Temporary cofferdam structure and temporary cofferdam construction method

Abstract

To provide a temporary cofferdam structure which can be easily transported, assembled and installed on site and can be constructed efficiently in a short period of time, and a temporary cofferdam construction method.SOLUTION: A temporary cofferdam structure 1 for forming a dry space on an upstream side U of a dam comprises a watertight layer 2 disposed on a wall surface of a dam body D and extending in the vertical direction, a fixing member 4 disposed in close contact with the watertight layer 2, a bracket 10, a left-side cofferdam wall portion and a right-side cofferdam wall portion 30 disposed on the bracket 10 and connected to the fixing member 4, and a connecting cofferdam wall portion 40 disposed on the bracket 10 and connecting the other ends of the left-side cofferdam wall portion and the left-side cofferdam wall portion 30. The watertight layer 2 is formed by filling unevenness in the wall surface of the dam body D with a filler such as underwater mortar or underwater putty, and the wall surface is formed flat after filling with the filler.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a temporary cofferdam structure and a temporary cofferdam construction method that use general-purpose steel materials to carry out construction work that requires dry construction in the fields of marine and river construction and dam construction. [Background technology]

[0002] As is well known, there are cases where redevelopment (improvement work) is required, such as adding an outlet pipe to the dam body while it is in operation. When adding an outlet pipe to the dam body while it is in operation, the upstream intake section is constructed first, and then holes are drilled into the dam body from the downstream face. This type of construction method is essential for the redevelopment of structures in operation in the fields of marine and river engineering and dam construction.

[0003] This type of advance construction of the upstream intake section must be carried out during the dry season, as the work is carried out while the system is in operation, and it must be completed quickly within a limited number of work days. Furthermore, the construction of the upstream intake section mainly involves the installation of steel materials such as bellmouth pipes and gates, and dry construction is essential to ensure watertightness.

[0004] When constructing a dam embankment, temporary cofferdams may be constructed upstream or downstream of the dam site as temporary structures to block the river and divert it into a temporary drainage channel, or to prevent backflow from downstream. In this way, various technologies have been disclosed for installing temporary cofferdams, in order to prevent diversion of water into temporary drainage channels or backflow from downstream, by installing temporary steel cofferdams on the upstream side to secure space for dry construction (Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] "Floating Upstream Cofferdam in the Tsuruta Dam Redevelopment Project" (2013 Ministry of Land, Infrastructure, Transport and Tourism "National Land Technology Research Association" paper) [Retrieved March 6, 2024] Internet <URL:https: / / www.mlit.go.jp / chosahokoku / giken / program / kadai / pdf / jusyo / H25 / innova1_01.pdf> Summary of the Invention [Problem to be solved by the invention]

[0006] However, the box-shaped steel cofferdam described in Non-Patent Document 1 has a complex structure, including an airtight chamber, and therefore requires fabrication in a factory. When fabricating a steel cofferdam in a factory, the fabrication process takes several months, and the construction period from completion to transportation, assembly, and installation is long, resulting in high installation costs. Furthermore, installation may require a large crane of, for example, 100 tons or more, and the location of the dam or other structure to be constructed may be a constraint. Therefore, there is a demand for a technology relating to a temporary cofferdam structure and a temporary cofferdam construction method that can be easily transported, assembled, and installed on site in a short period of time.

[0007] The present invention aims to provide a temporary cofferdam structure and a temporary cofferdam construction method that can be easily transported to a site, assembled, and installed, and can be constructed efficiently in a short period of time. [Means for solving the problem]

[0008] The present invention provides A temporary cofferdam structure that is installed on the outer side of a levee installed in an ocean or river or on the upstream side of a dam, and that forms a dry space on the outer side or upstream side of the levee, Fixing members are attached to the wall surface of the embankment body on the upstream side or on the left and right sides of the wall surface at a distance from each other in a watertight manner in the vertical direction; a base portion having a floor plate formed in a flat plate shape, connected to the wall surface in a watertight manner, and disposed substantially horizontally; a left-side closing wall portion disposed on the base portion, one end of which is connected to the fixing member at the left side position and the other end of which is disposed apart from the wall surface; a right-side closing wall portion disposed on the base portion, one end of which is connected to the fixing member at the right position and the other end of which is disposed apart from the wall surface; a connecting cutoff wall portion disposed on the base portion and connecting the other end of the left cutoff wall portion to the left cutoff wall portion; Equipped with It is characterized by the fact that or The fixing member is A connecting hole formed as an elongated hole extending toward a side away from the bank body is formed. It is characterized by the fact that or The fixing member is It is composed of L-shaped steel beams that have an approximately L-shaped cross section when viewed along the longitudinal direction. It is characterized by the fact that or The left side cutoff wall portion, the right side cutoff wall portion, and the connecting cutoff wall portion are It is constructed by stacking steel closure members. It is characterized by the fact that or The steel material is It is composed of H-shaped steel, a channel or a square pipe formed into a substantially H-shaped cross section when viewed along the longitudinal direction. It is characterized by the fact that or A watertight layer is provided on the left and right sides of the wall surface so as to extend in the vertical direction, and a filler such as underwater mortar or underwater putty is filled into the unevenness of the wall surface, and the wall surface is formed flat after filling with the filler. The fixing member is attached along the vertical direction so as to be in close contact with the watertight layer. It is characterized by the fact that or The left side cutoff wall portion, the right side cutoff wall portion, and the connecting cutoff wall portion are When stacking H-shaped steel beams that have a cross section that is roughly H-shaped when viewed along the longitudinal direction, the flange end of the lower H-shaped steel beam and the flange end of the upper H-shaped steel beam are stacked together. It is characterized by the fact that or A temporary cofferdam construction method for constructing a temporary cofferdam structure that is installed on the outer side of a levee installed in an ocean or river or on the upstream side of a dam, and that forms a dry space on the outer side or upstream side of the levee, comprising: The unevenness of the wall surface on the upstream side or outside the embankment of the embankment is filled with a filler such as underwater mortar or underwater putty, and the wall surface after filling is made flat, thereby forming watertight layers on the left and right sides of the embankment surface, which extend in the vertical direction at intervals on the left and right sides. a fixing member made of an L-shaped steel formed to have a substantially L-shaped cross section when viewed in the longitudinal direction, which is attached to the embankment body in a watertight manner by being in close contact with the watertight layers at the left and right positions; a base portion formed in a flat plate shape is watertightly connected to the bank body and disposed substantially horizontally; A plurality of closure members each made of an H-shaped steel having a substantially H-shaped cross section when viewed along the longitudinal direction are prepared; The partition members are arranged on the base portion in correspondence with the fixing members at the left and right positions, one end of the partition member is connected to the corresponding fixing member, and the other end is arranged spaced apart from the bank body, and partition members are stacked on the left partition member connected to the fixing member at the left position and the right partition member connected to the fixing member at the right position, and the connection with the corresponding fixing member is repeated to form the left partition wall portion and the right partition wall portion, At any timing during the formation of the left and right limiting wall portions or after the left and right limiting wall portions have been formed, a limiting member is disposed on the other end side of the left limiting member and the other end side of the right limiting member and is connected to the other end sides of the left and right limiting members to form a connected limiting wall portion between the left and right limiting wall portions, thereby constructing a temporary limiting structure. It is characterized by: [Effects of the Invention]

[0009] The temporary cofferdam structure and temporary cofferdam construction method of the present invention make it possible to construct a temporary cofferdam efficiently and in a short period of time by facilitating the processes from the preparation of cofferdam steel materials to processing, transporting, and assembly. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a plan view illustrating a schematic configuration of a temporary cofferdam structure according to a first embodiment of the present invention. [Figure 2] 1 is a front view illustrating a schematic configuration of a temporary cofferdam structure according to a first embodiment. [Figure 3] 1 is a side view seen from the right side, illustrating the schematic configuration of a temporary cofferdam structure according to a first embodiment. FIG. [Figure 4] FIG. 2 is a conceptual diagram illustrating the function of underwater mortar (filler) in the watertight layer according to the first embodiment. [Figure 5] FIG. 2 is a perspective view illustrating a schematic configuration of a fixing member made of an L-shaped steel according to the first embodiment. [Figure 6] 3 is a conceptual diagram illustrating the schematic configuration of a floorboard member that constitutes the bracket (base portion) according to the first embodiment, as viewed from the side. FIG. [Figure 7] 4 is a conceptual plan view illustrating an example of connection between a fixing member and a left-side shutoff member according to the first embodiment. FIG. [Figure 8] FIG. 2 is a perspective view illustrating a schematic configuration of a stack of left-side shutoff members according to the first embodiment. [Figure 9] FIG. 10 is a conceptual diagram illustrating a schematic configuration of a molded rubber (watertight member) applied to a left-side shutoff member according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a temporary cofferdam structure according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a plan view illustrating the schematic configuration of a temporary cofferdam structure according to a first embodiment of the present invention, FIG. 2 is a front view, and FIG. 3 is a side view seen from the right side. In the figure, symbol 1 indicates a temporary cofferdam structure, symbol 2 indicates a watertight layer, symbol 4 indicates a fixing member, symbol 10 indicates a bracket (base portion), symbol 12 indicates a floor panel member, symbol 20 indicates a left-side cofferdam wall portion, symbol 30 indicates a right-side cofferdam wall portion, symbol 40 indicates a connecting cofferdam wall portion, and symbol D indicates a dam body.

[0012] As shown in Figures 1 to 3, the temporary closure structure 1 is arranged on the left and right sides of the wall surface on the upstream side U of the dam's embankment body D with a gap between them on the left and right sides, and is equipped with watertight layers 2 extending in the vertical direction, fixing members 4 on the left and right sides that are arranged in close contact with the watertight layers 2 on the left and right sides and are attached in the vertical direction, fixing members 4 on the left and right sides, a bracket (base portion) 10 having a floor panel member 12 formed in a flat plate shape and connected to the embankment body D, a left closure wall portion 20 arranged on the bracket (base portion) 10, a right closure wall portion 30, and a connecting closure wall portion 40.

[0013] The watertight layer 2 is formed by filling the irregularities formed on the wall surface of the dam body D with a filler material, and by forming the wall surface flat after filling with the filler material. The type of filler can be set arbitrarily, and for example, underwater mortar, underwater putty, etc. can be used. The watertight layer 2 is formed by filling small rough irregularities on the wall surface of the embankment D as shown in Fig. 4(A) or large wavy irregularities (corrugated) as shown in Fig. 4(B) that create gaps between the wall and the fixing members 4 with a filler such as underwater mortar to smooth the surface and make it flat. In other words, it is composed of a flat surface formed over a predetermined area where the fixing members 4 can be attached. In addition, the width (horizontal dimension) of the watertight layer 2 is formed wider than the width of the fixing member 4, which is advantageous in that the fixing member 4 abuts over a large area with the wall surface of the embankment body D via the watertight layer 2 throughout the entire width direction, thereby improving watertightness and stably fixing the fixing member 4. The configuration of the watertight layer 2 may be set arbitrarily, and in cases where the wall surface of the embankment body D is flat, for example, and watertightness is ensured to ensure a dry space without using the watertight layer 2, the configuration may not include the watertight layer 2.

[0014] The fixing members 4 are attached to the embankment body D in the vertical direction in close contact with the watertight layers 2 at the left and right positions. In this embodiment, the fixing member 4 is made of an L-shaped steel (for example, 150 mm×150 mm) formed in a substantially L-shape when viewed along the longitudinal direction. As shown in Figure 5, the mounting piece portion 4A, which is attached to the embankment body D via the watertight layer 2, has multiple (e.g., two) circular mounting holes 4H formed therein, and the fixing piece portion 4B, which is formed perpendicular to the mounting piece portion 4A and is connected to the left-side closing wall portion 20 and the right-side closing wall portion 30, has multiple (e.g., two) connecting holes 4L consisting of elongated holes extending in a direction approximately perpendicular to the longitudinal direction. The fixing member 4 has a longitudinal dimension of, for example, 360 mm. This allows the fixing member 4 to be easily and stably attached to the wall surface of the embankment body D even if the watertight layer 2 is not formed linearly over the entire length. Note that the fixing member 4 may be configured so that a single member is installed over the entire vertical range on the left side where the left-side cut-off wall 20 is provided and on the right side where the right-side cut-off wall 30 is provided.

[0015] 3, the bracket (base portion) 10 includes a floor plate member 12 formed in a flat plate shape and arranged substantially horizontally, a main girder member 14 on which the floor plate member 12 is placed, a base support member 16 that supports the main girder member 14, and a base fixing member 18 for fixing the base support member 16 to the embankment body D. A left-side cut-off wall portion 20, a right-side cut-off wall portion 30, and a connecting cut-off wall portion 40 are installed on top of the bracket (base portion) 10.

[0016] The floor plate member 12 is formed, for example, from a rectangular flat steel plate, and one side of the floor plate member 12 is connected to the embankment body D in a watertight manner. Specifically, as shown in Figure 6, a watertight layer 2P is formed horizontally on the wall surface of the embankment body D, and is then adhered to the surface of the watertight layer 2P.Then, the edge of one end (one side) of the floor board member 12 is placed on a fixing member 4P attached using an anchor bolt and nut embedded in the embankment body D, and the fixing member 4P is fixed using a bolt and nut (fastening member). The space between the floorboard member 12 and the fixing member 4P is formed to be watertight. The watertight layer 2P and the fixing member 4P are similar to the watertight layer 2 and the fixing member 4 described above except that they are arranged along the horizontal direction, and therefore a description thereof will be omitted.

[0017] The main girder member 14 is a frame-shaped member formed by arranging H-shaped steel (H-200 x 200) formed into an approximately H-shape when viewed along the longitudinal direction in the left-right direction and in a direction perpendicular to the embankment body D, and the floor plate member 12 is placed on it. The base support member 16 is a columnar member that supports the main girder member 14 on which the floor plate member 12 is arranged from the diagonally below, and its lower end is connected to a bracket fixing member 18 that is attached horizontally to the embankment body D. As it moves away from the embankment body D, it extends upward at an angle of 45° and its upper end is connected to the other end of the main girder member 14. The main girder member 14, base support member 16, and bracket fixing member 18 may be configured as desired, and may be made of, for example, L-shaped steel, channels, H-shaped steel, square pipes, etc. The base support member 16 may also be configured to provide support from below upward. Furthermore, the bracket 10 is not limited to a configuration in which the main girder member 14, base support member 16, and bracket fixing member 18 are installed in two sets in the left-right direction, but may be installed in multiple sets spaced apart in the left-right direction. Furthermore, the floor slab member 12 is not limited to a configuration in which a single steel plate is laid on the main girder member 14, but may be a configuration in which multiple steel plates are laid depending on the size of the temporary cofferdam structure 1. In this way, when multiple steel plates are laid as the floor slab member 12, it is preferable that the contact points between the steel plates are positioned on the main girder member 14, and it is also preferable to ensure watertightness at the contact points between the steel plates by adhering a watertight material (not shown), such as a tape-like rubber watertight material, to ensure watertightness. Furthermore, the bracket 10 is configured so that the floor plate 12 is installed watertight via the watertight layer 2P and the fixing member 4P, but if the main girder 14 is installed watertight on the wall surface of the embankment body D, a water-stopping material can be placed on the main girder 14 and the floor plate 12 can be laid on top of it, ensuring watertightness by the weight of the floor plate 12 without using bolts or nuts.

[0018] As shown in FIG. 2, the left-side partition wall portion 20 is formed by stacking a plurality of (for example, nine) left-side partition members 22, for example. The left-side shutoff member 22 is made of, for example, an H-shaped steel (H-400×400) formed into an H shape when viewed along the longitudinal direction. 7 and 8, the left-side shutoff wall portion 20 is connected to the fixing member 4 on the left side by bolts (fastening members) inserted into connecting holes 4L at a position where one longitudinal end of each of the multiple left-side shutoff members 22 abuts against the wall surface of the embankment body D. At this time, even if the screw holes of the left-side shutoff members 22 are displaced along the inclination (relative to the vertical) of the wall surface of the embankment body D, the connecting holes 4L are elongated holes so that the bolts can be properly fastened into the displaced screw holes.

[0019] In addition, the left-side closing members 22 are stacked along the left edge of the floor member 12, and the left-side closing member 22 in the lowest row is positioned with its flange end 22F facing downward and in contact with the upper surface of the floor member 12, and the left-side closing members 22 above the second row are stacked on the left-side closing member 22 in the row below with their flange end portions 22F butted together at a position where one end is in contact with the wall surface of the embankment D.

[0020] 8, in order to prevent water from entering through the abutting portion between the flange ends 22F of the left-side partition member 22, it is preferable to ensure watertightness by attaching a water-stopping material 24 to the flange side surface at the abutting portion between the outer flange ends 22F of each left-side partition member 22. The water-stopping material is not limited to the above-mentioned tape-like rubber water-stopping material, and a waterproof rubber sheet (not shown) may be placed between the flange ends 22F to improve watertightness.

[0021] In this embodiment, the length of the fixing member 4 is set to, for example, 360 mm, which is shorter than one side of the H-section steel (H-400×400). Therefore, as shown in FIG. 8, when the left-side shutoff member 22 is stacked, gaps are formed between the fixing members 4, and the water-stopping material 24 can be easily and efficiently attached to the abutting portions of the flange end portions 22F. Furthermore, it is preferable to pull the left-side closing wall portion 20 using multiple (e.g., two) chain blocks (not shown) installed by connecting the top left-side closing member 22 and the bracket (base portion) 10 to prevent it from floating up and ensure stable fixation.

[0022] The right-side partition wall portion 30 is formed by stacking, for example, a plurality of (for example, nine) right-side partition members 32 along the right edge portion of the floor member 12, as shown in FIGS. The right-side cutoff member 32 is made of, for example, an H-shaped steel (H-400×400). The configuration of the right-side partition wall 30 and the right-side partition member 32 and their fixation to the fixed member 4 at the right side position are similar to the configuration of the left-side partition wall 20 and the left-side partition member 22 and their fixation to the fixed member 4 at the left side position, and therefore a description thereof will be omitted.

[0023] As shown in FIGS. 1 to 3, the connecting partition wall portion 40 is formed by stacking a plurality of (for example, nine) connecting partition members 42, which are stacked along the upstream edge of the floor member 12, for example. The connecting cutoff members 42 are made of, for example, H-shaped steel (H-400 x 400) formed into an H shape, and each connecting cutoff member 42 connects the other end (upstream U side) of the corresponding left cutoff member 22 of the left cutoff wall 20 to the other end (upstream U side) of the corresponding right cutoff member 32 of the right cutoff wall 30 using fastening members such as bolts and nuts. If necessary, a filler such as underwater mortar or underwater putty is used to make the connection watertight. Here, "corresponding" means that they are in the same layer number in the stacking direction.

[0024] The construction of laminating the connecting partition members 42 and applying waterproof tape to the areas where the flange portions abut against each other is the same as that of the left partition wall portion 20, and therefore a description thereof will be omitted. In addition, it is preferable to pull the connecting partition wall portion 40 using multiple (e.g., two) chain blocks (not shown) installed by connecting the uppermost connecting partition member 42 and the bracket (base portion) 10 to prevent it from floating up and ensure stable fixation.

[0025] A method for constructing the temporary cofferdam structure 1 according to the first embodiment will be described below. (1) First, measure the unevenness of the wall surface on the upstream side U of the dam body D where the temporary cofferdam structure 1 will be installed. It is preferable to measure the unevenness to a depth of, for example, about 1 cm. If necessary, the dam body D may be cut to make it flat. (2) Next, a fixing member 4 made of an L-shaped steel is installed in the vertical direction at the dam joint of the end of the temporary cofferdam steel material. (3) Fill the gap that occurs between the upstream wall of the embankment body D and the fixed member (L-shaped steel) 4 with underwater mortar or underwater putty. (4) A bracket (base) 10 is installed on the wall of the embankment body D. (5) The main girder H-shaped steel (H-200 x 200) is installed on the bucket in the left and right bank directions, and the floor plate members (steel plates) 12 are laid on top of it. The joints of the floor plate members 12 are filled with underwater putty or the like from the underside. (6) A left-side partition member 22 and a right-side partition member 32, each made of, for example, an H-shaped steel (H-400 x 400), are placed on the floorboard member 12 and fixed to the fixing member 4. It is preferable to place watertight rubber on the underside of the steel to prevent water leakage from underneath. (7) A connecting fastening member 42, for example, made of H-shaped steel (H-400 x 400), is placed on top of the floorboard member 12 and connected and fixed to the other end of the left-side closing member 22 and the right-side closing member 32 by bolt connection or the like. (8) Repeat steps (6) and (7) above to stack the left-side partition member 22, the right-side partition member 32, and the connecting partition member 42 to a predetermined height to form the left-side partition wall portion 20, the right-side partition wall portion 30, and the connecting partition wall portion 40. In addition, watertight rubber is placed in advance on the underside of the left-side closing member 22, right-side closing member 32, and connecting fastening member 42 of each stage to prevent water leakage. (9) Next, as a measure to prevent lifting, one end of a chain block is installed at the top of the left-side cutoff wall 20, the right-side cutoff wall 30, and the connecting cutoff wall 40, and the other end is tensioned and fixed to the floor panel member 12.

[0026] According to the temporary cofferdam structure 1 of the first embodiment, the left cofferdam wall 20, the right cofferdam wall 30, and the connecting cofferdam wall 40 are constructed by stacking H-shaped steel, which is a general-purpose steel material. This reduces the number of manufacturing processes in the factory and shortens the process from setup to processing, transportation, and assembly, allowing the temporary cofferdam structure 1 to be installed in a short period of time. Furthermore, the watertight structure reduces the amount of water leaking into the temporary cofferdam structure 1. Even if water does leak, it can be pumped out to create a dry space on the upstream side U of the embankment body D.

[0027] Furthermore, according to the temporary cofferdam structure 1 and temporary cofferdam construction method of the first embodiment, they are constructed using general-purpose steel materials such as H-shaped steel and L-shaped steel, so there is no need to secure a large material yard, and they can be easily applied to dams in mountainous areas where location conditions are not good. Furthermore, since it is possible to shorten the construction period, even if there is a short period until the dry season, the timing of completion of the construction period can be brought forward to meet the dry season.

[0028] Next, a second embodiment will be described with reference to FIG. FIG. 9 is a conceptual diagram illustrating an outline of a molded rubber (watertight member) for ensuring watertightness between left-side partition members 22 according to the second embodiment, as viewed along the longitudinal direction of the left-side partition members. In Figure 9, reference numerals 25 and 26 denote molded rubber (watertight members). While Figure 9 illustrates the bottom and second-tier left-side partition members 22, the same applies to the upper-tier left-side partition members 22. The same can also be applied to the right-side partition member 32 and the connecting partition member 42. The second embodiment differs from the first embodiment in that molded rubber (watertight members) 25, 26 are used instead of the watertight material (a tape-shaped rubber watertight member) 24; otherwise, the second embodiment is similar to the first embodiment, and therefore a description thereof will be omitted.

[0029] As shown in Figure 9(A), the left-side partition member 22, which is made of an H-shaped steel and is placed at the bottom of the upper surface of the floorboard member 12, has a molded rubber (watertight member) 25 formed to complement the lower recess of the H-shaped steel. 9(B), the bottom-most left-side shutoff member 22 has a molded rubber (watertight member) 26 formed complementarily in the upper recess, and the upper half of the molded rubber (watertight member) 26 is formed complementarily in the lower recess of the second-stage (one stage above) left-side shutoff member 22. In other words, the molded rubber (watertight member) 26 is formed complementarily in the space formed by the upper and lower recesses by stacking the left-side shutoff members 22. Then, as shown in Figure 9(C), by stacking the second lowest left-hand side partition member 22 on the lowest left-hand side partition member 22, a molded rubber (watertight member) 26 is placed between the two stacked lowest left-hand side partition members 22, and the molded rubber (watertight member) 26 ensures watertightness between the flange end portions 22F.

[0030] According to the temporary cofferdam structure 1 of the second embodiment, in addition to the temporary cofferdam structure 1 of the first embodiment, a molded rubber (watertight member) 26 is formed complementarily to the space formed by the H-shaped steel constituting the lower left-side cofferdam member 22 and the H-shaped steel constituting the upper left-side cofferdam member 22, thereby ensuring high watertightness. Furthermore, since the molded rubber (watertight member) 26 acts as a guide when stacking the H-shaped steel, the left-side shutoff member 22 can be stacked easily and efficiently. Furthermore, by supporting the stacked H-shaped steel beams internally, the left-side shutoff member 22 is prevented from shifting laterally, and the left-side shutoff member 22 can be stably held in a predetermined position.

[0031] The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the invention. For example, in the above embodiment, the temporary cofferdam structure 1 is described as having a watertight layer 2 formed by filling a filler material on the wall surface of the embankment body D, but the configuration of the watertight layer 2 and whether or not the watertight layer 2 is provided may be set arbitrarily. For example, it may be formed of a material other than a filler material, or instead of the watertight layer 2, a fixing member 4 provided with a watertight member on the wall surface side of the embankment body D may be used.

[0032] In addition, in the above embodiment, the fixing member 4 is described as being made of an L-shaped steel beam of 150 mm x 150 mm, but the configuration of the fixing member 4 may be set arbitrarily, and for example, instead of an L-shaped steel beam, an H-shaped steel beam, a channel, a square pipe, etc. may be used.

[0033] Furthermore, in the above embodiment, a case has been described in which a connecting hole 4L consisting of a long hole is formed in the L-shaped steel that constitutes the fixing member 4, but the configuration of the connecting hole 4L may be set arbitrarily, and for example, a circular hole may be applied.

[0034] Furthermore, in the above embodiment, the case where the length of the fixing member 4 is formed to be shorter than the dimension in the stacking direction of the H-shaped steel has been described, but the length of the fixing member 4 may be set arbitrarily. For example, it may be set to a length corresponding to the length of the plurality of left-side closing members 22, right-side closing members 32, and connecting fastening members 42, or it may be formed as a single unit corresponding to the overall height.

[0035] In the above embodiment, the H-shaped steel beams constituting the left-side shutoff member 22, the right-side shutoff member 32, and the connecting fastening member 42 are stacked with the flange sections 22F butted together, but the orientation of the H-shaped steel beams when stacked can be set arbitrarily, and for example, they may be stacked with the flange surfaces abutting against each other.

[0036] Furthermore, in the above embodiment, an example has been described in which the connecting partition wall section 40 linearly connects the other end of the left-side partition wall section 20 and the other end of the right-side partition wall section 30, but the configuration of the connecting partition wall section 40 can be set as desired, and for example, the connecting partition wall section 40 may be formed by connecting a plurality of wall sections, and may have a configuration that is not linear in plan view, for example, includes a bent section.

[0037] Furthermore, in the above embodiment, the left-side cutoff wall 20, the right-side cutoff wall 30, and the connecting cutoff wall 40 are configured by stacking the left-side cutoff member 22, the right-side cutoff member 33, and the connecting cutoff member 44, which are made of H-shaped steel, respectively. However, the left-side cutoff wall 20, the right-side cutoff wall 30, and the connecting cutoff wall 40 may be configured in any manner. For example, they may be configured by stacking steel materials other than H-shaped steel, such as channels or square pipes, or they may be configured by a single panel made of steel plate or the like.

[0038] In addition, in the above embodiment, the temporary closure structure 1 is described as being installed upstream of the dam embankment D, but it may also be applied to temporary closures for creating a dry space outside an embankment in a river or ocean in order to construct a sluice gate or the like while operating the embankment in the ocean or river. [Explanation of symbols]

[0039] 1 Temporary cofferdam structure 2 Watertight layer 2P Watertight Layer (for brackets) 4 Fixing member 4L connection hole (long hole) 4P fixing member (for bracket) 10 Bracket (base part) 12 Flooring 14 Main girder members 16 Pedestal support member 18 Bracket fixing member 20 Left side cutoff wall 22 Left side closing member 24 Water-stopping material (tape-shaped watertight material) 25, 26 Molded rubber (watertight material) 30 Right side closing wall 32 Right-hand closure member 40 Connecting cutoff wall 42 Connecting closure member D. Dam U Upstream side

Claims

1. A temporary cofferdam structure that is installed on the outer side of a levee installed in an ocean or river or on the upstream side of a dam, and that forms a dry space on the outer side or upstream side of the levee, Fixing members are attached to the wall surface of the embankment body on the upstream side or on the left and right sides of the wall surface at a distance from each other in a watertight manner in the vertical direction; a base portion having a floor plate formed in a flat plate shape, connected to the wall surface in a watertight manner, and disposed substantially horizontally; a left-side closing wall portion disposed on the base portion, one end of which is connected to the fixing member at the left side position and the other end of which is disposed apart from the wall surface; a right-side closing wall portion disposed on the base portion, one end of which is connected to the fixing member at the right position and the other end of which is disposed apart from the wall surface; a connecting cutoff wall portion disposed on the base portion and connecting the other end of the left cutoff wall portion to the left cutoff wall portion; Equipped with A temporary cofferdam structure characterized by:

2. The fixing member is A connecting hole formed as an elongated hole extending toward a side away from the bank body is formed.

2. The temporary cofferdam structure according to claim 1.

3. The fixing member is It is composed of L-shaped steel formed into a substantially L-shaped cross section when viewed along the longitudinal direction.

2. The temporary cofferdam structure according to claim 1.

4. The left side cutoff wall portion, the right side cutoff wall portion, and the connecting cutoff wall portion are It is constructed by stacking steel closure members.

2. The temporary cofferdam structure according to claim 1.

5. The steel material is It is composed of H-shaped steel, a channel or a square pipe formed into a substantially H-shaped cross section when viewed along the longitudinal direction.

5. The temporary cofferdam structure according to claim 4.

6. A watertight layer is provided on the left and right sides of the wall surface so as to extend in the vertical direction, and a filler such as underwater mortar or underwater putty is filled into the unevenness of the wall surface, and the wall surface is formed flat after filling with the filler. The fixing member is attached along the vertical direction so as to be in close contact with the watertight layer.

2. The temporary cofferdam structure according to claim 1.

7. The left side cutoff wall portion, the right side cutoff wall portion, and the connecting cutoff wall portion are When stacking H-shaped steel beams formed to have a substantially H-shaped cross section when viewed along the longitudinal direction, the flange end of the lower H-shaped steel beam and the flange end of the upper H-shaped steel beam are stacked together.

2. The temporary cofferdam structure according to claim 1.

8. A temporary cofferdam construction method for constructing a temporary cofferdam structure that is installed on the outer side of a levee installed in an ocean or river or on the upstream side of a dam, and that forms a dry space on the outer side or upstream side of the levee, comprising: The unevenness of the wall surface on the upstream side or outside the embankment of the embankment is filled with a filler such as underwater mortar or underwater putty, and the wall surface after filling is made flat, thereby forming watertight layers on the left and right sides of the embankment surface, which extend in the vertical direction at intervals on the left and right sides. a fixing member made of an L-shaped steel formed to have a substantially L-shaped cross section when viewed in the longitudinal direction, which is attached to the embankment body in a watertight manner by being in close contact with the watertight layers at the left and right positions; a base portion formed in a flat plate shape is watertightly connected to the bank body and disposed substantially horizontally; A plurality of closure members each made of an H-shaped steel having a substantially H-shaped cross section when viewed along the longitudinal direction are prepared; The partition members are arranged on the base portion in correspondence with the fixing members at the left and right positions, one end of the partition member is connected to the corresponding fixing member, and the other end is arranged spaced apart from the bank body, and partition members are stacked on the left partition member connected to the fixing member at the left position and the right partition member connected to the fixing member at the right position, and the connection with the corresponding fixing member is repeated to form the left partition wall portion and the right partition wall portion, At any timing during the formation of the left and right limiting wall portions or after the left and right limiting wall portions have been formed, a limiting member is disposed on the other end side of the left limiting member and the other end side of the right limiting member and is connected to the other end sides of the left and right limiting members to form a connected limiting wall portion between the left and right limiting wall portions, thereby constructing a temporary limiting structure. A method for constructing a temporary cofferdam.

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