KR100938916B1 - Downward method by front reaming - Google Patents

Abstract

PURPOSE: A Top-down construction method through front end extension is provided to maximize bearing force of the tip of a column by constructing the front end of a column so that a stud meets the extension portion of the front end. CONSTITUTION: A Top-down construction method through front end extension comprises the steps for: constructing a retaining wall; vertically excavating from the position of a column(200) over the ground to the position of concrete bulb of the lowermost layer mat foundation; expanding the excavation caliber by executing horizontal excavation or executing horizontal excavation and perpendicular excavation by turns to the concrete bulb position of the lowermost layer mat foundation; constructing a column in the excavated column position forming the front end of the column as concrete bulb(200c) by filling expanded excavation portion under the mat foundation with concrete; constructing an interlayer structure; blasting; repeatedly executing the above process to the lowermost layer; executing the last blasting to the mat foundation position; and constructing the mat foundation.

Description

Downward Method by Front Reaming

The present invention relates to a reverse drilling method through a tip expansion that can improve the overall construction efficiency and construction economics by minimizing the drilling diameter for the pillar construction in the reverse drilling method.

Downward method (Downward method) is a method that allows the ground works to be carried out at the same time in some cases while proceeding to build a basement floor gradually from the ground floor. This reverse drilling method is possible to shorten the air by the combination of the trench and the ground work, and to secure the structural stability by using the permanent structure as the support of the earth wall, and it has the advantage of low noise and vibration, Is in the spotlight.

In the reverse drilling method, the column must support the construction load, so it must be constructed to exert sufficient end support force. Usually, the tip support of the column is solved by expanding the column tip in the column construction process.

In the reverse drilling method, pillar construction is carried out with excavation of a predetermined diameter, and so far excavation construction has been carried out by determining the excavation diameter with the diameter of the tip of the pillar to be constructed. In other words, the excavation equipment for normal vertical excavation at the position of the pillar is to excavate with a diameter corresponding to the tip of the pillar to be constantly constructed up to the basement depth of the basement floor.

However, the above excavation work is not efficient because it is a method to excavate more than necessary in other parts other than the tip of the column, and in addition, it is inevitable to increase the construction cost due to the use of a large excavation equipment because it is a method of excavating a large diameter.

The present invention has been developed to solve the column construction problem in the conventional reverse drilling method has the following technical problem.

First, the reverse drilling method aims to improve construction efficiency and construction economy by minimizing the digging diameter for pillar construction.

Second, the reverse drilling method is intended to provide a way to maximize the bearing capacity of the column tip to be constructed prior to the excavation.

The present invention to solve the above technical problem, (a) constructing a wall; (b) vertical excavation with a constant aperture from the ground column position to a concrete bulb formation position below the basement floor mat depth; (c) expanding the excavation aperture while performing horizontal excavation from the mat base position to the concrete bulb forming position or in parallel with the horizontal excavation and the vertical excavation; (d) constructing the pillar at the excavated pillar position, and filling the concrete in the expanded excavated portion below the mat-based position to form the tip of the pillar as a concrete bulb; (e) constructing the interlayer structure; (f) excavating; (g) repeating the steps (e) and (f) to the lowest layer every floor, but the final gulting process proceeds to the mat base position; And, (h) constructing the mat base; provides a reverse drilling method through the tip expansion, characterized in that comprises a.

According to the present invention, the following effects can be expected.

First, since the drilling diameter for the construction of the pillar can be minimized in the reverse drilling method, the excavation work can be performed smoothly and quickly. Accordingly, the reverse drilling method can be economically performed while improving the overall workability.

Second, since the column tip can be constructed so that the studs extend to the expanded portion of the tip, it is possible to maximize the bearing capacity of the column tip.

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

1A to 1H illustrate the reverse punching method according to the present invention in the construction order, and the present invention will be described step by step with reference to these drawings.

(a) construction of the retaining wall-Fig. 1a

Construct the earth wall 100 according to the construction line. The barrier wall 100 may be constructed as an H continuous pile, earth plate, CIP, SCW, sheet pile, etc., as well as underground continuous wall (slurry wall).

(b) Vertical excavation- FIG. 1B

Excavate vertically with a constant aperture from the position of the column on the ground to the position of concrete bulb formation below the basement depth of the basement floor. For vertical excavation, appropriate excavation equipment should be used considering the ground conditions. The present invention proposes an excavating equipment having an extended hammer as shown in FIGS. 2A to 2E as an example of an excavating equipment, and can use the excavating equipment to proceed vertical drilling of a constant diameter.

(c) Digging Excavation- FIG. 1B

Under the mat base position, the excavation aperture is extended by horizontal excavation or parallel drilling and vertical excavation from the concrete bulb formation position. In other words, the expansion of the tip end is carried out.

Expansion excavation is made possible by further excavating the side portion of the excavation hole which has already been vertically excavated, and the side excavation is made possible by using an excavation equipment having a side bit tip B21. Side excavation can be proceeded by repeating the horizontal excavation while changing the position of the side bit tip (B21) at the corresponding position, and also using the excavating equipment having a bottom bit tip (B22) with the side bit tip (B21) In this position, the horizontal drilling of the first side bit tip (B21) and then the vertical drilling of the bottom bit tip (B22) may proceed. In the present invention, as an example of the excavation equipment for expansion excavation, the excavation equipment having an expansion hammer as shown in Figures 2a to 2e proposes, the expansion hammer of this drilling equipment side bit tip (B21) and bottom bit tip (B22) This excavation equipment can be used to expand and drill both horizontal and vertical excavation.

(d) Column construction- Fig. 1b

Construct the pillar 200 in the excavated pillar position. At this time, by filling the concrete in the expanded excavated portion below the mat base position to form the tip of the column 200 as a concrete bulb (200c). Since the concrete is filled up to the expanded portion, the concrete bulb 200c is formed wide, whereby the supporting force of the column tip portion 200a is stably secured through the concrete bulb 200c.

The pillar construction process includes: (d1) inserting the pillar 200 into the excavated pillar position; (d2) positioning the pillars 200; (d3) filling the concrete to form a concrete bulb (200c); can be subdivided into. At this time, the step (d2) may be performed by fixing the pillar 200 to the temporary seat while holding the center of the pillar after installing the temporary seat on the ground, in which case the pillar 200 floats about 1 m from the ground floor. It is preferable to fix in a state that is to ensure the stable formation of the concrete bulb (200c).

On the other hand, in the present invention, the pillar 200 may be any shape such as RC pillar, steel pillar, PC pillar, CFT pillar, etc., and in any case, the concrete bulb 200c by cast-in-place concrete may be formed. However, in the case of construction with dry materials such as steel pillars, PC columns, CFT columns, prepared with a pillar 200 having studs 220 and 230 at the tip, and the stud 220 is expanded and excavated below the mat base position. Located in the part is constructed to be embedded in the concrete bulb (200c). This is to reinforce the supporting force of the column tip portion (200a). Furthermore, the studs 220 and 230 may be prepared as a pillar 200 in which the folding is combined, and the pillar 200 is inserted into the pillar position where the studs 220 and 230 are folded, and the studs 220 and 230 are folded. ) Reaches the expanded excavated part of the mat base position and is installed in the unfolded state. The pillar 200 of the folding stud structure can be prepared and installed as shown in Figures 3 to 5, the specific shape and installation method for the pillar 200 of the folding stud structure will be described later.

(e) Interlayer Structure Construction- FIG. 1E

The interlayer structure 300 (beams and slabs) is constructed. Prior to construction of the interlayer structure 300, a part of the gulting work may be performed to secure a construction space. The interlayer structure 300 is preferably constructed so as to directly support the retaining wall 100, because it does not use a separate temporary brace. The interlayer structure 300 may be constructed in various structural forms according to the secured construction space, and furthermore, it may be constructed while appropriately using a copper bar system as well as an unsupported formwork system.

(f) Oyster-Fig 1f

Considering the support state of the retaining wall 100 is carried out to the extent that the construction space can be secured downstairs.

(g) Repeated construction-Fig 1g

Steps (e) and (f) are repeated repeatedly to the lowest layer. At this time, the last gulto process proceeds to the last matulite position.

(h) Mat foundation construction-Fig. 1h

Construct a mat base (400). The construction of the mat base 400 is completed the bottom of the basement floor. After the mat foundation 400 is constructed, the work for increasing the cross section of the pillar may be further performed around the pillar 200 in some cases.

Figures 2a to 2e shows an example of the extended hammer that can be preferably used as a drilling equipment in the excavation step in performing the reverse drilling method according to the present invention.

The expansion hammer is composed of a hammer body (A), air hammer (B), hydraulic cylinder (C), lifting block (D), as such an expansion hammer is coupled to the bottom of the connecting rod (a) assembled in the excavator and multi-stage Completed with horizontal excavation equipment.

The hammer body (A) has a cylindrical shape as a whole, and the upper end of the hammer body (A) is coupled to the lower end of the connecting rod (a) assembled with the excavator and the multi-stage, and accordingly the hammer body (A) rotates as the connecting rod (a) rotates. ) Rotates together to perform excavation work. The hammer body (A) is arranged in a plurality of regular intervals of the open portion (A1) is cut open in the vertical direction to the side of the connecting rod (a), each of these openings (A1) is equipped with an air hammer (B) . Compressed air is supplied into the air hammer (A) through an air tube (b) connected to the upper end of each of the air hammer (B) through the connecting rod (a) and the upper end of the hammer body (A).

Air hammer (B) is installed in each of the opening portion (A1) of the hammer body, as shown in Figures 2c and 2d is accommodated in a state where the lower end of the air hammer (B) spread outward. The upper portion of the air hammer (B) is pinned to the hammer body (A) in the open portion (A1) can be rotated, the lower portion of the air hammer (B) is equipped with a hammer bit (B2). The hammer bit B2 has a side bit tip B21 on the side and a bottom bit tip B22 on the bottom. In addition, the inside of the air hammer (B) is provided with an upper air chamber and a lower air chamber, as in the general air hammer and is provided with a piston that operates up and down, a detailed description thereof will be omitted. However, a specific shape of the back head B3 and the back head connecting boss B4 connected to the air tube b is shown in FIG. 2E, and the back head B3 installed inside the air hammer B is The ball bearing type, and the back head connecting boss (B4) for connecting it has a spherical shape to accommodate the ball head-type back head (B3).

Hydraulic cylinder (C) is mounted to the central portion of the upper inner surface of the hammer body (A) as shown in Figures 2c and 2d, the lifting block (D) is coupled to the lower end of the piston rod (C1) of the hydraulic cylinder.

Lifting block (D) is coupled to the lower end of the piston rod (C1) of the hydraulic cylinder as shown in Figure 2b, the hydraulic cylinder (C) with the outer surface of the lifting block (D) in contact with each of the air hammer (B). ) Ascending and descending. As the lifting block D rises, each of the air hammers B is pushed outward to open the air hammer B, thereby increasing the excavation radius of the hammer bits B2. Lead pipe (B1) is preferably provided in each of the air hammer (B) in the longitudinal direction as shown in Figure 2c and 2d to guide the lifting operation of the lifting block (D). In addition, the lifting block (D) is provided with a guide groove (D1) is cut in the vertical direction at the position corresponding to the lead pipe (B1) as shown in Figure 2b to accommodate the lead pipe (B1) is provided with a lifting block When the elevating operation of (D) the lead pipe (B1) is maintained in the state accommodated in the guide groove (D1) can be made stable up and down operation. Guide groove (D1) has a narrow outer inlet and a wide structure inside the lead pipe (B1) is accommodated in the guide groove (D1) coupled to the lifting operation is possible, but the lead pipe (B1) guide groove ( It is not easy to deviate from D1). This lifting block (D) has an inclined surface toward the center so that the cross-sectional area gradually increases toward the bottom as shown in Figure 2b, the guide groove (D1) also inclined together along the inclined surface of the lifting block (D) It is preferably formed to

In the case of Figure 2c shows the position of the elevating block (D) and the air hammer (B) during the first excavation work, the elevating block (D) is lowered and located in the lower portion of the hammer body (A) because of the air hammer ( B) is also collected around the lifting block (D) to minimize the excavation radius. 2d shows the positions of the elevating block (D) and the air hammer (B) in the expansion operation through the second excavation, the elevating block (B) is raised by the operation of the hydraulic cylinder to the hammer body (A) Move to the top of the air hammer (B) is also spread out by the lifting block (D) to expand the excavation radius. By operating the air hammer (B) while rotating the connecting rod (a) and raising the lifting block (D) in this manner, as shown in FIG. have.

3 to 5 show an embodiment of the tip-extended pillar proposed to be preferably applied to the reverse drilling method through the tip expansion described above. These tip extension pillars have a common feature in that the studs 220 and 230 are mounted in a folding manner. The foldable studs 220 and 230 are intrusive in a state where they are in contact with each other, and expand at the expanded excavated portion, thereby expanding the column tip portion 200a.

3 is an example of the tip-extended pillar member composed of the pillar body 210 and the stud 220. The pillar body 210 is manufactured in a pillar shape of steel or PC. The stud 220 is foldably coupled to the distal end of the pillar body 210, and specifically, the stud 220 includes first and second rotary shafts 221 and 223 and upper and lower wings 222 and 224. The first rotary shaft 221 is configured to be fixed to the end of the pillar body 210, the upper blade 222 is connected to the first rotary shaft 221 is the pillar body 210 in accordance with the rotation of the first rotary shaft 221 ) Is configured to rotate toward the outside, the second rotary shaft 223 is a configuration fixed to the lower end of the upper blade 222, the lower blade 224 is connected to the second rotary shaft 223 is connected to the second rotary shaft 223 Rotation toward the pillar body 210 according to the rotation of the). The stud 220 of this configuration should be provided so that the lower end of the lower wing 224 is lowered below the pillar body 210 in a state in which the upper blade 222 is folded toward the pillar body 210. Thus, when the pillar 200 is inserted into the pillar position, the lower end portion of the lower wing 224 than the pillar body 210 first touches the ground to press the ground bottom to induce rotation of the first and second rotation shafts 221 and 223. can do. As the angle between the upper blade 222 and the lower blade 224 decreases due to the rotation of the first and second rotary shafts 221 and 223, the second rotary shaft 223 gradually moves away from the pillar body 210, thereby studs. As the 220 is formed to protrude out of the pillar body 210, the pillar tip portion 200a is extended.

4 is an example in which the stud 220 further includes a support plate 226, a recess 226a, and a protrusion 224b in the tip extension pillar of FIG. 3. The support plate 226 is configured to be installed in the pillar body 210 under the first rotation shaft 221, the groove 226a is configured to be formed in the middle of the support plate 226, and the protrusion 224b is the groove 226a. The lower blade 224 is configured to protrude inwardly, and these additional components have a protrusion 224b in the state where the upper blade 222 is folded toward the pillar body 210. 226a) it should be placed in close contact with the support plate 226 below. The projection 224b is provided so as to lean against the support plate 226 so that the acupressure force (protrusion force pushing the support plate) of the projection 224b acts on the support plate 226. Thus, when the lower end portion of the lower blade 224 presses the ground bottom, when the rotation of the first and second rotation shafts 221 and 223 is induced, the protrusion 224b pushes the support plate 226 and moves upward along the support plate 226. It can be fitted into the groove 226a, and furthermore, the projection 224b can be fixed to the protrusion 224b in a state of being fitted into the groove 226a. In this case, the protrusion 224b and the groove 226a are preferably in the shape as shown in FIG. 3 (b). This shape is such that the protrusion 224b slides into the groove 226a and is easily fitted into the groove once. 226a) so that it hardly falls out.

Furthermore, in FIG. 4, the stud 200 is further configured to further include a guide tube 227, a horizontal bar 228, and a guide bar 229. Guide tube 227 is a configuration that is installed in the vertical direction to the column body 210 on both sides with the lower wing 224 or the upper wing 222 between, the horizontal bar 228 between the lower wing 224 It is configured to be mounted on the lower wing 224 so as to protrude horizontally on both sides, the guide bar 229 is inserted so as to pass freely through the guide tube 227 while the lower end is coupled to the end of the horizontal bar 228 . With this additional configuration, the bearing pressure of the protrusion 224b can be stably acted on the support plate 226. That is, since the guide bar 229 is inserted into the guide tube 227 and restrained, the lower blade 224 connected to the guide bar 229 through the horizontal bar 228 is also restrained by the guide tube 227. As the lower end of the lower blade 224 presses the ground bottom, when the rotation of the first and second rotation shafts 221 and 223 is induced, the lower blade protrusion 224 is constrained to the guide tube 227 and the protrusion of the lower blade ( 224b moves upward while pushing the support plate 226.

On the other hand, in the column as shown in Figures 3 and 4, the stud 220 is preferably provided with a bent portion 224a bent toward the outside of the pillar body 210, the lower blade 224, which is the lower wing This is to induce a stable rotation of the first and second rotation shafts 221 and 223 by continuously contacting the bottom of the lower blade 224 to the bottom in the process of folding (224). In addition, the outer surface of any one of the lower wing 224 or the upper wing 222 in the stud 220 may be provided with a projection piece 225 to protrude, and the projection piece 225 and the concrete bulb (200c) To strengthen the integrity of

5 is an example of a tip-extended pillar in which the column tip portion 200a is composed of an outer pillar 240, an inner pillar 250, and a stud 230. The tip-extended pillar has a post-extended column 200b is composed of a portion in which any one or more of the outer column 240 and the inner column 250 is extended, in FIG. 5, the column rear end 200b is the outer column 240. You can see the shape consisting of this extended part.

Outer column 240 is made of steel or PC tubular, the through-hole 241 is formed. The inner pillar 250 is made of steel or PC and is inserted into the outer pillar 240, and a spacer is disposed on the outer surface of the inner pillar 250 to insert the inner pillar 250 into the inner center of the outer pillar 240. 251 may be mounted. The stud 230 is coupled to the inner surface of the inner cylinder 250 foldable, specifically, the stud 230 is composed of a central axis of rotation 231 and the blade 232. Rotation center axis 231 is a configuration that is fixed to the inner pillar 250, the rotary blade 232 is connected to the rotation center axis 231 in a configuration having a size passing through the through-hole 241 of the outer pillar It is configured to rotate in accordance with the rotation of the rotation center axis (231). The stud 230 of this configuration should be installed so that the end of the rotary blade 232 spans the through-hole 241 of the outer pillar with the rotary blade 232 folded toward the inner cylinder 250. Thus, when pushing or pulling any one of the outer column 240 or the inner column 250, the rotary blade 232 of the folded state is unfolded and protrudes through the through-hole 241 of the outer column, as a result of the column The tip end is extended. In FIG. 5, the outer blade 240 may be pushed down to check the unfolded state of the rotary blade 232 by pressing the rotary blade 232 with the outer pillar 240.

The present invention has been described in detail above with reference to specific embodiments, but the embodiments are only for illustrating the present invention, and thus the embodiments substituted, added, and modified within the scope without departing from the spirit of the present invention are also described below. It will be said to belong to the protection scope of the present invention as defined by the claims appended hereto.

1A to 1H show the construction sequence of the reverse perforation method according to the present invention.

Figure 2a to 2e shows an example of the horizontal excavation drilling equipment used in the reverse drilling method according to the present invention.

3 to 5 show an embodiment of the tip-extended pillar member used in the reverse drilling method according to the present invention.

<Description of the symbols for the main parts of the drawings>

100: retaining wall

200: pillar

210: pillar body

220, 230: stud

240: outer pillar

250: inner pillar

300: interlayer structure

400: mat base

Claims (8)

delete delete (a) constructing an earthquake wall 100; (b) vertical excavation with a constant aperture from the ground column position to a concrete bulb formation position below the basement floor mat depth; (c) expanding the excavation aperture while performing horizontal excavation from the mat base position to the concrete bulb forming position or in parallel with the horizontal excavation and the vertical excavation; (d) constructing the pillar 200 at the position of the excavated pillar, and filling the concrete in the expanded excavated portion under the mat-based position to form the tip portion of the pillar 200 as a concrete bulb 200c; (e) constructing the interlayer structure 300; (f) excavating; (g) repeating the steps (e) and (f) to the lowest layer every floor, but the final gulting process proceeds to the mat base position; And, (h) constructing the mat base 400; is made, including, The pillar 200 of step (d), The stud 220 is configured to include; a pillar body 210 made of steel or PC; and a stud 220 provided on an outer surface of the tip end portion of the pillar body 210. A first rotation shaft 221 fixed to the tip end of the pillar body 210; An upper blade 222 connected to the first rotation shaft 221 and rotating toward the outside of the pillar body 210 according to the rotation of the first rotation shaft 221; A second rotating shaft 223 fixed to the lower end of the upper blade 222; And a lower blade 224 connected to the second rotating shaft 223 and rotating toward the pillar body 210 according to the rotation of the second rotating shaft 223. ) Is provided so that the lower end of the lower wing 224 is lowered below the pillar body 210 in a state in which the pillar body 210 is folded toward the pillar body 210. In step (d), (d1) penetrating and installing the pillar 200 at the excavated pillar position in a state in which the upper blade 222 of the stud is folded toward the pillar body 210; (d2) As the lower wing 224 of the stud touches the ground bottom and presses the ground bottom, the second rotating shaft 223 is guided by the pillar body 210 while inducing rotation of the first and second rotating shafts 221 and 223. Expanding the column tip by moving away, and then fixing the column 200 in position; (d3) filling concrete to form concrete bulbs 200c while purchasing studs 220; Reverse punching method through the tip expansion, characterized in that consisting of. In claim 3, The stud 220 of the pillar, A support plate 226 mounted to the pillar body 210 under the first rotation shaft 221; And, Grooves (226a) formed in the middle of the support plate (226); A protrusion 224b having a shape fitted into the groove 226a and protruding from the inner side of the lower wing 224; It is configured to further include, wherein the projection 224b in the state in which the upper wing 222 is folded toward the pillar body 210 is characterized in that the device is installed so as to lean close to the support plate 226 under the groove 226a. Reverse punching method through tip expansion. In claim 4, The stud 220 of the pillar, A guide tube 227 disposed vertically to the column body 210 on both sides of the lower wing 224 or the upper wing 222 therebetween; A horizontal bar 228 mounted on the lower blade 224 to protrude horizontally to both sides with the lower blade 224 therebetween; And, A guide bar 229 inserted into the guide tube 227 to be freely passed through, and having a lower end coupled to an end of the horizontal bar 228; Reverse punching method through the tip expansion, characterized in that the configuration further comprises. The method according to any one of claims 3 to 5, The stud 220 of the pillar, The lower perforation through the tip expansion, characterized in that the lower end of the lower blade 224 is provided with a bent portion (224a) bent toward the outside of the pillar body (210). The method according to any one of claims 3 to 5, The stud 220 of the pillar, A projection piece 225 provided to protrude on the outer surface of either the lower wing 224 or the upper wing 222; Reverse punching method through the tip expansion, characterized in that further comprises a. (a) constructing an earthquake wall 100; (b) vertical excavation with a constant aperture from the ground column position to a concrete bulb formation position below the basement floor mat depth; (c) expanding the excavation aperture while performing horizontal excavation from the mat base position to the concrete bulb forming position or in parallel with the horizontal excavation and the vertical excavation; (d) constructing the pillar 200 at the position of the excavated pillar, and filling the concrete in the expanded excavated portion under the mat-based position to form the tip portion of the pillar 200 as a concrete bulb 200c; (e) constructing the interlayer structure 300; (f) excavating; (g) repeating the steps (e) and (f) to the lowest layer every floor, but the final gulting process proceeds to the mat base position; And, (h) constructing the mat base 400; is made, including, The pillar 200 of step (d), The outer column 240 is made of steel or PC tubular and formed through-hole 241; An inner pillar 250 made of steel or PC and inserted into the outer pillar 240; And a stud 230 coupled to an outer surface of the inner pillar 250; a pillar tip portion 200a is formed, and the pillar is a portion in which at least one of the outer pillar 240 and the inner pillar 250 extends. As the rear end 200b is configured, the stud 230 of the pillar, A rotation center shaft 231 fixed to the inner pillar 250; and a size passing through the through hole 241 of the outer pillar and connected to the rotation center shaft 231 to be connected to the rotation center shaft 231. Rotating blade 232 that rotates in accordance with the rotation; while the rotary blade 232 is folded toward the inner cylinder 250, the end of the rotary blade 232 is the through hole 241 of the outer pillar Is designed to span) In step (d), (d1) injecting and installing the pillar 200 into the excavated pillar position in a state in which the rotary blade 232 is folded toward the inner pillar 250; (d2) The tip of the column 200a by protruding through the through-hole 241 of the outer column while spreading the rotary blade 232 in the folded state by pushing or pulling any one of the outer column 240 or the inner column 250. ) And then fixing the column 200 in position; (d3) filling concrete to form concrete bulbs 200c while purchasing studs 230; Reverse punching method through the tip expansion, characterized in that consisting of.

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