KR101585161B1

KR101585161B1 - Micro-pile and Construction method thereof

Info

Publication number: KR101585161B1
Application number: KR1020150096550A
Authority: KR
Inventors: 김태헌; 허남헌; 오순옥
Original assignee: 주식회사 산천개발
Priority date: 2015-07-07
Filing date: 2015-07-07
Publication date: 2016-01-13

Abstract

The present invention relates to a method of constructing a micro pile using a perforated casing, which is developed so as to prevent leakage of a grouting material injected into a gap between a casing and a ground perforation when a micro pile is constructed by a pressurized grouting method, Quot; microfiles constructed by the method ".
In the present invention, it is possible to form a ground perforation, insert a perforated casing, form a support layer perforation, arrange core members in the ground perforation and support layer perforation, install upper and lower packers in a perforated casing, form a first pressurized sphere, A method of constructing a micropile comprising the steps of filling, finishing a packer, forming a second pressurized ball and a third pressurized ball, and a microfabricated by such a construction method.

Description

[0001] The present invention relates to a micro-pile construction method using a perforated casing,

The present invention relates to a micro-pile and a method of constructing the micro-pile, and more particularly, to a method of constructing a micro-pile by pressurizing grouting The present invention relates to a microfiber construction method using a perforated casing and a microfilm constructed by such a construction method.

Micro-piles have been installed in the ground and used as the foundation of structures in areas where reinforcement of existing structures or entry of large equipment is difficult. A conventional technique for microfiles is disclosed in Korean Patent Registration No. 10-1027668.

Generally, the microfiles are installed in the order of ground penetration, casing insertion, support layer piercing, core material and packer installation, and grouting pressurization in support layer. Specifically, the ground is perforated to form a ground perforation, and then a casing made of a steel pipe is inserted into the ground perforation in order to prevent collapse of the perforation. The base layer is drilled deeper into a support layer made of a rock layer below the section where the casing is provided to form a support layer perforation and the rod core member is inserted into the casing so that the end portion of the core is positioned in the support layer perforation. In addition, a packer for closing the end face of the casing is installed inside the casing so as to prevent the grouting material from flowing into the casing inside the lower end portion of the casing.

When the core material and the packer are installed, the grouting material is injected into the support layer perforation so that the grouting material is formed into a spherical shape while expanding the excavation surface of the support layer perforation. Finally, the inside of the casing is also filled with grouting material.

However, in this conventional technique, when the grouting material is pushed into the support layer perforation, the grouting material leaks out between the casing and the ground perforation or the support layer perforation, so that the excavation surface expansion of the support layer perforation is not properly performed. In order to facilitate the insertion of the casing into the ground penetration, the ground penetration is made by drilling the ground with a larger diameter than the outer diameter of the casing. In order to recover the excavator, the support pierced holes are drilled to the same diameter as the ground piercing. Therefore, when the casing is inserted into the ground perforation, there is a gap between the outer surface of the casing and the inner surface of the ground perforation. When the lower end of the casing is embedded in the upper end of the support layer perforations for a predetermined depth, there is also a gap between the outer surface of the casing and the inner surface of the support layer perforations. In addition, when the ground is drilled, the soil is loosened (ground loosened) around the perforated ground.

When there is a gap between the outer surface of the casing and the inner surface of the ground perforation or between the outer surface of the casing and the inner surface of the support perforation and the soil on the inner surface of the ground perforation is loosened due to the ground penetration, Even when the grouting material is injected into the perforation, the grouting material leaks out at an interval existing on the outer surface of the casing, so that sufficient pressure of the grouting material is not applied to the excavation surface of the perforation layer. The spheres may not be properly formed.

In this case, if a problem occurs that the spherical shape of the extended shape is not properly formed in the supporting layer, the microfiles are regarded as "construction failure ", and a new microfilm must be re- Generally, since a plurality of microfiles are installed on a limited area, it is often difficult to re-install a new microfile at a neighboring location if the microfiles are determined to have failed construction.

Korean Patent Registration No. 10-1027668 (published on Apr. 12, 2011).

The present invention has been developed in order to solve the problems of the prior art as described above, and it is an object of the present invention to provide a microfabrication apparatus, in which micro piles are installed in the order of ground penetration, casing insertion, support layer piercing, core member and packer installation, It is possible to effectively prevent a phenomenon in which the grouting material pressurized and injected into the support layer perforations leaks out through the gap of the outer surface of the casing due to the gap existing on the outer surface of the casing and the soil relaxed state around the perforation, So that the construction of the microfiles can be prevented from failing.

Further, in the construction of the microfiles as described above, the present invention can enhance the horizontal supporting force of the microfiles by strengthening the ground at the portion where the casing is installed, thereby improving the economical efficiency of the microfiles and And to provide a technique capable of improving competitiveness.

In order to accomplish the above object, according to the present invention, there is provided a method of manufacturing a ground penetrating apparatus, comprising the steps of: forming a ground penetrating hole in a ground penetrating hole; Forming a support layer perforation in the support layer below the ground perforation; Disposing a core material in the ground penetration and the support layer perforation; Installing upper and lower packers in the perforated casing at the upper and lower positions of the section where the injection holes are formed in the perforated casing; Forming a first pressurizing sphere in the ground by pressurizing and injecting a grouting material into the perforated casing in a section where the upper and lower packers are installed; And forming a second pressing sphere in the support layer by pressurizing and injecting the grouting material into the support layer perforation.

In the construction method of the present invention as described above, it is possible to use a structure in which an upper injection hole is formed at the upper end thereof as a perforated casing. In this case, after forming the first pressure sphere, Filling the grouting material down to a region where the injection hole is formed; In addition to forming the second pressing sphere by pressurizing and injecting the grouting material into the support layer perforation, a third pressing sphere surrounding the outside of the perforation casing is formed in the ground by pressurizing the grouting material in the perforation casing in the section where the upper injection hole is formed . Particularly, in this case, in order to form the third pressurized sphere, an uplift mat pressing the ground surface before the grouting material is pushed into the perforated casing in the section where the upper injection hole is formed may be provided on the ground.

In order to achieve the above-mentioned object, the present invention provides a microfilm which is vertically installed on a ground and a support layer, and is installed and installed by the construction method of the present invention.

According to the present invention, it is possible to effectively prevent or suppress the leakage of the grouting material injected under pressure by the support layer perforation between the soil and the perforated casing and between the ground particles loosened by the perforation of the ground, It is possible to construct a micro-file that can prevent construction and avoid the re-construction due to construction failure, and it is possible not only to reduce the construction cost, but also to construct the micro file in the designed position, File can be applied and utilized effectively.

According to the present invention, it is possible to further increase the frictional force between the perforated casing and the ground, thereby increasing the vertical resistance and the pulling resistance that can be exerted by the micro pile, It is possible to reduce the length in the longitudinal direction, thereby reducing the drilling operation of the support layer perforation, reducing the drilling cost, and reducing the material and other costs required for grouting reinforcement, There are advantages to be able to do.

In particular, in the present invention, it is possible to further form a third pressing sphere. In this case, since the grounding rigidity is increased through the formation of the third pressing sphere, the horizontal supporting force of the micro pile greatly increases, It is possible to reduce the number of microfiles, and the economical efficiency of the microfiles and the competitiveness against other types of bases are greatly improved.

1 is a schematic flowchart of a microfabrication method according to a first embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view sequentially showing the steps from the formation of the ground piercing to the formation of the support piercing in the micro pile construction method according to the first embodiment of the present invention.
FIG. 3 is a schematic cross-sectional view sequentially showing steps from the step of installing the core material to the step of forming the first pressing sphere in the micro pile construction method according to the first embodiment of the present invention.
FIG. 4 is a schematic cross-sectional view sequentially showing the steps of filling a grouting material in a perforated casing, forming a second pressurized sphere, and constructing a base concrete in a micro pile construction method according to a first embodiment of the present invention.
5 is a schematic perspective view of a perforated casing used in a micro pile construction method according to a first embodiment of the present invention.
FIG. 6 is a schematic flowchart of a microfabrication method according to a second embodiment of the present invention.
FIG. 7 is a schematic cross-sectional view sequentially showing an entire process of a microfabrication method according to a second embodiment of the present invention.
8 is a schematic cross-sectional view showing only the steps of (h) and (i) in FIG. 7 in detail.
FIG. 9 is a schematic cross-sectional view showing only the steps (j) and (k) in FIG. 7 in detail.
10 is a schematic perspective view of a perforated casing used in a micro pile construction method according to a second embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Although the present invention has been described with reference to the embodiments shown in the drawings, it is to be understood that the technical idea of the present invention and its essential structure and operation are not limited thereby.

FIG. 1 is a schematic flow chart of a micro pile construction method according to a first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing a step of inserting a perforated casing 1 and forming a support layer perforation 3 in a micro pile construction method according to a first exemplary embodiment of the present invention, and FIG. 3 The core 5 is installed in the micro pile construction method according to the first embodiment of the present invention and the first pressurization is performed in a section where the injection hole 10 is formed in the perforated casing 1, And a step of forming a sphere are sequentially shown. 4, in the microfabrication method according to the first embodiment of the present invention, the grouting material is filled in the perforated casing 1 and the grouting material is injected into the support layer perforation 3, And a step of forming a pressurized sphere and a step of constructing the base concrete 400 are shown in a schematic cross-sectional view. 5 is a schematic perspective view of a perforated casing 1 used in a micro pile construction method according to a first embodiment of the present invention.

As shown in FIGS. 1 and 2 (a) and 2 (b), in the micro pile construction method according to the first embodiment of the present invention, the ground piercing 2 is firstly drilled vertically in the ground, A perforated casing (1) for preventing collapse of the perforation (2) is inserted into the ground perforation (2). Unlike the prior art, the present invention uses a perforated casing 1 in which an injection hole 10 is formed at a lower end. As illustrated in FIG. 5, the perforated casing 1 used in the construction method of the present invention is made of a pipe member such as a steel pipe, and a plurality of injection holes 10 are formed through the lower end thereof. The grouting material is discharged from the perforated casing 1 through the injection hole 10 formed in the perforated casing 1 to be filled in the gap between the perforated casing 1 and the ground perforation 2, (2) is injected into the ground where the soil is loosened and cured, thereby forming the first pressing sphere (100).

The plurality of injection holes 10 are formed over a predetermined lengthwise (longitudinal) direction of the perforated casing 1, and are preferably formed in a section within about 2 m from the lowermost end of the perforated casing 1. It is preferable that the injection hole 10 is formed as a micro hole having a size that prevents soil from flowing in the vicinity of the ground perforation 2. In order to maintain the rigidity of the perforated casing 1, The balls 10 are preferably arranged in a zigzag pattern. That is, as illustrated in the drawing, a plurality of injection holes 10 are arranged at intervals along the circumference of the perforated casing 1 to form ring-shaped rows, and a row of the injection holes 10 arranged in this ring shape The piercing casing 1 may be arranged in a zigzag manner so that the injection holes 10 are offset from each other between the rows of the injection holes 10 adjacent to each other in the longitudinal direction. It is a great help to maintain.

2 (c), after the perforated casing 1 is disposed, the ground perforation 2 is formed in the ground consisting of gravel, The perforation 3 is perforated. 2 (d), after forming the support layer perforation 3, the perforator 9 is taken out and removed.

When the perforation of the support layer perforation 3 is completed, as shown in FIG. 3 (e), the core 5 is inserted into the ground perforation 2 and the support layer perforation 3. The core member 5 may be a rod member, for example, a rebar, and may be connected to a plurality of rod members, if necessary, so that the lower end of the core member 5 can reach the ground perforation 2. [ Reference numeral 51 in the drawing is a centralizer 51 which is installed if necessary so that the core 5 can be disposed at a central position within the ground penetrating base 2 and the support layer perforation 3. [

3 (f), in the ground perforation 2, the first pressing spheres 100 are arranged in parallel with the arrangement of the core material 5 in the ground perforation 2 and the support layer perforation 3. [ The upper packer 61 and the lower packer 62 are disposed in the perforated casing 1 so as to form the upper boundary and the lower boundary of the section where the upper and lower packers 61 and 62 form the upper and lower boundaries. That is, the inner surface of the perforated casing 1 is formed so that the upper packer 61 is positioned above the section where the injection hole 10 is formed in the perforated casing 1 in the longitudinal direction and the lower packer 62 is located below the section. The upper and lower packers 61 and 62 are provided so as to close each other so that the injection hole 10 is present in a section between the upper and lower packers 61 and 62. When the upper and lower packers 61 and 62 are installed, the end face of the perforated casing 1 is closed. In this manner, both longitudinally opposite sides of the perforated casing 1 are closed by the upper and lower packers 61 and 62, A section between the lower packers 61 and 62, that is, a section in which the injection hole 10 is formed, constitutes a "first pressing spherical forming section ".

3 (g), when the upper and lower packers 61 and 62 are installed, the grouting material G is pressurized and injected into the perforated casing 1 in the first pressurized spherical forming section, Thereby forming the first pressing sphere 100 which surrounds the outer surface of the casing 1. In FIG. 3 (g) and FIG. 4 (i) described later, reference numeral 8 denotes an injection tube 8 for pressurizing the grouting material G. FIG.

The inner diameter of the ground perforation 2 is made larger than the outer diameter of the perforated casing 1 so that the perforated casing 1 can be easily inserted into the ground perforation 2 when the ground perforation 2 is formed, There is a gap between the outer surface of the perforated casing 1 and the inner surface of the ground perforation 2 when the perforated casing 1 is inserted into the ground perforation 2. [ In the process of perforating the ground, the ground is disturbed and the soil around the ground perforation (2) is loosened and the ground is in a relaxed state. In this state, when the grouting material G is pushed into the perforated casing 1 in the first pressurized spherical forming section as described above, the upper and lower sides of the first pressurized sphere forming section are divided into upper and lower packers 61 and 62 The grouting material G injected under pressure passes through the injection hole 10 of the perforated casing 1 and flows to the outside so that the outer surface of the perforated casing 1 and the inner surface of the ground perforation 2 And further penetrates into the gap between the soil particles in the relaxed state around the ground perforation 2 while expanding the excavation surface of the support layer perforation 2 to be formed into a sphere. The grouting material G is also filled in the perforated casing 1 in the first pressing sphere forming section. That is, by the grouting material (G) pressurization injection in the first pressing sphere forming section, the outer surface of the perforated casing 1 surrounds the perforated casing 1 and has a larger diameter than the perforated casing 1, The first pressing spheres 100 formed by the grouting material having a predetermined length (a length longer than the first pressing spherical forming section) are formed in a cylindrical shape. The first pressing member 100 formed in the ground at the outer side of the perforated casing 1 functions to smoothly form the second pressing member 200 as described later.

After the formation of the first pressing spheres 100 is completed by hardening the grouting material, the grouting material G is press-injected into the supporting layer perforations 3 to form the second pressing spheres 200. The operation of filling the grouting material G in the perforated casing 1 upwardly of the upper packer 61 is carried out before forming the second pressing sphere 200 as shown in Figure 4 (h) You can do it first. That is, when the grouting material G is poured into the perforated casing 1 upwardly of the upper packer 61 and the grouting material G is gravity filled in the perforated casing 1, the core material 5 is pushed into the grouting material G So as to be buried. However, filling the grouting material G on the upper portion of the upper packer 61 may be performed after the formation of the second pressing member 200. [

After the formation of the first pressing sphere 100 is completed or the formation of the first pressing sphere 100 and the grouting material G in the ground perforation 2 above the upper packer 61 are completed after the curing of the grouting material is completed, 4 (i), the grouting material G is injected in a pressurized state in the support layer perforation 3 so that the inside of the support layer perforation 3 is filled with the grouting material G So that the grouting material G penetrates into the space between the rocks of the support layer through the inner surface of the support layer perforation 3 to form the second pressing member 200 in the support layer.

When the grouting material G is injected into the support layer perforation 3 at a high pressure to form the second pressing sphere 200 as in the prior art, Can be introduced at the upper end at the interval between the perforated casing (1) and the support layer perforation (3). However, unlike the prior art, in the present invention, the first pressing member 100 is formed so as to surround the outer surface of the perforated casing 1 at the lower end of the perforated casing 1 prior to the formation of the second pressing member 200. That is, a cylindrical first pressing ball 100 having an outer diameter larger than the diameter of the supporting layer perforation 3 is formed on the ground above the upper end of the supporting layer perforation 3. [ Therefore, not only the gap between the perforated casing 1 and the support layer perforation 3 is clogged by the first pressing sphere 100 but also the ground is loosened at the upper end of the support layer perforation 3 I will not. Therefore, even if the grouting material G injected into the support layer perforation 3 at a high pressure flows into the gap between the perforated casing 1 and the support layer perforation 3, the grouting material G can not flow further upward. That is, even if there is a gap on the outer surface of the perforated casing 1 from above the support layer perforation 3 and the soil around the perforation is in a slight relaxed state, in the present invention, Even if the ash (G) does not leak out through the gap of the outer surface of the casing or leaks out, only an extremely small amount of the ashes leaks out.

Therefore, in the present invention, the grouting material G injected into the support layer perforation 3 can maintain a high pressure, so that sufficient pressure from the grouting material G is applied to the excavation surface of the support layer perforation 3 So that the second pressurizing member 200 having an expanded cross section is formed smoothly as intended in the support layer perforations 3. [ Therefore, according to the present invention, it is possible to effectively prevent the failure of the micro pile due to the loss of the filling pressure of the grouting material (G), which is pressurized and injected into the support layer perforation (3)

After the formation of the second pressing member 200 is completed, as shown in FIG. 4 (j), a supporting plate 401 and a fastening nut (not shown) are attached to the upper end of the core 5, The base concrete 402 may be combined with the base concrete 400 to perform a finishing work.

As described above, according to the microfabrication method of the present invention, it is possible to effectively prevent or inhibit the leakage of the grouting material injected by the support layer perforation between the soil and the perforated casing and between soil particles loosened by the perforation of the ground Accordingly, it is possible to prevent the microfile construction failure and to construct the microfiles conforming to the design. Therefore, according to the present invention, it is possible to avoid the re-construction due to construction failure in using the micro-file, thereby reducing the construction cost, and it is possible to construct the micro file in the designed position, So that it can be utilized effectively.

Further, in the micro pile construction method of the present invention, the frictional force between the perforated casing 1 and the ground is formed through the first pressing sphere 100 formed in a cylindrical shape on the outer surface of the perforated casing 1 in the first pressed sphere forming section It can be further increased. Therefore, there is a large frictional resistance between the casing and the surrounding ground, in which friction resistance is not taken into consideration, to be considered in the design, thereby increasing the vertical resistance and the pulling resistance which the micro pile can exhibit. As described above, according to the present invention, it is expected to increase the vertical and pull-out resistance due to the increase of the frictional resistance, so that the longitudinal length of the second pressing sphere 200 to be formed in the lower portion of the micro pile can be reduced, 3) can be reduced, the punching cost can be reduced, and the material and other costs required for re-injection of grouting can be reduced, thereby making it possible to construct micro piles more economically.

On the other hand, in the micro pile construction method of the present invention in which the second pressing sphere 200 is formed after forming the first pressing sphere 100 as described above, The pressing member 300 may be further formed.

6 is a schematic flow chart of a micro pile construction method including a step of forming a third pressing sphere 300 at the top of a perforated casing 1 as a second embodiment of the present invention. FIG. 7 is a schematic cross-sectional view showing the entire process of a microfabrication method according to a second embodiment of the present invention. 8 is a schematic cross-sectional view showing only the steps (h) and (i) in FIG. 7 in detail. In the microfabrication method according to the second embodiment of the present invention, after the first pressing sphere is formed, There is shown a schematic sectional view showing in detail the process of filling the grouting material G and installing the finishing packer 63 and the ridge-preventive mat 64 in sequence. FIG. 9 is a schematic cross-sectional view showing only steps (j) and (k) in FIG. 7 in detail. In the microfabrication method according to the second embodiment of the present invention, the second pressurized sphere and the third pressurized sphere are formed, A concrete cross-sectional view illustrating a process of installing a foundation concrete 400 in detail in a sequential manner. 10 is a perspective view of a second embodiment of the present invention in which a lower injection hole 10a for forming a first pressing sphere is formed at the lower end and an upper injection hole 10b is formed for forming a third pressing sphere at the upper end. There is shown a schematic perspective view of a perforated casing 1 used in a microfabrication method.

7 (a) to 7 (g), that is, the steps of forming the ground piercing 2 and inserting the perforation casing 1, The first and second packers 61 and 62 are formed in the first pressurizing-concrete-forming section in which the perforation 3 is formed, the core 5 is disposed, the upper and lower packers 61 and 62 are installed, The first press forming stage by grouting re-press injection is the same as the micro-pile construction method according to the first embodiment of the present invention described above with reference to Figs. 1 to 5, and thus repeated description thereof will be omitted.

In the micro pile construction method according to the second embodiment of the present invention, after the first pressing sphere 100 is formed, as shown in Figs. 7 and 8 (h), the upper pillar 61 is punched The work of filling the grouting material G in the casing 1 is essentially performed. That is, by pouring the grouting material G into the perforated casing 1 upwardly of the upper packer 61 and filling the grouting material G in the perforated casing 1 gravitationally, the core material 5 is fed to the grouting material G It is essential to carry out the work to be buried.

10, the perforated casing 1 used in the micro pile construction method according to the second embodiment of the present invention has a lower injection hole 10a formed at the lower end thereof for forming the first pressing sphere. In addition, an upper injection hole 10b is additionally formed in a section of a certain length from the upper end, that is, in the third pressuring spherical forming section. The upper injection hole 10b and the lower injection hole 10a are spaced apart from each other along the circumference of the perforation casing 1 in the same manner as the injection hole 10 formed in the first pressurized spherical forming section in the first embodiment It is possible to have a configuration in which a plurality of the ring-shaped rows of the injection holes are arranged sequentially in the longitudinal direction. The upper and lower injection holes 10b and 10a may also be arranged in a staggered manner so that the injection holes are displaced from each other between rows of injection holes adjacent in the longitudinal direction.

The perforated casing 1 used in the micro pile construction method according to the second embodiment of the present invention has an upper injection hole 10b in the third pressurized sphere forming section in addition to the lower injection hole 10a in the lower end, When the grouting material G is gravity-filled in the perforated casing 1 upwardly of the upper packer 61 after the formation of the first pressing sphere 100, only the lower boundary of the third pressing sphere forming section And only the lower portion of the section where the upper injection hole 10b is formed is filled.

After the filling and curing of the grouting material G above the upper packer 61 is completed, the perforation casing 1 at the top of the third pressing sphere forming section as shown in Figs. 7 and 8 (i) And the upper end of the perforated casing 1 is closed by the finishing packer 63. As shown in Fig. When the finishing packer 63 is installed as described above, a third pressurizing spherical forming section is formed between the upper surface of the grouting material G filled above the upper packer 61 and the finishing packer 63, The injection hole 10 is formed in the perforated casing 1 through the through hole. If necessary, it is also preferable to further lay the flooring with an anti-protector mat 64 for temporarily pressurizing the floor down to prevent the floor from swelling in the formation of the third pressing sphere.

7 and 9 (j), when the grouting material G is pressed in the support layer perforation 3, as shown in Fig. 7 and Fig. 9 (j) The grouting material G is pressurized and injected into the perforated casing 1 in the third pressurized sphere forming section to form the third pressurizing sphere 300, . That is, in the same manner as the first embodiment of the present invention, the grouting material G is injected into the support layer perforation 3 in a pressurized state so that the inside of the support layer perforation 3 is filled with the grouting material G The grouting material G is also penetrated through the inner surface of the support layer perforation 3 and also between the rock gaps of the support layer to form the second pressing member 200 in the support layer. The advantageous effect of the first pressing member 100 when the second pressing member 200 is formed is the same as that of the first embodiment of the present invention described above.

The grouting material G is pressed and injected into the perforated casing 1 in the third pressurized spherical forming section in parallel with the formation of the second pressurizing sphere 200 as described above, The grouting material G is filled in the space between the perforated casing 1 and the ground perforation 2 through the formed upper injection hole 10b and at the same time the ground in the state where the soil is loosened around the ground perforation 2 So that the third pressing member 300 is formed in the ground. That is, by the grouting material (G) pressurization injection in the third pressurized spherical forming section, the outer surface of the perforated casing 1 surrounds the perforated casing 1 and has a larger diameter than the perforated casing 1, The third pressing member 300 formed of a grouting material having a predetermined length is formed into a cylindrical shape.

7 and 9 (k), the support plate 401 and the fastening nut 402 are attached to the upper end of the core material 5 protruding from the ground, It is possible to perform the finishing work of placing the foundation concrete 400. At this time, after the finish packer 63 is removed, the basic concrete construction work as described above may be performed.

In the micro pile construction method according to the second embodiment of the present invention, the third pressing sphere 300 is formed at a predetermined depth in the vicinity of the ground, and the third pressing sphere 300 increases the ground stiffness, The horizontal support force which is a weak point of the micro file is greatly increased. Generally, in the case of microfiles, since the horizontal supporting force is significantly smaller than the vertical supporting force, when designing the ground supporting structure using microfiles, the number of microfiles is determined by the horizontal supporting force of each microfiles. The horizontal bearing capacity of the microfiles is strongly dependent on the ground stiffness of the microfiber head section (near the ground). In the microfabrication method according to the second embodiment of the present invention, the grouting material is injected into the third pressurized compact formation section in the vicinity of the ground, and the grout material thus injected is injected into the soil particles of the ground, And hardened, thereby increasing the ground stiffness. Particularly, when the uplift mat 64 for pressing the ground is installed on the ground, when the grouting material seeps into the ground in the third pressurized sphere forming section, the soil particles to be pushed due to the grouting material and to be raised to the ground, 64, so that the surrounding ground of the third pressurizing member 300 is hardened more, so that the ground density is increased and the ground stiffness is greatly increased.

Since the ground rigidity is increased through the formation of the third pressing member 300, the horizontal supporting force of the micropile is greatly increased, and the number of micropile installation can be reduced. As a result, The effect of improving the competitiveness on the basis of the form is remarkably improved.

Of course, even in the case of the microfabrication method according to the second embodiment of the present invention, various advantageous effects exhibited in the microfabrication method according to the first embodiment described above can be equally expected.

In the description of the microfibre construction method according to the second embodiment of the present invention, a step of forming the second pressing sphere 200 by pressurizing the grouting material (G) into the support layer perforation 3, And the step of forming the third pressing spheres 300 by pressurizing the grouting material (G) to the three-pressing spherical forming section are simultaneously performed. In this case, by operating the apparatus for pressurizing the grouting material G one time, it is possible to simultaneously perform the two steps (the formation of the second pressurized sphere and the formation of the third pressurized sphere) have. However, if necessary, the step of forming the second pressing spheres 200 and the step of forming the third pressing spheres 300 may be carried out with a time lag. For example, after the formation of the second pressing sphere 200 is completed, the third pressing sphere 300 can be formed. Of course, the second pressing member 200 may be formed after the third pressing member 300 is formed first.

1: Perforated casing
2: Geotechnical investigation
3:
5: core
100: first pressure sphere
200: second pressure sphere
300: Third pressurized sphere

Claims

Inserting a perforated casing (1) having a ground penetrating hole (2) formed therein and an injection hole penetratingly formed at a lower end thereof into a ground perforation (2);
Forming a support layer perforation (3) in the support layer below the ground perforation (2);
Disposing a core material (5) in the ground penetration (2) and the support layer perforation (3);
The upper and lower packers 61 and 62 are installed in the perforation casing 1 at the upper and lower positions of the section where the injection hole is formed in the perforated casing 1 and the upper and lower packers 61 and 62 are punched Closing the cross section of the casing (1) so that both longitudinal sides of the section where the injection hole is formed are closed;
The grouting material G is pressurized and injected into the perforated casing 1 in the section where the upper and lower packers are installed and the longitudinally opposite sides are closed so that the grouting material G is also filled in the perforated casing 1 The grouting material G injected under pressure passes through the injection hole 10 of the perforated casing 1 and flows out to the outside so that the gap between the outer surface of the perforated casing 1 and the inner surface of the ground perforation 2 Not only the gap is filled but also the excavation surface of the support layer perforation 2 is extended to penetrate into the gap between the sandstones in the relaxed state around the ground perforation 2 so that the perforation in the ground above the upper end of the support layer perforation 3 The outer periphery of the casing 1 is formed into a cylindrical shape having a diameter larger than the outer diameter of the perforated casing 1 so that the upper end of the supporting layer perforation 3 is located between the perforated casing 1 and the support layer perforation 3 The first pressing member 100, Step such that; And
The grouting material G is pressurized and injected into the support layer perforation 3 so that the inside of the support layer perforation 3 is filled with the grouting material G, The step of forming the second pressing sphere 200 having a section larger than the diameter of the support layer perforation 3 originally excavated in the supporting layer by allowing the grouting material G to permeate into the supporting layer through the inner surface of the support 3 Wherein said microfilm comprises a plurality of microfibers.

The method according to claim 1,
An upper injection hole 10b is formed through the upper end of the perforated casing 1;
After forming the first pressing sphere 100, a step of filling the grouting material G to the lower part of the section where the upper injection hole 10b is formed in the perforated casing 1 above the upper packer 61 is performed ;
The grouting material G is pressurized and injected into the support layer perforation 3 to form the second pressing member 200. In parallel with the formation of the upper injection hole 10b in the perforation casing 1, To form a third pressing sphere (300) for enclosing the outside of the perforated casing (1) in the ground.

3. The method of claim 2,
An anti-protector mat 64 for pressing the ground before pressurizing the grouting material G in the perforated casing 1 in the section where the upper injection hole 10b is formed is formed for forming the third pressing sphere 300 Wherein the microfilm is installed on the ground.

Microfiles installed vertically on the ground and supporting layer,
The microfilm according to any one of claims 1 to 3, which is installed and installed.