Liner plate connecting structure and retaining wall for shafts

Abstract

To provide a liner plate connecting structure that can reduce a bending moment generated at an intersection of straight sections by installing an arc-shaped liner plate with curved surfaces both inside and outside at the intersection where straight sections intersect and reduce the overall cost by reducing the size of the intersection.SOLUTION: In a liner plate connecting structure 1 in which liner plates are mechanically connected to each other, an arcuate liner plate 2 with curved inner and outer surfaces is provided at an intersection of a linear liner plate 3 and another linear liner plate 3 to reduce the maximum bending moment generated at the intersection.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a liner plate connection structure in which liner plates, which are corrugated steel plates, are connected to form a retaining structure, and a retaining wall for a shaft.

Background Art

[0002] For the purpose of preventing earth and sand from flowing in from the surroundings at locations that are being excavated or have been excavated for various applications such as shafts, deep foundation work, landslide countermeasures work, and tunnel lining work, a liner plate connection structure is known in which liner plates provided with assembly flanges at the four corners of corrugated steel plates are connected to form a retaining structure in a rectangular, circular, semi-circular, gourd-shaped, or oval shape.

[0003] Such a liner plate connection structure is often used as a retaining wall for a shaft, and generally most are rectangular or circular in plan view. However, depending on the shape of structures such as foundations constructed inside the shaft, there is a problem that dead space that is not required for construction becomes large in a rectangular or circular retaining wall in plan view. Also, even in such cases where it is not required structurally, an extra amount of excavation has to be carried out, and there is also a problem that the amount of excavated soil becomes unnecessarily large.

[0004] Moreover, when the liner plate connection structure is rectangular in plan view, the connection work between the liner plates at the corner portions can only be carried out from the outside of the retaining wall, so it has to be carried out in advance of the connection work for the liner plates in the straight portions, and there is a problem that there are restrictions on the construction sequence.

[0005] Also, a liner plate connection structure that is rectangular in plan view has a problem that it cannot be assembled unless it is attached or welded with a corner angle and set in a V-shaped state before installation, which takes a lot of work.

[0006] Furthermore, the rectangular liner plate connecting structure in plan view suffers from a problem where stress concentrates at the corners, resulting in large bending moments. This means that the overall thickness of the liner plates, the pitch of the reinforcing rings, and the size of the steel materials are determined by the stress at the corners, making it uneconomical.

[0007] For example, Patent Document 1 discloses a retaining wall for a polygonal shaft, in which the retaining wall of the shaft is made polygonal in plan view according to the purpose of the shaft for excavation, and liner plates that are easy to connect and assemble are made at the corners of the polygon (see the claims of Patent Document 1, the 10th line in the upper right column of page 2 to the 19th line in the upper right column of page 3 of the specification, and Figures 3 to 8 of the drawings, etc.).

[0008] However, in the polygonal shaft retaining wall described in Patent Document 1, even though the liner plate connecting structure is polygonal, the reinforcing rings remain rectangular, making it impossible to reduce the generated stress. Therefore, it was not possible to reduce the overall cost of the retaining wall by widening the pitch of the reinforcing rings or reducing the size of the steel materials. Furthermore, since the reinforcing rings remain rectangular, it was not possible to reduce the amount of excavated soil, and thus cost reduction was not possible in that respect either.

[0009] Furthermore, the retaining wall for polygonal shafts described in Patent Document 1 involves making triangular cuts in the flange portion of the liner plate and bending the inner surface of the liner plate into a polygonal shape, which presented problems in terms of stress concentration. For this reason, the retaining wall for polygonal shafts described in Patent Document 1 required reinforcement by attaching a reinforcing plate 23, and it was not possible to reduce the cost of the liner plate connecting structure by reducing the size.

[0010] Furthermore, Patent Document 2 discloses a method for constructing a shaft, in which a hole is formed by excavating the ground, a liner plate is placed along the circumferential wall of the hole, vertical beams extending in the vertical direction are installed inside the liner plate, and horizontal beams extending in the circumferential direction of the hole are installed further inside (see the claims of Patent Document 2, from line 10 in the upper right column of page 2 to line 19 in the upper right column of page 3, and Figures 3 to 8 of the drawings).

[0011] However, the liner plate connecting structure used in the shaft construction method of Patent Document 2 had a problem in that even if the pitch of the crossbeams could be widened, the number of vertical beams would increase, and the overall cost of the liner plate connecting structure could not be reduced. In addition, the shaft construction method of Patent Document 2 also failed to solve the problems of large amounts of dead space that were not needed during construction and an unnecessarily large amount of excavated soil.

[0012] Furthermore, Patent Document 3 discloses a segmented connecting structure having a segment piece with an arc-shaped curved surface portion at a position where a straight portion intersects the connecting structure (Claim 2 of the claims in Patent Document 3, paragraphs

[0033] to

[0037] of the specification). It is also stated that "segment" has a broad meaning that includes liner plates (paragraph

[0002] of the specification).

[0013] However, the segment connecting structure described in Patent Document 3 is used, for example, by connecting it at the top of a shaft, pressing it in and pushing it downwards, constructing a new segment connecting structure in the space that was pushed down, and then sequentially pressing the segment connecting structures in the direction of excavation.

[0014] In contrast, the liner plate connecting structure is constructed by first excavating a shaft and then sequentially connecting new liner plates to the lower end of the liner plate connecting structure in the space created. In other words, the liner plate connecting structure is generally not designed to withstand the stress required for press-fitting, and the corrugation direction of the liner plate is perpendicular to the direction of excavation, resulting in a structure that is weak against press-fitting. Furthermore, the curved portion of the segment connecting structure described in Patent Document 3 was not a liner plate, but rather a segment made by combining flat steel plates that are easy to process into a curved shape.

[0015] Therefore, although the segment connecting structure described in Patent Document 3 can reduce the amount of excavated soil, when the liner plate connecting structure is used for press-fitting applications, it requires a significant increase in size, such as thickening the steel plate of the liner plate, which is uneconomical. In short, the invention described in Patent Document 3 did not have the idea of ​​reducing the size and overall cost of the liner plate connecting structure by suppressing the bending moment generated at the corner portion.

[0016] As mentioned above, conventional liner plate connecting structures, which are formed by connecting liner plates to create an oval shape, are known. However, creating an oval shape by placing semicircular liner plates between straight sections presents significant problems compared to rectangular liner plate connecting structures, such as creating unnecessary dead space during construction and unnecessarily increasing the amount of excavated soil. [Prior art documents] [Patent Documents]

[0017] [Patent Document 1] Japanese Patent Application Publication No. 58-94528 [Patent Document 2] Japanese Patent Application Publication No. 11-324557 [Patent Document 3] Japanese Patent Application Publication No. 11-193685 [Overview of the project]

Problems to be Solved by the Invention

[0018] Therefore, the present invention has been devised in view of the above-described problems, and its object is to provide an arcuate liner plate having a curved surface both inside and outside at an intersection where straight portions intersect, thereby reducing the generated bending moment at the intersection and achieving cost reduction by downsizing as a whole, and to provide a liner plate connection structure and a shaft retaining wall for a shaft.

Means for Solving the Problems

[0019] The liner plate connection structure according to the first invention is The plate body is made of steel plate with a corrugated surface. a liner plate connection structure in which liner plates are mechanically connected to each other, and an arcuate liner plate having a curved surface both on the inner surface and the outer surface is provided at a portion where a linear liner plate and another linear liner plate intersect, and the maximum generated bending moment at the intersection is reduced. Plan view with radius of curvature of 300mm to 1500mm at the joint position It is characterized by reducing the maximum generated bending moment at the intersection.

[0020] The liner plate connection structure according to the second invention further includes a reinforcing ring made of a section steel for reinforcing the liner plate, and the reinforcing ring also has an arcuate section steel having a curved surface both inside and outside at a portion where a linear section steel and another linear section steel intersect.

[0022] The 3 shaft retaining wall for a shaft according to the invention is a shaft retaining wall, and is characterized in that the liner plate connection structure according to claim 1 or 2 is used as the retaining wall.

Advantages of the Invention

[0023] According to the first invention to the 3 invention, an arcuate liner plate having a curved surface both inside and outside is provided at an intersection where straight portions intersect, thereby reducing the generated bending moment at the intersection and achieving cost reduction by downsizing as a whole. Furthermore, according to the first to third inventions, the reduction rate of the generated bending moment is high when an arc-shaped liner plate is provided, which is advantageous in terms of structural design.

[0024] In particular, according to the second invention, even when the excavation depth is deep, the generated bending moment at the intersection can be reduced, and cost reduction due to size reduction can be achieved as a whole.

[0026] In particular, according to the 3 invention, the above-described effects can be achieved in the retaining wall of a shaft with a high utilization rate of the liner plate.

Brief Description of the Drawings

[0027] [Figure 1] FIG. 1 is a plan view showing a liner plate connection structure according to the present embodiment. [Figure 2] FIG. 2 is an elevation view showing the same liner plate connection structure. [Figure 3] FIG. 3 is a view showing an arc-shaped liner plate constituting the same liner plate connection structure, where (a) is a front view seen from the inside, (b) is a vertical cross-sectional view, and (c) is a plan view. [Figure 4] FIG. 4 is a perspective view showing the same arc-shaped liner plate. <00​​​​​​​​​​​​​​​Figure 10 is a perspective view showing a connecting fitting used to fasten and join liner plates together. [Modes for carrying out the invention]

[0028] Hereinafter, a liner plate connecting structure according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0029] [Liner plate connecting structure] First, the overall configuration of the liner plate connecting structure according to an embodiment of the present invention will be described using Figures 1 and 2. Figure 1 is a plan view showing the liner plate connecting structure 1 according to this embodiment, and Figure 2 is an elevation view showing the liner plate connecting structure 1.

[0030] As shown in Figure 1, the liner plate connecting structure 1 according to this embodiment is a structure in which multiple liner plates, each made of corrugated steel, are bolted together to connect them. However, the bolt portion is omitted in the illustrated form. Furthermore, the joining of the liner plates is not limited to bolt joining; they may also be joined by riveting or by inserting the joining fittings shown in Figure 10 into holes in the flanges of the liner plates and rotating them to secure them. In short, the joining of the liner plates can be done mechanically, such as by combining bolt joining, riveting, or joining with joining fittings.

[0031] As shown in Figures 1 and 2, the liner plate connecting structure 1 according to this embodiment consists of three liner plates and is used as a retaining wall for shafts such as deep foundation tunneling methods, investigation shafts, temporary cofferdams, and deep foundation retaining walls, with dimensions of width W1=4476mm × length L1=5889mm × depth D1=1500mm. Of course, the liner plate connecting structure according to the present invention is not limited to these uses and may also be used as a retaining wall for launching and receiving shafts in tunneling methods or as a retaining wall for wells in landslide prevention works. Furthermore, the liner plate connecting structure according to the present invention is not limited to retaining walls and can also be used as a lining for various tunnels and culverts that are horizontal shafts for roads, railways, waterways, etc.

[0032] Note that the above dimensions are approximate center-to-center dimensions of the liner plate, and more precisely, they are the center-to-center distances of the bolt holes described later, which are drilled in the center line of the portion excluding the plate thickness that is the joining position.

[0033] As shown in Figure 1, the liner plate connecting structure 1 is a structure assembled in a rectangular shape with rounded corners in plan view by combining two types of liner plates, an arc-shaped liner plate 2 and a straight liner plate 3, with reinforcing rings 4 made of steel, which are bolted together. Furthermore, as shown in Figure 2, the liner plate connecting structure 1 is composed of three stages of liner plates, in which the arc-shaped liner plate 2 and the straight liner plate 3 are joined horizontally, and four stages of reinforcing rings 4 are provided vertically at 500 mm intervals between them.

[0034] (liner plate) Next, the liner plates constituting the liner plate connecting structure 1 will be described in detail using Figures 3 to 6. Figure 3 shows the arc-shaped liner plate 2 constituting the liner plate connecting structure 1, where (a) is a front view seen from the inside, (b) is a vertical cross-sectional view, and (c) is a plan view. Figure 4 is a perspective view showing the arc-shaped liner plate 2. Figure 5 shows the straight liner plate, where (a) is a front view seen from the inside, (b) is a vertical cross-sectional view, and (c) is a plan view. Figure 6 is a perspective view showing the straight liner plate.

[0035] The two types of liner plates 2 and 3 that constitute the liner plate connecting structure 1 are both liner plates made of general structural rolled steel (SS330) with a thickness of 2.7 mm to 7.0 mm, which are corrugated and have their upper and lower flanges bent, and the vertical flanges welded. Of course, the type of steel and the thickness of the steel plates are not limited to those exemplified, and can be appropriately changed according to the scale and application of the liner plate connecting structure 1.

[0036] (Arch-shaped liner plate) As shown in Figures 3 and 4, the arc-shaped liner plate 2 is formed by corrugating a rectangular steel plate and then bending it into an arc shape in plan view, as shown in Figures 3(c) and 4. It comprises an upper flange 21 formed by bending the upper end of the plate body 20, and a lower flange 22 formed by bending the lower end of the plate body 20. In addition, a pair of left and right vertical flanges 23, 23 made of strip steel plate are welded to the left and right edges of the plate body 20.

[0037] Furthermore, when applying the present invention to the lining of a tunnel or the like, the upper and lower flanges are flanges perpendicular to the excavation direction (circumferential flanges if the shaft is circular), and the pair of left and right vertical flanges are flanges aligned with the excavation direction (axial flanges).

[0038] Furthermore, the radius of curvature of the arc-shaped plate body 20 according to this embodiment is set to 550 mm. However, the radius of curvature of the arc-shaped liner plate according to the present invention is preferably 300 mm to 1500 mm. As described later, by rounding the corners as in the liner plate connecting structure 1, stress concentration at the corners is prevented compared to conventional liner plate connecting structures that have a rectangular frame shape in plan view, reducing the maximum bending moment generated and significantly reducing the thickness of the liner plate and the size of the reinforcing rings, or widening the pitch. Note that the numerical value of the radius of curvature also refers to the radius of curvature at the center position of the bolt holes 21a and 22a, which are the joining positions.

[0039] Furthermore, the upper flange 21, the lower flange 22, and the pair of left and right vertical flanges 23, 23 are each provided with multiple bolt holes 21a, 22a, 23a, each with a diameter of 22 mm, for joining to other liner plates and reinforcing rings 4. In addition, the pair of left and right vertical flanges 23, 23 are also provided with drainage holes 23b, each with a diameter of 12 mm.

[0040] (Straight liner plate) As shown in Figures 5 and 6, the linear liner plate 3 comprises a plate body 30 that is linear in plan view, formed by corrugating a rectangular steel plate, an upper flange 31 formed by bending the upper end of the plate body 30, and a lower flange 32 formed by bending the lower end of the plate body 30. In addition, a pair of left and right vertical flanges 33, 33 made of strip steel plates are welded to the left and right edges of the plate body 30.

[0041] Furthermore, similar to the arc-shaped liner plate 2, the upper flange 31, lower flange 32, and the pair of left and right vertical flanges 33, 33 are each provided with multiple bolt holes 31a, 32a, 33a, each with a diameter of 22 mm, for joining to other liner plates and reinforcing rings 4. In addition, the pair of left and right vertical flanges 33, 33 are also provided with drainage holes 33b, each with a diameter of 12 mm.

[0042] (Reinforcement ring) Next, the reinforcing ring 4 of the liner plate connecting structure 1 will be described using Figure 7. Figure 7 is a plan view showing only the reinforcing ring 4 of the liner plate connecting structure 1.

[0043] The reinforcing ring 4 according to this embodiment is an H-shaped steel beam with dimensions H = 125 mm × 125 mm × 6.5 mm × 9.0 mm. As shown in Figure 7, the reinforcing ring 4 is composed of a plurality of straight H-shaped steel beams 40 and arc-shaped H-shaped steel beams 41 provided at the four corners, and these straight H-shaped steel beams 40 and arc-shaped H-shaped steel beams 41 are joined via a splice plate 5.

[0044] Furthermore, the web portion of the H-shaped steel of the reinforcing ring 4 is provided with multiple bolt holes for inserting bolts into the bolt holes 21a and 22a of the arc-shaped liner plate 2 and the bolt holes 31a and 32a of the straight liner plate 3.

[0045] The radius of curvature of the arc-shaped H-beam 41 is set to 550 mm, the same as that of the arc-shaped liner plate 2, with a preferred range of 300 mm to 1500 mm. However, conventional bending processes made it difficult to bend the H-beam within the radius range of 300 mm to 1500 mm. However, by using a high-frequency induction heating device in conjunction with the bending process, it became possible to bend the H-beam within the above radius of curvature range.

[0046] Next, to confirm the effect of reducing the generated bending moment, a simulation was performed using structural calculations. Figure 8 is a distribution diagram of the bending moment of a conventional rectangular frame-shaped liner plate connecting structure with a width W1 = 4476 mm × length L1 = 5889 mm × depth D1 = 1500 mm, and Figure 9 is a distribution diagram of the bending moment of the liner plate connecting structure 1 according to the embodiment of the present invention described above.

[0047] As shown in Figure 8, calculations revealed that in the case of a conventional rectangular frame-shaped liner plate connecting structure, the corner section (corner section) experienced the maximum bending moment, which was 1.234 kN·m. In contrast, as shown in Figure 9, the maximum bending moment of liner plate connecting structure 1 was 0.726 kN·m. Therefore, the reduction effect on the maximum generated bending moment was 58.84%.

[0048] The reason the maximum bending moment was reduced is thought to be that the arc-shaped liner plate 2 of the liner plate connecting structure 1 has a smooth, uniform curvature on both the inside and outside, so stress does not concentrate but is distributed, resulting in a reduction of the large bending moment.

[0049] To put this in terms of the effect of reducing the size of the components, the H-shaped steel used for the reinforcing rings of a conventional rectangular frame-shaped liner plate connecting structure required four rows of H-shaped steel measuring H=150mm×150mm×7.0mm×10.0mm at 500mm intervals. However, as with the liner plate connecting structure 1 mentioned above, it is sufficient to use only four rows of H-shaped steel measuring H=125mm×125mm×6.5mm×9.0mm at 500mm intervals.

[0050] As described above, the liner plate connecting structure 1 according to this embodiment is provided with an arc-shaped liner plate 2, which has curved inner and outer surfaces, at the intersection where two straight sections intersect. This reduces the bending moment generated at the intersection, and allows for cost reduction through a reduction in the thickness of the liner plates 2 and 3 and the overall size of the reinforcing ring.

[0051] According to the liner plate connecting structure 1, since a reinforcing ring 4 and an arc-shaped H-beam 41 are provided, even when the excavation depth is deep, the bending moment generated at the intersection where the straight H-beams 40 intersect can be reduced, and overall cost reduction can be achieved by reducing the size of the reinforcing ring 4 and liner plates 2 and 3.

[0052] Although the liner plate connecting structure 1 according to an embodiment of the present invention has been described in detail above, the embodiments described above or illustrated are merely examples of embodiments that have been materialized in carrying out the present invention. Therefore, the technical scope of the present invention should not be interpreted as being limited by these embodiments.

[0053] In particular, the explanation focused on the case where straight liner plates intersect at right angles as an example of a liner plate connecting structure. However, this method can also be applied when straight liner plates intersect at acute or obtuse angles. This is because even at acute or obtuse intersections, stress concentration at the corners can be prevented by providing a gently curved liner plate with a certain curvature.

[0054] Furthermore, while we have illustrated the case where the arc-shaped liner plates provided at the corners are constructed from a single, integrated liner plate, it is also possible to combine, for example, two arc-shaped liner plates, each at a 45-degree angle. This is because it is possible to similarly prevent stress concentration at the corners. [Explanation of symbols]

[0055] 1: Liner plate connecting structure 2: Arc-shaped liner plate (liner plate) 20: Plate body 21: Upper flange 22: Lower flange 23: Vertical flange 21a, 22a, 23a: Bolt holes 23b: Drainage hole 3: Straight liner plate (liner plate) 30: Plate body 31: Upper flange 32: Lower flange 33: Vertical flange 31a, 32a, 33a: Bolt holes 33b: Drainage hole 4: Reinforcement ring 40: Straight H-shaped steel 41: Arc-shaped H-beam 5: Splice plate

Claims

1. A liner plate connecting structure comprising liner plates having plate bodies made of steel plates that have been corrugated, mechanically connected to each other, At the point where a straight liner plate intersects with another straight liner plate, a liner plate with a curved inner and outer surface, and a radius of curvature of 300 mm to 1500 mm at the joint, is provided, reducing the maximum bending moment generated at the intersection. A liner plate connecting structure characterized by the following.

2. It further includes a reinforcing ring made of structural steel that reinforces the liner plate, The reinforcing ring also has a curved, arc-shaped steel section on both the inside and outside at the point where a straight steel section intersects with another straight steel section. A liner plate connecting structure according to claim 1, characterized by the above.

3. It is a retaining wall for a shaft, The liner plate connecting structure described in claim 1 or 2 is used as a retaining wall. A retaining wall for shafts characterized by the following features.

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