JP6085239B2 - Core material for earth retaining wall, and upper core material removal method of the core material - Google Patents

Description

  The present invention relates to a core material that is built into a retaining wall and can be divided into upper and lower parts, and an upper core material removing method for removing the upper core material of the core material from the retaining wall.

  When an underground structure or the like is constructed by excavating the ground, a retaining wall is constructed by the SMW method or the like so as to surround the planned excavation area of the ground prior to the construction work. Thereby, the excavation of the ground in the construction work and the collapse of the ground during the construction of the underground structure are prevented and the work safety is achieved. In the earth retaining wall, a plurality of core members made of H-section steel or the like are built in parallel at a predetermined interval from the ground surface downward.

  Here, in urban areas, construction work for underground structures has been completed because there is a possibility that burial work such as communication cables and water and sewage pipes will be carried out near the ground surface in the construction work area of underground structures in the future. Later, removal of the upper portion of the core may be required.

  As the core material for the retaining wall considering the removal of the upper portion of the core material, the one described in Patent Document 1 is known. The core material described in Patent Document 1 is divided into an upper core material and a lower core material, and an upper core material and an upper core material and a lower core material so that a lower end portion and an upper end portion of the lower core material are fitted to each other. The lower core material was stepped, a lower plate welded with a nut was attached to the upper end portion of the lower core material, and a through hole was opened in the upper end portion of the upper core material. A top plate is installed. Then, by inserting a long bolt into the through hole of the upper plate and screwing it into the nut of the lower plate, the upper core member and the lower core member are connected, and by loosening the long bolt, the upper core member and the lower core member are connected. The core material is separated, and only the upper core material is configured to be removable from the earth retaining wall.

JP 2011-63957 A

  However, in the core material for retaining walls described in Patent Document 1, it is necessary to perform complicated processing on each end portion of the upper core material and the lower core material, and the lower core material from the upper end portion of the upper core material. Since a long bolt extending to the upper end portion is required and the manufacturing cost of the core material that can be divided into upper and lower parts is increased, a core material that can remove the upper core material with a simple structure is required.

  The present invention has been made paying attention to such an actual situation, and provides a core material for retaining wall that can remove the upper core material with a simple structure, and a method for removing the upper core material of the core material. The purpose is to do.

  In response to the above problems, the core material for the retaining wall according to the present invention is, as one aspect thereof, built in the retaining wall that partitions the planned excavation area and the non-excavation area of the ground, and extends downward from the ground surface side. A steel core extending toward the surface, comprising a shape steel having a pair of first flanges and a first web, an upper core forming the upper part of the core, and a pair of second flanges, A lower core material forming a lower part of the core material, and connecting means for releasably connecting a lower end portion of the first flange to an upper end portion of the second flange. The connecting means sandwiches the first flange and the second flange flush with each other, and the upper end of the connecting means is joined to the lower end of the first flange, and the connecting means So that the lower end of the second end is joined to the upper end of the second flange And the upper core material is applied to the upper end portion of the upper core material in a direction perpendicular to the web surface of the first web, so that the upper core material is brought down and the connection means causes the first The joining strength to the first flange at the upper end portion of the connecting means and the joining strength to the second flange at the lower end portion of the connecting means so that the connection between the first flange and the second flange is released. Different configuration.

  Moreover, as for the upper core material removal method which concerns on this invention, the core material of the said one aspect | mode is the said excavation plan as one aspect | mode of the said outer surface of one side of a pair of said 1st flange, and the said 2nd flange of a pair. An upper core material removal method that is built in the earth retaining wall toward the region side and removes the upper core material of the core material from the earth retaining wall, wherein the upper part of the earth retaining wall is the upper part A space or a loose ground is formed by excavating a portion adjacent to the side on which the core material is collapsed, and a force of a predetermined value or more is applied to the upper end portion of the upper core material in one direction orthogonal to the web surface of the first web. By adding the upper core member to the space or the loose ground side, the connection between the upper core member and the lower core member by the connecting means is released, and the upper core member is placed in the earth retaining wall. Removed from the structure.

According to the one aspect of the core material for retaining walls according to the present invention, the connecting means simply sandwiches the first flange of the upper core material and the second flange of the lower core material flush with each other, and The upper end of the connecting means is joined to the lower end of the first flange, and the lower end of the connecting means is joined to the upper end of the second flange. Then, simply by making the joining strength to the first flange at the upper end of the connecting means different from the joining strength to the second flange at the lower end of the connecting means, a force greater than a predetermined value is applied to the upper end of the upper core member. Is added in a direction perpendicular to the web surface of the first web, the upper core member is brought down and the connection between the first flange and the second flange is released. Further, the upper core material is simply made of a shape steel material having a pair of first flanges and a first web, and the lower core material is also made of a shape steel material simply having a pair of second flanges and a second web. As the upper core material and the lower core material, for example, standard H-section steel, I-section steel, and C-section steel can be used as they are without complicated processing.
In this way, the joining strength of the connecting means to the first flange (upper core material) and the joining strength to the second flange (lower core material) are appropriately varied, and the first flange and lower core material of the upper core material are made different. Since it is only necessary to provide simple connection means for sandwiching the second flange with the second flange, it is not necessary to perform complicated processing on the upper core material and the lower core material. Thus, the core material for earth retaining wall which can remove an upper core material with a simple structure can be provided.

According to the one aspect of the method for removing the upper core material according to the present invention, when removing the upper core material of the core material for the retaining wall according to the one aspect, first, the upper core material of the retaining wall is brought down. By excavating a portion adjacent to the side to form a space or a loose ground, and then applying a force of a predetermined value or more to the upper end of the upper core in one direction perpendicular to the web surface of the first web, The core material is tilted toward the space or the loose ground, the connection between the upper core material and the lower core material by the connecting means is released, and the upper core material is removed from the earth retaining wall. For this reason, for example, after excavating the part of the retaining wall on the side where the upper core member is to be collapsed from the ground surface side, the web surface of the first web is also simply applied from the ground surface side to the upper end portion of the upper core member. The connection between the upper core member and the lower core member can be released simply by applying a force of a predetermined value or more from one direction orthogonal to the upper core member and lying down.
In this way, the upper core material can be removed using a core material with a simple structure, and an upper core material removal method is provided that allows the upper core material to be easily removed only from the ground surface side. Can do.

It is sectional drawing for demonstrating schematic structure of the core material for earth retaining walls which concerns on one Embodiment of this invention, and is sectional drawing which shows the state in which the core material is built in the earth retaining wall. It is the figure which looked at the construction state of the core material shown in FIG. 1 from the excavation plan area side. It is an enlarged view of the A section shown in FIG. It is a BB arrow sectional view of Drawing 3. It is CC sectional view taken on the line of FIG. FIG. 4 is a partial side view of the core viewed from the direction of arrow D shown in FIG. 3. It is the partial side view of the core material seen from the E arrow direction shown in FIG. It is a top view of the earth retaining wall seen from the F arrow direction shown in FIG. It is a figure for demonstrating the upper core material removal method which concerns on one Embodiment of this invention, and is the figure which expanded the side close | similar to the ground surface of FIG. It is the figure which showed the state which has fallen the upper core material shown in FIG. FIG. 11 is a diagram illustrating a state in which the upper core material further falls down and is disconnected from the lower core material after FIG. 10. It is the figure which showed the state which has fallen the upper core material adjacent to the upper core material by which connection was cancelled | released. It is a figure which shows the state from which the said adjacent upper core material shown in FIG. 12 was removed.

Hereinafter, embodiments of the core material for retaining walls according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a diagram showing a schematic configuration of a core material 1 for a retaining wall according to an embodiment of the present invention, and shows a state where the core material 1 is built in a retaining wall 10. FIG. 2 is a view of the built-up state of the core material 1 shown in FIG. 1 as viewed from the excavation planned region G0 side.

The earth retaining wall 10 has a ground excavation area (that is, an area where an underground structure is to be constructed) G0 and a non-excavation area (prior to the construction work for excavating the ground and burying underground structures and the like). In the following, it is constructed so as to partition G1). Specifically, the earth retaining wall 10 is a wall made of soil mortar constructed so as to reach the water-impermeable layer G2 from the ground surface by, for example, the SMW method, the TRD method, or the like. It is located at the boundary with G1. This prevents the natural ground G1 from collapsing or the groundwater from flowing into the construction work area from the natural ground G1 side during the ground excavation and the construction of the underground structure in the construction work.
In the earth retaining wall 10, as shown in FIG. 2, a plurality of cores 1 (six in FIG. 2) are arranged in parallel at predetermined intervals from the ground surface downward. Yes. In the following, the direction in which the earth retaining wall 10 extends in the horizontal direction with respect to the ground surface is referred to as a horizontal extending direction (see FIGS. 4, 5, 8 and 9 described later).

  The core material 1 extends downward from the ground surface in the earth retaining wall 10 and includes an upper core material 2, a lower core material 3, and connecting means 4. In the present embodiment, as shown in FIG. 1, the core material 1 has an outer surface of one 2a of a pair of first flanges 2a and 2b, which will be described later, and an outer surface of one 3a of a pair of second flanges 3a and 3b. It is embedded in the retaining wall 10 toward the excavation planned area G0 side.

  The upper core material 2 is made of a shaped steel material having a pair of first flanges 2 a and 2 b and a first web 2 c, and forms the upper part of the core material 1. The pair of first flanges 2a and 2b are opposed to each other and extend in the vertical direction, and the first web 2c connects between the pair of first flanges 2a and 2b. For example, as the upper core material 2, a standard H-shaped steel is appropriately cut into an appropriate length (for example, about 1 to 4 m) according to the depth from the ground surface required to remove the core material. The lower end portion of the upper core member 2 is abutted against the upper end portion of the lower core member 3. In this state, the upper core member 2 and the lower core member 3 are connected to each other via the connecting means 4. And the core material 1 connected beforehand in this way is built in the earth retaining wall 10 so that the upper end part of this upper core material 2 may be appropriately exposed from the ground surface.

The lower core member 3 is made of a shaped steel material having a pair of second flanges 2a, 2b and a second web 2c, and forms the lower part of the core member 1. The pair of second flanges 3a and 3b are opposed to each other and extend in the vertical direction, and the second web 3c connects between the pair of second flanges 3a and 3b. For example, as the lower core material 3, an H-section steel having the same standard as the upper core material 2 is used by being cut to an appropriate length according to the height of the earth retaining wall 10. The upper end portion of the lower core member 3 is connected to the lower end portion of the upper core member 2 through the connecting means 4.
As described above, the upper core member 2 and the lower core member 3 of the present embodiment have a simple structure obtained by simply cutting a standard H-shaped steel to an appropriate length.

  The connecting means 4 releasably connects the lower end portion of the upper core member 2 to the upper end portion of the lower core member 3, and the first flanges 2 a and 2 b of the upper core member 2 and the first core member 2 of the lower core member 3. 2 flanges 3a and 3b are flush with each other, and the upper end of the connecting means 4 is joined to the lower ends of the first flanges 2a and 2b, and the lower end of the connecting means 4 is the second flanges 3a and 3b. It is comprised so that it may join to the upper end part. Then, when a force equal to or greater than a predetermined value is applied to the upper end portion of the upper core member 2 in one direction orthogonal to the web surface of the first web 2c, the upper core member 2 is brought down as shown in FIG. Thus, the connection strength between the first flanges 2a and 2b at the upper end of the connection means 4 and the connection means 4 so that the connection between the first flanges 2a and 2b and the second flanges 3a and 3b by the connection means 4 is released. The bonding strength to the second flanges 3a and 3b at the lower end of the plate is different. Note that the predetermined value is one of the weaker strengths of the joining strength of the connecting means 4 to the first flanges 2a and 2b and the joining strength of the connecting means 4 to the second flanges 3a and 3b. It depends on the bonding strength.

  Below, the more concrete shape of the connection means 4 in this embodiment and the joining method to the upper core material 2 and the lower core material 3 are explained in full detail with reference to FIGS. 3 is an enlarged view of part A in FIG. 2, FIG. 4 is a cross-sectional view taken along the line B-B in FIG. 3, FIG. 5 is a cross-sectional view taken along the line C-C in FIG. 7 is a partial side view of the core material viewed from the direction of arrow D, and FIG. 7 is a partial side view of the core material viewed from the direction of arrow E shown in FIG.

In the present embodiment, as shown in FIGS. 3 to 7, the connecting means 4 is provided corresponding to the four corners of the lower ends of the first flanges 2 a and 2 b and the upper ends of the second flanges 3 a and 3 b. Yes. Each of these connecting means 4a, 4b, 4c, 4d is formed in a U-shaped cross section. Each connecting means 4a, 4b, 4c, 4d is composed of a side wall facing each other and a bottom wall connecting the end portions of the side walls, and a flange (2a, 2b, 3a, 3b) can be fitted. Moreover, the side wall and the bottom wall are formed using, for example, a steel plate having a thickness approximately equal to the thickness of the flange.
In the following, each of the connecting means 4a, 4b, 4c, 4d is divided into a pair of connecting means 4a, 4b on the side where the upper core member 2 is tilted and another pair on the opposite side of the pair of connecting means 4a, 4b. The connection means 4c and 4d will be described separately. In FIG. 6, only the connecting means 4a described later is shown for simplification of the drawing, but the connecting means 4a and the connecting means 4b have the same shape. Similarly, in FIG. 7, only the connecting means 4 c described later is shown for simplification of the drawing, but the connecting means 4 c and the connecting means 4 d have the same shape.

Of the pair of connecting means 4a and 4b, the connecting means 4a includes a lower end of one first flange (excavation planned region G0 side) 2a of the upper core material 2 and one second flange (excavated) of the lower core material 3. The first flange 2a and the second flange 3a are sandwiched with each other by fitting the upper end portion of the planned area G0 side) 3a to the lower side and the upper side in one groove. As described above, the connecting means 4a sandwiches the edges of the first flange 2a and the second flange 3a across the first flange 2a and the second flange 3a. Similarly, the connecting means 4b includes a lower end portion of the other first flange (ground mountain G1 side) 2b of the upper core material 2 and an upper end portion of the other second flange (ground mountain G1 side) 3b of the lower core material 3. Are placed flush with each other. In this way, the connecting means 4b sandwiches the edges of the first flange 2b and the second flange 3b across the first flange 2b and the second flange 3b.
Further, specifically, as shown in FIGS. 3 to 6, the pair of connecting means 4a and 4b has upper ends joined to the first flanges 2a and 2b by fillet weld W1, and the lower ends are dotted. Temporarily joined to the second flanges 3a and 3b by the adhesive welding W2. In this way, the joining strength to the first flanges 2a and 2b at the upper ends of the pair of connecting means 4a and 4b and the joining strength to the second flanges 3a and 3b at the lower ends of the pair of connecting means 4a and 4b are obtained. It is different. When an external force is applied to the upper end portion of the upper core member 2 from one direction orthogonal to the surface of the web 2c, the dotted welding W2 portion at the lower end portions of the pair of connecting means 4a and 4b is subjected to this external force. When the tensile force acts and the magnitude of the external force exceeds a predetermined value, the spot weld W2 portion is broken and the joint by the spot weld W2 portion is released. Therefore, in the present embodiment, the above-mentioned force applied to the upper end portion of the upper core member 2 breaks the spot welding W2 portion having a weak joint strength, and the joining by this spot welding W2 portion. Is an external force of a releasable magnitude.

On the other hand, among the other pair of connecting means 4c and 4d, the connecting means 4c is arranged so that the lower end portion of one first flange 2a and the upper end portion of one second flange 3a are flush with each other like the connecting means 4a. Is sandwiched. The connecting means 4d sandwiches the lower end portion of the other flange 2b and the upper end portion of the other flange 3b in the same manner as the connecting means 4b. In addition, screw holes 4f (see FIG. 7) into which the push bolts 4e are screwed are respectively formed in a portion sandwiching the flange 2a of each side wall of the connecting means 4c and a portion sandwiching the flange 2b of each side wall of the connecting means 4d. It has been established. The first flanges 2a and 2b are fastened by the push bolts 4e from both sides.
Further, as shown in FIGS. 3 to 5 and FIG. 7, specifically, the other pair of connecting means 4c and 4d are joined at their lower ends to the second flanges 3a and 3b by fillet weld W1, respectively. ing. On the other hand, the upper ends of the connecting means 4c and 4d are temporarily fixed (temporarily joined) to the upper core member 2 through a tightening force generated by tightening the push bolt 4e. In this way, the upper end portions of the connecting means 4c and 4d are temporarily joined to the first flanges 2a and 2b by the push bolts 4e and 4e screwed to both side walls of the connecting means 4c and 4d. In FIGS. 1 and 2 and FIGS. 8 to 13 described later, the push bolt 4e is omitted for simplification of the drawing.

Next, a method of removing the upper core material 2 of the core material 1 in the present embodiment from the earth retaining wall 10 will be briefly described with reference to FIGS. 2 and 8 to 13. In addition, the removal method of the upper core material 2 demonstrated below is also description of one Embodiment of the upper core material removal method which concerns on this invention.
In addition, as shown in FIG. 8 which is the top view of the earth retaining wall 10 seen from the F arrow direction of FIG. 2 and FIG. 2, the core material 1 in this embodiment is directed downward from the ground surface. A case will be described in which a plurality of wires are installed side by side at a predetermined interval and the upper core member 2 is sequentially removed from the rightmost side to the left side in the drawing.

  First, as shown in FIG. 8 (shaded portion) and FIG. 9 which is an enlarged view of the side close to the ground surface of FIG. 2, the earth retaining wall 10 is built on the rightmost side in the figure. A portion adjacent to the right side of the core material 1 (that is, one side in the horizontal extending direction of the retaining wall 10 in the core material 1) is excavated by an excavator or the like installed on the ground surface side. In this way, the right side of the upper core material 2 is the side on which the upper core material 2 is tilted, and the portion of the retaining wall 10 adjacent to the side on which the upper core material 2 is tilted (the portion indicated by hatching in FIG. 8). Is excavated to form a space S. In FIG. 8, the earth retaining wall 10 in the groove defined by the first web 2c of the upper core member 2 and the first flanges 2a and 2b, that is, the soil mortar is also excavated and removed. However, the present invention is not limited to this, and the soil mortar in the groove may be simply broken and left. In this case, as will be described later, when the upper core member 2 is turned down, the soil mortar in the groove is peeled off from the groove or left in the groove of the fallen upper core member 2 as it is. In FIG. 8, only the portion of the retaining wall 10 is excavated, but the present invention is not limited to this, and the excavation may be performed by protruding to the planned excavation region G0 and the natural ground G1 side.

  Next, as indicated by a hollow arrow in FIG. 9, a force of a predetermined value or more is applied to the upper end portion of the upper core member 2 in a direction orthogonal to the web surface of the first web 2 c. Here, since the pair of connecting means 4a and 4b are firmly joined to the upper core member 2 by the fillet weld W1, they are integrated with the upper core member 2. Another pair of connecting means 4c and 4d are integrally joined to the lower core member 3 because they are firmly joined to the lower core member 3 by fillet weld W1. Therefore, when the force is applied to the upper end portion of the upper core member 2 as described above, the upper core member 2 has its first flanges 2a and 2b starting to come out of the grooves of the connecting means 4c and 4d, and the bonding strength. As shown in FIG. 10, the pair of weakly connecting means 4a and 4b starts to fall toward the space S as shown in FIG.

  Then, as shown by a two-dot chain line in FIG. 11, when the upper core member 2 is further tilted, the joining by the fastening of the push bolts 4e and 4e is released, and the points at the lower ends of the pair of connecting means 4a and 4b A tensile force of a predetermined value or more acts on the spot welding W2 part, and the spot welding W2 part is broken by this tensile force, and the joining by the spot welding W2 is also released. In this way, by applying a force of a predetermined value or more to the upper end portion of the upper core material 2 in a direction orthogonal to the web surface of the first web 2c, the upper core material 2 and the lower core material 3 by the connecting means 4 are connected. The connection is released, and then the upper core member 2 is removed from the earth retaining wall by, for example, lifting upward as shown by the white arrow in the figure by a crane or the like installed on the ground surface side. In addition, after removing the upper core material 2, the space S is refilled.

  Next, as shown in FIG. 11, the soil mortar on the space S side of the upper core material 2 ′ as shown in FIG. To drill. Then, as shown in FIG. 12, the upper core member 2 ′ is tilted in the same manner as the upper core member 2, the connection is released, and the upper core member 2 ′ is pulled upward, and as shown in FIG. Remove 2 '. The above procedure is repeated to remove the remaining upper core material.

According to the core material 1 for retaining walls according to this embodiment, the connecting means 4 simply connects the first flanges 2a, 2b of the upper core material 2 and the second flanges 3a, 3b of the lower core material 3. The upper ends of the connecting means 4 are joined to the lower ends of the first flanges 2a and 2b, and the lower ends of the connecting means 4 are joined to the upper ends of the second flanges 3a and 3b. It is comprised so that. And the upper core material 2 is simply made by differentiating the joining strength to the first flanges 2a, 2b at the upper end of the connecting means 4 and the joining strength to the second flanges 3a, 3b at the lower end of the connecting means 4. When a force of a predetermined value or more is applied to the upper end of the first web 2c in a direction orthogonal to the web surface of the first web 2c, the upper core member 2 is tilted, and the first flanges 2a, 2b and the second flanges 3a, 3b Is disconnected. Further, the upper core member 2 is simply made of a shape steel material having a pair of first flanges 2a and 2b and a first web 2c, and the lower core member 3 is also simply a pair of second flanges 3a and 3b and a second member. Since the upper core material 2 and the lower core material 3 are made of a shape steel material having the web 3c, for example, a standard H-shape steel can be used as it is without performing complicated processing.
In this way, the joining strength of the connecting means to the first flanges 2a, 2b (upper core material 2) and the joining strength to the second flanges 3a, 3b (lower core material 3) are appropriately made different, and the upper core material is made different. The first and second cores 2a and 2b and the second flanges 3a and 3b of the lower core 3 need only be provided with simple connecting means for sandwiching each of the upper and lower cores. There is no need for complicated processing. Thus, the core material for earth retaining wall which can remove an upper core material with a simple structure can be provided.

  Further, in the present embodiment, the core material 1 has the outer surface of one 2a of the pair of first flanges 2a and 2b and the outer surface of one 3a of the pair of second flanges 3a and 3b facing the planned excavation region G0 side of the ground. Embedded in the earth retaining wall 10, the moment of inertia of the section of the natural ground G1 due to the earth pressure and the like is large, and the first flanges 2 a and 2 b of the upper core member 2 and the lower portion are connected by the connecting means 4. Since the second flanges 3a and 3b of the core material 3 are sandwiched in a flush manner, it acts on the core material 1 when excavating the ground in the planned excavation area G0 in order to construct an underground structure. It can effectively resist a bending moment caused by earth pressure or the like from the natural ground G1.

And according to the upper core material removal method by this embodiment, in removing the upper core material 2 of the core material 1 for the earth retaining wall 10, first, the side of the earth retaining wall 10 where the upper core material 2 is brought down. A space S is formed by excavating a portion adjacent to the upper core member 2, and then a force of a predetermined value or more is applied to the upper end portion of the upper core member 2 in one direction orthogonal to the web surface of the first web 2 c, 2 is tilted to the space S side, the connection between the upper core member 2 and the lower core member 3 by the connecting means 4 is released, and the upper core member 2 is removed from the earth retaining wall 10. For this reason, for example, after excavating the portion of the retaining wall 10 on the side on which the upper core member 2 is to be tilted from the ground surface side, the first web is simply applied from the ground surface side to the upper end portion of the upper core member 2. The connection between the upper core member 2 and the lower core member 3 can be released simply by applying a force of a predetermined value or more from one direction orthogonal to the web surface of 2c and laying the upper core member 2 sideways.
In this way, the upper core material can be removed using a core material with a simple structure, and an upper core material removal method is provided that allows the upper core material to be easily removed only from the ground surface side. Can do.

In the present embodiment, the pair of connecting means 4a and 4b on the side on which the upper core member 2 is tilted has been described in the case where the upper ends are joined to the upper core member 2 by fillet welding W1, Not limited to this, through holes are formed in the upper ends of the connecting means 4a and 4b and the first flanges 2a and 2b, bolts are inserted into the through holes, and nuts are screwed into the bolt ends. The upper ends of the pair of connecting means 4a and 4b may be completely fixed to the first flanges 2a and 2b. The pair of connecting means 4a and 4b has been described in the case where the lower end portions are temporarily joined to the lower core member 3 by spot welding W2, but the present invention is not limited thereto, and the lower end portions are formed by push bolts 4e and 4e. You may make it temporarily join.
Further, the other pair of connecting means 4c and 4d are temporarily joined to the upper core member 2 by push bolts 4e and 4e whose upper ends are screwed to both side walls of the connecting means 4c and 4d, respectively. Not limited to this, the upper end portion may be temporarily joined by spot welding W2. The pair of connecting means 4c and 4d have their lower ends joined to the lower core member 3 by the fillet weld W1, but the present invention is not limited to this, and the lower ends of the second flange 3a are bolts and nuts. , 3b may be completely fixed.
That is, the joining strength of the pair of connecting means 4a, 4b to the first flanges 2a, 2b is greater than the joining strength of the pair of connecting means 4a, 4b to the second flanges 3a, 3b, and another pair of connecting means. The joining strength of 4c, 4d to the first flanges 2a, 2b may be set to be smaller than the joining strength of the other pair of connecting means 4c, 4d to the second flanges 3a, 3b.

Moreover, in this embodiment, after removing the first upper core member 2, the soil mortar on the space S side of the upper core member 2 'adjacent to the upper core member 2 is brought down before the upper core member 2' is brought down. Although it demonstrated as what is excavated, it is not restricted to this, As shown in FIG. 11, in the state in which the soil mortar which partly collapsed and loosened remains on the space S side of upper core material 2 'remains, upper core material You may defeat 2 '. In this case, the soil mortar left on the space S side of the upper core material 2 ′ is collapsed to the space S side where it was initially formed by tilting the upper core material 2 ′. Then, the remaining upper core material is removed in the same manner. Thereby, in the removal work of the upper core material 2 of the core material 1 arranged in parallel, the excavation work only needs to be performed once, and the work can be simplified.
As described above, a portion of the earth retaining wall 10 adjacent to the side on which the upper core member 2 is tilted is excavated to form a space S or a loose ground, and a force greater than a predetermined value is applied to the upper end portion of the upper core member 2. Is applied in one direction orthogonal to the web surface of the first web 2c, the upper core material 2 is tilted toward the space S or the loose ground, and the connection between the upper core material and the lower core material by the connecting means 4 is released. do it.

  Further, in the present embodiment, a case has been described in which a plurality of core members 1 are sequentially removed from the right side to the left side. However, the present invention is not limited thereto, and may be sequentially removed from the left side to the right side. . In this case, the arrangement of the pair of clamping parts 4a and 4b and the arrangement of the other clamping parts 4c and 4d provided with the push bolt 4e may be reversed left and right. Moreover, although the case where the standard H-shaped steel was used as it was as the upper core material 2 and the lower core material 3 was described as it is, the upper core material 2 and the lower core material 3 face each other up and down. It is only necessary to have a pair of flanges extending in the direction and a web connecting between the pair of flanges.

  Moreover, in this embodiment, although the upper core material 2 and the lower core material 3 each demonstrated the case where H-section steel was used, not only this but I-section steel may be sufficient. Moreover, you may use not only H-section steel and I-section steel but C-section steel. When using C-shaped steel, the core material 1 is built in the earth retaining wall 10 so that the groove of the C-shaped steel opens to the space S or the loose ground side, and the pair of first cores of the upper core material 2 is used. What is necessary is just to connect the lower end part of the flanges 2a and 2b to the lower end part of a pair of 2nd flanges 3a and 3b of the lower core material 3 only using a pair of connection means 4a and 4b.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not restrict | limited to the said embodiment, A various deformation | transformation and change are possible based on the technical idea of this invention.

DESCRIPTION OF SYMBOLS 1 ..... Core material 2 ..... Upper core material 2a, 2b ... A pair of 1st flange 2c ..... First web 3 .... Lower core material 3a, 3b ... Pair of second flanges 3c ... Second web 4 ... Connection means 4a, 4b ... Pair of connection means 4c, 4d ... Another pair of connecting means 4f ···················································· 10 ··· Space W1 ··· Fillet welding W2 ··· Spot welding

Claims (10)

A steel core that is built in a retaining wall that partitions the planned excavation area and the non-excavation area of the ground and extends downward from the ground surface side,
An upper core material comprising a section steel material having a pair of first flanges and a first web, and forming an upper part of the core material;
A lower core material comprising a section steel material having a pair of second flanges and a second web, and forming a lower part of the core material;
Connecting means for releasably connecting the lower end of the first flange to the upper end of the second flange;
Comprising
The connecting means sandwiches the first flange and the second flange flush with each other, and an upper end portion of the connecting means is joined to a lower end portion of the first flange, and a lower end portion of the connecting means is Configured to be joined to the upper end of the second flange;
When a force of a predetermined value or more is applied to the upper end portion of the upper core material in one direction orthogonal to the web surface of the first web, the upper core material is brought down, and the first flange by the connecting means The joining strength to the first flange at the upper end portion of the connecting means and the joining strength to the second flange at the lower end portion of the connecting means are made different so that the connection with the second flange is released. , Core material for retaining walls. The connecting means is provided corresponding to the four corners of the lower end of the first flange and the upper end of the second flange, respectively.
The bonding strength to the first flange of the pair of connecting means on the side where the upper core member is tilted among the connecting means is greater than the bonding strength of the pair of connecting means to the second flange,
The joining strength of the other pair of connecting means on the opposite side of the pair of connecting means to the first flange is greater than the joining strength of the other pair of connecting means to the second flange. The core material for earth retaining walls according to claim 1, which is small. Each connecting means is formed in a U-shaped cross section,
The core material for earth retaining walls according to claim 2, wherein the pair of connecting means has upper ends joined to the first flange by fillet welding.   The core member for earth retaining wall according to claim 3, wherein the pair of connecting means is temporarily joined at its lower end portion to the second flange by spot welding.   4. The core material for a retaining wall according to claim 3, wherein each of the pair of connecting means is temporarily joined to the second flange by a push bolt having a lower end screwed to both side walls of the connecting means.   6. The core material for a retaining wall according to claim 3, wherein each of the other pair of connecting means has a lower end joined to the second flange by fillet welding.   The core member for the retaining wall according to any one of claims 3 to 6, wherein each of the another pair of connecting means has an upper end portion temporarily joined to the first flange by spot welding.   The said another pair of connection means is each temporarily joined to the said 1st flange with the push bolt by which the upper end part was screwed together by the both-sides wall of this connection means. Core material for earth retaining walls.   9. The structure according to claim 1, wherein one outer surface of the pair of first flanges and one outer surface of the pair of second flanges are built in the retaining wall toward the planned excavation region side. Core material for earth retaining wall as described in 2. An upper core material removing method for removing the upper core material of the core material according to claim 9 from the earth retaining wall,
Of the retaining wall, excavating a portion adjacent to the side on which the upper core is to be overturned to form a space or loose ground,
By applying a force of a predetermined value or more to the upper end portion of the upper core material in one direction orthogonal to the web surface of the first web, the upper core material is brought down to the space or the loose ground side, and the connecting means The connection between the upper core member and the lower core member is released by
A method of removing the upper core material, wherein the upper core material is removed from the earth retaining wall.