JP2020097841A - Joint structure of underground wall - Google Patents

Abstract

To secure the integrity of a leading continuous wall and a trailing continuous wall constructed in the ground, and provide a joint structure having a high shear force transmission effect between the leading continuous wall and the trailing continuous wall, which is a simple structure.SOLUTION: A partition plate 4 is provided on a trailing excavation groove 9 side of a rebar cage 1A installed in a leading excavation groove 8 that is excavated in the ground. An additional material 6 in which a plurality of holes 6a are formed at intervals in the height direction at a projecting portion facing the direction intersecting a surface of the partition plate 4 or a protrusion continuous to the projecting portion, is joined to at least one surface continuously or intermittently in the height direction of the partition plate 4 and embedded in concrete that is cast into at least one of the leading excavation groove 8 and the trailing excavation groove 9.SELECTED DRAWING: Figure 1

Description

The present invention relates to a joint structure of an underground continuous wall that secures the integrity of a preceding continuous wall and a trailing continuous wall constructed in the ground.

An underground continuous wall constructed through the steps of forming excavation trenches in the ground, installing rebar cages in the excavation trenches, and placing concrete is a section divided in the continuous direction of the underground excavation wall. Operations from the formation of excavation trenches to the placing of concrete are performed in units. In this relationship, the adjacent section is divided into a leading section and a trailing section, and the work up to the concrete placing in the trailing section is performed after the work up to the concrete placing in the leading section is completed. The preceding section is a section where one adjacent section is skipped, and the skipped section may be a trailing section.

A partition plate is placed on the boundary surface between the preceding section and the following section, which serves as a barrier for the concrete in the preceding section, but to ensure the integrity (continuity) between the concrete in the preceding section and the concrete in the following section. In addition, the horizontal bar of the rebar cage installed in the preceding section penetrates the partition plate and is also arranged in the following section. In order to make the continuous wall of the preceding section (preceding continuous wall) and the continuous wall of the following section (rearward continuous wall) into one piece, both continuous walls are sheared not only in the in-plane direction but also in the out-of-plane direction. It may not be sufficient for the transverse muscles to span between the two continuous walls, as the forces must be transmissibly joined.

In order to transfer shear force in the in-plane direction and the out-of-plane direction between the leading continuous wall and the trailing continuous wall using a partition plate, plates are projected on both sides of the partition plate and projections are formed on the plate. There is a method (see Patent Document 1) or a method in which plates are arranged in parallel and a steel bar is installed between the openings formed in the opposing plates (see Patent Document 2). In addition to this, there is also a method of forming a large number of recesses on both sides of the partition plate (see Patent Document 3).

JP-A-59-217829 (Claim 1, claim 2, page 2, upper left column, line 7 to lower left column, line 10, FIGS. 1 to 4) Japanese Unexamined Patent Publication No. 61-31522 (claim 1, page 2, upper right column, line 6 to page 3, upper left column, line 11, FIGS. 3 to 6) Japanese Patent No. 2631600 (claim 1, paragraphs 0013 to 0017, FIGS. 1 and 2)

The method of Patent Document 1 requires the work of welding a large number of steel materials such as round steel to the plate in order to form the projections on the plate, and the method of Patent Document 2 manufactures a plate having openings, and Since the work of erection of steel bars is required, it takes time and effort to manufacture the partition plate.

In the method of Patent Document 3, by forming concave portions (recesses) arranged in two directions from one surface side of the partition plate and forming a large number of convex portions on the other surface, the convex portion adjacent to the other surface is also formed. Although a concave portion is formed between them, the amount of protrusion of the projection from the surface of the partition plate is small, so that the effect of transmitting the shearing force by the concave portions on both sides of the partition plate is not high.

From the background described above, the present invention proposes a joint structure of an underground continuous wall having a higher shearing force transmission effect than that of Patent Document 3 while having a simple structure.

The joint structure for an underground continuous wall according to claim 1, wherein a rebar cage is provided in a preceding excavation groove that is excavated in the ground first, and a partition plate on the trailing excavation groove side adjacent to the preceding excavation groove. Installed, after placing concrete in the preceding excavation groove, excavating the trailing excavation groove to the position of the excavation groove adjacent to that side, installing a rebar cage in the following excavation groove, concrete Is a joint structure of an underground continuous wall that connects the preceding continuous wall constructed in the preceding excavation groove by casting, and the succeeding continuous wall constructed in the following excavation groove,
Addition in which a plurality of holes are formed at intervals in the height direction at the protruding portion or at a protruding portion continuous with the protruding portion, the protruding portion facing in a direction intersecting with the surface of the partition plate. In the concrete, the material is joined to at least one surface of the partition plate continuously or intermittently in the height direction, and is placed in at least one of the preceding excavation groove and the following excavation groove. It is required to be buried in.

The "reinforcing bar cage provided with a partition plate on the trailing excavation groove side" means a partition plate near the trailing excavation groove 9 of the reinforcing rod cage 1A installed in the preceding excavation groove 8 as shown in Fig. 2-(a). 4 is attached integrally, and means that the partition plate 4 is connected to the rebar cage 1A by some means in the installed state of the rebar cage 1A (the state before placing concrete). For example, as shown in FIG. 1 and the like, the horizontal bars 3 of the reinforcing bar cage 1A penetrate the partition plates 4 so that the partition plates 4 are supported by the horizontal bars 3, and as shown in FIG. In the case of not penetrating, it includes being supported by the vertical streak 2, the horizontal streak 3 or the like via a binding wire or the like. Without being supported by the vertical bars 2 and the horizontal bars 3, a steel material or the like temporarily fixed by being sandwiched by both the reinforcing bar cage 1A and the reinforcing bar cage 1B in the trailing excavation groove 9 via a spacer or the like. It may be held by an auxiliary material or the like. The partition plate 4 is formed on the boundary surface between the preceding continuous wall 10 constructed by placing concrete in the preceding excavation groove 8 and the succeeding continuous wall 11 constructed by placing concrete in the following excavation groove 9. Become.

“Having an overhanging portion facing the direction intersecting the surface of the partition plate” means that when the additional material 6 is bonded (fixed) to the surface of the partition plate 4 as shown in FIG. Means that the center line or the surface of the partition plate 4 intersects with the center line of the partition plate 4 or the surface. Further, the additional material 6 need only have the projecting portion 61 as a plate element or the like, and it means that the additional material 6 itself does not matter in cross-sectional shape. When the additional material 6 includes only the overhanging portion 61, the additional material 6 is formed from a plate, a flat bar, or the like in an I-shaped cross section. Steel is mainly used as the additional material 6, but it is not always necessary to use steel.

The "protruding portion 62 continuous to the overhanging portion 61" means that the projecting portion 62 as a plate element or the like is continuous from the tip end side of the overhanging portion 61 when viewed from the partition plate 4 and is orthogonal to the overhanging portion 61. Etc. are formed so as to face in the intersecting direction. More specifically, it means that the additional material 6 is L-shaped, T-shaped or the like from the overhanging portion 61 and the protruding portion 62 except for the joint portion to the partition plate 4, for example. The plurality of holes 6a are formed in at least one of the overhang portion 61 and the protruding portion 62. Since the partition plate 4 bears a placing pressure as a concrete dam which is placed in the preceding excavation groove 8, it has a width across the opposing groove walls of the excavation groove, and is basically made of a steel plate.

The plurality of holes 6a formed in the additional material 6 exert a shearing resistance force by the concrete placed in at least one of the preceding excavation groove 8 and the following excavation groove 9 entering into the hole 6a. As shown in the figure, at least the height direction (vertical direction) is arranged at intervals. “At least in the height direction” means that a plurality of holes 6a may be arranged in the width direction of the overhanging portion 61 or the protruding portion 62 as shown in FIG. The shearing resistance force due to the concrete entering the hole 6a functions mainly for the in-plane and out-of-plane shearing forces between the adjacent preceding continuous wall 10 and the following continuous wall 11.

By the concrete entering the holes 6a of the additional material 6, in addition to the adhesive force with the concrete on both sides in the thickness direction of the overhanging portion 61 and the like, the outer peripheral surface of the columnar concrete existing in the holes 6a and the holes 6a The bearing pressure acting on the peripheral surface and the shear resistance force on both axial end faces of the concrete in the hole 6a are summed as the resistance force against the shear force acting between the overhanging portion 61 and the concrete. Hereinafter, the resistance force generated in the hole 6a is referred to as "resistance force in the hole 6a". The hole 6a is formed in a circular shape, a polygonal shape, or the like, and the shape is not limited.

The resistance force in the hole 6a generated in the plurality of holes 6a formed at intervals in the height direction of the additional material 6 mainly acts in the direction orthogonal to the axis of the columnar concrete existing in the hole 6a. Therefore, when the hole 6a is formed in the overhang portion 61, the resistance force in the hole 6a effectively functions mainly against the in-plane shearing force generated between the leading continuous wall 10 and the trailing continuous wall 11. .. As shown in FIG. 11, if the hole 6a is formed in the projecting portion 62 that is oriented in the direction intersecting the overhanging portion 61, the resistance force in the hole 6a is mainly generated between the leading continuous wall 10 and the trailing continuous wall 11. Effectively works against shear force in the out-of-plane direction. The shear force in the in-plane direction is a shear force that acts on the partition plate 4 between the preceding continuous wall 10 and the following continuous wall 11 in the vertical direction (horizontal direction in the entire continuous walls 10 and 11), and the out-of-plane direction. Is a shearing force acting between the leading continuous wall 10 and the trailing continuous wall 11 in the horizontal direction of the wall thickness direction.

The resistance in the hole 6a exerts an effect on the shearing force between the leading continuous wall 10 and the trailing continuous wall 11, mainly in the in-plane direction and the out-of-plane direction, so that one piece (one piece) is added. Only by joining the material 6 to the partition plate 4, it is possible to obtain a high shearing force transmission effect between the partition plate 4 in which the additional material 6 is integrated and the concrete. Further, if the holes 6 a are formed in the additional material 6 in advance, the partition plate 4 with the additional material 6 can be manufactured only by welding the additional material 6 to the partition plate 4 or by bolting or the like. The production of the plate 4 is simplified. The term "mainly for shear force" means that the effect can be exerted also on bending moments in the vertical direction and the horizontal direction.

The term "(additional material is continuously joined)" in claim 1 means that the additional material 6 has a continuous length in a certain axial section, and that the additional material 6 has a continuous axial length. Although it does not have such a length, a plurality of additional materials 6 may be axially butted against each other and joined to the partition plate 4. “Intermittently joined” means joined to the partition plate 4 while ensuring a space between the additional members 6 adjacent to each other in the axial direction. In both continuous and intermittent cases, the additional material 6 is different from a bar material such as a stud bolt in that the additional material 6 has a length of a certain length or more in the axial direction so that when the additional material 6 is joined to the partition plate 4, In addition to exerting a resistance against the shearing force, it exerts a function of imparting bending rigidity to the partition plate 4, and functions to prevent the partition plate 4 from bending and deforming due to the placing pressure received from concrete.

When the additional material 6 is joined to both sides of the partition plate 4 (Claim 2), the resistance force in the hole 6a forms a couple force by sandwiching the partition plate 4, and therefore the front continuous wall 10 and the rear continuous wall 10 are formed. It also resists horizontal and vertical bending moments acting between the row continuous walls 11. When the additional materials 6 and 6 are joined to both surfaces of the partition plate 4, both additional materials 6 and 6 are arranged at symmetrical positions with respect to the center line in the in-plane direction of the partition plate 4 as shown by a solid line in FIG. It does not necessarily have to be provided, and as shown by the chain line in FIG. 1, they may be arranged in a staggered manner in the direction of the center line of the partition plate 4.

When the additional materials 6 and 6 are joined to both sides of the partition plate 4, if the hole 6a is formed in the overhang portion 61, the couple due to the resistance force in the hole 6a is mainly in the vertical direction (center of the partition plate 4). It also resists bending moment around the horizontal axis including the line). When the hole 6a is formed in the projecting portion 62, the couple due to the resistance force in the hole 6a also becomes a resistance force mainly against a bending moment in the horizontal direction (around the vertical axis). In particular, when the hole 6a is formed in the projecting portion 62 or also in the projecting portion 62, compared to the case where the hole 6a is formed in the projecting portion 61, up to the position where the resistance force is generated in the hole 6a of the projecting portion 62. However, since the distance from the surface of the partition plate 4 increases, the resistance force to the bending moment in the horizontal direction increases.

When the additional material 6 is joined to both sides of the partition plate 4 (claim 2), the penetrating line 7 is formed in the hole 6a formed in the overhang portion 61 of each additional material 6 as shown in FIG. It can also be inserted (claim 3). 1 to 5 show an example in which the horizontal bar 3 penetrates the partition plate 4 in the thickness direction, but the horizontal bar 3 has the horizontal bar 3 in the preceding excavation groove 8 and the following excavation groove 9 as shown in FIG. It may be arranged in internal units. In that case, the joining state of the leading continuous wall 10 and the trailing continuous wall 11 is maintained mainly by the resistance force exerted by the partition plate 4 and the additional materials 6 joined to both surfaces thereof.

When the penetrating bar 7 is inserted into the additional material 6, the penetrating bar 7 is arranged in at least one of the preceding excavating groove 8 and the following excavating groove 9 of the rebar cage 1A installed in at least the preceding excavating groove 8. Streaked (Claim 3). In this case, when the resistance force in the hole 6a is exerted, the penetrating muscle 7 bears the bending moment while exerting the resistance force, so that the shear force in the in-plane direction and the resistance force to the bending moment are increased. The penetrating muscle 7 does not need to straddle between the lateral reinforcing muscles 3 and 3 of the reinforcing bar cage 1A, but if both ends of the penetrating muscle 7 can be locked to the lateral reinforcing muscles 3 and 3, for example, the bending moment that the penetrating muscle 7 bears Is transmitted to the horizontal bars 3 and 3 of the reinforcing bar cage 1A, so that the leading continuous wall 10 and the trailing continuous wall 11 as a whole bear a bending moment.

Inserting the penetrating line 7 into the hole 6a formed in the overhang portion 61 of the additional material 6 is not limited to the case where the additional material 6 is bonded to both surfaces of the partition plate 4 (claim 2). Absent. However, when the additional material 6 is joined to both sides of the partition plate 4, the resistance force exerted by the penetrating muscles 7 is generated on both sides of the partition plate 4, and this resistance force is generated. It has the meaning of acting in equilibrium on both sides of, or forming a couple.

A tension member (tie rod) 5 is connected to the partition plate 4 on the side of the preceding continuous wall 10 as shown in FIG. 4 for resisting the placing pressure when the concrete forming the preceding continuous wall 10 is placed. (Claim 4). Further, as shown in FIG. 5, in the rebar cage 1A, the horizontal bar 3 bears the tensile force acting between the leading continuous wall 10 and the trailing continuous wall 11, while transmitting to the concrete through the adhesive force. It can be said that it is a reinforcing material in the sense that it reinforces the concrete against the tensile force acting in the concrete by being laid through the partition plate 4 so as to straddle the leading continuous wall 10 and the trailing continuous wall 11.

In these cases, the tensile force of the reinforcing material tends to concentrate near the position where the reinforcing material (tensile material) is connected to the partition plate 4, or near the position where the reinforcing material (horizontal bar 3) penetrates the partition plate 4, so that the partition plate If the additional material 6 is joined to the vicinity of the reinforcing material 4 (claim 4), the effect of preventing the bending deformation of the partition plate 4 by the above-mentioned additional material 6 is likely to be effectively exhibited. The reinforcing material includes the tensile member 5 and the lateral streaks 3, but also includes tensile force resistance materials other than these. The reinforcing material is arranged in the preceding excavation groove 8.

When the additional material 6 is joined to the trailing excavation groove 9 side of the partition plate 4 as shown in FIG. 9 (Claim 5), the additional material 6 penetrates through the partition plate 4 and the trailing excavation groove 9 is passed. It can serve as a guide for guiding the elevating and lowering of the washing device for washing the lateral streak 3 projecting to the side before the concrete is cast on the trailing continuous wall 11. In this case, since the additional material 6 also serves as a guide for installing the cleaning device, it is not necessary to separately join a guide for the cleaning device to the partition plate 4.

An additional material, in which a plurality of holes are formed at intervals in the height direction, on an overhanging portion facing the direction intersecting the surface of the partition plate, or on a protruding portion continuous with the overhanging portion, is joined to at least one surface of the partition plate. This resists the shearing force and bending moment between the leading continuous wall and the trailing continuous wall, thus simplifying the production of the partition plate with additional material while effectively exerting the resistance force in multiple holes. be able to.

(A) is a plan view (horizontal cross-sectional view) showing a state where a reinforcing bar basket with a partition plate for a preceding continuous wall is installed in the preceding excavation trench, and one additional material is joined to each side of the partition plate. In the case of doing, (b) is an elevation view of (a) showing an arrangement state of the reinforcing bar cage, and (c) is a view taken along line xx of (a). (A) shows a state in which a reinforcing bar cage with a partition plate for a preceding continuous wall is installed in the preceding excavation groove, and a reinforcing bar cage for a succeeding continuous wall is installed in a following excavation groove, with 2 on each side of the partition plate. The top view which showed the example at the time of joining and joining the additional material of one sheet, (b) is the elevation view of (a) which showed the rebar cage, (c) is the xx arrow line view of (a). Drawing (d) is a yy line arrow view of (a). (A) is a plan view showing an example in which a penetrating muscle is inserted into a hole of an additional material, (b) is an elevation view of (a), (c) is an xx line arrow of (a). It is a perspective view. It is the top view which showed the example at the time of making the additional material hold|maintain the tension material as a reinforcement material which reinforces the concrete of a preceding continuous wall. It is the top view which showed the example at the time of making the additional material hold|maintain the horizontal reinforcement which comprises the reinforcing-bar cage in the preceding continuous wall. (A) is a plan view showing an example in which the horizontal bar of the reinforcing bar cage in the preceding excavation groove does not penetrate the partition plate, and the reinforcing bar cage in the preceding excavation groove and the reinforcing bar cage in the following excavation groove are separated. And (b) is a sectional view taken along line xx, (b) is an elevational view of (a), (c) is a sectional view taken along line yy of (a), and (d) is z of (a). It is a z-line sectional view. (A) is a plan view showing a state in which an additional material, which is a steel plate (plate) consisting only of overhangs, is joined to a partition plate, and (b) is an elevation view of (a). (A) is a plan view showing a state where an additional material having an L-shaped cross-section having an overhanging portion and a base portion as a joint portion to the partition plate is joined to the partition plate, (b) is an elevation view of (a) It is a figure. FIG. 3 is a plan view showing an example of a case where an additional material has a role of a guide for guiding the lifting and lowering of a cleaning device for cleaning a horizontal bar projecting to the trailing excavation groove side of a reinforcing bar cage in the preceding excavation groove. is there. (A) is a plan view showing a state in which an additional material having an H-shaped cross section having an overhanging portion and a projecting portion and having holes formed in the overhanging portion is joined to a partition plate, and (b) is (a) ) Is an elevation view of FIG. (A) is a plan view showing a state in which an additional material having an H-shaped cross section having an overhanging portion and a protruding portion and having holes formed in the protruding portion is joined to a partition plate, and (b) is a diagram (a). And (c) is a side view taken along line xx of (a). Fig. 1 is a graph showing the relationship between the displacement of concrete on both sides of the partition plate (continuous wall) and the shear stress acting on both sides of the partition plate with and without the additional material is there.

1-(a) to (c) show a rebar cage 1A having a partition plate 4 on a trailing excavation groove 9 side adjacent to the preceding excavation groove 8 in the preceding excavation groove 8 excavated in the ground. Is installed and concrete is placed in the preceding excavation groove 8, and then the rebar cage 1B is installed in the trailing excavation groove 9 and the concrete is placed to construct the preceding continuous wall 10 in the preceding excavation groove 8. And an example of a joint structure of a continuous underground wall which connects the continuous trailing wall 11 constructed in the trailing excavation groove 9 with each other. The excavation grooves (leading excavation groove 8 and trailing excavation groove 9) are formed by, for example, a bucket type excavator, a horizontal multi-axis excavator, or the like, but the forming method is not limited.

At least one surface of the partition plate 4 has an overhanging portion 61 that is orthogonal to the surface of the partitioning plate 4 and is oriented in an intersecting direction, and the overhanging portion 61 or a projecting portion 62 formed continuously with the overhanging portion 61. The additional material 6 made of, for example, steel, in which a plurality of holes 6a are formed at intervals in the height direction, is joined (fixed) continuously or intermittently in the height direction. The additional material 6 may be pre-joined before the rebar cage 1A with the partition plate 4 is carried into the site, or may be pre-joined, but in principle, it is pre-joined. 1 to 3 show an example in which the additional material 6 has a flat plate shape including only the overhang portion 61, but when the additional material 6 includes the overhang portion 61 and the protruding portion 62, the additional material 6 Is formed in an arbitrary cross-sectional shape.

Reinforcing bar baskets 1A and 1B are basically two planar reinforcing bar units assembled by combining vertical bars 2 and horizontal bars 3 in a lattice pattern, as shown in FIG. 2-(a). It is configured by holding both reinforcing bar units on the partition plate 4 at the portion of the horizontal bar 3 penetrating the partition plate 4. The end portion of the horizontal streak 3 on the partition plate 4 side penetrates through the partition plate 4 and is stretched to the trailing excavation groove 9 side in order to transmit tensile force with the concrete placed in the trailing excavation groove 9. put out. The vertical streak 2 is also connected to the portion of the horizontal streak 3 that projects toward the trailing excavation groove 9 side.

As shown in FIG. 2-(a), the distance between the parallel lateral bars 3 and 3 of the reinforcing bar cage 1B installed in the trailing excavation groove 9 that is parallel to the preceding excavation groove 8 is the reinforcing bar installed in the preceding excavation groove 8. Due to the lap joint of the cage 1A with the horizontal bar 3 protruding from the partition plate 4 via the adhesive force with the concrete, the distance between the parallel horizontal bars 3 and 3 of the reinforcing bar cage 1A in the preceding excavation groove 8 is smaller than the distance. Has become.

FIG. 1 shows an example of manufacturing the reinforcing bar cage 1A in the case where the additional material 6 has a flat cross section and the additional material 6 is joined to both surfaces of the partition plate 4. Here, when the additional material 6 is composed of only the projecting portion 61, one additional material 6 is bonded to one side of the partition plate 4 near the center of the partition plate 4 in the width direction. In FIG. 1 and subsequent figures, an example in which the additional material 6 is continuous in the height direction is shown.

Between the holes 6a adjacent to each other in the height direction, a distance is secured so as not to cause deformation around the holes 6a as a result of the columnar concrete entering the holes 6a bearing the shearing force in the direction orthogonal to the axis. To be done. The shape of the hole 6a is mainly circular as shown in FIG. 1-(b), but is not necessarily limited to circular. Although FIG. 1 to FIG. 3 show an example in which the holes 6a are arranged in one row in the width direction of the overhang portion 61 as shown in FIG. 1B, the width of the overhang portion 61, or the holes Depending on the size of 6a, a plurality of rows may be arranged in the width direction of the overhang portion 61 or the width direction of the protruding portion 62, or may be arranged in a staggered manner.

When an in-plane (vertical) shearing force is applied between the continuous walls 10 and 11 (concrete) on both sides of the partition plate 4, the displacement between the continuous walls 10 and 11 and the partition plate 4 are caused. FIG. 12 shows the relationship between the shear stress levels acting on both sides. The broken line shows the history when the horizontal streak 3 only penetrates the partition plate 4, and the solid line shows the history when the additional materials 6, 6 are joined to both surfaces of the partition plate 4 as shown in FIG. From FIG. 12, when the additional materials 6 and 6 are joined to the partition plate 4, as compared with the case where the horizontal streak 3 only penetrates through the partition plate 4, equal shear force stresses are applied between both surfaces of the partition plate 4. It can be seen that the displacement displacement when acted is about a fraction.

FIG. 2 shows an example in which two or more additional materials 6 and 6 having the shape shown in FIG. 1 are arranged side by side in the width direction of the partition plate 4 (preceding excavation groove 8) and bonded to both surfaces of the partition plate 4. Indicates. As described above, in the trailing excavation groove 9, the distance between the horizontal bars 3 and 3 of the reinforcing bar cage 1B near the partition plate 4 is smaller than the distance between the horizontal bars 3 and 3 of the reinforcing bar cage 1A. It is arranged at a position within 9 that does not contact the horizontal bar 3 of the reinforcing bar cage 1B. In particular, on the vertical surface of the trailing excavation groove 9, as shown in FIG. 2-(a), the additional material 6 in the trailing excavation groove 9 has a width such that the horizontal bar 3 of the rebar cage 1B and the additional material 6 overlap. In the case, or when the horizontal bar 3 has a length such that the additional material 6 overlaps, the axial tensile force of the horizontal bar 3 is transmitted between the additional material 6 and the horizontal bar 3 via the adhesive force of concrete. It becomes a state.

FIG. 3 shows an example in which the penetrating muscle 7 is inserted into the hole 6a formed in the overhang portion 61 of the additional material 6. In FIG. 3, the penetrating bar 7 is arranged so as to straddle at least the transverse bars 3 and 3 of the reinforcing bar cage 1A that face each other in the width direction of at least one of the preceding excavation groove 8 and the following excavation groove 9. However, both end portions in the axial direction of the penetrating muscle 7 may not intersect the lateral muscles 3 and 3 on a plane. As shown in FIG. 3-(c), when both ends of the penetrating muscle 7 are arranged in a state in which the penetrating muscle 7 can be locked vertically to the transverse muscles 3 and 3, the bending moment that the penetrating muscle 7 bears is a reinforcing bar cage. It is transmitted to the transverse muscles 3 and 3 of 1A. When the additional material 6 is joined to both sides of the partition plate 4, the bending moment generated in the preceding continuous wall 10 is transmitted to the succeeding continuous wall 11, and the bending moment generated in the succeeding continuous wall 11 precedes. It is in a state of being transmitted to the continuous wall 10.

FIG. 4 shows a case where a tensile member 5 as a reinforcing member for reinforcing concrete placed in the preceding excavating groove 8 and 9 is connected to the partition plate 4 from the tensile member 5. An example in which the additional material 6 is joined to the partition plate 4 so as to suppress the bending deformation of the partition plate 4 due to the tensile force acting on the partition plate 4 will be shown. The additional material 6 is joined by welding or the like so that the overhang portion 61 faces the direction of the surface of the partition plate 4. Since reinforcing bars and steel bars are mainly used for the tensile member 5, in FIG. 4, the partition plate 4 is penetrated to project the end portion of the tensile member 5 toward the trailing excavation groove 9 side. The tension member 5 is connected to the partition plate 4 by screwing a fastener 51 such as a nut to the portion.

The tensile member 5 resists the tensile force from the partition plate 4 when the pressure of the concrete when it is placed in the preceding excavation groove 8 acts on the partition plate 4, and the partition plate 4 moves toward the trailing excavation groove 9 side. It works to prevent movement. From this, the tensile member 5 is mainly arranged (bar arrangement) on the preceding excavation groove 8 side of the partition plate 4, and in FIG. 4, the additional member 6 having only the overhanging portion 61 in which the hole 6a is formed is used. Although it is joined only to the surface of the partition plate 4 on the leading excavation groove 8 side, it may be joined to the surface of the trailing excavation groove 9 side as well.

In the case of the example shown in FIG. 4, the overhanging portion 61 of the additional material 6 is arranged along the axial direction of the tension material 5, and the centerline (front surface) of the overhanging portion 61 is aligned with the centerline (front surface) of the partition plate 4. The axes of the holes 6a are oriented parallel to the center line of the partition plate 4 such that they intersect with each other at right angles. Since the additional material 6 has a role of stiffening the vicinity of the connection portion of the tension member 5 (reinforcement material) to the partition plate 4, it is arranged along the tension material 5 (reinforcement material). Since the behavior is different, it is separated from the tensile member 5.

FIG. 5 is a partition in the case where the reinforcing material which is arranged in at least one of the preceding excavation groove 8 and the following excavation groove 9 and which reinforces the concrete placed in the excavation grooves 8 and 9 is the horizontal bar 3. An example of joining the additional material 6 to the plate 4 is shown. The horizontal bar 3 arranged in the preceding excavation groove 8 penetrates the partition plate 4 and projects to the trailing excavation groove 9 side, but in FIG. 5, as in the example of FIG. The additional material 6 having only the overhang portion 61 on the surface is joined. Also in this example, the center line of the overhang portion 61 faces the direction intersecting the center line of the partition plate 4, and the axis of the hole 6a faces the direction of the center line of the partition plate 4. In this case as well, the additional material 6 is arranged along the lateral streaks 3 (reinforcing material), but separated from the tensile material 5.

In FIG. 6, the horizontal bars 3 of the reinforcing bar cage 1A in the preceding excavation groove 8 do not penetrate the partition plate 4, and the reinforcing bar cage 1A in the preceding excavation groove 8 and the reinforcing bar cage 1B in the following excavation groove 9 sandwich the partition plate 4. An example of the bar arrangement in each of the excavation grooves 8 and 9 when they are separated by is shown. FIG. 6 shows an example in which the vertical bar 2 is arranged so as to surround at least a plurality of horizontal bars 3 in the excavation grooves 8 and 9 as shown in (b) to (d) and also serves as a shear reinforcing bar. But also. In this example, since the horizontal bars 3 of the reinforcing bar cage 1A and the reinforcing bar cage 1B do not penetrate the partition plate 4, the partition plate 4 is connected to the horizontal bar 3 or the vertical bar 2 through a binding wire or an auxiliary material fixed temporarily. Indirectly supported. In this example, the leading continuous wall 10 and the trailing continuous wall 11 resist the shearing forces in the respective out-of-plane directions due to the adhesive force on both surfaces of the partition plate 4 and the resistance force generated in the additional material 6, and thus the additional material. 6 are joined to both sides of the partition plate 4, and a plurality of them are arranged in the width direction of the partition plate 4.

7 and 8 show specific examples of the additional material 6 of the joining examples shown in FIGS. 1 to 5. 7 shows that the additional material 6 is composed only of the flat plate-shaped overhang portion 61, and when the additional material 6 is butt welded to one surface of the partition plate 4, the additional material 6 is continuous to the overhang portion 61 and the partition plate 4 side in FIG. This is a case where the base portion 63 is formed in an L-shaped cross section and is joined to the partition plate 4 at the base portion 63 by welding or bolts. In any of the examples, the holes 6a are formed in the overhang portion 61 at intervals in the height direction. In the example of FIGS. 7 and 8, the holes 6a are arranged in one row in the width direction of the overhang portion 61, but they may be arranged in a plurality of rows or may be arranged in a staggered pattern.

FIG. 9 shows an example in which the additional material 6 is joined to the surface of the partition plate 4 on the trailing excavation groove 9 side. In this example, the dirt that has adhered to the horizontal stirrup 3 that penetrates through the partition plate 4 and projects toward the trailing excavation groove 9 until the completion of placing concrete into the preceding excavation groove 8 is removed. It is assumed that the additional material 6 has a function of supporting a cleaning device for cleaning before placing concrete inside. In this case, the additional material 6 functions as a guide material (guide) for moving up and down while being gripped by the cleaning device. The additional material 6 used in this example is formed to have a cross-sectional shape having at least two portions, an overhang portion 61 and a projecting portion 62, so that the cleaning device holds the additional material 6 and does not separate from the additional material 6 when moving up and down. It

10 and 11 show specific examples of the additional material 6 of the joining example shown in FIG. 8 in the case where the H-shaped steel is used as the additional material 6. In these examples, the additional material 6 is the overhanging portion 61, the protruding portion 62 that is continuous from the tip end side of the overhanging portion 61 when viewed from the partition plate 4 to both sides in the thickness direction of the overhanging portion 61, and the overhanging portion. The partition plate 4 side of 61 has a shape having three portions of a base portion 63 continuous on both sides in the thickness direction of the overhang portion 61. When the additional material 6 has the protruding portion 61 and the protruding portion 62, the base portion 63 may not be provided, and the protruding portion 62 and the base portion 63 may be formed only on one side in the thickness direction of the protruding portion 61, The additional material 6 may have a T-shaped cross section, a C-shaped cross section, or the like.

10 shows an example in which the holes 6a are formed in one row only in the overhanging portion 61, and FIG. 11 shows an example in which the holes 6a are formed in two rows in the width direction of the protruding portion 62 only in the protruding portion 62. In the example shown in FIG. 11, since the hole 6a is formed in the protruding portion 62 farthest from the center line of the partition plate 4, the partition plate of the shear resistance force generated in the columnar concrete filled in the hole 6a is formed. 4 Since the distance from the center line becomes large, it is expected that the resistance force in the hole 6a also functions as a resistance force against the bending moment acting in the thickness direction of the partition plate 4.

1A: Reinforcing bar cage (in the preceding excavation groove), 1B: Reinforcing bar cage (in the backward excavation groove),
2...longitudinal streaks, 3...horizontal streaks, 4...partition plates, 5...tensiles, 51...fasteners,
6... additional material, 61... overhanging portion, 62... protruding portion, 63... base portion, 6a... hole,
7... Penetrating muscle,
8... Leading trench, 9... Trailing trench,
10... Leading continuous wall, 11... Trailing continuous wall.

Claims (5)

In the preceding excavation groove that was excavated earlier in the ground, a rebar basket equipped with a partition plate was installed on the trailing excavation groove side adjacent to this preceding excavation groove, and concrete was placed in the preceding excavation groove. After that, the trailing excavation trench is excavated to the position of the excavation trench adjacent to that side, a rebar cage is installed in the trailing excavation trench, and concrete is poured to construct the preceding excavation trench in the preceding excavation trench. It is a joint structure of a continuous wall and an underground continuous wall that connects the continuous trailing wall constructed in the trailing excavation trench,
Addition in which a plurality of holes are formed at intervals in the height direction at the protruding portion or at a protruding portion continuous with the protruding portion, the protruding portion facing in a direction intersecting with the surface of the partition plate. In the concrete, the material is joined to at least one surface of the partition plate continuously or intermittently in the height direction, and is placed in at least one of the preceding excavation groove and the following excavation groove. It is a joint structure of underground wall which is characterized by being buried in. The joint structure for a continuous underground wall according to claim 1, wherein the additional material is joined to both surfaces of the partition plate. A penetrating bar is inserted into the hole formed in the overhang portion of the additional material, and at least the inside of the preceding excavation groove and the following excavation groove of the rebar cage installed in at least the preceding excavation groove. The underground continuous wall joint structure according to claim 2, wherein the joint structure is arranged on either one of the sides. A reinforcing material that is arranged in the preceding excavation groove and that reinforces the concrete is connected to the partition plate, and the additional material 6 is joined in the vicinity of the reinforcing material. Item 2. A joint structure for an underground continuous wall according to Item 2. The joint structure for a continuous underground wall according to claim 1, wherein the additional material is joined to the trailing excavation groove side of the partition plate.

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