JP5031463B2 - Earth retaining wall reinforcement structure and method - Google Patents

Description

  The present invention relates to a reinforcing structure and method for retaining wall steel installed in the ground.

  The earth retaining walls that have been used in the past are steel earth retaining walls such as steel sheet piles, steel pipe sheet piles, H-shaped steel sheet piles, etc., and soil cement underground continuous walls using H-shaped steel such as SMW as the core, and reinforced concrete ground. There are medium continuous walls.

  For example, as shown in FIG. 15, the earth retaining wall 8 receives earth water pressure from the ground 80 toward the A direction. In general, the member cross-section of the retaining wall 8 is determined according to the amount of bending deformation of the retaining wall top 81, and sometimes a member having higher rigidity is required. In particular, the tendency of a retaining wall made of steel material is greater than that of a concrete retaining wall.

  Normally, when the front excavation depth in the retaining wall becomes deep, it will be constructed by reinforcing the retaining wall using a beam support, but for example, when the retaining wall is formed only on one side If the area of the beam support is increased, the beam support itself is difficult or uneconomical. In such a case, a retaining wall combined with an anchor method is used. An anchor is constructed and fixed on the ground extending from the front of the retaining wall to the rear of the retaining wall. However, when a private house or the like is present on the rear of the retaining wall, it is difficult to apply this. At this time, it is possible to cope by constructing a self-supporting earth retaining wall, but there is a problem that the rigidity of the earth retaining wall is limited as described above.

On the other hand, a method of reinforcing a steel girder such as a bridge by tensioning a steel wire rod has also been proposed (see, for example, Patent Document 1). However, such a reinforcing method extends the steel wire in the horizontal direction to the last, and the bending deformation generated in the bridge and the bending deformation of the retaining wall top 81 are different in size from each other. There is a difference in distribution tendency. Furthermore, because the retaining wall is to be installed in the ground, when a steel wire is attached to it, there is a case where tension is not actually required and the steel wire has to be removed. In addition, there is a problem that this cannot be realized simply by diverting a conventional method of reinforcing a bridge or the like.
JP 2003-269093 A

  Accordingly, the present invention has been devised in view of the above-described problems, and reduces the construction cost by improving the rigidity as the retaining wall member without increasing the member cross section of the retaining wall. It is another object of the present invention to provide a structure and a method for reinforcing a retaining wall capable of shortening the construction period and further reducing the necessary site as much as possible.

  In order to solve the above-described problems, the retaining wall reinforcing method to which the present invention is applied is to fix the locking members to the upper end and the lower end of the retaining wall member, and from the cross-sectional core of the retaining wall member. While hooking the curved portion of the steel wire rod that is eccentric to the natural ground side and curved substantially downward in the axial direction of the retaining wall member and configured in a substantially U shape, to the locking member at the lower end, By locking both end portions on the upper end side to the locking member of the upper end portion, this is attached along the axial direction of the retaining wall member, the retaining wall member is built in, and the retaining wall member Tension force is introduced into the steel wire rod so that the force to bend and deform against the natural ground side acts against the one that undergoes earth and water pressure and tries to bend and deform on the excavation side. The steel wire rod is pulled up from the upper end portion.

  In the present invention having the above-described configuration, the earth retaining wall member is given tension by a steel wire rod. Moreover, since this steel wire is attached to the flange-side steel plate on the back side, by introducing tension to the steel wire, the retaining wall member is subjected to bending stress toward the back side. Will be. As a result, the earth retaining wall member tends to bend and deform toward the back side.

  In the present invention, because the steel wire attached to the back side of the earth retaining wall member as described above exerts a force to bend and deform toward the back side of the earth retaining member based on the tension force. Can counteract stress based on soil water pressure. As a result, it is possible to suppress the amount of displacement of the upper end portion of the retaining wall member based on the earth water pressure toward the front side.

  In particular, in the present invention, the steel wire can be arranged in a U-shape and can be fixed by being hooked on the locking member. For this reason, according to the principle of a pulley, it becomes possible to obtain twice the tension force by introducing the tension force once for the steel wire rod.

  Moreover, in this invention, when the tension | tensile_strength becomes unnecessary after the function of a retaining wall is complete | finished, the said steel wire can be removed. That is, since the end of this steel wire rod is positioned near the ground, it can be easily pulled up.

  Moreover, in this invention, since the deformation | transformation of the upper end part based on earth water pressure can be suppressed with the steel wire mentioned above instead of improving the rigidity of a retaining wall member, in other words, the rigidity of a retaining wall member is improved. There is no need. For this reason, it is not necessary to increase the member cross section of the retaining wall member, the construction cost can be reduced, and the construction period can be shortened. Furthermore, according to the present invention, it is possible to reduce the land necessary for constructing the retaining wall as much as possible.

  Hereinafter, as a best mode for carrying out the present invention, a reinforcing structure of a retaining wall will be described in detail with reference to the drawings.

  The earth retaining wall reinforcing structure 1 to which the present invention is applied reinforces an earth retaining wall 3 applied as a retaining wall or the like for fastening a natural mountain 5 at the end of a road 2 as shown in FIG. The earth retaining wall 3 is embodied by an earth retaining wall member 4 using a steel sheet pile, a steel pipe sheet pile, an H-shaped steel material or the like. In the following description, a case where an H-shaped steel material is configured as the retaining wall member 4 will be described as an example.

  Fig.2 (a) has shown the top view of the retaining wall 3 in the state by which the retaining wall member 4 was embedded. Moreover, Fig.3 (a) has shown the front view of the earth retaining wall member 4 seen from Fig.2 (a) B direction.

  The retaining wall member 4 includes flange steel plates 42 a and 42 b provided at both ends of a web steel plate 41. At both ends of the flange steel plates 42a and 42b, joints 46a and 46b for connecting to the flange steel plates 42a and 42b in the other retaining wall members 4 adjacent to each other are provided. Moreover, the retaining wall member 4 shall be arrange | positioned so that the flange steel plate 42a may be located in the natural ground 5 side, and the flange steel plate 42b may be located in the road 2 side. That is, the flange steel plate 42 a is located on the back side that receives the soil water pressure from the natural ground 5, and the flange steel plate 42 b is located on the front side facing the road 2.

  FIG. 2B is a plan view of the earth retaining wall 3 in which the configuration of the joint is omitted and the H-shaped steel members 60 are simply arranged in parallel. Of course, even if the configuration of the joint is omitted, it is possible to obtain the intended effects of the present invention described below.

  A metal fitting 44 is attached at the upper end on the back side of the flange steel plate 42a, and a locking member 48 is attached at the lower part.

  The metal fitting 44 may have any configuration as long as a through-hole is formed at least vertically. For example, as shown in FIGS. 2 (c) and 2 (d), the taper is tapered downward. You may provide the through-hole 56 in which 57 was formed. The metal fitting 44 is attached to the back side of the flange steel plate 42a by means such as welding 55.

  The locking member 48 may be configured in a shape in which a curved portion is provided downward. The locking member 48 may have a shape in which a groove is formed to the extent that a later-described steel wire rod can be locked. Moreover, as shown in FIG.3 (c), it may be comprised by the shape only in which the groove | channel was formed, and the U-shaped through-hole 56 was formed as shown in FIG.3 (d). It may consist of things.

  Further, when the steel wire 11 is fixed to the metal fitting 44, for example, as shown in FIG. 3 (e), the wedge 53 is fitted into the through hole 56 of the metal fitting 44, and the steel 53 is made in the center of the wedge 53. The wire 11 may be inserted. When the wedge 53 is fitted into the through hole 56 of the metal fitting 44, a tightening force acts inward along with the angle gradient of the taper 57, and the steel wire 11 can be firmly fixed. Become.

  Further, as shown in FIG. 3 (a), a steel wire 11 is attached to the earth retaining wall member 4 in a substantially U shape by being bent downward. Both ends 11 b of the steel wire 11 are inserted and fixed in through holes in the metal fitting 44. Further, the bent portion 11 a bent in the steel wire 11 is locked to the locking member 48.

  This steel wire 11 may be made of PC steel, steel bar or flat steel. Incidentally, tension is introduced into the steel wire 11. This tension force may be introduced by, for example, a tension device (not shown) screwed to both ends of the steel wire 11. That is, the tension can be increased or decreased depending on the tightening degree of the bolt (not shown). Moreover, the tension apparatus which is not shown in figure which can pull the said steel wire 11 to the ground side may be provided in the both ends of this steel wire 11. This makes it possible to increase or decrease the tension force freely on the ground based on the state of displacement of the retaining ring.

  FIG.3 (b) has shown other embodiment of the reinforcement structure 1 of the retaining wall to which this invention is applied. In the example of FIG. 3B, instead of providing the steel wire 11 in a U shape as described above, two steel wires 111 are attached in a substantially linear shape. At this time, the steel wire rods 111 are attached to each other in a state of being eccentric from each other at positions away from the centroid while being separated from each other. You may make it fix this steel wire 111 through the metal fitting 44 attached up and down, respectively. This steel wire 111 is similarly introduced with tension.

  Such a retaining wall 3 may further include soil cement or concrete 39 around the retaining wall member 4 provided with the steel wire 11.

  Next, the construction method of the retaining wall reinforcing structure 1 to which the present invention is applied will be described.

  First, the metal fitting 44 and the locking member 48 are attached to the back surface side of the flange steel plate 42 a in the retaining wall member 4. Next, the steel wire 11 is attached to the metal fitting 44 and the locking member 48 and fixed thereto. At this stage, tension may be applied.

  Next, this earth retaining wall member 4 is built in the ground. As a method of building the earth retaining wall member 4 into the ground, after excavating the earth and sand with a continuous excavator, it may be built with a crane and cast concrete, or a soil cement may be formed as in the so-called SMW method. After that, it may be built with a crane. Further, a vibro method or a press-fitting method may be used. After the installation is finally finished, the tension force may be applied and increased or decreased using the tension device (not shown) described above.

  The retaining wall reinforcing structure 1 constructed by such a method has the following effects.

  First, the retaining wall member 4 is given tension by the steel wire 11. Moreover, since this steel wire 11 is attached to the flange steel plate 42a, by introducing tension to the steel wire 11, bending stress toward the back side as shown in FIG. 4 (a). Will be loaded. As a result, the earth retaining wall member 4 tends to bend and deform toward the back side.

  Generally, stress based on earth water pressure acts from the natural ground 5 located on the back side of the retaining wall member 4 as shown in FIG. 5, and in particular, the displacement of the upper end portion of the retaining wall member 4 becomes large. End up. This is because excavation is performed to form the road 2 on the front side of the retaining wall member 4. However, in the present invention, based on the tension force by the steel wire 11 attached to the back side of the earth retaining wall member 4 as described above, the force to bend and deform the earth retaining member 4 toward the back side. Therefore, it is possible to counter the stress based on the soil water pressure. As a result, as shown by the solid line in FIG. 4B, it is possible to suppress the amount of displacement of the upper end portion of the retaining wall member 4 based on the earth water pressure toward the front side. Incidentally, the example shown by the dotted line in FIG. 4B shows a deformed state of the retaining wall member 4 when the steel wire 11 is not arranged.

  In particular, in the present invention, the steel wire 11 is arranged in a U shape, and is hooked and fixed in a groove provided in the locking member 48. For this reason, according to the principle of a pulley, it becomes possible to obtain twice the tension force by introducing the tension force to the steel wire 11 once.

  Moreover, in this invention, after attaching the steel wire 11, even if the tension | tensile_strength actually becomes unnecessary and the case where the said steel wire 11 must be removed arises, the edge part of this steel wire 11 is produced. Since it is located near the ground, it can be easily pulled up.

  Moreover, in this invention, since the deformation | transformation of the upper end part based on earth water pressure can be suppressed by the steel wire 11 mentioned above instead of improving the rigidity of the earth retaining wall member 4, in other words, the rigidity of the earth retaining wall member 4 Need not be improved. For this reason, it is not necessary to enlarge the member cross section of the retaining wall member 4, the construction cost can be reduced, and the construction period can be shortened. Furthermore, according to the present invention, it is possible to reduce the site necessary for constructing the retaining wall 3 as much as possible.

  Incidentally, in the form as shown in FIG. 3 (b) described above, similarly, the tension force is introduced through the steel wire 111, so that the front surface of the upper end portion of the retaining wall member 4 based on the soil water pressure. It is possible to suppress the amount of displacement to the side.

Moreover, as for the steel wire rod 11, an upper end part is located above the excavation bottom face 2a, and a lower end part is located below the excavation bottom face. The excavation bottom surface 2 a means the ground surface of the front excavation 2. Thereby, there exists an effect which can make small deformation of the earth retaining wall member 4 efficiently.
Note that the retaining wall reinforcement method to which the present invention is applied is not limited to the above-described embodiment.

  6 (a) to 6 (c) show other application examples in the retaining wall reinforcement method to which the present invention is applied. First, as shown to Fig.6 (a), the structure 51 is constructed | assembled in the front side of the earth retaining wall 3 to which the steel wire 11 constructed | assembled based on the method mentioned above was attached. Next, as shown in FIG. 6B, the upper portion of the structure 51 is backfilled with earth and sand. At this stage, the earth retaining wall 3 is supported by the earth and sand buried back on the front side, and the force to bend toward the front side is reduced. For this reason, the steel wire 11 is pulled out from the earth retaining wall member 4 as shown in FIG.

  FIG. 7 shows a form in which the steel wire 11 is inserted into the pipe 52 and attached thereto. The tube 52 may be applied with a sheath made of metal or plastic, for example, and is disposed in a state where a gap is provided between the inner wall of the tube 52 and the steel wire 11. When the steel wire rod is left semi-permanently while being in tension, the steel wire rod 11 is inserted into the tube 52, and cement milk is filled in the gap. Then, the cement milk is solidified, so that the steel wire 11 can be firmly fixed to the pipe 52. Incidentally, the filling of the cement milk is executed after applying tension to the steel wire 11. Incidentally, this tension may be applied through a jack.

  FIGS. 8-10 has shown the other application example in the arrangement | positioning method of the steel wire 11. FIG. Fig.8 (a) has shown the example which attaches the steel wire 11 to the inner surface in the flange steel plate 42a. FIG. 8B shows an example in which the upper end of the steel wire 11 is attached to the outer surface of the flange steel plate 42a and the lower end of the steel wire 11 is attached to the inner surface of the flange steel plate 42a.

  Moreover, Fig.9 (a) has shown the example which attaches the upper end of the steel wire 11 to the outer surface in the flange steel plate 42a, and attaches the lower end of the steel wire 11 to the inner surface in the flange steel plate 42b. FIG.9 (b) has shown the example which attaches the upper end of the steel wire 11 to the outer surface in the flange steel plate 42b, and attaches the lower end of the steel wire 11 to the inner surface in the flange steel plate 42a.

  In FIG. 10A, the lower end of the steel wire 11 is fixed to the outer surface of the flange steel plate 42a, and the upper end of the steel wire 11 is protruded toward the flange steel plate 42b via the fixing jig 61 to fix it. ing. FIG. 10B is an adjustment of the bending moment distribution based on the introduced tension force by shifting the position of the fixing jig 61 downward. Further, in FIG. 10C, the lower end of the steel wire 11 is fixed to the inner surface of the flange steel plate 42a, and the upper end of the steel wire 11 is protruded toward the flange steel plate 42b via the fixing jig 61 and fixed. is doing. FIG. 10 (d) shows that the lower end of the steel wire 11 is fixed to the inner surface of the flange steel plate 42b, and once hooked on the fixing jig 61 on the flange steel plate 42a side, the upper end of the steel wire 11 is again connected to the flange steel plate. It protrudes to the 42b side and is fixed.

  In any of the embodiments, by introducing a tension force to the steel wire 11, the retaining wall member 4 can be subjected to a force to bend and deform toward the back side. The effect of the period can be obtained.

  FIG. 11A shows an example in which the upper and lower ends of the steel wire rods 11 and 111 are arranged on the outer surface of the front side flange steel plate 42b. Moreover, FIG.11 (b) is the example which has arrange | positioned the steel wire rods 11 and 111 on the inner surface of the flange steel plate 42b. By tensioning the steel wire 11 provided on the front side in this way, it is possible to prevent the central portion of the earth retaining member 4 from protruding to the front.

  In this invention, you may make it raise the tension | tensile_strength which should be loaded to the structural wire 11 etc. in steps according to the excavation depth of excavation side earth and sand. The reason for this is that the steel wire is first tightened after excavating the front surface, and then the steel wire is secondarily tightened after excavating the front surface. Deformation can be suppressed.

  Moreover, when providing the multiple steel members 11 so that the fixing position in the depth direction of the retaining wall member 4 of the retaining member of an upper end part may differ, the steel located below from the steel wire 11 located on the upper side You may make it introduce tension force in steps according to the excavation depth of excavation side earth and sand in order of the wire-making material 11. FIG. As a reason for this, as shown in FIG. 12, it is possible to efficiently suppress deformation by tensioning steel wires arranged in multiple stages in accordance with each stage of front excavation. FIG. 12 (a) shows a state where the front excavation is shallow. In such a case, the tension force is introduced from the upper stage to the upper stage of the earth retaining wall member 4. FIG. 12 (b) shows a state in which the front excavation has progressed to some extent. In such a case, the tension force is introduced over the upper and middle stages of the retaining wall member 4. FIG. 12 (c) shows a deeply advanced state where there is a front excavation. In such a case, the tension force is introduced over the upper, middle, and lower stages of the retaining wall member 4.

  The actual method for fastening the steel wire 11 in FIG. 12 is based on FIG. 9B, but is not limited to this, and any other fastening method described above is employed. It may be a thing.

  In addition, if the steel wire 11 is provided only on the back side of the retaining wall member 4, as shown in FIG. 13 (a), the central portion protrudes greatly in a convex shape on the front side. In particular, this tendency appears more prominently as the height of the retaining wall member 4 is higher. For this reason, as shown in FIG.13 (b), the metal fitting 61 and the latching member 62 are provided in the front side, and the steel wire 12 is arrange | positioned with tension | tensile_strength based on the method similar to the above-mentioned. At this time, the arrangement interval of the metal fitting 61 and the locking member 62 is set to be narrower than the interval between the metal fitting 44 and the locking member 48, and the length of the steel wire 12 to be arranged on this is also set shorter than that on the back side. Will do.

  By tensioning the steel wire 12 provided on the front side in this way, it is possible to prevent the central portion from protruding to the front as shown in FIG. 13 (b).

  Thus, in this invention, it is set as the self-supporting earth retaining wall structure which does not apply the support work constructed | assembled in order to maintain the stability of the earth retaining wall member 4, a ground anchor, etc. That is, in the present invention, the structure is a structure that secures a sufficient depth of penetration, resists the soil pressure load from the back side by the reaction force of the ground below the bottom of the excavation, and ensures the stability of the retaining wall.

  That is, the self-supporting retaining wall structure to which the present invention is applied has a large bending moment at the retaining wall member 4 below the bottom of the excavation as shown in the bending moment distribution diagram of FIG. Accordingly, as shown in the deformation distribution diagram of FIG. 14 (b), even if the displacement of the retaining wall member 4 to the excavation side can be increased, this is suppressed. Therefore, a tension force is applied to bend and deform the earth retaining wall member 4 to the back side. That is, by introducing the tension force in a range from the lower side of the excavation bottom to the upper side of the excavation bottom, the effect of dispersing the bending moment is exhibited as shown in the bending moment distribution diagram of FIG. Accordingly, as shown in the deformation distribution diagram of FIG. 14D, it is possible to suppress the displacement of the retaining wall member 4 toward the excavation side.

It is a figure which shows the reinforcement structure of the earth retaining wall to which this invention is applied. It is a top view of the earth retaining wall in the state where the earth retaining wall member was embedded. FIG. 2 (a) is a front view of the earth retaining wall member 4 as viewed from the B direction. It is a figure for demonstrating the effect | action of the reinforcement structure of the earth retaining wall to which this invention is applied. It is another figure for demonstrating the effect | action of the reinforcement structure of the earth retaining wall to which this invention is applied. It is a figure for demonstrating the other application example in the reinforcement method of the earth retaining wall to which this invention is applied. It is a figure which shows the form which attaches this by inserting a steel wire rod in a pipe | tube. It is a figure which shows the other application example in the arrangement | positioning method of a steel wire. It is a figure which shows the further another example of application in the arrangement | positioning method of a steel wire. It is a figure for demonstrating the other variation in the arrangement | positioning method of steel wires. It is the figure which has arrange | positioned the steel wire rod upper and lower ends to the outer surface or inner surface of a flange steel plate. It is a figure for demonstrating the problem in the case of providing a steel wire only in the back side of a retaining wall member. It is a figure which shows the example which enabled the efficient deformation | transformation suppression by tensioning the steel wire arrange | positioned in multiple steps according to each step of front surface excavation. It is an actual bending moment figure in a self-supporting earth retaining wall structure, and a deformation distribution figure. It is a figure for demonstrating the problem of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reinforcement wall reinforcement structure 2 Road 3 Earth retaining wall 4 Earth retaining wall member 5 Ground 11 Steel wire 41 Web steel plate 42 Flange steel plate 46 Joint 44 Metal fitting 48 Locking member

Claims (2)

Fixing the locking member to the upper end and the lower end of the earth retaining wall member,
The curved portion of the steel wire rod, which is eccentric to the natural ground side from the cross-sectional core of the retaining wall member and is curved substantially downward in the axial direction of the retaining wall member to form a substantially U shape, is Attach and fix both ends of the upper end of the locking member to the locking member of the upper end, and attach it along the axial direction of the retaining wall member.
The above earth retaining wall member is installed,
Introducing tension to the steel wire so that the earth retaining wall member is subjected to earth water pressure and acts to bend and deform on the excavation side against a force that tries to bend and deform on the ground.
The method for reinforcing a retaining wall, wherein the steel wire is pulled up from the upper end when the tension is unnecessary. The method for reinforcing a retaining wall according to claim 1, wherein a structure is constructed on the excavation side where the retaining wall member is built, and an upper portion of the structure is backfilled with earth and sand.

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