JP6454674B2 - Construction method of water stop working space - Google Patents

Description

  The present invention relates to a method for constructing a water stop working space, and more specifically, when a bridge pier or the like is constructed in a water area, the water stop work space can be efficiently constructed and deformation of a sheet pile that partitions the water area is suppressed. The present invention relates to a method for constructing a water stop working space.

  When constructing structures such as bridge piers in water areas such as the sea and rivers, first build a water stop working space where you can work in the air in the area where the structure is to be built, and then stop the water stop working space The structure will be constructed inside. Conventionally, when constructing a water stop working space in a water area, first, a sheet pile is placed on the bottom of the water, and the water stop target area and the area outside thereof are tightly closed. Thereafter, the water in the water stop target area is discharged in a plurality of stages at a predetermined depth, and the water level in the water stop target area is lowered stepwise. At each stage where the water level is lowered, the support is assembled and installed at the site in the lower air state, and the sheet pile is supported by the support (for example, see Patent Document 1). Thereafter, the bottom of the water stop target area is excavated to a desired depth, and the bottom board is formed by placing underwater concrete on the excavated water bottom. Then, the water stop working space is constructed in the water area by draining the water remaining in the water stop target area to the outside.

  However, in the conventional construction method described above, it is necessary to perform drainage work, on-site assembly and installation work of support works at each stage, and thus the work becomes very complicated. Along with this, work efficiency is lowered, which is one factor that hinders shortening of the construction period. In addition, since the support works are sequentially installed at the site that is in the air state while gradually lowering the water level in the water stop target region, there is also a problem that the accumulated deformation amount of the sheet pile due to water pressure increases.

JP 2011-247050 A

  An object of the present invention is to provide a construction method of a water stop working space that can efficiently construct a water stop work space when constructing a pier or the like in a water region and can suppress deformation of a sheet pile that partitions the water region. There is.

In order to achieve the above object, the construction method of the water stop working space of the present invention includes a partitioning step of partitioning into a water stop target water area and a non-target water area by a plurality of sheet piles placed adjacent to the bottom of the water, and the water stop target water area A support work installation process in which a support work is installed and the sheet pile is supported by the support work, and the water in the water stop target water area in which the support work is installed is discharged to the outside. In the construction method of the water stop working space having a drainage process to make the water stop working space in a state, the water level of the water stop target water area and the non-target water area is between the partitioning process and the support construction setting process. The excavation process of excavating the bottom of the water-stop target water area to a predetermined depth in a state where it is located at the upper end of the sheet pile, and after placing a plurality of intermediate piles on the bottom of the excavated water, Placing underwater concrete A bottom plate forming step, and in the support installation step, a large set support constructed in advance as the support is used, and the large set support is transferred from the atmosphere to the water stop target water area. In the state where the intermediate pile is placed at a position along the inner peripheral edge of the large support structure, the large support structure is placed on the bracket attached to each of the sheet pile and the intermediate pile. It is characterized by being installed .
In order to achieve the above object, another method for constructing a water stop working space according to the present invention includes a partitioning step of partitioning into a water stop target water area and a non-target water area by a plurality of sheet piles placed adjacent to the bottom of the water, and the water stop A support work installation process in which a support work is installed in the target water area and the sheet pile is supported by the support work, and the water in the water stop target water area in which the support work is installed is discharged to the outside. In the construction method of a water stop working space having a draining step for making the water stop working space in an air state, between the partitioning step and the support installation setting step, the water level of the water stop target water area and the non-target water area Excavation step of excavating the bottom of the water-stop target water area to a predetermined depth in a state where the bottom plate is positioned at the upper end of the sheet pile, and a bottom plate that forms a bottom plate by placing underwater concrete on the bottom of the excavated water Forming step, and In the pre-installation process, a plurality of large support works assembled in advance as the support works are used, and these large support works are sequentially set from the air to the water-stop target water area from the bottom to the top. A plurality of stages of the large group support works are installed.

  According to the present invention, since the excavation step and the bottom plate formation step are performed in a state where the water levels in both water areas are substantially the same, the water pressure acting on the sheet piles is balanced, and deformation of the sheet pile can be suppressed. . In addition, by substituting large supporters that have been pre-assembled as supporters into the water-stopping target water area from the air, there is no need for conventional drainage work, support work on-site assembly and installation work. Become. Thereby, shortening of a construction period can be aimed at. Furthermore, since the drainage is performed in a state where the bottom plate and all the large support works of all stages function, the accumulated deformation amount of the sheet pile due to water pressure can be reduced as compared with the conventional method.

  As the large support structure, for example, a large fire-type support structure is used. In the large fire-type support work, a large opening can be secured in the central portion, so that a large working space can be obtained. Therefore, it is advantageous to improve the construction efficiency when constructing a structure such as a pier in the water stop working space.

  For example, brackets are attached to a plurality of predetermined height positions spaced apart in the vertical direction on the intermediate pile and the sheet pile placed on the bottom of the water stop target water area, and the brackets are attached to the respective predetermined height positions. By supporting the large group supporting work by the above, a plurality of large group supporting works are installed at intervals in the vertical direction. In this case, it is possible to position and fix the large group support work by installing the large structure support work on the bracket attached in advance.

It is explanatory drawing which illustrates the water area partitioned off by the partition process of this invention by a longitudinal cross-sectional view. It is explanatory drawing which illustrates the water area of FIG. 1 by planar view. It is explanatory drawing which illustrates the water area excavated by the excavation process of this invention by a longitudinal cross-sectional view. It is explanatory drawing which illustrates the water area of FIG. 2 by planar view. It is explanatory drawing which illustrates the water area by which the bottom board was formed by the bottom board formation process of this invention by a longitudinal cross-sectional view. It is explanatory drawing which illustrates the water area where the bracket was installed by the support installation process of this invention by planar view. It is explanatory drawing which illustrates the condition which has installed the large group support work by the support work installation process of this invention by a longitudinal cross-sectional view. It is explanatory drawing which illustrates the water area by which the lowermost large support work was installed by the support work installation process of this invention by planar view. It is explanatory drawing which illustrates the water area where the large group support work of all the stages was installed by the support work installation process of this invention by a longitudinal cross-sectional view. It is explanatory drawing which illustrates the water stop working space constructed | assembled through the drainage process of this invention by a longitudinal cross-sectional view. It is explanatory drawing which illustrates the state which has constructed the pier in the water stop work space of FIG. 10 by a longitudinal cross-sectional view. It is explanatory drawing which illustrates the state which construction of the pier of FIG. 11 was completed by a longitudinal cross-sectional view.

  Hereinafter, the construction method of the water stop working space of the present invention will be described based on the embodiments shown in the drawings. In the present invention, the water stop working space is constructed in the water stop target water area by sequentially performing the five steps of the partitioning process, the excavation process, the bottom plate forming process, the support installation process, and the drainage process illustrated in FIGS. In the constructed water stop working space, a pier 16 as shown in FIG. 12 is constructed.

  In the partitioning process illustrated in FIGS. 1 and 2, a sheet pile 1 that partitions the water stop target water area WA <b> 1 is placed on the bottom G. The upper end of the sheet pile 1 is in a state of protruding above the water. A ruler material 2 extending in the horizontal direction is installed at the upper end of the sheet pile 1 that has been placed. A sheet pile 1 is driven on the bottom G so as to follow the ruler material 2, and joints between adjacent sheet piles 1 are connected. By using the ruler material 2, the sheet pile 1 can be positioned and shake during the placement of the sheet pile 1 can be suppressed. As the ruler material 2, for example, H-shaped steel is used.

  The water area is partitioned into a water-stopping target water area WA1 and an outer non-target water area WA2 by a plurality of sheet piles 1 placed adjacent to the bottom of the water. In this embodiment, a steel pipe sheet pile is used as the sheet pile 1, and the water-stop target water area WA1 (water stop working space DA) having a quadrangular shape in plan view is formed. In addition, as the sheet pile 1, for example, a hat-type steel sheet pile, a linear steel sheet pile, or the like can be used. The water-stop target water area WA1 can have an arbitrary shape such as a circle in plan view.

  Next, in the excavation process illustrated in FIGS. 3 and 4, the temporary support work 3 is installed at the upper end of the sheet pile 1 in the water stop target water area WA <b> 1, and the temporary support work 3 supports the sheet pile 1 in the horizontal direction. In this embodiment, the temporary support work 3 is a cut beam type temporary support work. Cut beam-type temporary support work is a cut beam that connects and supports the bulge 7 extending horizontally along the surface of the sheet pile 1 on the water stop target water area WA1 side and the bulge 7 facing each other. 8. Each cut beam 8 is provided with an extendable jack 10. The temporary support 3 is further provided with a fire beam 9 that reinforces the erection 7 and the cut beam 8. As the temporary support 3, for example, a large fire-type temporary support having a belly ridge 7 and a fire beam 9 that connects and supports the adjacent belly ridges 7 can be used.

  The procedure for installing the temporary support 3 is, for example, attaching the bracket 5 to a predetermined height position of the sheet pile 1. Then, the erection 7 is installed on the bracket 5, and the erection 7 is fixed to the sheet pile 1. Next, using the hoist ship 20 or the like, with the cut beam 8 disposed at a predetermined position between the opposed bulge 7 and the bulge 7, the jack 10 is extended to erection the cut beam 8. Keep it stretched between the two. Then, the cut beam 8 is erected and connected to 7. Next, a fire beam 9 is installed and reinforced around the intersection of the bulges 7 and around the intersection of the bulges 7 and the cut beam 8. As described above, the temporary support 3 is fixed to the sheet pile 1.

  Next, in the state where the water level WL1 of the water stop target water area WA1 and the water level WL2 of the non-target water area WA2 are substantially the same height position (for example, within 1 m or less), the water stop target water area WA1 is moved to the bottom G1 having a predetermined depth. Excavate. The bottom G1 is excavated by, for example, a grab dredger or a clamshell.

  In this embodiment, a communication hole 11 is formed at the upper end of the sheet pile 1. Water flows between the water-stopping target water area WA1 and the non-target water area WA2 through the communication hole 11. Therefore, the water level WL1 of the water stop target water area WA1 and the water level WL2 of the non-target water area WA2 are maintained at substantially the same height position at the upper end portion of the sheet pile 1. It is also possible to adjust the water level WL1 of the water-stop target water area WA1 and the water level WL2 of the non-target water area WA2 to be approximately the same height position using a pump or the like.

  Thus, in the present invention, the excavation process is performed in a state where the water level WL1 of the water-stopping target water area WA1 and the water level WL2 of the non-target water area WA2 are substantially at the same height position, so that the water pressure from both water areas acting on the sheet pile 1 is reduced. The deformation of the sheet pile 1 can be suppressed by balancing. In this embodiment, since the temporary support 3 is installed in the upper end part of the sheet pile 1, the water level WL1 of the water stop target water area WA1 is set to the non-target water area by excavating the water stop target water area WA1 to the bottom G1. Even when it is slightly lower than the water level WL2 of WA2, it is advantageous for the temporary support 3 to suppress the deformation of the sheet pile 1 due to water pressure. Therefore, the temporary support 3 is installed at the site where the deformation of the sheet pile 1 is likely to increase.

  Next, also in the bottom plate forming process illustrated in FIG. 5, following the excavation process, the water level WL1 of the water-stop target water area WA1 and the water level WL2 of the non-target water area WA2 are set to approximately the same height position. In the bottom plate forming step, first, a plurality of intermediate piles 4 are placed on the bottom G1 of the water stop target water area WA1. As the intermediate pile 4, for example, an H-section steel is used. The intermediate pile 4 is arrange | positioned in the position along the inner periphery of the large group support work 6 installed later. When the ground strength of the bottom G1 is insufficient, the ground strength of the bottom G1 is improved by a known ground improvement method.

  Next, the sand 13 is spread on the water bottom G1 of the water stop target water area WA1 and leveled. And underwater concrete is laid on the leveled sand 13 to form the bottom board 14, and then the temporary support 3 is removed from the sheet pile 1 and removed. In order to prevent material separation in water, underwater concrete uses, for example, underwater inseparable concrete to which an admixture such as an underwater inseparable admixture or a fluidizing agent is added.

  By forming the bottom board 14 in which the underwater concrete is solidified on the water bottom G1 of the water stop target water area WA1, the sheet pile 1 can be supported by the bottom board 14 in the horizontal direction. Thereby, a deformation | transformation of the sheet pile 1 can be suppressed more. The lower end of the intermediate pile 4 is firmly supported by the bottom board 14.

  Next, in the support work installation process illustrated in FIGS. 6 to 9, a plurality of large group support works 6 are installed at intervals in the vertical direction. First, as shown in FIG. 6, the brackets 5 are respectively attached to predetermined height positions where the intermediate pile 4 and the lowermost large support 6 of the sheet pile 1 are installed. Then, as shown in FIG. 7, the large assembly support 6 assembled in advance is submerged in the water-stopping target water area WA <b> 1 using the hoist ship 20 or the like and installed on the bracket 5. Underwater work is mainly performed by divers.

  As shown in FIG. 8, in this embodiment, a large fire-type support structure having a belly rise 7 and a fire beam 9 is used as the large group support structure 6. The fire beam 9 is a beam member that is slanted over the corner formed by the bulge 7. The large group support 6 is also provided with a beam 8 for reinforcing the erection 7 and the fire beam 9. An opening having a size that can accommodate a bridge pier 16 to be constructed in the future is formed in the central portion of the large support 6 in plan view. While placing the belly 7 on the bracket 5 attached to the sheet pile 1 and placing the fire beam 9 and the cutting beam 8 on the bracket 5 attached to the intermediate pile 4, a large support 6 is temporarily installed. To do.

  Next, as shown in FIG. 8, a large support for the sheet pile 1 is made by filling a filler 12 such as underwater concrete between the uplift 7 and the sheet pile 1 and solidifying the filler 12. 6 is fixed. This completes the installation of the one-stage large support structure 6. Similarly, by repeatedly performing the mounting work of the bracket 5, the setting work of the large structure supporter 6, and the filling work of the interstitial material 12, a plurality of pieces are spaced apart in the vertical direction from the lower stage to the upper stage as illustrated in FIG. 9. Set up a large support structure 6 of steps.

  Next, in the drainage process illustrated in FIG. 10, the water in the water-stopping target water area WA1 is made into a water-stopping working space DA in the air by discharging the water in the water-stopping target water area WA1 to the outside using a pump or the like. In this embodiment, since the communication hole 11 is formed in the sheet pile 1, the communication hole 11 is closed when performing a drainage process. Thus, the construction of the water stop working space DA is completed.

  After that, in the pier construction process illustrated in FIG. 11, the top plate 15 that forms the foundation of the pier 16 is formed by assembling the reinforcing bars on the bottom plate 14 and placing concrete. Then, a scaffold for constructing the pier 16 is constructed on the top plate 15. Next, the reinforcing bars constituting the lowermost stage of the pier 16 are assembled, and the formwork is installed outside the reinforcing bars. And the lowest stage of the pier 16 is constructed | assembled by placing concrete in a formwork. Similarly, the pier 16 is constructed sequentially from the lower stage to the upper stage by repeatedly assembling the reinforcing bars, installing the formwork, and placing the concrete.

  After the construction of the pier 16 is completed, water is poured into the water stop working space DA so that the water level W1 of the water stop target water area WA1 (water stop work space DA) is substantially the same as the water level WL2 with the non-target water area WA2. Say it. And the large group support work 6 is removed in the state which the water pressure from both water areas which act on the sheet pile 1 balanced. Subsequently, it cut | disconnects in the state which left the part embed | buried under the bottom G of the sheet pile 1, and removes the unnecessary part above it. The portion protruding above the top plate 15 of the intermediate pile 4 is also cut and removed. Finally, the construction of the pier 16 is completed as illustrated in FIG.

  In the present invention, as described above, since the large support 6 that has been assembled in advance as a support is submerged in the water-stopping target water area WA1 from the air, the conventional drainage work performed at each stage, assembling of the support in the field And installation work becomes unnecessary. As a result, the construction period can be greatly shortened as compared with the prior art. Conventionally, since the support work was installed from the upper stage to the lower stage, it was necessary to perform the installation work while avoiding the upper support work when installing the lower support work. Since the work 6 can be installed from the lower stage to the upper stage, the installation work of the large support structure 6 can be performed in a state in which a relatively wide work space is secured.

  In addition, in this embodiment, the large group support work 6 is configured by a large fire-type support work, and a large opening is formed in the central portion of the large structure support work 6, so when the pier 16 is constructed, As the construction progresses, it will not be necessary to relocate support works or scaffolds. Therefore, the construction period required for the construction of the pier 16 can be greatly shortened as compared with the conventional construction method in which a beam-type support is installed.

  Furthermore, in the present invention, since drainage is performed in a state where the bottom plate 14 and the support work (all-stage large support work 6) are functioning, the accumulated deformation amount of the sheet pile 1 due to water pressure is reduced as compared with the conventional method. be able to. Since the amount of accumulated deformation of the sheet pile 1 can be reduced, it is possible to reduce the number of stages of supporting works and the number of members as compared with the conventional case.

  When the bracket 5 is attached to the intermediate pile 4 and the sheet pile 1 at a predetermined height position, and then the large support structure 6 is submerged from the air into the water-stopping target water area WA1 and installed on the bracket 5, the bracket 5 As a result, positioning of the large support structure 6 can be performed with high accuracy.

  In the embodiment, the method of sequentially sinking one large group supporting work 6 assembled in advance in the supporting work installation step is exemplified. For example, a plurality of or all stages of large structure supporting works 6 are connected in advance. You can assemble it and sink it. Moreover, the large group support work 6 can also be comprised by a cut beam type support work etc.

  The present invention can also construct a water stop working space DA having an arbitrary shape such as a quadrangle, a circle, or an oval shape in a plan view. The configuration of the temporary support 3, the configuration of the large support 6, the position of the intermediate pile 4, the timing for placing the intermediate pile 4, and the like are not limited to the embodiment described above, and various configurations can be appropriately made. it can. In addition, the present invention is not limited to the case where the pier 16 is constructed, and may be employed, for example, when a column for wind power generation is constructed.

DESCRIPTION OF SYMBOLS 1 Sheet pile 2 Ruler material 3 Temporary support 4 Intermediate pile 5 Bracket 6 Large group support 7 Raise 8 Cut beam 9 Fire beam 10 Jack 11 Communication hole 12 Filling material 13 Laying sand 14 Bottom board 15 Top plate 16 Pier 20 Hoist Ship WA1 Water stop target water area WA2 Non-target water area DA Water stop working space G Water bottom G1 Water bottom WL1 Water stop target water level WL2 Water non-target water level

Claims (3)

A partitioning process of partitioning into a water stop target water area and a non-target water area by a plurality of sheet piles placed adjacent to the bottom of the water, and a support work in which a support is installed in the water stop target water area and the sheet pile is supported by the support work A water stop working space having an installation step and a draining step of making the water stop target water region into an air stop water work space by discharging the water in the water stop target water region where the support is installed to the outside. In the construction method,
Between the partitioning step and the support installation step, the bottom of the water stop target water area is excavated to a predetermined depth with the water levels of the water stop target water area and the non-target water area located at the upper end of the sheet pile. And a bottom plate forming step in which a plurality of intermediate piles are placed on the bottom of the water after the excavation, and then a bottom plate is formed by placing underwater concrete on the bottom of the water. In the installation process, using a large group supporting work assembled in advance as the supporting structure, the large structure supporting structure is submerged from the air into the water-stopping target water area, and the intermediate pile is supported by the large structure supporting structure. In the state of being arranged at a position along the inner peripheral edge of the water stop working space, the large support structure is placed and installed on a bracket attached to each of the sheet pile and the intermediate pile . Construction method. A partitioning process of partitioning into a water stop target water area and a non-target water area by a plurality of sheet piles placed adjacent to the bottom of the water, and a support work in which a support is installed in the water stop target water area and the sheet pile is supported by the support work A water stop working space having an installation step and a draining step of making the water stop target water region into an air stop water work space by discharging the water in the water stop target water region where the support is installed to the outside. In the construction method,
Between the partitioning step and the support installation step, the bottom of the water stop target water area is excavated to a predetermined depth with the water levels of the water stop target water area and the non-target water area located at the upper end of the sheet pile. multiple drilling and step, and a bottom plate forming a bottom plate and Da設underwater concrete over the bottom of the water after the drilling, in the shoring setting step, which are assembled in advance as the shoring that using a large set支保Engineering, features that subjected upper these large set支保Engineering from the lower, are sequentially sinking from in the air to the water stop target water area, placing the large set支保Engineering plurality of stages The construction method of the water stop working space. The construction method of the water stop working space according to claim 1 or 2 , wherein the large group support work is a large fire-type support work.

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