Method for removing steel sheet piles and upper steel sheet piles

Abstract

To provide a steel sheet pile and a removal method of an upper steel sheet pile allowing release connection between a lower steel sheet pile and the upper steel sheet pile to be easily and stably carried out.SOLUTION: A steel sheet pile 3 driven in the ground so as to separate it to an excavation side and a soil side is provided with: an upper steel sheet pile 4 of an upper part of the steel sheet pile 3; a lower steel sheet pile 5 of the steel sheet pile 3; a first anti-displacement member 21 abutting an inner surface 4a (surface of the excavation side) of the upper steel sheet plate 4 and an inner surface 5a of the lower steel sheet pile 5 (surface of the excavation side) so as to be disposed over the inner surface 4a of the upper steel sheet plate 4 and the inner surface 5a of the lower steel sheet pile 5; and a second anti-displacement member 22 abutting an outer surface 4b (surface of the soil side) of the upper steel sheet plate 4 and an outer surface 5b of the lower steel sheet pile 5 (surface of the soil side) in a state it crosses over the outer surface 4b of the upper steel sheet plate 4 and the outer surface 5b of the lower steel sheet pile 5. The first anti-displacement member 21 is fixed on both of the inner surface 4a of the upper steel sheet plate 4 and the inner surface 5a of the lower steel sheet pile 5. The second anti-displacement member 22 is fixed on both of the outer surface 4b of the upper steel sheet plate 4 and the outer surface 5b of the lower steel sheet pile 5.SELECTED DRAWING: Figure 6

Description

Technical Field

[0005] ,

[0006]

[0001] The present invention relates to a steel sheet pile driven so as to partition an excavation side and a natural ground side in the ground, and a method of removing an upper steel sheet pile from this steel sheet pile while leaving a lower steel sheet pile.

Background Art

[0002] When constructing an underground structure such as a tunnel structure, a retaining wall may be constructed at the construction site, and excavation may be performed inside while using this retaining wall to retain soil and prevent water leakage against the construction site.

[0003] In the construction of an underground structure using a retaining wall, for example, first, a retaining wall formed by a row of steel sheet piles is constructed from the ground surface side to reach an impervious layer. Next, excavation of the construction site is advanced while installing struts and crossbeams. Next, an underground structure is constructed at the excavated construction site. And after the construction of the underground structure, while backfilling, the struts and crossbeams are removed.

[0004] Here, in an urban area or the like, since there is a possibility that future installation work of communication cables, water pipes, gas pipes, etc. will be carried out near the construction site of an underground structure, when backfilling, it may be required to remove a portion (upper portion) in the range from the ground surface to a depth of about 1 to 4 m of the steel sheet pile. In such a case, as shown in Patent Document 1, etc., the steel sheet pile constituting the retaining wall is made into a connection structure of a lower steel sheet pile and an upper steel sheet pile, and at the time of backfilling, the upper steel sheet pile is separated from the lower steel sheet pile and removed.

[0005] Particularly, in the connection structure of the lower steel sheet pile and the upper steel sheet pile disclosed in Patent Document 1, plates that respectively abut on the excavation side surface (inner surface) and the natural ground side surface (outer surface) are provided so as to straddle the lower steel sheet pile and the upper steel sheet pile, these plates are welded and fixed to the lower steel sheet pile, and bolts are passed through the excavation side plate, the upper steel sheet pile, and the natural ground side plate in this order from the excavation side, and the bolt tip on the natural ground side is screwed into a nut fixed to the natural ground side plate and tightened.

[0006] In this type of connecting structure, when backfilling (specifically, when backfilling has reached the vicinity of the connection point between the lower and upper steel sheet piles), the connection between the lower and upper steel sheet piles can be released by rotating the bolt head from the excavation side to release the screw engagement with the nut, and then pulling out the bolt. This allows the upper steel sheet pile to be pulled out from the ground surface. Therefore, the connection between the lower and upper steel sheet piles can be released by pulling out the bolt from the excavation side, making it easier to remove the upper steel sheet pile. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 61-191725 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, in the structure disclosed in Patent Document 1, the nut into which the bolt is screwed is located deep inside (on the ground side) of the ground-side plate. As a result, when installing steel sheet piles, a large external force may be applied to the bolt, causing the bolt to bend or the nut to be crushed, making it difficult to release the screwed-on connection between the bolt and the nut.

[0009] This invention has been made in view of the above circumstances, and aims to provide a steel sheet pile (a connecting structure between a lower steel sheet pile and an upper steel sheet pile) that allows for easy and stable release of the connection between the lower steel sheet pile and the upper steel sheet pile. [Means for solving the problem]

[0010] Therefore, the steel sheet pile according to the present invention is driven into the ground so as to separate the excavation side from the natural ground side, and comprises an upper steel sheet pile forming the upper part of the steel sheet pile, a lower steel sheet pile forming the lower part of the steel sheet pile, a first anti-slip member that straddles the excavation side surface of the upper steel sheet pile and the excavation side surface of the lower steel sheet pile and abuts against the excavation side surface of the upper steel sheet pile and the excavation side surface of the lower steel sheet pile, and a second anti-slip member that straddles the natural ground side surface of the upper steel sheet pile and the natural ground side surface of the lower steel sheet pile and abuts against the natural ground side surface of the upper steel sheet pile and the natural ground side surface of the lower steel sheet pile, A reinforcing means for restricting bending at the boundary between the lower edge of the upper steel sheet pile and the upper edge of the lower steel sheet pile, The system includes the following: The first anti-slip member is fixed to both the excavation-side surface of the upper steel sheet pile and the excavation-side surface of the lower steel sheet pile. The second anti-slip member is fixed to either the ground-side surface of the upper steel sheet pile or the ground-side surface of the lower steel sheet pile, but not to the other. The reinforcing means comprises a first pipe member fixed to the upper steel sheet pile and extending vertically along the upper steel sheet pile, and a second pipe member fixed to the lower steel sheet pile and extending vertically along the lower steel sheet pile, wherein the first pipe member has an extension portion extending downward from the lower edge of the upper steel sheet pile, and the extension portion is inserted into the second pipe member. Alternatively, the reinforcing means comprises a first plate fixed to the upper steel sheet pile, a second plate fixed to the lower steel sheet pile, a long bolt inserted through a through hole in the first plate and a through hole in the second plate and extending vertically, and a female threaded portion for temporarily fixing the lower end of the long bolt to the second plate.

[0011] The method for removing an upper steel sheet pile according to the present invention is a method for removing an upper steel sheet pile from the aforementioned steel sheet pile, leaving the lower steel sheet pile in place. This method includes a disconnection step of releasing the connection between the excavation-side surface of the upper steel sheet pile and the excavation-side surface of the lower steel sheet pile via a first anti-slip member from the excavation side; a backfilling step of backfilling the excavation side; and a pulling-out step of pulling the upper steel sheet pile upward. [Effects of the Invention]

[0012] According to the present invention, the connection between the lower steel sheet pile and the upper steel sheet pile can be easily and stably released by releasing the connection between the excavation-side surface of the upper steel sheet pile and the excavation-side surface of the lower steel sheet pile via the first shear-preventing member from the excavation side. [Brief explanation of the drawing]

[0013] [Figure 1] This figure shows an example of construction of an underground structure using an earth retaining wall according to the first embodiment of the present invention. [Figure 2] Top view of the retaining wall in the first embodiment [Figure 3] Perspective view of the connection between the upper steel sheet pile and the lower steel sheet pile in the first embodiment, as seen from the excavation side. [Figure 4]Perspective view of the connection part between the upper steel sheet pile and the lower steel sheet pile in the first embodiment as seen from the ground side [Figure 5] Diagram showing the schematic configuration of the first displacement prevention member in the first embodiment [Figure 6] Diagram showing the schematic configuration of the second displacement prevention member in the first embodiment [Figure 7] Diagram showing the pulling-out process (removal process) of the upper steel sheet pile in the first embodiment [Figure 8] Top view of the earth retaining wall in the second embodiment of the present invention [Figure 9] Perspective view of the connection part between the upper steel sheet pile and the lower steel sheet pile in the second embodiment as seen from the excavation side [Figure 10] Perspective view of the connection part between the upper steel sheet pile and the lower steel sheet pile in the second embodiment as seen from the ground side

Modes for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an example of the construction of an underground structure using an earth retaining wall in the first embodiment of the present invention. FIG. 2 is a top view of the earth retaining wall in this embodiment. FIG. 3 is a perspective view of the connection part between the upper steel sheet pile and the lower steel sheet pile in this embodiment as seen from the excavation side. FIG. 4 is a perspective view of the connection part between the upper steel sheet pile and the lower steel sheet pile in this embodiment as seen from the ground side. Here, FIGS. 3 and 4 correspond to the portion P of FIG. 1.

[0015] When constructing an underground structure (embedded body) 2 in the ground below the ground surface 1, prior to this, an earth retaining wall is constructed for the purpose of retaining soil and preventing water leakage at the construction site. Therefore, the earth retaining wall partitions the excavation side (planned excavation area / excavation area) of the ground and the ground side (non-excavation area). In this embodiment, a steel sheet pile (sheet pile) 3 is used as the wall member constituting the earth retaining wall.

[0016] As shown in Fig. 2, the steel sheet pile 3 has a trapezoidal cross-section that is bent, with one of the front and back surfaces being the convex surface 31 and the other being the concave surface 32, and joints 35 at both ends. Therefore, by arranging the steel sheet piles 3 alternately with the front and back reversed and connecting adjacent steel sheet piles 3 with the joints 35, a soil retaining wall (wall body) can be constructed by the row of steel sheet piles 3.

[0017] The steel sheet pile 3 is driven (hammered in) from the ground surface 1 side downward (i.e., into the ground) so as to partition the excavation side (excavation side) and the natural ground side. Here, the surface on the excavation side of the steel sheet pile 3 is referred to as the inner surface 3a. Also, the surface on the natural ground side of the steel sheet pile 3 is referred to as the outer surface 3b.

[0018] In this embodiment, the steel sheet pile 3 is a U-shaped steel sheet pile. The steel sheet pile 3 has a web 33 extending in the vertical direction (up and down direction), a pair of flanges 34, 34 continuously formed at both ends of the web 33, and joints 35, 35 formed at the tips of these pair of flanges 34, 34. The aforementioned convex surface 31 is constituted by one surface of the web 33 and one surface of the flange 34. The aforementioned concave surface 32 is constituted by the other surface of the web 33 and the other surface of the flange 34.

[0019] The steel sheet pile 3 is composed of an upper steel sheet pile 4 forming its upper part, a lower steel sheet pile 5 forming its lower part, a reinforcing means 10, and a displacement prevention means 20. For the upper steel sheet pile 4 and the lower steel sheet pile 5, for example, they can be formed by cutting a single steel sheet pile vertically by cutting or the like before driving. Therefore, for the upper steel sheet pile 4 and the lower steel sheet pile 5 as well, similar to the aforementioned steel sheet pile 3, they each have an inner surface 4a, 5a, an outer surface 4b, 5b, a convex surface 41, 51, a concave surface 42, 52, a web 43, 53, flanges 44, 54, and joints 45, 55.

[0020] The reinforcing means 10 is intended to restrict (suppress) bending at the boundary between the lower edge 4t of the upper steel sheet pile 4 and the upper edge 5t of the lower steel sheet pile 5, caused by the force acting on the retaining wall (steel sheet pile 3) from the natural ground side as the excavation side of the ground is excavated. The reinforcing means 10 can be provided on at least one of the excavation side and the natural ground side of the steel sheet pile 3. In this embodiment, the reinforcing means 10 is provided on both the excavation side (inside) and the natural ground side (outside) of the steel sheet pile 3, and comprises an inner reinforcing means 11 and an outer reinforcing means 12.

[0021] The internal reinforcing means 11 includes a first pipe member 11a fixed to the lower part of the inner surface 4a of the upper steel sheet pile 4 by welding or the like and extending vertically along the inner surface 4a of the upper steel sheet pile 4, and a second pipe member 11b fixed to the upper part of the inner surface 5a of the lower steel sheet pile 5 by welding or the like and extending vertically along the inner surface 5a of the lower steel sheet pile 5. In this embodiment, the first pipe member 11a and the second pipe member 11b are each made of square pipes, but they may also be made of round pipes (circular pipes). In this embodiment, the first pipe member 11a and the second pipe member 11b are each made of, for example, steel (metal).

[0022] The first pipe member 11a has an extension portion 11d (see Figure 7, described later) that extends downward from the lower edge 4t of the upper steel sheet pile 4, and this extension portion 11d is inserted into the second pipe member 11b from above. Therefore, the first pipe member 11a having the extension portion 11d has a cross-sectional shape and dimensions (a cross-sectional shape and dimensions that allow for loose fitting) that can be inserted into the second pipe member 11b.

[0023] The lower end of the second pipe member 11b has a tapered surface 11c that slopes away from the inner surface 5a of the lower steel sheet pile 5 as it goes from bottom to top. This tapered surface 11c helps to prevent the inner reinforcing means 11 from becoming a resistance when the steel sheet pile 3 is driven in.

[0024] The outer reinforcing means 12 includes a first pipe member 12a fixed to the lower part of the outer surface 4b of the upper steel sheet pile 4 by welding or the like and extending vertically along the outer surface 4b of the upper steel sheet pile 4, and a second pipe member 12b fixed to the upper part of the outer surface 5b of the lower steel sheet pile 5 by welding or the like and extending vertically along the outer surface 5b of the lower steel sheet pile 5. In this embodiment, the first pipe member 12a and the second pipe member 12b are each made of square pipes, but they may also be made of round pipes (circular pipes). In this embodiment, the first pipe member 12a and the second pipe member 12b are each made of, for example, steel (metal).

[0025] The first pipe member 12a has an extension portion 12d (see Figure 7, described later) that extends downward from the lower edge 4t of the upper steel sheet pile 4, and this extension portion 12d is inserted into the second pipe member 12b from above. Therefore, the first pipe member 12a having the extension portion 12d has a cross-sectional shape and dimensions (a cross-sectional shape and dimensions that allow for loose fitting) that can be inserted into the second pipe member 12b.

[0026] The lower end of the second pipe member 12b has a tapered surface 12c that slopes away from the outer surface 5b of the lower steel sheet pile 5 as it goes from bottom to top. This tapered surface 12c helps to prevent the outer reinforcing means 12 from becoming a resistance when the steel sheet pile 3 is driven in.

[0027] In this embodiment, the first pipe members 11a and 12a are fixed to the concave surface 42 of the upper steel sheet pile 4 (specifically, the other surface of the web 43) by welding or the like, and extend vertically along the concave surface 42 of the upper steel sheet pile 4 (specifically, the other surface of the web 43). The second pipe members 11b and 12b are fixed to the concave surface 52 of the lower steel sheet pile 5 (specifically, the other surface of the web 53) by welding or the like, and extend vertically along the concave surface 52 of the lower steel sheet pile 5 (specifically, the other surface of the web 53).

[0028] In this embodiment, the first pipe members 11a and 12a, each having extensions 11d and 12d, are provided on the concave surface 42 of the upper steel sheet pile 4, and the second pipe members 11b and 12b are provided on the concave surface 52 of the lower steel sheet pile 5. However, in addition to or instead of this, the first pipe members 11a and 12a, each having extensions 11d and 12d, may be provided on the convex surface 41 of the upper steel sheet pile 4, and the second pipe members 11b and 12b may be provided on the convex surface 51 of the lower steel sheet pile 5.

[0029] Furthermore, in this embodiment, first pipe members 11a and 12a having extensions 11d and 12d are provided on the web 43 of the upper steel sheet pile 4, and second pipe members 11b and 12b are provided on the web 53 of the lower steel sheet pile 5. In addition to this, or instead, first pipe members 11a and 12a having extensions 11d and 12d may be provided on the flange 44 of the upper steel sheet pile 4, and second pipe members 11b and 12b may be provided on the flange 54 of the lower steel sheet pile 5.

[0030] In this embodiment, the inner reinforcing means 11 and the outer reinforcing means 12 can each function as a support material that restricts bending at the boundary between the lower edge 4t of the upper steel sheet pile 4 and the upper edge 5t of the lower steel sheet pile 5. Also, in this embodiment, as shown in Figure 2, the inner reinforcing means 11 and the outer reinforcing means 12 are arranged in a staggered pattern when viewed from above.

[0031] The anti-slip means 20 is for restricting (suppressing) the positional displacement between the upper steel sheet pile 4 and the lower steel sheet pile 5 when the steel sheet pile 3 is driven into the ground (specifically, the positional displacement between the lower edge 4t of the upper steel sheet pile 4 and the upper edge 5t of the lower steel sheet pile 5). The anti-slip means 20 comprises a first anti-slip member 21 and a second anti-slip member 22. The first anti-slip member 21 and the second anti-slip member 22 are each composed of, for example, a steel (metal) plate-shaped member.

[0032] Figure 5 shows a schematic configuration of the first anti-slip member 21. The first anti-slip member 21 straddles the inner surface 4a of the upper steel sheet pile 4 and the inner surface 5a of the lower steel sheet pile 5, and abuts against the inner surface 4a of the upper steel sheet pile 4 and the inner surface 5a of the lower steel sheet pile 5. The first anti-slip member 21 is fixed to both the lower part of the inner surface 4a of the upper steel sheet pile 4 and the upper part of the inner surface 5a of the lower steel sheet pile 5. In particular, in this embodiment, the first anti-slip member 21 is welded to both the lower part of the inner surface 4a of the upper steel sheet pile 4 and the upper part of the inner surface 5a of the lower steel sheet pile 5. Here, Figure 5 shows a welded joint 21b that fixes the first anti-slip member 21 to the inner surface 4a of the upper steel sheet pile 4. Also, Figure 5 shows a welded joint 21c that fixes the first anti-slip member 21 to the inner surface 5a of the lower steel sheet pile 5. Furthermore, the method of fixing the first anti-slip member 21 to both the inner surface 4a of the upper steel sheet pile 4 and the inner surface 5a of the lower steel sheet pile 5 is not limited to welding; for example, a fixing method using fastening means such as bolts may also be employed.

[0033] The lower end of the first anti-slip member 21 has a tapered surface 21a that slopes upward from the bottom, moving away from the inner surface 5a of the lower steel sheet pile 5. This tapered surface 21a helps to prevent the first anti-slip member 21 from acting as resistance when the steel sheet pile 3 is driven.

[0034] Figure 6 shows a schematic configuration of the second shearing member 22. The second shearing member 22 straddles the outer surface 4b of the upper steel sheet pile 4 and the outer surface 5b of the lower steel sheet pile 5 and abuts against the outer surface 4b of the upper steel sheet pile 4 and the outer surface 5b of the lower steel sheet pile 5. The second shearing member 22 is fixed to one of the lower part of the outer surface 4b of the upper steel sheet pile 4 and not to the other. In particular, in this embodiment, the second shearing member 22 is welded to the lower part of the outer surface 4b of the upper steel sheet pile 4 and not to the outer surface 5b of the lower steel sheet pile 5. Here, Figure 6 shows the welded portion 22b that fixes the second shearing member 22 to the outer surface 4b of the upper steel sheet pile 4. Furthermore, the method for fixing the second anti-slip member 22 to the outer surface 4b of the upper steel sheet pile 4 is not limited to welding; for example, a fixing method using fastening means such as bolts may also be employed.

[0035] The lower end of the second anti-slip member 22 has a tapered surface 22a that slopes away from the outer surface 5b of the lower steel sheet pile 5 as it moves from bottom to top. This tapered surface 22a helps to prevent the second anti-slip member 22 from acting as resistance when the steel sheet pile 3 is driven.

[0036] In this embodiment, as shown in Figure 2, the first anti-slip member 21 and the second anti-slip member 22 are arranged opposite each other with the steel sheet pile 3 (upper steel sheet pile 4 and lower steel sheet pile 5) in between, when viewed from above.

[0037] In this embodiment, the first anti-slip member 21 and the second anti-slip member 22 are provided spanning the flange 44 of the upper steel sheet pile 4 and the flange 54 of the lower steel sheet pile 5. However, in addition to or instead of this arrangement, the first anti-slip member 21 and the second anti-slip member 22 may be provided spanning the web 43 of the upper steel sheet pile 4 and the web 53 of the lower steel sheet pile 5.

[0038] The vertical lengths of the first anti-slip member 21 and the second anti-slip member 22 may be the same or different. For example, the vertical length of the second anti-slip member 22 may be made longer than the vertical length of the first anti-slip member 21, so that the second anti-slip member 22 extends downwards than the first anti-slip member 21.

[0039] The vertical length of the first anti-slip member 21 and the vertical length of the second anti-slip member 22 are each shorter than the vertical length of each component of the reinforcing means 10 (for example, the vertical lengths of the first pipe members 11a and 12a having extensions 11d and 12d, and the vertical lengths of the second pipe members 11b and 12b).

[0040] As shown in Figures 2 and 4, in this embodiment, a waterproofing tape 60 is attached across the outer surface 4b of the upper steel sheet pile 4 and the outer surface 5b of the lower steel sheet pile 5 so as to seal the boundary between the lower edge 4t of the upper steel sheet pile 4 and the upper edge 5t of the lower steel sheet pile 5 (the gap between the lower edge 4t of the upper steel sheet pile 4 and the upper edge 5t of the lower steel sheet pile 5). This waterproofing tape 60 is attached so as to wrap around the outer reinforcing means 12 and the second anti-slip member 22. The waterproofing tape 60 can appropriately break or peel off when the upper steel sheet pile 4 is pulled out (removed), as described later, and therefore does not provide resistance during such pulling out.

[0041] In this embodiment, the waterproofing tape 60 is applied across the outer surface 4b of the upper steel sheet pile 4 and the outer surface 5b of the lower steel sheet pile 5. However, in addition to this, or as an alternative, the waterproofing tape 60 may be applied across the inner surface 4a of the upper steel sheet pile 4 and the inner surface 5a of the lower steel sheet pile 5. In this case as well, the waterproofing tape 60 can appropriately break or peel off when the upper steel sheet pile 4 is withdrawn (removed), as described later, and therefore does not provide resistance during such withdrawal.

[0042] Next, we will explain a method for removing the upper steel sheet pile 4 from the retaining wall (steel sheet pile 3) while leaving the lower steel sheet pile 5 in place, after completing the earth retaining wall by erecting the steel sheet piles 3 (upper steel sheet pile 4 and lower steel sheet pile 5) having the aforementioned connected structure, excavating the interior of the wall to construct the underground structure 2, and then backfilling the wall.

[0043] When backfilling is completed up to the vicinity of the connection between the upper steel sheet pile 4 and the lower steel sheet pile 5, the connection between the inner surface 4a of the upper steel sheet pile 4 and the inner surface 5a of the lower steel sheet pile 5 via the first shearing member 21 is released from the excavation side (connection release step). In this step, for example, the fixing between the first shearing member 21 and the inner surface 5a of the lower steel sheet pile 5 is released by cutting the welded part 21c. Alternatively, the fixing between the first shearing member 21 and the inner surface 4a of the upper steel sheet pile 4 is released by cutting the welded part 21b. In addition, the fixing at the welded parts 21b and 21c may be left as is, and the connection between the inner surface 4a of the upper steel sheet pile 4 and the inner surface 5a of the lower steel sheet pile 5 via the first shearing member 21 may be released by cutting the part of the first shearing member 21 adjacent to the boundary between the lower edge 4t of the upper steel sheet pile 4 and the upper edge 5t of the lower steel sheet pile 5.

[0044] Next, the remaining excavated area is backfilled, for example, to a height of ground surface 1 (backfilling process).

[0045] Next, the upper steel sheet piles 4 are pulled upward from the ground surface 1 side using a pulling machine (reverse use of a press-in machine), jacks, wire traction with multiple pulleys, etc. (pulling process). Figure 7 shows the pulling process (removal process) of the upper steel sheet piles 4. Although Figure 7 shows the pulling of multiple upper steel sheet piles 4 simultaneously, normally the upper steel sheet piles 4 are pulled out one by one. Along with the pulling of the upper steel sheet piles 4, the extensions 11d and 12d of the first pipe members 11a and 12a are also pulled out from the second pipe members 11b and 12b. When the upper steel sheet piles 4 are pulled out, the waterproofing tape 60 breaks or peels off appropriately, so it does not provide resistance during the pulling process.

[0046] In this way, the lower steel sheet pile 5 can be left in the ground, and the upper steel sheet pile 4 can be easily removed.

[0047] According to this embodiment, the steel sheet pile 3 is driven into the ground so as to separate the excavation side from the natural ground side. The steel sheet pile 3 comprises an upper steel sheet pile 4 that forms the upper part of the steel sheet pile 3, a lower steel sheet pile 5 that forms the lower part of the steel sheet pile 3, a first anti-slip member 21 that straddles the excavation side surface (inner surface 4a) of the upper steel sheet pile 4 and the excavation side surface (inner surface 5a) of the lower steel sheet pile 5 and abuts against the excavation side surface (inner surface 5a) of the upper steel sheet pile 4 and the excavation side surface (inner surface 5a) of the lower steel sheet pile 5, and a second anti-slip member 22 that straddles the natural ground side surface (outer surface 4b) of the upper steel sheet pile 4 and the natural ground side surface (outer surface 5b) of the lower steel sheet pile 5 and abuts against the natural ground side surface (outer surface 4b) of the upper steel sheet pile 4 and the natural ground side surface (outer surface 5b) of the lower steel sheet pile 5. The first anti-slip member 21 is fixed (e.g., by welding) to both the excavation-side surface (inner surface 4a) of the upper steel sheet pile 4 and the excavation-side surface (inner surface 5a) of the lower steel sheet pile 5. The second anti-slip member 22 is fixed (e.g., by welding) to one of the ground-side surface (outer surface 4b) of the upper steel sheet pile 4 and the ground-side surface (outer surface 5b) of the lower steel sheet pile 5, but not to the other. Therefore, by releasing the connection between the excavation-side surface (inner surface 4a) of the upper steel sheet pile 4 and the excavation-side surface (inner surface 5a) of the lower steel sheet pile 5 via the first anti-slip member 21 from the excavation side, the connection between the lower steel sheet pile 5 and the upper steel sheet pile 4 can be released easily and stably.

[0048] Furthermore, according to this embodiment, the second anti-slip member 22 is fixed (for example, by welding) to the ground-side surface (outer surface 4b) of the upper steel sheet pile 4, but is not fixed to the ground-side surface (outer surface 5b) of the lower steel sheet pile 5. As a result, when the upper steel sheet pile 4 is pulled out (removed), the second anti-slip member 22 can also be removed together with the upper steel sheet pile 4.

[0049] Furthermore, according to this embodiment, in a top view, the first anti-slip member 21 and the second anti-slip member 22 are arranged to face each other, sandwiching the steel sheet pile 3 (upper steel sheet pile 4 and lower steel sheet pile 5). Therefore, by sandwiching the lower end of the upper steel sheet pile 4 and the upper end of the lower steel sheet pile 5 with the first anti-slip member 21 and the second anti-slip member 22, the positional displacement between the upper steel sheet pile 4 and the lower steel sheet pile 5 can be easily restricted.

[0050] Furthermore, according to this embodiment, the steel sheet pile 3 is further equipped with a watertight tape 60 that is attached to seal the boundary between the lower edge 4t of the upper steel sheet pile 4 and the upper edge 5t of the lower steel sheet pile 5. This ensures watertightness at the boundary between the lower edge 4t of the upper steel sheet pile 4 and the upper edge 5t of the lower steel sheet pile 5.

[0051] Furthermore, according to this embodiment, the steel sheet pile 3 is further provided with a reinforcing means 10 that restricts bending at the boundary between the lower edge 4t of the upper steel sheet pile 4 and the upper edge 5t of the lower steel sheet pile 5. The reinforcing means 10 is provided on at least one of the excavation side and the ground side of the steel sheet pile 3. Therefore, bending at the boundary between the lower edge 4t of the upper steel sheet pile 4 and the upper edge 5t of the lower steel sheet pile 5 can be restricted by a force acting on the retaining wall (steel sheet pile 3) from the ground side toward the excavation side.

[0052] Furthermore, according to this embodiment, the reinforcing means 10 includes first pipe members 11a, 12a fixed to the upper steel sheet pile 4 and extending vertically along the upper steel sheet pile 4, and second pipe members 11b, 12b fixed to the lower steel sheet pile 5 and extending vertically along the lower steel sheet pile 5. The first pipe members 11a, 12a have extensions 11d, 12d that extend downward from the lower edge 4t of the upper steel sheet pile 4, and the extensions 11d, 12d are inserted into the second pipe members 11b, 12b. As a result, when the upper steel sheet pile 4 is pulled out (removed), the first pipe members 11a, 12a having the extensions 11d, 12d can also be removed together with the upper steel sheet pile 4.

[0053] Alternatively, in the opposite case to this embodiment, each of the second pipe members 11b and 12b may have an extension portion that extends upward from the upper edge 5t of the lower steel sheet pile 5, and each extension portion may be inserted into the first pipe members 11a and 12a.

[0054] Furthermore, according to this embodiment, the method for removing the upper steel sheet pile 4 from the steel sheet pile 3 driven into the ground, leaving the lower steel sheet pile 5 in place, includes a connection release step of releasing the connection between the excavation-side surface (inner surface 4a) of the upper steel sheet pile 4 and the excavation-side surface (inner surface 5a) of the lower steel sheet pile 5 via the first shear-preventing member 21 from the excavation side, a backfilling step of backfilling the excavation side, and a pull-out step of pulling the upper steel sheet pile 4 upward. Therefore, in the aforementioned connection release step, the connection between the excavation-side surface (inner surface 4a) of the upper steel sheet pile 4 and the excavation-side surface (inner surface 5a) of the lower steel sheet pile 5 via the first shear-preventing member 21 is released from the excavation side, thereby easily and stably releasing the connection between the lower steel sheet pile 5 and the upper steel sheet pile 4.

[0055] Next, a second embodiment of the present invention will be described with reference to Figures 8 to 10. Figure 8 is a top view of the retaining wall in this embodiment. Figure 9 is a perspective view of the connection between the upper and lower steel sheet piles in this embodiment, seen from the excavation side. Figure 10 is a perspective view of the connection between the upper and lower steel sheet piles in this embodiment, seen from the ground side. The differences from the first embodiment described above will now be explained.

[0056] In this embodiment, reinforcing means 10' is used instead of reinforcing means 10 in the first embodiment described above. Reinforcing means 10' also plays a role in restricting (suppressing) bending at the boundary between the lower edge 4t of the upper steel sheet pile 4 and the upper edge 5t of the lower steel sheet pile 5 due to the force acting on the retaining wall (steel sheet pile 3) from the ground side as the excavation side of the ground is excavated. Reinforcing means 10' can be provided on at least one of the excavation side and the ground side of the steel sheet pile 3. In this embodiment, reinforcing means 10' is provided on both the excavation side (inside) and the ground side (outside) of the steel sheet pile 3, and comprises an inner reinforcing means 11' and an outer reinforcing means 12'.

[0057] The internal reinforcing means 11' comprises a first plate 71a, a second plate 71b, a long bolt 71c, and a female threaded portion (not shown) for temporarily fixing the lower end of the long bolt 71c to the second plate 71b. The first plate 71a is fixed to the upper end of the inner surface 4a of the upper steel sheet pile 4 by welding or the like. The second plate 71b is fixed to the upper end of the inner surface 5a of the lower steel sheet pile 5 by welding or the like. The long bolt 71c is inserted through through holes in the first plate 71a and the second plate 71b and extends vertically, has a head 71d at its upper end and a male threaded portion formed at least at its lower end. The male threaded portion of this long bolt 71c is screwed into the aforementioned female threaded portion. In this embodiment, the first plate 71a and the second plate 71b are each made of, for example, steel (metal).

[0058] The aforementioned female thread portion may be formed by a nut fixed to a position corresponding to the through hole on the lower surface of the second plate 71b. Alternatively, the through hole in the second plate 71b may be formed to become the female thread portion.

[0059] A cover member 71e is attached to the lower surface of the second plate 71b, covering the aforementioned female thread portion and the lower end of the long bolt 71c. This cover member 71e has a tapered surface that slopes away from the inner surface 5a of the lower steel sheet pile 5 as it goes from bottom to top. This tapered surface helps to prevent the inner reinforcing means 11' from becoming a resistance when the steel sheet pile 3 is driven in.

[0060] The outer reinforcing means 12' comprises a first plate 72a, a second plate 72b, a long bolt 72c, and a female threaded portion (not shown) for temporarily fixing the lower end of the long bolt 72c to the second plate 72b. The first plate 72a is fixed to the upper end of the outer surface 4b of the upper steel sheet pile 4 by welding or the like. The second plate 72b is fixed to the upper end of the outer surface 5b of the lower steel sheet pile 5 by welding or the like. The long bolt 72c is inserted through through holes in the first plate 72a and the second plate 72b and extends in the vertical direction, has a head 72d at its upper end, and has a male threaded portion formed at least at its lower end. The male threaded portion of this long bolt 72c is screwed into the aforementioned female threaded portion. In this embodiment, the first plate 72a and the second plate 72b are each made of, for example, steel (metal).

[0061] The aforementioned female thread portion may be formed by a nut fixed to a position corresponding to the through hole on the lower surface of the second plate 72b. Alternatively, the through hole in the second plate 72b may be formed to become the female thread portion.

[0062] A cover member 72e is attached to the lower surface of the second plate 72b, covering the aforementioned female thread portion and the lower end of the long bolt 72c. This cover member 72e has a tapered surface that slopes away from the outer surface 5b of the lower steel sheet pile 5 as it goes from bottom to top. This tapered surface helps to prevent the outer reinforcing means 12' from acting as resistance when the steel sheet pile 3 is driven into the ground.

[0063] In this embodiment, the first plates 71a and 72a are fixed to the concave surface 42 of the upper steel sheet pile 4 (specifically, the other surface of the web 43) by welding or the like. The second plates 71b and 72b are fixed to the concave surface 52 of the lower steel sheet pile 5 (specifically, the other surface of the web 53) by welding or the like.

[0064] In this embodiment, the first plates 71a and 72a are provided on the concave surface 42 of the upper steel sheet pile 4, and the second plates 71b and 72b are provided on the concave surface 52 of the lower steel sheet pile 5. However, in addition to or instead of this, the first plates 71a and 72a may be provided on the convex surface 41 of the upper steel sheet pile 4, and the second plates 71b and 72b may be provided on the convex surface 51 of the lower steel sheet pile 5.

[0065] Furthermore, in this embodiment, the first plates 71a and 72a are provided on the web 43 of the upper steel sheet pile 4, and the second plates 71b and 72b are provided on the web 53 of the lower steel sheet pile 5. However, in addition to or instead of this, the first plates 71a and 72a may be provided on the flange 44 of the upper steel sheet pile 4, and the second plates 71b and 72b may be provided on the flange 54 of the lower steel sheet pile 5.

[0066] In this embodiment, each of the inner reinforcing means 11' and the outer reinforcing means 12' can function as a support material that restricts bending at the boundary between the lower edge 4t of the upper steel sheet pile 4 and the upper edge 5t of the lower steel sheet pile 5. Furthermore, each of the inner reinforcing means 11' and the outer reinforcing means 12' can function as a temporary fixing means for temporarily fixing the upper steel sheet pile 4 and the lower steel sheet pile 5. In this embodiment as well, as shown in Figure 8, the inner reinforcing means 11' and the outer reinforcing means 12' are arranged in a staggered pattern when viewed from above.

[0067] Next, the method for removing the upper steel sheet pile 4 in this embodiment will be described. The differences from the method for removing the upper steel sheet pile 4 in the first embodiment described above will now be explained.

[0068] In the method for removing the upper steel sheet pile 4 in this embodiment, a temporary fixing release step is included between the backfilling step and the extraction step described above. In other words, in the method for removing the upper steel sheet pile 4 in this embodiment, the temporary fixing release step is performed after the backfilling step described above, and the extraction step described above is performed after this temporary fixing release step.

[0069] In the aforementioned temporary fixing release process, the heads 71d and 72d of the long bolts 71c and 72c are rotated from the ground surface 1 side to release the screwing between the male threaded portion at the lower end of the long bolts 71c and 72c and the aforementioned female threaded portion, thereby releasing the temporary fixing between the lower end of the long bolts 71c and 72c and the aforementioned female threaded portion. This also releases the temporary fixing between the upper steel sheet pile 4 and the lower steel sheet pile 5.

[0070] In particular, according to this embodiment, the reinforcing means 10' includes first plates 71a, 72a fixed to the upper steel sheet pile 4, second plates 71b, 72b fixed to the lower steel sheet pile 5, long bolts 71c, 72c that are inserted through through holes in the first plates 71a, 72a and the second plates 71b, 72b and extend vertically, and female threaded portions that temporarily fix the lower ends of the long bolts 71c, 72c to the second plates 71b, 72b. As a result, the reinforcing means 10' can also function as a temporary fixing means for temporarily fixing the upper steel sheet pile 4 and the lower steel sheet pile 5.

[0071] Furthermore, according to this embodiment, the method for removing the upper steel sheet pile 4 from the steel sheet pile 3 driven into the ground, leaving the lower steel sheet pile 5 in place, includes a connection release step of releasing the connection between the excavation-side surface (inner surface 4a) of the upper steel sheet pile 4 and the excavation-side surface (inner surface 5a) of the lower steel sheet pile 5 via the first shear-preventing member 21 from the excavation side; a backfilling step of backfilling the excavation side; a temporary fixing release step of releasing the temporary fixing between the lower ends of the long bolts 71c, 72c and the second plates 71b, 72b; and a pull-out step of pulling the upper steel sheet pile 4 upward. In this way, the connection between the lower steel sheet pile 5 and the upper steel sheet pile 4 (including the temporary fixing mentioned above) can be released easily and stably.

[0072] Furthermore, in the first and second embodiments described above, the steps of dividing (e.g., cutting) a single steel sheet pile into an upper steel sheet pile 4 and a lower steel sheet pile 5, and installing reinforcing means 10, 10' and anti-slip means 20 on the upper steel sheet pile 4 and the lower steel sheet pile 5, may be performed at a factory or other location away from the construction site, or at the construction site. In addition, these steps may be performed prior to driving the steel sheet piles into the ground, or during the process of driving the steel sheet piles into the ground.

[0073] Furthermore, both the reinforcing means 10 in the first embodiment and the reinforcing means 10' in the second embodiment may be applied to the connection between the upper steel sheet pile 4 and the lower steel sheet pile 5. In other words, the reinforcing means 10 in the first embodiment and the reinforcing means 10' in the second embodiment may be used in combination.

[0074] As is clear from the above description, the illustrated embodiments are merely illustrative of the present invention, and it goes without saying that the present invention includes not only those directly shown by the described embodiments, but also various improvements and modifications made by those skilled in the art within the scope of the claims. [Explanation of symbols]

[0075] 1...Ground surface, 2...Underground structure, 3...Steel sheet pile, 3a...Inner surface (excavation side surface), 3b...Outer surface (ground side surface), 4...Upper steel sheet pile, 4a...Inner surface (excavation side surface), 4b...Outer surface (ground side surface), 4t...Lower edge, 5...Lower steel sheet pile, 5a...Inner surface (excavation side surface), 5b...Outer surface (ground side surface), 5t...Upper edge, 10, 10'...Reinforcement means, 11, 11'...Inner reinforcement means, 11a...First pipe member, 11b...Second pipe member, 11c...Tapered surface, 11d...Extension part, 12, 12'...Outer reinforcement means, 12a...First pipe member, 12b...Second pipe member, 12c...Tapered surface, 12d...Extension part, 20...Slip prevention means, 21...First slip Retaining member, 21a...Tapered surface, 21b, 21c...Welded part, 22...Second shearing retaining member, 22a...Tapered surface, 22b...Welded part, 31...Convex surface, 32...Concave surface, 33...Web, 34...Flange, 35...Joint, 41...Convex surface, 42...Concave surface, 43...Web, 44...Flange, 45...Joint, 51...Convex surface, 52...Concave surface, 53...Web, 54...Flange, 55...Joint, 60...Waterproofing tape, 71a...First plate, 71b...Second plate, 71c...Long bolt, 71d...Head, 71e...Cover member, 72a...First plate, 72b...Second plate, 72c...Long bolt, 72d...Head, 72e...Cover member

Claims

1. A steel sheet pile driven into the ground to separate the excavation side from the natural ground side, The upper steel sheet pile forming the upper part of the aforementioned steel sheet pile, The lower steel sheet pile forming the lower part of the aforementioned steel sheet pile, A first anti-slip member that straddles the excavation-side surface of the upper steel sheet pile and the excavation-side surface of the lower steel sheet pile and contacts the excavation-side surface of the upper steel sheet pile and the excavation-side surface of the lower steel sheet pile, A second anti-slip member that straddles the ground-side surface of the upper steel sheet pile and the ground-side surface of the lower steel sheet pile and contacts the ground-side surface of the upper steel sheet pile and the ground-side surface of the lower steel sheet pile, A reinforcing means for restricting bending at the boundary between the lower edge of the upper steel sheet pile and the upper edge of the lower steel sheet pile, Equipped with, The first anti-slip member is fixed to both the excavation-side surface of the upper steel sheet pile and the excavation-side surface of the lower steel sheet pile. The second anti-slip member is fixed to one of the ground-side surfaces of the upper steel sheet pile and the ground-side surfaces of the lower steel sheet pile, but not to the other. The reinforcing means is, A first pipe member fixed to the upper steel sheet pile and extending vertically along the upper steel sheet pile, A second pipe member fixed to the lower steel sheet pile and extending vertically along the lower steel sheet pile, Equipped with, The first pipe member has an extension that extends downward from the lower edge of the upper steel sheet pile, A steel sheet pile in which the extension portion is inserted into the second pipe member.

2. A steel sheet pile driven into the ground so as to separate the excavation side from the natural ground side, The upper steel sheet pile forming the upper part of the aforementioned steel sheet pile, The lower steel sheet pile forming the lower part of the aforementioned steel sheet pile, A first anti-slip member that straddles the excavation-side surface of the upper steel sheet pile and the excavation-side surface of the lower steel sheet pile and contacts the excavation-side surface of the upper steel sheet pile and the excavation-side surface of the lower steel sheet pile, A second anti-slip member that straddles the ground-side surface of the upper steel sheet pile and the ground-side surface of the lower steel sheet pile and contacts the ground-side surface of the upper steel sheet pile and the ground-side surface of the lower steel sheet pile, A reinforcing means for restricting bending at the boundary between the lower edge of the upper steel sheet pile and the upper edge of the lower steel sheet pile, Equipped with, The first anti-slip member is fixed to both the excavation-side surface of the upper steel sheet pile and the excavation-side surface of the lower steel sheet pile. The second anti-slip member is fixed to one of the ground-side surfaces of the upper steel sheet pile and the ground-side surfaces of the lower steel sheet pile, but not to the other. The reinforcing means is, The first plate fixed to the upper steel sheet pile, A second plate fixed to the lower steel sheet pile, A long bolt extending vertically and inserted through the through hole of the first plate and the through hole of the second plate, The female thread portion for temporarily fixing the lower end of the long bolt to the second plate, A steel sheet pile equipped with [a specific feature / equipment].

3. The steel sheet pile according to claim 1 or 2, wherein the second anti-slip member is fixed to the ground-side surface of the upper steel sheet pile and is not fixed to the ground-side surface of the lower steel sheet pile.

4. The steel sheet pile according to claim 1 or 2, wherein the fixing is by welding.

5. The steel sheet pile according to claim 1 or 2, further comprising a watertight tape attached to seal the boundary between the lower edge of the upper steel sheet pile and the upper edge of the lower steel sheet pile.

6. The steel sheet pile according to claim 1 or 2, wherein the reinforcing means is provided on at least one of the excavation side and the ground side of the steel sheet pile.

7. A method for removing the upper steel sheet pile from the steel sheet pile described in claim 1, leaving the lower steel sheet pile in place, A connection release step is performed to release the connection between the excavation-side surface of the upper steel sheet pile and the excavation-side surface of the lower steel sheet pile via the first anti-slip member, from the excavation side. The backfilling process involves backfilling the excavated area, The extraction process involves pulling the upper steel sheet pile upwards. A method for removing upper steel sheet piles, including the method described above.

8. A method for removing the upper steel sheet pile from the steel sheet pile described in claim 2, leaving the lower steel sheet pile in place, A connection release step is performed to release the connection between the excavation-side surface of the upper steel sheet pile and the excavation-side surface of the lower steel sheet pile via the first anti-slip member, from the excavation side. The backfilling process involves backfilling the excavated area, The temporary fixing process involves releasing the aforementioned temporary fixing, The extraction process involves pulling the upper steel sheet pile upwards. A method for removing upper steel sheet piles, including the method described above.

9. A method for removing a steel sheet pile, which is driven into the ground to separate the excavation side from the natural ground side, and which comprises an upper steel sheet pile forming the upper part of the steel sheet pile and a lower steel sheet pile forming the lower part of the steel sheet pile, leaving the lower steel sheet pile in place, The aforementioned steel sheet pile is A first anti-slip member that straddles the excavation-side surface of the upper steel sheet pile and the excavation-side surface of the lower steel sheet pile and contacts the excavation-side surface of the upper steel sheet pile and the excavation-side surface of the lower steel sheet pile, A second anti-slip member that straddles the ground-side surface of the upper steel sheet pile and the ground-side surface of the lower steel sheet pile and contacts the ground-side surface of the upper steel sheet pile and the ground-side surface of the lower steel sheet pile, Equipped with, The first anti-slip member is fixed to both the excavation-side surface of the upper steel sheet pile and the excavation-side surface of the lower steel sheet pile. The second anti-slip member is fixed to one of the ground-side surfaces of the upper steel sheet pile and the ground-side surfaces of the lower steel sheet pile, but not to the other. A connection release step is performed to release the connection between the excavation-side surface of the upper steel sheet pile and the excavation-side surface of the lower steel sheet pile via the first anti-slip member, from the excavation side. The backfilling process involves backfilling the excavated area, The extraction process involves pulling the upper steel sheet pile upwards. A method for removing upper steel sheet piles, including the method described above.

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