KR20040065896A - Micro pile and assembly foundation reinforcement structure member and its method for pier - Google Patents

Abstract

PURPOSE: An assembling underpinning structure using a cast-in place micro-pile and an assembling bracket for a pier and a construction method thereof are provided to prevent scour around the pier by mounting the cast-in place micro-pile around the pier and mounting the assembling bracket on the micro-pile, and to stabilize the pier by improving bearing force of soil. CONSTITUTION: An assembling underpinning structure comprises: bores formed symmetrically around a pier(P); a cast-in place micro-pile(30) inserted into the bore and installed under the ground; an anchorage part installed in the upper parts of reinforcing steel bars placed in the cast-in place micro-pile; plural assembling brackets(70) installed around the pier by being formed of the right-angled triangle by using an H-steel, provided with the horizontal plane connected by a bolt and the vertical plane connected by an anchor(40), and installed by connecting L-steels; non-shrinkage mortar poured and cured between the horizontal plane of the assembling bracket and the anchorage part, and the vertical plane of the assembling bracket and the pier; and ripraps(100) placed to prevent scour around the assembling brackets and the pier.

Description

Micro pile and assembly foundation reinforcement structure member and its method for pier}

The present invention relates to a prefabricated foundation reinforcement structure for bridge piers using a field micro pile and a prefabricated bracket, and a construction method thereof. The field micro pile is installed in the ground adjacent to the outside of the piers, and a prefab bracket is installed on the field micro pile. The present invention relates to a prefabricated foundation reinforcement structure for bridge piers using on-site micro piles and prefabricated brackets to promote the stabilization of bridges by preventing ground scour around bridge piers.

In general, the bridge foundations of bridges installed in rivers are affected by the impact of acidity, alkalinity, salinity, and collisions of rocks moving through the river because the foundation of the bridge is always in contact with water. Over the years, scour phenomena cause corrosion of the pier's surface.

Here, the scour phenomenon of the bridge is progressed slowly in the water, so it is not easily found on the ground and develops to a level that impairs the safety of the bridge after a long time.

Therefore, in order to prevent the scour phenomenon of the bridge piers, a bridge reinforcement method has been conventionally proposed to increase the bearing capacity by increasing the concrete volume of the bottom of the piers to increase the floor volume.

In the conventional bridge piers reinforcement method as shown in Figs. 1 to 4, first, the sheet pile 110 is driven along the periphery of the pier P, and the ground reinforcement hole 120 is installed. Excavate the inside of the reinforcement 120, install the braces 130, do concrete chipping of the pier, install the shear and reinforcing anchor 140, the first place the concrete, ground reinforcement (120) ), The concrete is laid in the second order, and the construction is performed in the order of arranging the pier surface.

Conventional reinforcement method for bridge piers constructed as described above has the following problems.

First, the conventional reinforcement method for pier has a problem that the eccentric load is temporarily generated during the construction of the ground reinforcement around the piers.

Second, the conventional reinforcement method for piers have a problem that the stability around the piers before and after and left and right by digging around the piers as a whole during train operation.

Third, the conventional bridge reinforcement method has a problem that the economic loss occurs because the sheet pile is buried in the ground during the foundation reinforcement work.

Fourth, the conventional reinforcement method for bridge piers have a disadvantage of the earthwork disadvantage and rebar assembly due to the internal excavation due to the narrowing of the brace and the internal space.

Fifth, the conventional reinforcement method for piers has been pointed out as a problem that it is economically inefficient to install shear reinforcing bars and anchors throughout the reinforcement wall surface of the piers.

Sixth, the conventional reinforcement method for pier has a problem that is very vulnerable to vibration due to train operation on the top of the bridge brace.

Seventh, the conventional reinforcement method for piers has difficulty in driving the sheet pile due to limitation of the geometry space in the longitudinal direction of the piers.

Eighth, the conventional bridge reinforcement method has a disadvantage that the cross section is reduced according to the flow due to the increase in the volume of the concrete used to reinforce the bridge.

Ninth, the conventional reinforcement method for piers has a problem that the environmental pollution around the piers gradually increase due to rust generated in the sheet pile.

Tenth, the conventional reinforcement method for piers have a problem that the construction speed is delayed due to the failure to construct a plurality of piers at a time.

Accordingly, the present invention has been made to solve the problems described above, the field micropile is installed in the ground adjacent to the outer side of the pier, the prefabricated bracket is installed on the field micropile, The purpose of the present invention is to provide a prefabricated basic reinforcement structure for bridge piers using on-site micro piles and prefabricated brackets to prevent stagnation and to increase the bearing strength of the ground to stabilize the bridges.

The prefabricated foundation reinforcement structure for piers using field micro piles and prefabricated brackets according to the present invention for achieving the above object includes a drilled hole drilled symmetrically in a circumferential area around the piers after trenching; A field micro pile inserted into the drilling hole by a predetermined depth and embedded in the ground; A fixing unit installed on an upper part of the reinforcing bar installed in the field micro pile; The horizontal surface of the prefabricated bracket is connected to the bolt hole of the fixing unit at the same time, and the vertical surface of the prefabricated bracket is anchored to the drilling hole formed at the lower end of the piers to be assembled with H-shaped steel so as to form a right triangle overall. A plurality of prefabricated brackets installed and connected to each other by L-shaped steel; A non-shrink mortar that is pour-cured to fill the gap between the prefabricated bracket and the horizontal surface of the prefabricated bracket and the fixing unit, and the vertical surface and the piers of the bracket; Through the excavation of the residual soil between the prefabricated brackets, it is characterized in that the gravel or crushed stone of various sizes to prevent the riverbed around the piers to be crushed.

Method for constructing a prefabricated foundation reinforcement structure for piers using a field micro pile and a prefabricated bracket according to the present invention for achieving the above object comprises the steps of removing trench excavation to a part of a certain depth around the piers; Inserting and excavating a casing installed at the tip of the excavator to form a drilled hole in the drilled ground to form a drilled hole; Installing cross-shaped spacers and a plurality of reinforcing bars and injection pipes formed in the center of the reinforcing bars in the longitudinal direction of the reinforcing bars in order to maintain spacing of the reinforcing bars, and curing them after grouting to install field micro piles; Inserting reinforcing bars installed in the field micropile into an insertion hole provided in an upper part of the reinforcing bar installed in the field micropile and a lower part of the fixing unit; The prefabricated bracket made of a right triangle is installed by connecting the vertical surface of the prefabricated bracket with an anchor to the boring hole formed at the bottom of the pier by connecting the bolt with the horizontal surface of the prefabricated bracket to the bolt hole installed at the corners of the fixing unit. Fixing; Connecting lower portions of the prefabricated brackets installed around the piers with L-shaped steels; Pouring a non-shrink mortar into the L-shaped steel interconnecting the clearance between the horizontal surface and the fixing part of the prefabricated bracket and the prefabricated bracket, the gap between the vertical surface and the piers of the prefabricated bracket, and the prefabricated bracket; Excavating and removing residual soil between the prefabricated brackets 70; And laying gravel or crushed stone of various sizes up to the pier bottom surface of the excavated portion.

1 is a plan view 1 showing a conventional foundation reinforcement structure for piers;

2 is a cross-sectional view 1 showing a conventional reinforcement structure for piers;

Figure 3 is a plan view showing a conventional foundation reinforcement structure for piers 2,

Figure 4 is a cross-sectional view 2 showing a conventional foundation reinforcement structure for piers

5 is a field micro pile and a prefabricated bracket according to the present invention

Front view showing a prefabricated foundation reinforcement structure for piers,

Figure 6 using the field micro pile and prefabricated bracket according to the invention

Floor plan showing a prefabricated foundation reinforcement structure for piers,

Figure 7 is using the field micro pile and prefabricated bracket according to the present invention

Side view showing a prefabricated foundation reinforcement structure for piers,

8 is a field micro pile and a prefabricated bracket according to the present invention

Floor plan showing in-situ micro pile of prefabricated foundation reinforcement structure for piers,

Figure 9 using the field micro pile and prefabricated bracket according to the present invention

Side view showing an in-situ micropile of a prefabricated foundation reinforcement structure for piers,

10 is a field micro pile and a prefabricated bracket according to the present invention

Plan view showing the fixing part of the prefabricated foundation reinforcement structure for piers,

11 is a field micro pile and a prefabricated bracket according to the present invention.

Perspective view of a bracket of a prefabricated foundation reinforcement structure for piers,

12 (a) to 12 (h) illustrate the field micro pile and the assembled bracket according to the present invention.

Construction step diagram showing the construction state of the prefabricated foundation reinforcement structure for pier using.

Explanation of symbols on the main parts of the drawing

10: drilling hole 20: casing

30: Scene Micro File 33: Hole

34: Spacer 35: Binding Line

36: connector 37: injection pipe

38: rebar 40: anchor

50: grouting agent 60: fixing unit

62: bolt hole 70: prefabricated bracket

80: L-shaped steel 90: Non-shrink mortar

100: dead stone

110: sheet file 120: ground reinforcement

130: brace 140: anchor

P: Pier T: Excavation site

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

5 is a front view showing a prefabricated foundation reinforcement structure for piers using a field micro pile and a prefabricated bracket according to the present invention, Figure 6 is a prefabricated foundation reinforcement structure for a piers using a field micro pile and a prefabricated bracket according to the present invention. One is a plan view, Figure 7 is a side view showing a prefabricated foundation reinforcement structure for piers using a field micro pile and a prefabricated bracket according to the present invention.

As shown in these drawings, the prefabricated foundation reinforcement structure for the piers using the field micro pile and the prefabricated bracket according to the present invention is a symmetrical periphery of the piers (P) to be drilled to a predetermined diameter and depth in the ground (10) )and; A field micro pile 30 inserted into the drilling hole 10 by a predetermined depth and embedded in the ground; A fixing unit 60 installed on an upper portion of the reinforcing bar 38 installed in the field micro pile 30;

The horizontal surface of the prefabricated bracket 70 is connected to the bolt hole 62 of the fixing unit 60 and the vertical surface of the prefabricated bracket 70 is anchored to a drilling hole formed at the lower end of the pier P. A plurality of prefabricated brackets 70 connected to each other and installed as H-shaped steels so as to be generally triangular in shape and installed around the piers P and connected to each other by L-shaped steels 80;

The non-shrink mortar 90 is pour-cured to fill the gap between the horizontal surface of the prefabricated bracket 70 and the prefabricated bracket 70 and the fixing unit 60 and between the vertical surface of the bracket 70 and the piers P. ;

Between the prefabricated bracket 70 and around the piers (P) to install a sandstone 100, such as gravel or crushed stone of various sizes to prevent the lower bed around the piers (P) to be crushed.

Here, the field micro pile 30 is fixed so that the spacing of the plurality of reinforcing bars 38 and the injection pipe 37 and the reinforcing bars 38 in the drilling hole 10 having a predetermined diameter and length can be kept constant. A spacer 34 spaced apart from each other; A binding line 35 tied at regular intervals so that the reinforcing bars 38 are fixed to each other; It is to pour the grouting agent 50 in the drilling hole 10 is composed of a connector (36) installed to interconnect the reinforcing bars (38).

In addition, the spacer 34 is installed at regular intervals in order to maintain the spacing of the reinforcing bars 38 installed in the field micro pile 30 is a cross shape having a certain thickness of the reinforcing bar 38 is installed between the cross shape. The injection pipe 37 is installed using the hole 33 formed in the center, and the grouting agent 50 can be poured.

In addition, the fixing unit 60 is to be installed in the reinforcing bar 38 extending a predetermined length to the upper portion of the drilling hole 10, the square hole of the square iron plate of a certain size of the ball hole 62 is formed and The lower portion of the reinforcing bar 38 is to be inserted so that a plurality of insertion holes are installed.

In addition, the prefabricated bracket 70 is installed around the piers (P) is installed at a constant depth on the surface of the lower bed is to be installed on the sandstone 100 made of gravel or crushed stone thereon.

That is, the prefabricated foundation reinforcement structure for piers using the field micro pile and the prefabricated bracket according to the present invention includes a drill hole 10, a field micro pile 30, a fixing unit 60, an anchor 40, a bracket 70, The non-shrink mortar 90, the angle 80 and the dead stone 100 is organically coupled structure, characterized in that to stabilize the piers (P).

Here, the field micro pile 30 is provided with a plurality of reinforcing bars 38 in the drilling hole 10, the spacer 34 made of a cross-shaped flat plate with a constant diameter outside the reinforcing bars 38 is installed, A hole 33 is formed in the central portion of the spacer, an injection pipe 37 is provided in the hole 33, and the grouting agent 50 is poured into the hole 10 to cure.

That is, the spacing agent 34 installed at regular intervals to maintain the spacing of the reinforcing bars 38 installed in the field micro pile 30 is a cross shape having a predetermined thickness, and the reinforcing bars 38 are installed between the cross shapes. In addition, the reinforcing bar (38) is bundled with a binding line (35), a hole (33) formed in the center is formed, and the drilling hole (10) consisting of a connector (36) installed to interconnect the reinforcing bars (38). The curing process is carried out by pouring the grouting agent 50 into the inside.

In particular, the spacer 34 is made of a crisscross shape as a whole and at the same time made of a thick flat plate, and the hole 33 is formed at a predetermined size in the central portion to facilitate the injection of the grouting agent 50. In the four corners of the spacer, a chamfer is formed to have a predetermined curvature.

This is to facilitate the coupling with the reinforcing bar 38 is located at the four corners of the spacer 34 to facilitate the reinforcement by chamfering in the inner round shape of the annular shape of the reinforcement 38 and the cross-sectional shape surrounding it This is to facilitate the position fixing of (38).

In addition, the fixing unit 60 is to be installed in the reinforcing bar 38 extending a predetermined length to the upper portion of the drilling hole 10, the bolt hole 62 is formed in the four corners of the iron plate of a certain size A plurality of insertion holes are installed to allow the reinforcing bar 38 to be inserted into the lower part of the iron plate.

The reason for installing the fixing unit 60 in the field micropile 30 as described above is that the prefabricated bracket 70 on the fixing unit 60 rather than installing the prefabricated bracket 70 directly in the field micropile 30. This is because it is easy to install the prefabricated bracket 70 is enlarged the attachment area.

On the other hand, the prefabricated bracket (70) is formed as a H-shaped steel in a right triangle shape as a whole, a stud is installed to improve the adhesion with concrete therein, formed by pouring concrete, on the fixing unit 60 The horizontal surface of the prefabricated bracket 70 is fixedly installed by bolt fastening, and the vertical surface of the prefabricated bracket 70 is fastened to the anchor 40 to be fixedly installed.

As such, the reason why the prefabricated bracket 70 is installed in the piers P is to increase the bearing capacity for the purpose of stabilizing the piers according to the aging of the piers P and the scour and the increase of the live load.

It describes a method of building a prefabricated foundation reinforcement structure for piers using a field micro pile and a prefabricated bracket according to the present invention made of a structure as described above.

12 (a) to (h) is a construction step diagram showing the construction state of the prefabricated foundation reinforcement structure for piers using the field micro pile and the assembly bracket according to the present invention.

As shown in these drawings, the method of building a prefabricated foundation reinforcement structure for piers using the field micro pile and the prefabricated bracket according to the present invention comprises the steps of removing trench excavation to a part of a certain depth of the surrounding bed for each pier P. ;

Inserting and drilling a casing 20 provided at an end of the excavator to form the drilling hole 10 in the drilled ground to form the drilling hole 10;

A cross-shaped spacer having a hole 33 formed in the center of the reinforcing bar 38 in the longitudinal direction of the reinforcing bar 38 in order to maintain a distance between the plurality of reinforcing bars 38, the injection pipe 37, and the reinforcing bars 38 in the drilling hole 10. (34) and the front and rear reinforcement (38) of the spacer 34 is tied to the binding line 35 and installed, and pouring the grouting agent 50 to install the field micro pile (30);

Inserting a fixing unit (60) into an insertion hole provided in an upper portion of the reinforcing bar (38) installed in the field micro pile (30) and a lower portion of the fixing unit (60);

The prefabricated bracket 70 is connected to the horizontal hole of the prefabricated bracket 70 at the bolt hole 62 installed at the four corners of the fixing unit 60 at the same time as the bolt. Installing and fixing a prefabricated bracket 70 consisting of a right triangle and connecting a vertical surface with an anchor 40 as a whole;

Connecting lower portions of the prefabricated brackets 70 installed around the piers P with L-shaped steels 80;

L-shaped steel connecting the clearance between the horizontal surface of the prefabricated bracket 70 and the prefabricated bracket 70 and the fixing unit 60 and the vertical surface of the prefabricated bracket 70 and the piers P and the prefabricated bracket 70. Pouring the non-contraction mortar 90 into 80;

Excavating and removing residual soil between the prefabricated brackets 70;

It includes the step of laying a sandstone 100, such as gravel or crushed stone of various sizes to the lower surface of the piers (P) of the excavated portion.

That is, the method for constructing a prefabricated foundation reinforcement structure for piers using a field micro pile and a prefabricated bracket according to the present invention, as shown in Figure 12 (a) to (h), trench excavation removal step, drilling hole forming step, site Micro pile installation step, rebar insertion step, prefabricated bracket installation step, L-shaped steel connection step; Non-contraction mortar curing step; The remaining soil excavation step and the filling step of the sandstone are carried out sequentially to build the structure for improving the bearing capacity of the piers and preventing scour.

Here, the trench excavation removing step is to excavate and remove a portion of the surrounding lower bed at a certain depth for each pier P, and the base portion of the pier P using the backhoe sub to the adjacent portion of the pier P. At the same time to excavate the bed to a certain depth to make a step to maintain the excavation site (T) in a horizontal state.

Subsequently, the drilling hole forming step inserts and drills the casing 20 installed at the tip by using an excavator such as a crawler drill to form the drilling hole 10 at the excavated drilling site T. In the forming step, the casing 20 prevents the side wall on which the perforation hole 10 is formed from collapsing.

Thereafter, the fixing unit installation step is to install the fixing unit 60 by inserting the insertion hole of the fixing unit 60 in the upper portion of the reinforcing bar 38 installed in the field micro pile 30.

The reason for installing the fixing unit 60 on the field micro pile 30 as described above is to widen the attachment surface with the prefabricated bracket 70 installed on the fixing unit 60. It is much easier to install the prefabricated bracket 70 by using the fixing unit 60 than to attach the prefabricated bracket 70 directly to 30, so that the mounting area can be easily expanded so that the prefabricated bracket 70 can be easily installed. For sake.

Subsequently, the installation step of the prefabricated bracket 70 is made of H-shaped steel so as to be made in a right triangle shape as a whole, and a stud is installed in order to improve adhesion with concrete therein, and the prefabricated bracket 70 in which concrete is poured is fixed to the fixing part. The horizontal surface of the prefabricated bracket 70 is connected to the bolt hole 62 of the bolt 60 and at the same time, the vertical surface of the prefabricated bracket 70 is connected to the boring hole formed at the lower end of the pier by the anchor 40. This step is to increase the bearing capacity of the piers (P).

Subsequently, the prefabricated brackets 70 are connected to their lower parts using the L-shaped steel 80.

Here, the prefabricated bracket 70 has the effect of improving the overall construction speed by using the manufactured in the factory or the field.

Thereafter, the non-shrinkage mortar pouring step is a gap between the horizontal surface of the prefabricated bracket 70 and the prefabricated bracket 70 and the fixing unit 60 and between the vertical surface of the prefabricated bracket 70 and the piers P. Filling the gap and the connection part by pouring the non-shrink mortar 90 between the gap and the prefabricated bracket 70 and the L-shaped steel (80).

That is, the hardware consisting of a variety of bolts, nuts and anchors 40 connected to the prefabricated bracket 70 is connected to the non-shrink mortar at these connections because it is ultimately broken by water when exposed to water intact ( 90) and cure for a certain period of time.

Therefore, since the surface of the iron is covered with the non-shrink mortar 90 as described above, not only does it prevent the hardware from rusting from the influence of water, but the steel is rusted and contaminated the river because the rust is not exposed to the outside even if it is rusted. It has the effect of preventing it.

Subsequently, the residual soil excavation step is a step of excavating and removing the residual soil between the prefabricated brackets 70.

Lastly, the sandstone laying step is filled with the sandstone 100 to the lower surface of the prefabricated bracket 70 and the piers P. After reinforcing the foundation of the piers P, plate excavation around the piers P is spared. Filling the sand (100), such as gravel or rubble, mortar of various sizes in the site (T), is a step of recovering the excavation site (T) so that the impact of shaking or scouring of the bracket (70).

The prefabricated foundation reinforcement structure for the piers using the field micro pile and the prefabricated bracket according to the present invention having the configuration and construction as described above, and the construction method thereof, are oriented by reducing the front trench of the piers P during train operation. Stability can be achieved in front, rear, left and right of P), and the water flow cross-sectional area decreases and decreases due to the foundation reinforcement of the piers (P), and can be solved by backfilling the excavation site (T). The construction speed can be improved in consideration of the seasonal characteristics of the river construction, and the efficient operation of the equipment can be achieved by eliminating the restriction of the geometry space due to the superstructure in the longitudinal direction of the piers (P). By adopting (30), there is an effect that can compensate for the shortcomings of the gravitational piers (P) foundation.

As described above, the prefabricated foundation reinforcement structure for bridge piers using the field micro pile and the prefabricated bracket according to the present invention and the construction method thereof have the following effects.

First, the prefabricated foundation reinforcement structure for piers using the field micro pile and the prefabricated bracket according to the present invention installs the field micro pile in the ground adjacent to the outside of the piers, and installs the prefabricated bracket on the field micro pile, Prevents scour, and improves the bearing strength of the ground, which has the advantage of stabilizing the pier.

Second, the prefabricated foundation reinforcement structure for bridge piers using the field micro pile and the prefabricated bracket according to the present invention can improve the bearing strength in the ground due to the field micro-pile using reinforcing bars and the grouting agent placed on the field micro-pile.

Third, the prefabricated basic reinforcement structure for piers using the field micro pile and the prefabricated bracket according to the present invention is improved by using the prefabricated bracket manufactured in the factory or the field, thereby improving the construction speed of the base reinforcement, and improving stability and economic efficiency. There is an advantage.

That is, because the brackets manufactured in the factory or the field is installed on the field micro pile separately, the construction speed of the foundation reinforcement of the piers is fast, and there is an advantage of suppressing displacement of the existing structure due to construction delay after excavation.

Fourth, the prefabricated foundation reinforcement structure for piers using the field micro pile and the prefabricated bracket according to the present invention has the advantage that can increase the efficiency due to the anchor installation in the required location of the piers.

Fifth, the prefabricated foundation reinforcement structure for piers using the field micro pile and the prefabricated bracket according to the present invention has the advantage that the influence of the limitation of the geometry space in the longitudinal direction of the piers does not occur.

Sixth, since the prefabricated foundation reinforcement structure for piers using the field micro pile and the prefabricated bracket according to the present invention do not have a separate cross section when the foundation of the lower surface of the piers is reinforced, it maintains the same flow of the existing flow. There is an advantage to running water.

That is, since trench excavation of the adjacent part of the piers, field micro piles and brackets are installed at the excavation sites, and the excavation between the brackets is filled with sandstones, the volume of the piers is not increased, so the cross section of the piers is not necessary. There is little advantage in the flow of the flowing water before and after the foundation reinforcement work of the bridge.

Seventh, the prefabricated foundation reinforcement structure for piers using the field micro pile and the prefabricated bracket according to the present invention has little rust to the outside because the field micro pile is inserted into the ground, so it does not pollute the river has an environmentally friendly advantage.

Eighth, the prefabricated foundation reinforcement structure for piers using the field micro pile and the prefabricated bracket according to the present invention has the advantage that the construction speed of the foundation reinforcement can be improved by simultaneously drilling a plurality of piers symmetrically.

Ninth, the prefabricated foundation reinforcement structure for piers using the field micro pile and the prefabricated bracket according to the present invention is installed in the lower section between the brackets, because the brackets and excavation of the piers filled with sandstone, the bracket shakes due to external influences There is an advantage that does not occur phenomenon that occurs or the lower part of the piers.

Tenth, the prefabricated foundation reinforcement structure for bridge piers using the field micro pile and the prefabricated bracket according to the present invention can perform the foundation reinforcement work irrespective of the vibration generated by the train operation on the upper part of the bridge during the foundation reinforcement work of the piers There is an advantage.

Claims (6)

A perforation hole symmetrically around the piers with a predetermined diameter and depth in the ground; A field micro pile inserted into the drilling hole by a predetermined depth and embedded in the ground; A fixing unit installed on an upper part of the reinforcing bar installed in the field micro pile; The horizontal surface of the prefabricated bracket is connected to the bolt hole of the fixing unit at the same time, and the vertical surface of the prefabricated bracket is connected to the anchor at the perforated hole formed at the lower end of the piers. A plurality of prefabricated brackets installed and connected to each other by L-shaped steel; A non-shrink mortar that is pour-cured to fill the gap between the prefabricated bracket and the horizontal surface of the prefabricated bracket and the fixing unit, and the vertical surface and the piers of the bracket; A prefabricated prefabricated structure for piers using on-site micro piles and prefabricated brackets, by installing gravel or crushed stone of various sizes between the prefabricated brackets and around the piers to prevent crushing of the riverbed around the piers. The method of claim 1, wherein the field micro pile is a spacing agent installed at regular intervals so that the spacing of the plurality of reinforcing bars and the injection pipe and the reinforcement in the drill hole made of a predetermined diameter and length; Prefabricated foundation for piers using on-site micro piles and prefabricated brackets, characterized in that the grouting agent is poured into the drilled hole, which consists of connecting wires tied at regular intervals to connect the reinforcing bars with each other. Reinforcement structure. The method according to claim 1 and 2, Spacers installed at regular intervals in order to maintain the spacing of the reinforcing bars installed in the field micro pile as a cross shape having a certain thickness so that the reinforcing bars are installed between the cross shape, install an injection pipe in the hole formed in the center, A prefabricated foundation reinforcement structure for piers using field micro piles and a prefabricated bracket, characterized in that the grouting agent can be poured using the injection pipe. The method of claim 1, The fixing unit is to be installed in the reinforcing bars extending a predetermined length to the upper portion of the drilling hole, characterized in that a bolt hole is formed in a square iron plate square of a predetermined size and a plurality of insertion holes are installed so that the reinforcing bars can be inserted in the lower portion of the iron plate. Prefabricated reinforcement structure for piers using field micro piles and prefabricated brackets. The method of claim 1, The prefabricated bracket is installed around the piers, but is installed at a constant depth from the surface of the lower bed, the gravel or crushed stone is installed on it, the prefabricated foundation reinforcement structure for the piers using the prefabricated brackets and field micro piles. Trench excavating the bottom bed around the pier to a constant depth; Inserting and excavating a casing installed at the tip of the excavator to form a drilled hole in the drilled ground to form a drilled hole; In order to maintain the spacing of a plurality of reinforcing bars and injection pipes and reinforcing bars in the perforation holes, cross-shaped spacers formed with holes in the center of the reinforcing bars in the center and reinforcing bars before and after the spacers are installed by tying the binding lines and curing Installing an on-site micro file; Installing a fixing unit in an insertion hole provided in an upper part of the reinforcing bar installed in the field micro pile and a lower part of the fixing unit; The prefabricated bracket made of a right triangle is installed by connecting the vertical surface of the prefabricated bracket with an anchor to the boring hole formed at the bottom of the pier by connecting the bolt with the horizontal surface of the prefabricated bracket to the bolt hole installed at the four corners of the fixing unit. Fixing; Connecting the lower parts of the prefabricated brackets installed around the piers with L-shaped steels; Pouring a non-shrink mortar into the L-shaped steel interconnecting the clearance between the horizontal surface and the fixing part of the prefabricated bracket and the prefabricated bracket, the gap between the vertical surface and the piers of the prefabricated bracket, and the prefabricated bracket; Excavating and removing residual soil between the prefabricated brackets; Method of building a prefabricated foundation reinforcement structure for piers using on-site micro piles and prefabricated brackets comprising the step of laying a sandstone made of gravel or crushed stone of various sizes up to the pier bottom surface of the excavated portion.