KR20190006671A - Structural continuation method of reinforcing concrete structure and earth transitional zone - Google Patents

Abstract

The present invention relates to a structural continuation method of a reinforcing concrete structure and an earth transitional zone. According to the present invention, the structural discontinuity caused by a difference in material stiffness can be overcome between a wall structure and a backside earth portion, and thus it is possible to prevent the settlement of the earth portion and lateral oscillation of the wall structure attributable to the difference in material stiffness. The construction method includes (a) a step of causing initial settlement and increasing the stiffness of an embankment of an earth transitional zone by performing multi-layer installation and tramping of geogrid extending to the back side of both wall structures constructed as a reinforcing concrete structure after bed excavation, (b) a step of reducing the earth pressure acting on the two-wall structure by integrating the embankment and the two-wall structure; and (c) a step of preventing lateral oscillation of the two-wall structure by integrated formation of both ends between the upper ends of the two-wall structure and generation of horizontal resistance at the upper end of the two-wall structure.

Description

TECHNICAL FIELD [0001] The present invention relates to a structural continuous construction method for a reinforced concrete structure and an earth connection,

BACKGROUND OF THE INVENTION Field of the Invention [0002] The present invention relates to a method of constructing a structural continuous structure of a reinforced concrete structure and a ground contact portion. More specifically, it is possible to overcome the structural discontinuity caused by the difference in material stiffness between the wall structure and the soil at the back surface, and to prevent the settlement of the soil due to the difference in material stiffness and the lateral flow of the wall structure, And a method for constructing a structural continuity of the earth connection portion.

FIG. 1A is a view showing a bridge connecting structure between a bridge and a railway in a conventional railway slab track structure. The bridge 10 is composed of a concrete treated gravel 30, an underfill and an underfill, a concrete treated road 40, As shown in FIG.

That is, in the case of a road bridge, a railroad bridge, etc., the alternation 10 is mainly composed of reinforced concrete, and the earth connection portion formed on the rear surface thereof is reinforced by the concrete treated gravel 30, As shown in A, the earth contact portion sinks due to the difference in material rigidity, and it can be seen that the portion where the alternating portion 10 contacts with the earth connection portion is easily buried.

Further, as shown in FIG. 1B, Japanese Patent No. 10-1507523 (railway slab track structure having a grid-type approach block and its construction method) filed and registered by the applicant of the present invention is also introduced.

A concrete treated gravel (30) installed on the back surface of the alternation (10) so as to secure the end supporting force at the girder (11) of the bridge and the earth connection portion of the railway; A bottom embankment 50 laminated on the paperboard at the side of the concrete treated gravel 30; Shaped frame structure composed of upper and lower concrete transverse members and upper and lower concrete longitudinal members so as to behave as a Rahmen and is designed to gradually change the support rigidity in the vertical direction in the earth connection portion of the bridge and the railway, It is understood that a lattice approach block 20 in which lower concrete longitudinal members different from each other are continuously buried on the concrete treated gravel 30 is introduced.

Therefore, it is possible to prevent settlement after laying of the concrete slab track by the lattice-type approach block having better workability and superior performance than the conventional planar slab-type approach block, It can be seen that there is an advantage that cracks can be prevented from occurring,

It is possible to exclude construction of the concrete treated road 40 as compared with FIG. 1A.

1A and 1B, the girder 11 of the bridge is mounted on the upper surface of the bridge 10 by the bridge support 12, so that the bridge 10 supports the girder 11 And it is very difficult to optimize the alternate section because it is designed as a cross section which can support the earth pressure by the concrete treated gravel (30) and the lower clayey soil and the upper clayey soil.

1C shows a construction cross-sectional view of a skeletal structure of a bridge using a bridge portion 61, a reinforcing mat 62 and a wall 63 in a conventional bridge.

That is, the wall 63 is firstly installed, the supporting pile 64 is connected up and down while the reinforcing mat 62 is laminated on the back surface of the wall 63, And the bridge portion 61 and the wall portion 63 are separated from each other so that the bridge portion 61 serving as an alternate portion can be minimized.

However, since the separation and construction method of the bridge portion 61 and the wall body 63 requires the pile 64 to be stacked up and down on the back surface of the wall body 63, the workability is lowered, There is a limitation that it is not.

FIGS. 1D and 1E show construction drawings of a reinforced earth retaining wall for integrally constructing reinforcing fibers using a wall and a filler.

A front wall 70 forming a front wall of the retaining wall and a fillet 80 formed by successively laminating a fillet layer on a rear surface of the front wall 70; The embankment layer constituting the embankment layer 80 includes a primary geosynthetic fiber 81 disposed over the back surface and the ground surface of the front wall 70 so as to cover the entire surface, the lower surface and the upper surface of the embankment layer, A reference frame 82 positioned on the back surface of the front wall 70 in the inner space surrounded by the reference frame 81 to maintain the shape of the embankment layer, a secondary geosynthetic fiber 83 installed on the reference frame 82, And a filler 84 filled in a space enclosed by the secondary geoscientific fibers 83. [

That is, it can be understood that the embankment 80 using the geosynthetics can be integrated when the concrete is poured for constructing the front wall 70 using the reference frame 82.

In order to prevent uneven settlement due to the difference in material stiffness between the bridge and the railway connecting portion of the conventional bridge and railway, it is known that the ground block is provided with an approach block, a concrete treated gravel, a concrete treated road and a grid type approach block. Optimization of the structure is not an approach through the section, but can be done.

Further, as shown in FIG. 1D and FIG. 1E, it is possible to form a clay part using a conventional reinforcing mat or geosynthetic fiber at the earth connection part of a bridge and a railway. However, such a reinforcing mat and a clay part using the geosynthetic fiber It can be seen that there is a limit to the application because the difference is inevitably generated.

Korean Patent No. 10-1730866 (title of the invention: structure of a bridge of a bridge and its construction method, published on May 11, 2017) Korean Patent No. 10-1730866, entitled " Railway slab track structure provided with a grid-type approach block and method of construction thereof, public date: Apr. 06, 2015) Korean Patent No. 10-0956280, entitled: Reinforced earth retaining wall and reinforced concrete retaining wall structure using rigid wall, and method of construction thereof, published on May 10, 2010)

Accordingly, in the reinforced concrete structure and the earth connection portion, the sections having the structural discontinuity are integrated to maximize the section of the wall structure, thereby solving the problem of settlement due to the difference in material rigidity, ) To provide a structural sequential construction method for a reinforced concrete structure and an earth connection part that can provide structural continuity between reinforced concrete structures and earth connection parts.

In order to accomplish the above object, the present invention provides a method for constructing a continuous connection structure between a reinforced concrete structure and an earth connection portion, comprising the steps of: (a) installing and compaction of a geogrid extending toward the back surface of both wall structures constructed as a reinforced concrete structure, To increase the hardness of the clay soil and induce initial settlement;

(b) reducing the earth pressure acting on the two-wall structure by integrating the embankment and the two-wall structure; And (c) both end portions are formed between the upper ends of the both wall structures so as to generate a horizontal resistance force at the top of the both wall structures to prevent lateral flow of the wall structure.

Also preferably,

The two-wall structure in step (a) is composed of a basic bottom plate and a wall plate as alternating alternations of the railway bridge, and the geogrid is installed so as to be first laid out and plumbed in a multilayered structure In step (b), the alternate two-wall structure and the embankment are integrated by using the supporting frame connected with the geogrid.

Also preferably,

In the step (c), a girder of a railway bridge is formed on the top of the two-wall structure so that horizontal resistance is generated, and the girder is tightly integrated with the upper surface of the alternate wall structure.

Also preferably,

The two alternating sections composed of the foundation bottom and the wall part are constructed such that a pile is further installed on the lower ground so that the two alternating sections can be constructed with a reduced cross section by the embankment integrated with the pile.

Also, preferably, the railway bridge constructed by the structural continuous construction method of the reinforced concrete structure and the earth connection portion by the structural continuous construction method of the reinforced concrete structure and the earth connection portion can be constructed.

Also preferably,

The two-wall structure of step (a) is configured such that both side walls of the underground box structure are formed on the bottom plate, and the geogrid is firstly laid down and plastered in multiple layers so that the horizontally extended length becomes longer toward the back side of the bottom plate In the step (b), the alternate two-wall structure and the embankment are integrated by using the supporting frame connected with the geogrids.

Also preferably,

The top plate of the underground box structure is formed on the top of the two-wall structure so that the horizontal resistance of the step (c) is generated, and the top plate is tightly integrated between the side walls of the two-wall structure.

Also preferably,

The top plate is pre-cast or spot-laid concrete so that it is integrated between the tops of both side walls.

Also, preferably, the railway bridge constructed by the structural continuous construction method of the reinforced concrete structure and the earth connection portion by the structural continuous construction method of the reinforced concrete structure and the earth connection portion can be constructed.

Also, it is preferable to provide an underground box structure constructed by a structural quickening construction method of the reinforced concrete structure and the earth connection portion.

According to the method of constructing the reinforced concrete structure and the earth connection structure according to the present invention, the earth soil on the back surface of the wall structure is constructed of a reinforced earth portion integrated with the reference frame and the geogrid, thereby reducing the earth pressure on the back surface of the wall structure, . Accordingly, the structural continuity due to the difference in material rigidity of the earth connection portion can be sufficiently secured by the reinforced earth portion by making the wall structure constructed by reinforced concrete concrete slim.

In addition, the girder and top plate of the reinforced concrete structure are integrated with the wall structure so as to be able to horizontally support against the back earth pressure acting on the wall structure at the upper part of the wall structure, thereby eliminating the structural discontinuity due to the difference in material rigidity. Thereby making it possible to reduce the settlement of the study and the lateral flow.

FIGS. 1A and 1B are diagrams showing the construction of a connection structure of a bridge and a railway in a conventional railway slab track structure,
1C is a construction sectional view of a bridge portion, a reinforcing mat and a wall in a conventional bridge,
1D and 1E are views showing the construction of a reinforced earth retaining wall for integrally constructing reinforcing fibers using a wall and filler,
FIGS. 2A and 2B are construction diagrams of the reinforced concrete structure and the earth connection portion of the present invention,
FIGS. 3 and 4 are flowcharts of the construction of the reinforced concrete structure and the earth connection portion of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

[The reinforced concrete structure of the present invention and the earth connection portion (100)]

FIGS. 2A and 2B show construction drawings of the reinforced concrete structure and the earth connection portion of the present invention.

2A, the reinforced concrete structure and the earth connection portion of the present invention have a structure in which the reinforced concrete structure and the earth connection portion are connected to each other in the form of a wall structure, In the box structure, it can be divided into the top plate, the side wall which is the wall structure, and the toe of the back wall structure.

First, as shown in FIG. 2A, the reinforced concrete structure and the earth connection unit 100, which are composed of the wall structure 110 installed on both sides of the railway bridge 111 and the ground 130 on the back of the wall structure, will be described as follows .

The railway bridge is constructed to include the two sheaves 111 and the girder 120 which are the wall structures 110,

The two alternating sections 111 are constructed as a reinforced concrete structure composed of a foundation bottom plate and a wall section. A girder 120 is mounted between upper ends of both alternations. .

As a result, the shift 111 can basically slim the cross section by the pile 112.

The back surface of the wall structure 110 constructed with the two alternating turns 111 may be referred to as a furrow portion as a toe portion. Since the wall structure 110 is constructed of reinforced concrete, there is a difference in rigidity from the toe portion 130, So that the connection between the wall structure 110 and the soil 130 causes sinking or the like, and lateral flow phenomenon of the wall structure 110 occurs.

In order to prevent this, in the present invention, the soil 130 is integrated with the two alternations 111 using the geogrid 131.

In other words, since the grounding structure 130 is grounded for installation of the wall structure 110, the geogrid 131 is installed in the form of extending the horizontally extending length from the lower part of the wall structure 110 to the upper part, Thereby increasing the rigidity of the seat 130.

That is, it can be seen that the triangular-shaped soil 130 has a larger compaction density due to its own weight and the geogrid 131, so that the shear resistance against the horizontal force becomes larger and the supporting rigidity against the load becomes larger.

The supporting rigidity of the wall structure 110 is maximized because the multilayered geogrid 131 is disposed on the backside of the wall structure 110. The supporting rigidity is gradually reduced as the wall structure 110 is further away from the backside.

Therefore, it can be seen that the structural discontinuity due to the material stiffness can be reduced toward the back side from the wall structure 110 constructed with reinforced concrete.

At this time, the wall structure 110 and the earthwork 130 are integrally formed by installing the concrete for the wall in a state in which the geogrid is installed using the reference frame extending inside the wall structure 110.

The geogrid 131 is a lattice-shaped reinforcing material and serves to overcome structural discontinuities. In addition, the geogrid 131 provides a shear resistance force in the process of transmitting the earth pressure by the soil to the walls 111, And a function of further reducing the slimness through the reduction.

In the present invention, the ends of the girders 120 are integrated with each other at the upper ends of the two shifts 111, which are the wall structures 110, and the girders 120 are supported by the bridge supports on the upper surfaces of the two alternations. So that the girder 120 plays a role of supporting the two shifts 111 in the horizontal direction so as to effectively resist the lateral flows of the two shifts 111. [

The girder 120 may be constructed by fastening the ends of the girders 120 to the upper surfaces of the two alternating sections without using a bridge support by using connecting rods and fixing nuts not shown on the upper surfaces of the two alternating sections 111 and the like.

2B, a reinforced concrete structure including a top plate 140, which is a wall structure 110, and a toe 130 on the back of both side walls 113, which are wall structures, in the underground box structure, As follows.

The underground box structure is constructed such that both side walls 113 are installed on the bottom plate 114 as a wall structure 110 in the ground and the upper plate 140 is installed between the upper ends of both side walls 113 .

These two side walls 113 are also reinforced concrete structures, and it can be seen that the upper plate 140 is installed between the upper ends and the lower plate 114 is installed between the lower portions of the side walls 113.

At this time, the back surface of the both side walls 113 may be also called the embankment as the embankment 130. Since the both side walls 113 are constructed of the reinforced concrete as the wall structure 110, the difference in stiffness with the embankment 130 So that a sinking or the like occurs and lateral flow phenomenon of the side walls 113 occurs.

Thus, the soil 130 is integrated with both side walls 113 by using the geogrid 131 as well.

The geogrid 131 is installed in the form of a horizontally extending length extending from the bottom plate 114 under the both side walls 113 to the upper part because the grounding part 130 is grounded for the construction of both side walls 113. [ And the stiffness of the soil 130 through the soil compaction.

That is, it can be seen that the supporting stiffness with respect to the load becomes large due to the increase in the compaction density due to the own weight and the geogrid of the triangular-shaped soil 130, and the shear resistance against the horizontal force becomes large.

Accordingly, the support rigidity is maximized because the multi-layered geogrid 131 is disposed on the back surface of both side walls 113, which are the wall structures, and the supporting rigidity is gradually reduced as the side walls 113 are further away from the back surface.

Therefore, the material stiffness gradually decreases from the side wall 113, which is a wall structure constructed using reinforced concrete, toward the back side, and the structural discontinuity due to the material stiffness is reduced.

At this time, the wall structure 110 and the earthwork 130 are integrated with each other by installing the concrete for the sidewall in a state in which the geogrid is installed using a reference frame (not shown) extending to the inside of the wall structure 110.

The geogrid 131 has a function of overcoming the structural discontinuity and provides a shear resistance force in the course of the earth pressure caused by the soil to the both side walls 113 to reduce the earth pressure acting on the both side walls 113, It also has a function to make it possible.

At this time, the upper plate 140 is integrally formed between the upper ends of the side walls 113. In order to rapidly construct the upper plate 140, recently, the upper plate 140 is formed by precast casting, or the end of the upper plate 140, 113 so that the upper plate 140 functions to support the both side walls 113 in the horizontal direction so as to effectively resist the lateral flow of the both side walls 113. [

The upper plate 140 may be constructed such that both ends of the upper plate 140 are fastened to each other on the upper surfaces of the side walls using connecting rods and fixing nuts (not shown) on both upper surfaces of the side walls or connecting reinforcing bars extending from upper surfaces of both side walls.

[Construction Method of Reinforced Concrete Structure and Earth-Earth Connection (100) of the Present Invention)

FIGS. 3 and 4 illustrate a construction sequence of the reinforced concrete structure and the earth connection portion of the present invention.

FIG. 3 is a flowchart illustrating the construction of a reinforced concrete structure and an earth connection unit 100, which are constructed by alternating the wall structure 110 in the railway bridge and the soil on the backside of the wall structure.

First, as shown in FIG. 3A, two alternating sections 111 are constructed as a railway bridge wall structure 110.

Such an alternation 111 is usually set by using the pile 112 and the wall part is constructed integrally with the soil 130 by the geogrid.

Then, the geogrid 131 is horizontally installed rearward in a space formed at the backside of the wall with the base bottom as a reference point, and then the multi-stage construction is performed at a constant height through compaction.

At this time, the horizontally extended length of the geogrid 131 becomes longer toward the upper part, so that the rigidity of the material from the wall structure is gradually decreased toward the side.

If the earth structure 130 is first applied to the geogrid 131 before the wall structure 110 is constructed, the earth structure 130 is stabilized through the operation time and a predetermined period of time (inducing initial settlement) It is possible to reduce the earth pressure of the back surface of the tanks 110,

In addition, since the geogrid 131 is manufactured in a lattice form, the geogrid 131 supports the wall structure 110 in the horizontal and vertical directions, thereby enabling alternation of slimness and reduction of the bottom plate. Can also be reduced.

Next, as shown in FIG. 3B, the walls of the two alternating sections 111 are constructed as the wall structure 110. The two wall portions are installed together with the geogrid 131 on the bottom plate of the foundation so that the supporting frame exposed from the soil is positioned inside the two wall portions and the wall portion concrete is laid by using the formwork, It is only required to integrally construct the earthworks 130 with each other. In other words, by connecting the geogrid to the support frame (a kind of frame) and by placing the support frame inside the both wall parts, the wall structure and the toe are integrally constructed with each other.

Thus, the soil 130 and the two-wall structures 110 are integrally constructed so that the rigidity due to the material difference does not cause a sharp difference in the wall structure 110 and the soil 130.

3C, the girder 120 is integrated between the upper ends of the wall structure 110 in a state where the wall structure 110 is constructed by the walls 111 constituted by the base bottom and the wall, .

PSC girder or the like may be used for the girder 120. Both ends of the girder 120 may be fastened to the upper surface of the both walls 111 by a connecting rod and a fixing nut.

As a result, the reinforced concrete structure and the earth connection unit 100 of the present invention are constructed as a reinforced concrete structure, a railway bridge including a wall structure composed of a girder and a wall, and a earth connection unit in which a geogrid is integrally formed with the wall structure Able to know.

4 is a flowchart illustrating the construction of the reinforced concrete structure and the earth connection unit 100, which are constructed of the sidewalls of the wall structure 110 and the back of the wall structure in the underground box structure.

First, as shown in FIG. 4A, the bottom plate 114 is constructed as the wall structure 110 of the underground box structure.

The bottom plate 114 is usually constructed in situ by a cast concrete method and the bottom plate 114 serves as a reference for the construction of the side walls 113.

The geogrid 131 is horizontally installed rearward horizontally in a space formed on the back surface of the side wall 113 with the bottom plate formed at the bottom of both side walls 113 as a reference point.

At this time, the horizontal extension length of the geogrid 131 increases to the upper part, so that the material rigidity gradually decreases from the wall structure to the side.

If the soil 130 is first installed as the geogrid 131 prior to the construction of the wall structure 110 such as the side walls 113, it is also stabilized through the operation time and a predetermined period (initial settlement inducement) It is possible to reduce the earth pressure on the back surface of the wall structure 110 by the damper 130 and reduce the uneven settlement.

In addition, since the geogrid 131 is also formed in a lattice shape, the geogrid 131 supports the wall structure 110 in the horizontal and vertical directions, thereby enabling alternation of slimness and reduction of the bottom plate. So that the number can also be reduced.

Next, as shown in FIG. 4B, both side walls 113 are constructed as the wall structure 110. The two side walls 113 are installed together with the geogrid (not shown) on both sides of the bottom plate 114 so that the supporting frame exposed from the soil is positioned inside the side walls 113, You can install it all by installing it. The wall structure 110 and the soil 130 are integrally formed by connecting the geogrid to the supporting frame (a kind of frame) and positioning the supporting frame inside the both side walls.

Thus, the soil 130 and the two-wall structures 110 are integrally constructed so that the rigidity due to the material difference does not cause a sharp difference in the wall structure 110 and the soil 130.

Next, as shown in FIG. 4C, in a state where the wall structure 110 is formed by the bottom plate and both side walls 113, the top plate 140 is integrated between the tops of the wall structures 110 to be constructed.

The top plate 140 may be formed of precast or cast concrete. Both ends of the side walls 113 may be fastened to the upper surface of both side walls without using a bridge support by using connecting rods and fixing nuts.

The reinforced concrete structure and the earth connection part 100 of the present invention are constructed as a reinforced concrete structure in which an underground box structure including a wall structure composed of an upper plate and both side walls and a earth connection part in which a geogrid is integrally formed with the wall structure .

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

100: Reinforced concrete structure and earth connection
110: wall structure 111: shift
112: pile 113: side wall
114: bottom plate 120: girder
130: Satoyama 131: Geogrid
140: top plate

Claims (9)

(a) The stiffness of the embankment 130 of the earth connection portion is increased by multi-layering and compaction of the geogrid 131 extending to the backside of the wall structure 110, which is constructed as a reinforced concrete structure after the earthquake, ;
(b) reducing the earth pressure acting on the two-wall structure 110 by integrating the embankment 130 and the two-wall structure 110; And
(c) forming both end portions between the upper ends of the two wall structures 110 so as to generate a horizontal resistance force on the upper portions of both wall structures to prevent lateral flow of the wall structure 110. [ And a method for constructing the continuous connection of the earth connection part. The method according to claim 1,
Both wall structures 110 of step (a)
The alternation 111 is composed of a foundation bottom plate and a wall portion as positive alternations 111 of the railway bridge so that the geogrid 131 is firstly laid and piled up in multiple layers so that the horizontally extended length becomes longer toward the upper side of the bottom plate, the reinforced concrete structure and the earth connection unit are constructed such that the two-wall structure 110 and the fillet 130 are alternately integrated using the support frame connected to the geogrids in step (b). 3. The method of claim 2,
The girder 120 of the railway bridge is formed on the upper part of the wall structure so that the horizontal resistance of the step (c) is generated. The girder 120 is reinforced concrete Construction Sequential Construction Method of Structure and Earth Connection. The method of claim 3,
The piles 112 are further installed on the lower ground so that the piles 112 can be constructed in a reduced cross section by the embankment 130 integrated with the pile 112. [ A method of structural sequential construction of reinforced concrete structure and earth connection. A railway bridge constructed by a structural sequential construction method of the reinforced concrete structure and the earth connection part of any one of claims 1 to 4. The method according to claim 1,
Both wall structures 110 of step (a)
The side wall 113 as the side wall 113 of the underground box structure is configured to be formed on the bottom plate 114 so that the geogrid 131 is firstly laid and laid in multiple layers such that the horizontal extension length becomes longer toward the back side of the bottom plate. The reinforced concrete structure and the earth connection unit are constructed such that the two-wall structure 110 and the fillet 130 are integrated by using the support frame connected to the geogrid in step (b). The method according to claim 6,
The upper plate 140 of the underground box structure is formed on the top of the two wall structures so that the horizontal resistance of the step (c) is generated. The upper plate 140 is reinforced between the side walls 113, Construction Sequence Construction Method of Concrete Structure and Earth Connection Part. 8. The method of claim 7,
Wherein the upper plate (140) is constructed so as to be integrated between the upper ends of both side walls (113) by precast or spotted concrete. An underground box structure constructed by a structural quickening construction method of the reinforced concrete structure and the earth connection part of any one of claims 7 to 8.

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