KR102643931B1 - Pile construction method - Google Patents

Abstract

The pile construction method of the present invention includes the steps of introducing a pile with a circular cross-section into the ground around a nuclear power plant or where radioactive waste is buried; Discharging soil from the ground within the pile; examining a first area and a second area having weak ground compared to the first area by examining the ground material; drilling the pile located in the second area; and injecting grout liquid into the pile.

Description

Pile construction method

The present invention relates to a pile construction method.

A pile foundation is a type of structural foundation used when a shallow foundation is not appropriate because hard ground, such as rock, is located deep beneath relatively soft ground. The bearing capacity of a pile can be mainly exerted by the tip bearing force and the peripheral friction force.

The tip bearing capacity is the bearing force that appears when the bottom surface of the pile is supported on solid ground, and the peripheral friction force is the bearing force caused by the friction between the sides of the pile and the surrounding ground. In particular, to improve friction between the main surfaces, grouting techniques are often used when constructing pile foundations.

Pile is a type of pile that is installed by drawing in a steel pipe using hydraulic pressure or driving it with a hammer. It is widely used because it has excellent mechanical performance and shows uniform rigidity regardless of direction.

The grouting liquid used in the grouting technique for pile installation is injected into the ground through the bottom surface (tip) of the steel pipe. However, for the purpose of pile installation, the bottom of the pile is generally located in solid ground. For this reason, the grouting liquid must pass through relatively low permeability ground, making it difficult to spread far. In addition, the soft zone that actually needs reinforcement is often located at a shallower depth than this. Therefore, there is a need for technology that allows grouting liquid to be injected to a desired depth and direction.

The problem to be solved by the present invention is to provide a pile construction method that can safely perform pile construction even if an elevated area with relatively soft ground is thickly distributed to avoid the tsunami threat when constructing a new safety-related structure.

The problems of the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

A pile construction method according to an aspect of the present invention for achieving the above problem includes the steps of inserting a pile with a circular cross-section into the ground around a nuclear power plant or where radioactive waste is buried; Discharging soil from the ground within the pile; examining a first area and a second area having weak ground compared to the first area by examining the ground material; drilling the pile located in the second area; and injecting grout liquid into the pile.

After the step of drilling the pile, the step of inserting a partition into the upper part of the second area or expanding the volume of the partition so that the grout liquid is injected into the periphery of the second area may be further included.

The step of investigating the ground may be conducted using at least one of drilling survey or physical exploration.

In the step of investigating the ground, the section and range that require ground reinforcement or improvement of friction on the main surface of the pile may be investigated.

In the step of investigating the ground, ground materials recovered during the pile construction process may be investigated.

In the step of drilling the pile, the pile is drilled to form a plurality of drilling holes, and the plurality of drilling holes may be arranged to be offset from the most adjacent neighboring drilling holes in the vertical direction.

In the step of drilling the pile, the plurality of drilling holes may be drilled so that they are spaced apart from each other along the spiral direction.

The step of inserting the pile and the step of discharging the soil of the ground within the pile may be performed simultaneously.

The step of injecting the grout liquid into the pile includes first injecting the grout liquid; removing the compartment or reducing the volume of the compartment; And it may include the step of secondarily injecting the grout liquid into the upper portion of the firstly injected grout liquid.

The step of reducing the volume of the compartment may include restoring the shape of the compartment by removing fluid inside the compartment or bursting the compartment.

The step of drilling the pile may be performed with a shaped peony.

The compartment may include a packer or a pocket filled with fluid.

Specific details of other embodiments are included in the detailed description and drawings.

According to the present invention as described above, one or more of the following effects are achieved.

According to the pile construction method of the present invention, the friction force around the pile can be improved by injecting the grouting liquid into the desired depth and direction around the pile, that is, into the required area such as soft ground, so that the hard ground is more effective than the soft ground. Even if formed in deep places, the piles can be supported.

In addition, according to the present invention, ground reinforcement can be effectively achieved even if soft ground is irregularly or non-homogeneously distributed within the site.

Figure 1 is a flowchart showing a pile construction method according to an embodiment of the present invention.
Figure 2 is a diagram illustrating inserting a pile and discharging the ground within the pile in the pile construction method according to an embodiment of the present invention.
Figure 3 is a view showing drilling a pile in the pile construction method according to an embodiment of the present invention.
Figure 4 is a view showing insertion of a partition part of the pile construction method according to an embodiment of the present invention.
Figure 5 is a view showing injection of grout liquid into a pile in the pile construction method according to an embodiment of the present invention.
Figure 6 is a view showing grout liquid being injected into a pile in the pile construction method according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms. The present embodiments are merely intended to ensure that the disclosure of the present invention is complete and to provide common knowledge in the technical field to which the present invention pertains. It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

Spatially relative terms such as “below”, “beneath”, “lower”, “above”, “upper”, etc. are used as a single term as shown in the drawing. It can be used to easily describe the correlation between elements or components and other elements or components. Spatially relative terms should be understood as terms that include different directions of the element during use or operation in addition to the direction shown in the drawings. For example, if an element shown in the drawings is turned over, an element described as “below” or “beneath” another element may be placed “above” the other element. Accordingly, the illustrative term “down” may include both downward and upward directions. Elements can also be oriented in other directions, so spatially relative terms can be interpreted according to orientation.

Although first, second, etc. are used to describe various elements, elements and/or sections, it is understood that these elements, elements and/or sections are not limited by these terms. These terms are merely used to distinguish one element, element, or section from other elements, elements, or sections. Therefore, it goes without saying that the first element, first element, or first section mentioned below may also be a second element, second element, or second section within the technical spirit of the present invention.

The terminology used herein is for describing embodiments and is not intended to limit the invention. As used herein, singular forms also include plural forms, unless specifically stated otherwise in the context. As used herein, “comprises” and/or “comprising” refers to the presence of one or more other components, steps, operations and/or elements. or does not rule out addition.

Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used with meanings that can be commonly understood by those skilled in the art to which the present invention pertains. Additionally, terms defined in commonly used dictionaries are not interpreted ideally or excessively unless clearly specifically defined.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description with reference to the accompanying drawings, identical or corresponding components will be assigned the same reference numbers regardless of the reference numerals, and overlapping elements will be assigned the same reference numbers. The explanation will be omitted.

Figure 1 is a flowchart showing a pile construction method according to an embodiment of the present invention. And Figure 2 is a diagram showing the pile in the pile construction method according to an embodiment of the present invention and discharging the ground in the pile, and Figure 3 is a view showing the pile in the pile construction method according to an embodiment of the present invention. This is a drawing showing how to drill a hole.

In addition, Figure 4 is a view showing insertion of a partition part of the pile construction method according to an embodiment of the present invention, and Figure 5 is a view showing injection of grout liquid into the pile of the pile construction method according to an embodiment of the present invention. It is a drawing showing, and Figure 6 is a drawing showing the grout liquid being injected into the pile of the pile construction method according to an embodiment of the present invention.

Referring to Figures 1 to 6, the pile construction method includes the steps of inserting a pile with a circular cross-section into the ground around a nuclear power plant or where radioactive waste is buried (S110), and discharging soil and sand from the ground within the pile. (S120), examining the material of the ground to examine the first area and the second area having weak ground compared to the first area (S130), drilling the pile located in the second area (S140), It may include inserting a partition into the upper part of the second area or expanding the volume of the partition so that the grout solution is injected into the periphery of the second area (S150), and injecting the grout solution into the pile (S160).

First, in the step (S110) of inserting the pile 10 into the ground around a nuclear power plant or where radioactive waste is buried, the pile 10 can be pressed into the ground. Here, the pile 10 is a pile having a circular cross-section and may be made of a pile capable of drilling. By way of example, the pile 10 may be a steel pipe pile. However, it is not limited to this and various piles that can be drilled can be applied.

Driving the pile 10 into the ground can utilize driving or hydraulic pressure. For example, the step (S120) of press-fitting the pile 10 through a press-in device (not shown) and simultaneously discharging the soil of the ground within the pile 10 may be performed. However, it is not limited to this, and various modifications are possible.

And the step (S120) of discharging the soil of the ground within the pile 10 is as follows.

As mentioned above, the step of discharging the soil (S120) may be performed simultaneously with the step of introducing the pile 10 (S110).

To discharge the soil of the ground within the pile 10, the soil inside the pile 10 can be removed by discharging the soil within the pile 10 using a drill, high-pressure water, and/or compressed air.

Exemplarily, equipment for soil discharge may be drilling equipment/excavation equipment 20, high-pressure water sprinkling equipment (may be a special high-pressure piston pump, not shown), and/or a compressor (not shown).

Next, the step (S130) of investigating the first area S1 and the second area S2 by examining the ground material may be conducted using drilling survey or physical exploration. Here, the second area S2 may have weaker ground compared to the first area S1.

The ground investigation can investigate the section and range that require ground reinforcement or improvement of the frictional force of the main surface of the pile 10. In other words, it is investigated where the second area (S2) is located on the ground so that the grout solution can be injected into the second area (S2), which has weaker ground compared to the first area (S1).

For example, ground investigation can be accomplished by examining ground materials recovered during the construction process of the pile 10.

Next, the step of drilling the pile 10 located in the second area (S140) is to inject the grout liquid into the second area S2 through the drilling hole 11 of the pile 10.

Drilling of the pile 10 involves drilling the pile 10 to form a plurality of drilling holes 11. The plurality of drilling holes 11 may be formed to be offset from the most adjacent drilling holes 11 in the vertical direction. For example, the plurality of drilled holes 11 may be arranged to be spaced apart from each other along the spiral direction so that they are not concentrated in some areas in terms of structural integrity.

The pile 10 is drilled by sending the drilling device 30 down to the position (second area S2) where the grout liquid is injected through the step S130 of irradiating the second area S2. ), the wall surface of the steel pipe pile 10 can be drilled by aligning one or more drilling devices 30 with the position/direction of the drilling hole 11.

And the perforation device 30 may use a shaped charge (which may be called a shaped charge). The shaped charge can utilize the Munroe effect, in which the explosive is processed into a shape such as a cone, and the explosive force is concentrated in one place (the location where the drill hole 11 is formed). In addition, the molded peony may be of a preset size so that a plurality of pieces can be simultaneously inserted into the pile 10. Since the wall of the pile 10 can be instantly drilled upon detonation, rapid construction may be possible compared to mechanical drilling devices such as a drill. The molded peony is installed on the inner wall of the pile (10) and can be drilled from the inside to the outside.

In this way, rather than forming the drilling hole 11 in advance in the pile 10, the drilling hole 11 is formed after the pile 10 is inserted into the ground for the following reasons.

If the pile 10 is provided with a drilled hole 11 in advance, there is a risk that the pile 10 may be deformed due to stress being concentrated in the drilled area during driving for pile installation. Accordingly, this embodiment does not provide a pile in which the drilling hole 11 is already provided, but forms the drilling hole 11 after the pile 10 is inserted into the ground, so stress is concentrated in a specific area (drilling hole area). This can prevent deformation/crack problems that occur.

In addition, since the drilling hole is not constructed in advance, it is possible to prevent the problem of soil or groundwater flowing in through the pre-drilled injection hole during the pile construction process.

In addition, when high-pressure water, compressed air, etc. are used to remove the soil inside the pile 10, the soil outside the pile 10 is not discharged unnecessarily through the mirror-formed drill hole, so the soil inside the pile 10 is removed. It is possible to prevent problems such as lowering work efficiency or eroding the soft zone of the ground around the drilling hole (11). In other words, the drilling hole 11 is formed after the pile 10 is introduced and the soil is removed, and problems caused by the drilling hole 11 can be prevented.

In addition, if the pile 10 is drilled at the factory before being installed in the ground, there is a problem in that it is difficult to quickly change and apply various drilling patterns on site depending on the ground conditions. However, in this embodiment, drilling is performed according to the characteristics of the ground. It can be achieved.

Next, the step (S150) of inserting the partition 40 into the upper part of the second area (S2) or expanding the volume of the partition 40 so that the grout liquid is injected into the periphery of the second area (S2), This is to ensure that the grout liquid is concentrated and injected into the second area (S2). In other words, this is to ensure that the second area (S2), which has soft ground, is strengthened compared to the first area (S1).

Inserting the partition 40 or expanding the volume of the partition 40 prevents the grouting liquid from overflowing into the upper opening of the pile 10 and injects the grouting liquid into the ground at high pressure by inserting a portion of the pile 10. An inflatable grout packer or pocket can be used to seal the section. Here, the volume expansion of the partition 40 occurs when a hose is connected to the partition 40 and grout and/or fluid (which may be a gas such as air/nitrogen) is injected into the partition 40. ) can expand in volume.

In addition, the partition 40 may be shaped like a donut so that the grout liquid can be injected into the lower area of the partition 40, so that the grout liquid injection hose can pass therethrough.

Next, the step of injecting the grout liquid into the pile 10 (S160) involves injecting the grout liquid not only into the pile 10 but also into the second area S2 through the drilling hole 11 of the pile 10. You can.

For example, the grouting liquid can be injected from the bottom of the pile 10. This can be done by means of a grout liquid injection hose, as previously mentioned. In addition, the grouting liquid can be injected not only into the pile 10 located in the second area S2 sealed by insertion of the partition 40, but also into the ground of the second area S2 through the drilling hole 11. This is because the partition 40 has the effect of sealing the space.

In this way, after the grouting liquid is injected into the interior and ground of the pile 10 located in the second area S2, the grouting liquid can be further injected into the upper area of the partition 40. For this purpose, the partition 40 is removed or the volume of the partition 40 is reduced, so that the first area S1 and the second area S2 inside the pile 10 partitioned by the partition 40 are separated. Space can be formed into one space again. However, various modifications are possible in this embodiment, such as secondary grout liquid injection into the upper part of the partition 40 in an expanded state without the partition 40 being removed.

In other words, when the grout liquid is injected into the ground located outside the pile 10 through the drilling hole 11, the grout liquid is injected into the remaining area, the upper part of the partition 40, so that the inside of the pile 10 is filled with the grout liquid. Various modifications that can all be filled are possible.

This grout liquid injection step (S160) includes the first injection of the grout liquid (S161), the step of reducing the volume of the partition 40 or removing the partition 40 (S162), and the first injection of the grout. It may include a second injection of the grout liquid into the upper part of the liquid (which may be the upper area of the partition 40) (S163). In addition, step S162 may be omitted according to a modified example of the embodiment.

Here, the volume reduction of the partition 40 can be performed by removing the partition 40, restoring the shape of the partition 40 (removing the fluid), or bursting the partition 40. .

Restoring the shape of the partition 40 can be achieved by removing the fluid injected into the partition 40 again. At this time, the fluid inside the partition 40 can be removed by withdrawing the fluid through a hose connected to the partition 40.

As another example, the process of bursting the partition 40 may be performed through a second injection of grouting liquid. This means that the partition 40 does not burst during the first injection of the grouting solution, but the partition 40 bursts at a thickness during the process of additionally injecting the grouting solution, that is, the second injection of the grouting solution. This can be achieved by providing 40).

And the first injection of the grouting liquid is performed by measuring the amount of grouting liquid according to the position/height of the second area (S2) and the ground of the second area (S2) through the perforation hole (11) in the step of investigating the second area (S130). This can be achieved by setting a sufficient amount of grouting liquid to be injected and designing it so that the partition 40 bursts when the amount added to the corresponding grouting liquid is injected. However, since this is only an example, it is of course not limited thereto.

In addition, the bearing capacity can be confirmed by performing compression and pulling load tests after grout curing (G).

The pile construction method according to this embodiment is to inject grouting liquid into a necessary area such as the desired depth and direction around the pile 10, that is, the second area S2 made of soft ground, and the main surface of the pile 10. Since friction can be improved, the pile 10 can be supported even if hard ground is formed deeper than soft ground.

In addition, according to the present invention, ground reinforcement can be effectively achieved even if soft ground is distributed irregularly and non-homogeneously within the site.

Although embodiments of the present invention have been described with reference to the above and the attached drawings, those skilled in the art will understand that the present invention can be implemented in other specific forms without changing the technical idea or essential features. You will understand that it exists. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive.

10: pile 11: drilling hole
20: drilling equipment 30: drilling device
40: compartment

Claims (12)

Inserting a pile with a circular cross-section into the ground around a nuclear power plant or where radioactive waste is buried;
Discharging soil from the ground within the pile;
examining a first area and a second area having weak ground compared to the first area by examining the ground material;
drilling the pile located in the second area;
inserting a partition into the upper part of the second area or expanding the volume of the partition so that the grout liquid is injected into the periphery of the second area; and
Including the step of injecting grout liquid into the pile,
The step of injecting grout liquid into the pile is,
Primary injection of the grout liquid;
removing the compartment or reducing the volume of the compartment; and
A pile construction method comprising the step of secondarily injecting the grout liquid into an upper portion of the firstly injected grout liquid. delete According to paragraph 1,
The step of investigating the ground is,
A pile construction method that is investigated using at least one of drilling investigation or physical exploration. According to paragraph 1,
The step of investigating the ground is,
A pile construction method that investigates the section and range that requires ground reinforcement or increased friction on the main surface of the pile. According to clause 4,
The step of investigating the ground is,
A pile construction method for examining ground materials recovered during the pile construction process. According to paragraph 1,
The step of drilling the pile is,
Perforating to form a plurality of perforation holes,
A pile construction method wherein the plurality of drilling holes are arranged to be offset in the vertical direction from the most adjacent neighboring drilling holes. According to clause 6,
The step of drilling the pile is,
A pile construction method in which a plurality of the drilling holes are drilled so that they are spaced apart from each other along the spiral direction. According to paragraph 1,
A pile construction method in which the step of inserting the pile and the step of discharging the soil of the ground within the pile are performed simultaneously. delete According to paragraph 1,
The step of reducing the volume of the compartment is,
A pile construction method of removing the fluid inside the partition to restore the shape of the partition or bursting the partition. According to paragraph 1,
The step of drilling the pile is,
A method of pile construction, performed with molded peony. According to paragraph 1,
The partition is a pile construction method including a packer or a pocket whose interior is filled with fluid.

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