of a pile according to the present invention.

FIG. 2 is an enlarged perspective view of a part of the pile illustrated in FIG. 1.

Figure 3 is a perspective view showing a construction state of the pile according to the present invention.

Figure 4 is a flow chart showing an example of the construction method of the pile according to the present invention.

Hereinafter, the present invention will be described in detail through exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

1 is a cross-sectional view of the pile according to the present invention, Figure 2 is an enlarged perspective view of a portion of the pile shown in FIG.

As shown in these figures, the pile 1 according to the present invention, the outer tube 10 is installed in the drilling hole 3 formed in the ground (2); An inner tube 20 installed in the outer tube; A reinforcing member 30 disposed in the inner tube and extending over at least the entire length of the inner tube; And grout 40 injected and cured between the outer tube and the inner tube and between the inner tube and the reinforcing material.

The drilling hole 3 of the ground 2 can be formed using various drilling machines (not shown), for example, a hydraulic drill. Such a hole may be formed stepped at a predetermined depth as shown in FIG. In this case, the outer tube 10 may be inserted into the enlarged drilled hole 3a and the inner tube 20 may be inserted into the drilled hole 3b which is relatively reduced.

The outer tube 10 and the inner tube 20 are hollow members having a predetermined length, but the outer tube is preferably shorter than the inner tube, but is not necessarily limited thereto. In order to inject the grout 40 between the outer tube and the inner tube, the inner tube is spaced apart from the inner surface of the outer tube.

In addition, a plurality of through holes 22 may be formed on the surface of the inner tube 20 so that the grout 40 injected by being pressed into the inner tube 20 may flow out toward the outer tube 10.

These through holes 22 may be formed in a row or a plurality of rows along the longitudinal direction of the inner tube 20, and may be randomly distributed two-dimensionally on the surface of the inner tube without forming them. You may form in a suitable position.

Since the through hole 22 performs a function of passing the uncured grout 40 and at the same time, it is a means for strengthening the bonding force between the cured grout 40 and the inner tube 20. The formation density of the through holes 22 on the surface of the inner tube can be determined by adjusting according to the required bonding force.

However, the plurality of through holes 22 may be formed only in a region corresponding to the outer tube 10 on the surface of the inner tube 20, and thus the grout 40 is formed through the inner tube and the outer tube through the through hole. It will be injected into the space between them.

The reinforcing material 30 is a solid member having a predetermined length and may be inserted into the inner tube 20. As such a reinforcing material, a steel having a circular cross section having a predetermined diameter is preferable, but the shape and material of the reinforcing material are not necessarily limited thereto.

In addition, although not shown, the reinforcing material 30 is, for example, a plurality of reinforcing material is joined together in a bundle or at least a portion by welding or the like and arranged radially in the inner tube 20 together, the pile 1 of the present invention You may make it distribute | distribute the stress added to evenly.

In addition, the reinforcing material 30 may be configured by aligning a plurality of reinforcing material in series along its longitudinal direction and connecting adjacent ends to each other. In this case, a coupler 32 may be interposed between adjacent ends of the plurality of stiffeners, which coupler may engage with each end, for example, in a threaded manner.

As such, by connecting the plurality of reinforcing materials 30 in the lengthwise direction by the coupler 32, the reinforcing material can be inserted in the inner tube 20 while supplementing the reinforcing material, and finally, as shown in FIG. 1. The reinforcement will be able to be located over the entire length of the drilled hole 3 from the top of the drilled hole to the lower end of the drilled hole in the ground 2. If necessary, the reinforcing material 30 may have a length that can protrude from the inner tube.

At least some outer circumferential surface of the reinforcement 30 or the inner tube 20 may be formed with a threaded portion or a plurality of projections extending radially. Thereby, the surface area which can contact the grout 40 in the outer peripheral surface of the reinforcement or the inner tube is increased, and the reinforcement or the inner tube and the grout can be integrally and firmly combined.

Cement milk or mortar may be used as the grout 40, but is not necessarily limited thereto. Any grout, such as a resin-based grout using epoxy, may be used.

The grout 40 is provided on one side of the inner tube 20 which is installed on the ground, that is, on the ground and is opened to the ground by any grout injector (not shown) including a tank, a pump, a mixer, and the like. Can be injected through. Since the grout injection apparatus is already well known, a detailed description thereof will be omitted herein.

The pile 1 of the present invention, as shown in Figure 1, including a grout 40 is injected into the drilled hole 3 formed in the ground (2), the lower portion of the pile can be connected to the ground have. A reinforcement 30 is embedded in the grout of the pile, which extends from the full length of the inner tube 20 to the full length of the pile in the longitudinal direction of the pile.

As shown in this, at the upper end of the pile 1 according to the present invention, for example, connecting plate 50 for connecting to the foundation structure 4, such as reinforced concrete may be installed. The connecting plate is welded to the upper end of the reinforcing material 30, or the reinforcing material 30 is screwed into the screw hole of the connecting plate, or the reinforcing material 30 passes through the through hole of the connecting plate, the fastening nut 52 to the reinforcing material Is fastened so that the connecting plate is fixed between the fastening nut and the outer tube or the inner tube, it can be connected integrally with the reinforcement.

Subsequently, an upper portion of the connecting plate 50 and the reinforcement 30 may be embedded by the foundation structure 4.

As for the pile 1 which concerns on this invention, the upper end part is surrounded by the outer side pipe | tube 10, and is reinforced by this outer side pipe | tube. The outer tube is preferably buried in the upper portion of the foundation structure 26 and the lower portion is buried in the ground.

This outer tube 10 can be manufactured to the required length. For example, the horizontal force applied to the pile using the result of investigating the ground condition based on the basic equation (Winkler model) that idealized the pile for the section in which the horizontal soil pressure occurs, assuming that the pile is supported on the elastic ground. Can be interpreted. The basic equation is shown in Equation 1 below.

Where E is the modulus of elasticity of the pile, I is the cross-sectional secondary moment of the pile, and EI represents the bending stiffness (kN · m 2) of the pile. X is the depth from the ground (cm), y is the horizontal displacement of the pile (cm), and P is the horizontal ground reaction force (kN / m 2).

Then, the depth from the ground involved in the horizontal resistance is calculated, which can be obtained by determining the characteristic value β of the pile. The characteristic value of the pile may be determined by Equation 2 below.

Here, β is the characteristic value of the pile (cm ^-1 ), K _h is the ground reaction coefficient (kN / ㎥) in the horizontal direction, D is the diameter of the pile (cm). Similarly, E is the elastic modulus of the pile, I is the cross-sectional secondary moment of the pile, and EI represents the bending stiffness (kN · m 2) of the pile.

Thus, the diameter of the outer tube 10 is determined according to the horizontal load to be applied to the pile, and the characteristic value β of the pile is obtained using the diameter, and then the inverse of the characteristic value, i.e., 1 / β, It is possible to calculate the preferred length.

In the pile 1 which concerns on this invention, the inner space of the inner side pipe | tube 20 is filled with the hardened grout 40, and the reinforcement 30 is embedded in this grout as mentioned above. In addition, the grout is injected toward the outer tube 10 through the plurality of through holes 22, so that the hardened grout is filled in the space between the inner tube and the outer tube.

Ultimately, the pile 1 according to the present invention is excellent by increasing the bending rigidity of the pile through the integration behavior of the reinforcing material 30 inserted into the ground 2 and the outer tube 10 to increase the horizontal resistance force It will have a horizontal resistance.

For example, as a result of the comparison test between a general micropile having a diameter of 165 mm and a micropile having an outer tube of 200 mm in diameter, the horizontal resistance of the micropile having an outer tube is approximately 1.6 times higher than that of the general micropile. I could see.

In addition, when the reinforcing material 30 protrudes from the inner tube 20 toward the ground 2, as shown in FIG. Cured grout may also be filled in the spaces between the side walls (ie, ground) of 3).

Accordingly, the pile 1 according to the present invention can not only exhibit the structural performance it has basically, but also the bearing force by filling the grout 40 in the ground to combine the reinforcing material 30 and the ground (2) integrally Will be able to improve.

As described above, the pile 1 according to the present invention, the grout 40 injected around the reinforcing material 30 is in close contact with the inner tube 20 and the ground 2 and hardened to have a large bearing capacity to fully load the upper load. It can support and at the same time provide resistance to lateral forces and bending stresses.

Further, in the pile 1 according to the present invention, grout is filled in the space between the inner tube 20 and the outer tube 10 through the plurality of through holes 22 formed in the inner tube 20. Therefore, it is possible to improve the stability against the horizontal displacement of the pile by enabling the rigid integration behavior of the reinforcing material 30 and the outer tube 10, increasing the bending rigidity, and by expanding the cross-sectional area of the upper portion.

Accordingly, according to the pile according to the present invention, it is possible to reduce the number of installation of the pile, it is possible to achieve the effect of shortening the construction period, reducing the construction cost and reducing the environmental load.

The construction method of the pile 1 according to the present invention comprises the steps of: forming a drilling hole (3) in the ground (2); Installing the outer tube 10 in the drilling hole 3; Installing the inner tube 20 in the outer tube; Inserting the stiffener 30 into the inner tube; And injecting and curing the grout 40 in the inner tube so that the reinforcing material is embedded.

First, the drilling hole 3 is formed while excavating the ground 2 using various drilling machines such as a hydraulic drill. The outer tube 10 may be installed in such a drilling hole, and then the inner tube 20 may be installed in the outer tube.

In particular, when the outer tube 10 whose length is shorter than the inner tube 20 is applied as shown in FIG. 1, the perforation hole 3 may be formed stepwise at a predetermined depth.

As described above, in the stepped boring hole 3, the outer tube 10 may be inserted into the low depth and enlarged boring hole 3a, and the inner side of the boring hole 3b deeper and relatively smaller from the ground. Tube 20 may be inserted and installed.

Alternatively, as shown in FIG. 4, the lower depth of the drilled hole 3a is first excavated, and then the outer tube 10 is installed in the enlarged drill hole, and then the shaft diameter is relatively smaller from the bottom of the enlarged drill hole. After the drilled hole 3b is excavated, the inner tube 20 may be installed in the reduced diameter hole.

In this way, the outer tube 10 installed on the upper portion of the pile 1 according to the present invention is to reinforce the upper portion of the pile surrounding the upper portion of the pile, the horizontal resistance of the pile is increased by such an outer tube It will be possible.

The length of the outer tube 10 may be determined from the characteristic value β of the pile as described above, wherein the characteristic value of the pile may be obtained by Equation 2 above, from which the length of the outer tube is the inverse of the characteristic value ( 1 / β).

When the installation of the inner tube 20 is completed in the drilling hole 3, the reinforcing material 30 is inserted into the inner tube. This reinforcement can be constructed by aligning a plurality of reinforcements in a straight line along its longitudinal direction and connecting adjacent ends to one another. In this case, a coupler 32 may be interposed between adjacent ends of the plurality of stiffeners.

As such, by connecting the plurality of reinforcing materials 30 in the lengthwise direction by the coupler 32, the reinforcing material can be inserted in the inner tube 20 while supplementing the reinforcing material, and finally, as shown in FIG. 1. The reinforcement may be located over the entire length of the drilled hole 3 from the top of the drilled hole to the lower end of the drilled hole in the ground 2.

Next, by injecting grout 40 through one side opening of the inner tube 20 open to the ground by a grout injection device installed on the ground, the inner space of the inner tube and between the inner tube and the outer tube 10. Fill grout in the space.

In particular, when the reinforcing material 30 protruding from the inner tube 20, as shown in Figure 1 is applied, the grout 40 is also filled in the space between the protruding reinforcing material and the side wall of the drilling hole (3).

At the same time as the grout 40 is injected, the grout passes through the through-hole 22 of the inner tube 20 and flows out toward the outer tube 10, and the spilled grout adheres to and hardens in and out of the inner tube. It will strengthen the bond between the hardened grout and the inner tube.

Thereafter, the injected grout 40 is waited to harden, and when the grout is hardened, the reinforcing material 30 is embedded therein, and the upper part has a cross-sectional area extended by the outer tube 10, In the part, the pile 1 of the present invention having a coupling portion of the reinforcement and the grout and the ground is completed.

Next, as shown in Figures 3 and 4, the connecting plate 50 is installed on the upper end of the pile (1) according to the present invention. It can thereby be connected to the foundation structure 4, for example reinforced concrete. Subsequently, backfilling of the earth and sand is performed around the outer tube 10 so that the lower portion of the outer tube is buried in the ground, while the entire connecting plate 50 and the upper portion of the outer tube and the reinforcement 30 are formed by the foundation structure. Build foundation vines to be buried. As a result, the pile connecting the structure and the ground is completed.

The pile 1 of the present invention constructed as described above, the reinforcing material 30 by the grout 40 injected into the inner tube 20 and the outer tube 10 while using the structural performance of the existing pile as it is ) And the inner tube and the outer tube enable a solid integration behavior, and by expanding the cross-sectional area of the upper portion it is possible to significantly increase the horizontal resistance.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

As described above, the present invention is useful for construction of pile foundations of structures, seismic reinforcement of existing structures, ground reinforcement, slope stabilization, and the like.

Claims

An outer tube installed in a drilling hole formed in the ground;

An inner tube installed in the outer tube;

A reinforcement disposed in the inner tube and extending over at least the entire length of the inner tube; And

Grout injected and cured between the outer tube and the inner tube and between the inner tube and the reinforcement

Piling including.
The method of claim 1,

The outer tube is a pile, characterized in that the length is shorter than the inner tube.
The method of claim 2,

The length of the outer tube is determined as the inverse of the characteristic value after determining the diameter of the outer tube and obtaining the characteristic value β of the pile using the diameter,

The characteristic value
A pile, which is obtained from the following equation.
The method of claim 1,

The inner tube is a pile, characterized in that spaced apart from the inner surface of the outer tube.
The method of claim 4, wherein

The surface of the inner tube is a pile, characterized in that a plurality of through-holes are formed so that the grout injected into the inner tube can flow toward the outer tube.
The method of claim 1,

The reinforcing member is a pile, characterized in that the solid member having a predetermined length.
The method of claim 6,

And a plurality of stiffeners are arranged in series along the longitudinal direction and adjacent ends of the stiffeners are connected to each other.
The method of claim 7, wherein

And a coupler interposed between adjacent ends of the plurality of stiffeners.
The method of claim 6,

The reinforcement protrudes from the inner tube toward the ground,

The grout is filled in the space between the reinforcing material protruding from the inner tube and the side wall of the drilling hole.
The method of claim 1,

At least a part of the outer circumferential surface of the reinforcing material or the inner tube pile is characterized in that a plurality of projections extending radially or radially.
The method of claim 1,

The upper end of the pile is provided with a connecting plate for connecting to the foundation structure,

The connecting plate is a pile, characterized in that connected to the reinforcement.
Forming a perforation hole in the ground;

Installing an outer tube in the drilling hole;

Installing an inner tube in the outer tube;

Inserting a reinforcing material into the inner tube; And

Injecting and curing the grout in the inner tube so that the reinforcement is embedded

Construction method of the pile comprising a.
The method of claim 12,

The drilling holes are pile construction method characterized in that the step is formed at a predetermined depth.
Forming a drilled hole in the ground;

Installing an outer tube in the enlarged drilling hole;

Forming a drilled hole relatively reduced in diameter from the bottom of the expanded drilled hole;

Installing an inner tube in the reduced diameter drilling hole;

Inserting a reinforcing material into the inner tube; And

Injecting and curing the grout in the inner tube so that the reinforcement is embedded

Construction method of the pile comprising a.
The method according to claim 12 or 14, wherein

When the hardening of the grout is completed, installing the connecting plate on the upper end of the pile, and further comprising the step of constructing the foundation yard so that the connecting plate can be embedded by the foundation structure.