JP6010070B2 - Temporary closing method for existing underwater structures - Google Patents

Description

  The present invention is an existing underwater structure in which the work is carried out by temporarily closing the periphery of the underwater structure with a steel panel etc. and draining the inside of the underwater structure such as a bridge pier for investigation, repair, reinforcement, etc. This relates to the temporary cut-off method for objects.

  Conventionally, as a temporary work for surveying, repairing and reinforcing existing underwater structures such as river piers and underwater bridges, steel sheet piles have been driven from a baseboard or the like outside the foundation of existing underwater structures. In addition to drawing up the water inside and draining it, the work was carried out by constructing a dry work area by dripping all the earth and sand.

  However, the steel sheet pile has a narrow width, which inevitably increases the number of places to be driven, and there is a problem that it cannot be constructed in an environment where there are severe restrictions on the empty head. Moreover, since the short steel sheet pile once used becomes scrap handling, there also existed a problem that it was uneconomical. Furthermore, there are concerns about river blockage and securing of the channel during construction, and if the ground is soft ground by driving steel sheet piles, the depth of rooting becomes deep, the construction period becomes longer, and construction costs increase. There was also a problem.

  In addition, as a temporary closing method without using a steel sheet pile, for example, in Patent Document 1, the outer periphery of the pier 1 is bent and bent by the cylindrical temporary cutting wall 14, the inside is drained, and the reinforcement work is performed. In the temporary closing method in which the temporary cutoff wall 14 is removed after completion, the temporary cutoff wall 14 is divided into a plurality of panel units 16 divided in the vertical direction along the circumferential direction, and the temporary cutoff wall 14 is formed. The guide frame 10 is installed on the footing 2 part of the pier 1 and the panel unit 16 is suspended and supported so that the inner surface side of each panel unit 16 is locked to the guide frame 10. Water-tightness is secured by fixing the water to the bottom ground 3 along the outer periphery of the footing part 2 by pouring concrete and interposing panel seals 16 between adjacent panel units 16 in the circumferential direction. While ensuring Disclosed is a temporary cut-off method in which the nell units 16 are connected in the circumferential direction to form a cylindrical shape (claim 1 of patent document 1, paragraphs 0018 to 0042 of the specification, FIG. 1 of the drawings). ˜22 etc.).

  However, in the temporary closing method described in Patent Document 1, because the temporary closing wall 14 is installed outside the footing portion 2 of the pier 1, it is necessary to make a dredge in advance until the top end of the buried footing portion 2 is exposed. Depending on the ground, it was necessary to drive an underwater earth retaining wall (steel sheet pile) 5. Therefore, when the earth covering to the top edge of the footing part 2 is deep, as with the conventional construction method using steel sheet piles, there are adverse effects on neighboring structures and pollution of neighboring environments such as rivers, etc. In addition to concerns about environmental issues, there was a problem that the cost of the dredging treatment increased.

  Further, as developed by the applicant of the present application, Patent Document 2 includes (1) a step of installing a press-fitting reaction force means on an existing structure in water, and (2) a plurality of divisions on the outer periphery of the existing structure. Connecting the cut-off steel plates in the circumferential direction to form a lowermost reinforcing ring body, and (3) installing a press-fitting girder and a press-in jack on the lowermost reinforcing ring body, A step of press-fitting into the bottom of the ground through a press-fitting reaction force means, a press-in jack, and a guide member; (4) a step of excavating the bottom of the bottom of the ground closed by the lowermost reinforcing ring; and (5) a press-fitting girder and press-fitting Removing the jack, assembling the next reinforcing ring body, connecting the second-stage reinforcing ring body to the top of the lowermost reinforcing ring body, and (6) a press-fitting girder on the second-stage reinforcing ring body Install the press-fit jack, the lowermost reinforcing ring body and the second-stage reinforcing ring. A step of press-fitting the body into the foundation, and (7) repeating the above-described steps, and a step of press-fitting the reinforcing ring body from the top of the bottom of the bottom to the desired depth in the bottom of the bottom, and (8) from the top of the reinforcing ring. A step of installing a ring-shaped liner plate or steel ring as a cut-off member extending to the surface of the water; and (9) from the top of the bottom floor in a space surrounded by the reinforcing ring body and the ring-shaped liner plate or steel ring. Excavating to a desired depth, attaching a water-stopping material, placing water-stopping concrete, drawing water in the temporary shut-off structure and forming a dry work space, and having an existing structure in water A temporary cut-off method of an object is disclosed (see claim 7 of patent document 2, paragraph 0016 of the specification, FIG. 3 of the drawing, etc.).

  However, the temporary closing method for an existing structure in water described in Patent Document 2 has a problem in that it cannot cope with a change in the cross-sectional shape of the pier, although the range of the trough is limited. In addition, there is a problem that the steel ring body 5 cannot be accurately press-fitted when it is press-fitted into the underwater ground.

JP 2003-232044 A JP 2005-264500 A

  Therefore, the present invention has been devised in view of the above-described problems, and the object of the present invention is to minimize the range of dredging and reduce the man-hours and work period without adversely affecting the environment. The provisional construction method for existing underwater structures that can be accurately pressed into the underwater ground as well as responding to changes in the cross-sectional shape of the pier can be provided. There is to do.

  The temporary closing method for an existing underwater structure according to the first invention is a temporary closing method for an existing underwater structure in which the periphery of the existing underwater structure such as a pier is closed with a temporary closing body and the interior is drained to perform the main construction. A reaction force bracket installation step for installing a reaction force bracket for obtaining a reaction force from the existing underwater structure when the deadline temporary structure is press-fitted into the underwater ground; The cut-off temporary body press-fitting and excavating step of digging the underwater ground inside the cut-off temporary body while press-fitting the cut-off temporary body into the underwater ground with a press-fit jack while obtaining a reaction force from the existing underwater structure with a force bracket And a guide bracket having a roller member or a slidable contact member at a tip that contacts the temporary cut-off temporary body, and lowering the temporary cut-off temporary body while guiding it. To.

The temporary closing method for an existing underwater structure according to the second aspect of the present invention is the temporary cutting bracket installation step of installing a temporary receiving bracket as a temporary receiving base for initial assembly of the cutoff temporary structure in the first aspect of the invention. An initial assembly process of a temporary cut-off body for assembling one or more stages from the lowest stage of the cut-off temporary structure on the bracket, and the tip of the temporary receiving bracket is replaced with a roller member or a sliding contact member, and the temporary receiving bracket is used as the guide bracket. A bracket tip replacement step to be changed; and a settling step for the cutoff temporary body that sinks while guiding the cutoff temporary body with the guide bracket.

A temporary closing method for an existing underwater structure according to a third invention is the lower part of the first invention or the second invention , having a roller member or a sliding contact member at a lower end of the cutoff temporary body at a tip abutting the temporary cutoff body. A lower guide bracket attaching step for attaching a guide bracket is provided, and when the cut-off temporary structure is press-fitted into the underwater ground by a press-fitting jack, the lower guide bracket guides.

  A temporary closing method for an existing underwater structure according to a fourth invention is the method according to the third invention, wherein water-stopping concrete is placed at a lower end of the cutoff temporary structure while the lower guide bracket holds the temporary cutoff body so as not to move. It has the water-stop processing process to perform.

Provisional deadline method of existing underwater structure according to the fifth invention, in any one of the first invention to fourth invention, since the pull out the deadline temporary body to obtain a reaction force from the footing of the existing underwater structures A drawing steel material installation step of installing the drawing steel material, and a drawing step of the cut-off temporary body for drawing out the cut-off temporary structure using the drawing steel material.

  According to the first to fifth inventions, it is only necessary to scoop the inside of the temporary cut-off temporary body that is the work space for the construction work, so that the scissor range is minimized and the environment is less adversely affected. . Further, since the cutoff temporary structure is lowered while being guided by the guide bracket, it is not necessary to assemble a large scaffold as in the invention described in Patent Document 1, and the water flow is applied when the cutoff temporary structure is landed. The deadline temporary body is less likely to tilt and is extremely safe. Moreover, according to the first to fifth inventions, since the guide is guided by the guide bracket, it is possible to cope with the case where the cross-sectional shape of the pier changes, and it is possible to accurately press-fit into the underwater ground.

In particular, according to the second invention, the initial assembly of the cut-off temporary structure can be performed using the temporary receiving bracket. For this reason, it is easy to assemble the cut-off temporary structure even in a confined place subject to the empty head restriction or even when the suspended load is rotated by wind or the like. In addition, the tip of the temporary support bracket can be changed to a guide bracket to accurately guide the position of the deadline temporary body upon landing, so that the work period can be further reduced and the construction cost can be reduced.

In particular, according to the third aspect of the present invention, when the cut-off temporary structure is pressed into the underwater ground by the press-fitting jack, the lower guide bracket guides the press-fitting of the cut-off temporary structure into the underwater ground accurately and guides vertically downward. And can be press-fitted smoothly without receiving unnecessary resistance. For this reason, the work period can be further reduced to reduce the construction cost. Moreover, the case where the cross-sectional shape of a pier changes by changing the length of a lower guide bracket can also be coped with.

  In particular, according to the fourth aspect of the present invention, the waterproof concrete is placed at the lower end of the cutoff temporary body while the lower guide bracket holds the cutoff temporary body so that it does not move. It is possible to temporarily fix the cut-off temporary structure so that it does not move due to the water flow during curing, and to prevent the water-stopping concrete from solidifying well.

  In particular, according to the fifth aspect of the invention, the temporary cut-off body can be pulled out using the steel for drawing. For this reason, the dismantling / removal work of the temporary cut-off temporary body can be easily performed in a short time. For this reason, the work period can be further reduced to reduce the construction cost.

It is a perspective view which shows the existing underwater structure and deadline temporary structure which concern on embodiment of this invention. It is a vertical sectional view along the width direction of the bridge showing the existing underwater structure and the deadline temporary structure. It is a top view which shows the existing underwater structure and deadline temporary structure same as the above. It is a vertical sectional view along the axial direction of a bridge showing the existing underwater structure and the deadline temporary structure. It is explanatory drawing which looked at the bridge pier which shows the (1) assembly type float installation process of the temporary closing method of the existing underwater structure which concerns on embodiment of this invention in the width direction of the bridge. It is explanatory drawing which shows the (2) overhead crane installation process of the temporary closing method of the existing underwater structure same as the above. It is explanatory drawing which shows the (3) reaction force bracket installation process of the temporary closing method of the existing underwater structure same as the above. It is explanatory drawing which shows the (4) temporary receiving bracket installation process of the temporary closing method of the existing underwater structure same as the above. It is a side view which mainly shows the provisional receiving bracket installed in the process same as the above. It is explanatory drawing which shows the initial stage assembly process of the (5) deadline temporary structure of the temporary deadline construction method of the existing underwater structure same as the above. It is a side view which mainly shows the guide bracket assembled in the tip replacement process of the temporary closing method of the existing underwater structure same as the above (6) bracket tip replacement process. It is explanatory drawing which shows the sedimentation and assembly process of the (7) deadline temporary structure of the temporary deadline construction method of the existing underwater structure same as the above. It is explanatory drawing which shows the (8) lower guide bracket attachment process of the temporary closing method of the existing underwater structure same as the above. It is explanatory drawing which shows the (9) assembly, press-fit, and excavation process of the temporary closing method of the existing underwater structure same as the above. It is explanatory drawing which shows the state which the (9) press-fit and excavation process same as the above completed. It is explanatory drawing which shows the (10) water stop process of the temporary closing method of the existing underwater structure same as the above. It is explanatory drawing which shows the (11) drainage process of the temporary closing method of the existing underwater structure same as the above. It is explanatory drawing which shows the installation process of the steel material for (12) water injection and drawing of the temporary closing method of the existing underwater structure same as the above. It is explanatory drawing which shows the drawing-out and dismantling process of the (13) deadline temporary structure of the temporary deadline construction method of the existing underwater structure same as the above. It is explanatory drawing which shows the (14) backfilling process of the temporary cutoff method of the existing underwater structure same as the above. It is explanatory drawing which shows the removal process of (15) other temporary installations of the temporary closing method of the existing underwater structure same as the above.

  Hereinafter, an embodiment for carrying out a temporary closing method for an existing underwater structure according to the present invention will be described in detail with reference to the drawings. In addition, the pier of the road bridge crossing a river is illustrated and demonstrated as an existing underwater structure.

[Outline of the temporary cut-off body]
First, with reference to FIGS. 1 to 4, an overall outline of a cut-off temporary body temporarily installed by a temporary cut-off method for an existing underwater structure will be described. As shown in FIGS. 1 and 3, etc., a temporary cut-off body 1 that is temporarily installed by a temporary cut-off method for an existing underwater structure has a plurality of arc-shaped cut-off members 2 in a plan view made of a steel material along the circumferential direction. It is a combined cylindrical structure, and the horizontal cross section of the pier P is installed with a space around the oval-shaped column part P1, and the water inside the pier P is pumped to investigate and repair the pier P. The purpose is to construct a dry work area with the pier P for the main work such as reinforcement.

  The pier P, which is an existing underwater structure, is mainly composed of a column part P1 having an oval horizontal cross section and a beam part P2 projecting left and right above the column part P1, and is a T-shaped pier in front view. The pillar portion P1 is fixed to the ground via a circular footing F and a foundation pile (not shown) in plan view. In the figure, the X direction indicates the bridge axis direction of the bridge, the Y direction indicates the width direction of the bridge, and the Z direction indicates the vertical direction.

  The cut-off temporary body 1 will be described in detail later, and as shown in FIGS. 2 and 4 and the like, the reaction force bracket 3 attached to the column portion P1 of the pier P obtains a reaction force from the column portion P1, while The press-in jack 4 made of a jack is pressed into each lot until the lower end reaches the top end of the footing F of the pier P, and is constructed by placing water-stopping concrete 5 inside the lower end. In addition, as shown in the figure, the left and right and the vertical direction of the cutoff member 2 are reinforced with a reinforcing steel material in addition to being connected with bolts or the like.

  Moreover, although the cylindrical thing was illustrated as the cut-off temporary structure 1, of course, it is good also as an oval shape according to the pillar part P1 made into an oval shape, and when a pillar part is a horizontal cross-section rectangle, it is plane according to it. A rectangular frame may be used. In short, the shape of the temporary cut-off body may be a shape that can secure an appropriate work space according to the shape of the existing underwater structure or the main work.

  The cut-off member 2 made of steel is exemplified as the cut-off member constituting the cut-off temporary body, but of course, it may be made of PC (precast concrete) material or other metal material. In short, the material and the like are not limited to steel as long as the cutoff member and the temporary cutoff body have rigidity and water tightness that can withstand water pressure and earth pressure to form a fixed working space. However, in view of versatility, economy of repeated use, etc., it can be said that a steel material is preferable.

[Temporary cut-off method for existing underwater structures]
Next, the temporary closing method for the existing underwater structure according to the embodiment of the present invention will be described with reference to FIGS. In addition, the existing underwater structure etc. are the same as that of having demonstrated with the above-mentioned temporary cut-off temporary body, The same code | symbol is attached | subjected and description is abbreviate | omitted.

(1) Assembly-type float installation process First, as shown in FIG. 5, the assembly-type float 6 is installed around the pier P as a scaffold for work. The assembly type float 6 is a rectangular frame shape in plan view in which a plurality of floats having a rectangular shape in plan view are combined with the pier P as a center, and functions as a scaffold for lifting members and the like.

(2) Overhead Crane Installation Step Next, as shown in FIG. 6, the necessary number of overhead cranes 7 for installing and transporting materials are installed under the bridge girder with a sky head restriction. The overhead crane 7 is an electric hoist or the like, and may be a non-electric power such as a winch as long as the ascending or descending operation can be performed from the assembly type float 6. In addition, the overhead crane 7 may be attached easily with a clamp or the like, or may be configured to be horizontally movable on the runway.

(3) Reaction Force Bracket Installation Step Next, as shown in FIG. 7, the reaction force bracket 3 for obtaining a reaction force from the pier P when press-fitting the temporary cut-off temporary body 1 is provided on the upper portion of the column portion P1 of the pier P. Install. The reaction force bracket 3 is a steel bracket, and is fixed to the pillar portion P1 by a post-installed anchor such as a chemical anchor using a hole drilled in the pillar portion P1. Moreover, it is preferable that the reaction force bracket 3 is provided at a height directly below the beam portion P2 that is limited to the empty head so that a sufficient lifting space can be obtained at the upper portion of the column portion P1. The number of installations may be the required number, but in the present embodiment, a total of 6 one by two on the front and back sides of the pier P viewed in the direction of the bridge axis, and one on each side directly below the beam part P2. The base is installed (see Fig. 3). Note that the reaction force bracket 3 is illustrated with the wand positioned below, but needless to say, the illustrated one may be upside down.

(4) Temporary Bracket Installation Step Next, as shown in FIG. 8, the temporary bracket 8 is used as a temporary support for assembling the cutoff temporary structure 1 so that the column P1 side of the pier P becomes the base end. Install and install on P1. As shown in FIG. 9, the temporary bracket 8 is a steel bracket, and a temporary receiving member 8 a serving as a temporary holder is connected to the tip of the bracket by bolting. In this temporary receiving member 8a, a receiving piece 8c made of H-shaped steel serving as a temporary receiving base is welded to the upper surface of an extending member 8b extending the beam material of the bracket. In addition, when the water depth of the bridge pier P is shallow, it is also possible to assemble a scaffolding on the outer side of the temporary cut-off temporary body and install the temporary support bracket 8 so that the scaffolding becomes a base end part.

  The installation height of the temporary bracket 8 is determined in consideration of the number of steps of the cutoff temporary body 1 assembled on the temporary bracket 8, the separation distance from the reaction force bracket 3, the size of the press-fit jack 4, and the like. is there. As shown in FIG. 8, the installation height of the temporary bracket 8 according to the present embodiment is equal to or lower than the water level at the time of construction. Therefore, the temporary bracket 8 is provided with a plurality of post-construction anchors A ( It is attached to the pillar portion P1 by being bolted to (see FIG. 9).

(5) Initial Assembly Process of Cut-off Temporary Body Next, as shown in FIG. 10, on the temporary receiving bracket 8 installed in the previous process, the lowermost cut-off member 2 ′ and the second stage (2 Assembling the lot member 2), the temporary cut-off body 1 having two stages is constructed. Of course, the number of steps (number of lots) for assembling the temporary cut-off body here may be determined appropriately according to the empty head limit, the height at which the reaction force bracket 3 can be installed, the water level at the time of construction, and the like.

  Thus, the cut-off temporary structure 1 is assembled on the temporary bracket 8 supported by the pillar portion P1 of the pier P, which is an existing structure, not on the assembly type float 6 that swings up and down and left and right due to waves and winds. Work efficiency such as bolting, lifting and unloading of parts can be greatly improved, construction period can be shortened and construction costs can be reduced, and safety can be improved significantly.

(6) Bracket Tip Replacement Process Next, the temporary cut-off temporary body 1 assembled up to the second stage is once lifted by the overhead crane 7, and then the bolts that have been tightened are removed and the tip of the temporary bracket 8 shown in FIG. The temporary receiving member 8a is replaced with a roller member 8a 'shown in FIG. 11, and the temporary receiving bracket 8 is changed to the guide bracket 8'. As shown in FIG. 11, the guide bracket 8 ′ guides the temporary cut-off temporary body 1 by a roller member 8 a ′ having a plurality of roller mechanisms so as to slide without damaging the inner wall of the cut-off temporary temporary body 1. It has a function.

  The guide bracket 8 'is made of a stainless steel plate or wear-resistant resin (6 nylon with improved wear resistance: (registered trademark) MC nylon, etc.) instead of a roller-joined member such as the roller member 8a'. An equivalent function can also be exhibited as a sliding contact member that is in sliding contact with the inner wall of the temporary cut-off temporary body 1 by a mechanism that reduces the frictional resistance with a curved surface structure composed of the like.

(7) Settling and assembly process of deadline temporary body Next, as shown in FIG. 12, the deadline temporary body 1 assembled up to the second stage is attached to the roller member 8a 'of the guide bracket 8' and the inner wall of the deadline temporary body 1 is attached. While sliding and guiding, it is suspended by the overhead crane 7 to a height at which the third stage can be assembled, and is landed and settled (down) in the water. Then, the third stage (third lot) of the temporary cut-off temporary body 1 is assembled using the space formed above.

  In this way, when the deadline temporary body 1 is submerged in water and settled (lowered), it can be settled while being guided by the guide bracket 8 ′. Without being pushed away by the water flow, the cutoff temporary body 1 can be vertically lowered efficiently and safely in a short time. In addition, when assembling the third stage (third lot) of the temporary cut-off body 1, since it is guided by the guide bracket 8 ', the shaking is remarkably reduced and the working efficiency of the assembling work is improved.

(8) Lower Guide Bracket Attaching Step Next, as shown in FIG. 13, the temporary cut-off temporary body 1 is settled, the fourth stage of the final cut-off temporary body 1 is assembled, and the lower part of the temporary cut-off temporary body 1 (this embodiment) Then, the lower guide bracket 9 is attached to the second stage), and the lower end of the cutoff temporary body 1 is grounded to the underwater ground. In addition, when the distance from the water level at the time of construction to the top of the underwater ground is deep, the above-described settling and assembling of the temporary cut-off body 1 is repeated as many times as necessary.

  The lower guide bracket 9 has substantially the same configuration as the guide bracket 8 ′ shown in FIG. 11 except that the base end side of the bracket is the inner wall of the cutoff temporary structure 1. The abutting tip is a roller member 9a having the same configuration as the roller member 8a ′. The lower guide bracket 9 has a function of guiding a lower end, which is a cutting edge portion at the time of press-fitting the cutoff temporary structure 1, vertically downward along the column portion P <b> 1. In addition, when the cross-sectional shape of the pier changes, for example, the pillar portion of the pier is tapered, it is preferable to guide while changing the length of the lower guide bracket 9.

(9) Assembly / Press-fit / Drilling Step Next, as shown in FIG. 14, the cut-off temporary structure 1 is moved by the press-fit jack 4 while the reaction force bracket 3 attached to the column P1 obtains a reaction force from the column P1. Press fit into the underwater ground. In this embodiment, in order to adjust the interval and prevent the temporary cut-off temporary body 1 from being damaged, a biting material such as a square member (end thick corner) or a steel material is engaged between the press-fit jack 4 and the upper end of the cut-off temporary set 1. Moreover, it is press-fitted with a press-fitting jack 4.

  In parallel with the press-fitting operation of the temporary cut-off body 1, the ground inside the cut-off temporary body 1 is excavated or dredged (soiled) by a diver D using a vacuum pump or the like.

  Then, the next stage (the fifth stage in the figure) of the cutoff temporary body 1 is assembled using the upper space vacated by the press-fitting. In this way, the assembly, press-fitting and excavation steps are repeated until the lower end of the cutoff temporary body 1 reaches the top end of the footing F of the pier P. FIG. 15 shows a state where the top end of the footing F has been reached.

(10) Water stop treatment step Next, as shown in FIG. 16, the underwater mold is installed by the diver D, and the water stop concrete 5 is driven into the gap between the lower end of the cutoff temporary body 1 and the underwater mold. Set up. At this time, since the lower guide bracket 9 exists immediately above the water-stopping concrete 5, it can be temporarily fixed so that the cut-off temporary body 1 does not move due to a water flow when the water-stopping concrete 5 is placed and cured. It is possible to prevent the water concrete 5 from being hardened well. That is, the lower guide bracket 9 also has a function as a support work for holding the mold frame until the water-stopping concrete 5 is hardened.

(11) Drainage process Next, as shown in FIG. 17, after the waterproofing concrete 5 is hardened, the lower guide bracket 9, the reaction force bracket 3, the press-fit jack 4, and the like are removed using the overhead crane 7 or the like. And the drainage in the deadline temporary body 1 is drained using a pump etc., and a dry work area is constructed between the bridge piers P.

  After that, the main work such as investigation, repair, reinforcement and the like of the bridge pier P is performed such as wrapping a reinforcing member P3 (for example, a reinforcing steel plate) (see FIG. 18) around the pier P for earthquake resistance reinforcement. At this time, the guide bracket 8 'is also removed according to the progress of the main work.

(12) Water Injection and Pulling Steel Material Installation Step Next, as shown in FIG. 18, a drawing steel material 10 for pulling out the cut-off temporary body 1 by obtaining a reaction force from the footing F is applied to the inner wall of the cut-off temporary body 1. Along the footing F of the pier P along. In addition, a drawing jack 11 made of a hydraulic jack is installed on the uppermost stage of the drawing steel material 10, and a drawing piece 2 a is attached to the upper end of the cutoff temporary structure 1.

  Subsequently, the surrounding water is poured into the cutoff temporary body 1 using a pump or the like. Together with the water injection, the lowermost bolt connecting the cut-off temporary structure 1 is cut by the diver D, and only the first cut-off member 2 'is cut off.

(13) Drawing-off and dismantling process of the cut-off temporary body Next, as shown in FIG. 19, using the pull-out jack 11, the cut-off temporary body 1 is pulled out leaving only the lowermost cut-off member 2 'and disassembled sequentially from the upper stage. Go. Moreover, the drawing piece 2a is refilled each time and attached to the uppermost stage.

(14) Backfilling step Next, as shown in FIG. 20, after the cut-off temporary body 1 is pulled out and disassembled, the place where the cut-off temporary body 1 was located is backfilled according to the original underwater ground. At this time, the lowermost cut-off member 2 ′ and the water-stopping concrete 5 that have been pulled out are backfilled together. However, the cut-off member 2 ′ and the water-stopping concrete 5 may be removed in consideration of various conditions such as economy, process, and covering.

(15) Other Temporary Removal Process Finally, as shown in FIG. 21, other temporary objects such as the overhead crane 7 and the assembly float 6 are removed, and the temporary undercutting method for the existing underwater structure according to the present embodiment. Ends.

  According to the above-described temporary closing method for an existing underwater structure according to the embodiment of the present invention, only the inside of the temporary closing body 1 that becomes the work space of the main work needs to be scooped, so that the scissor range is minimized. And less harmful to the environment. In addition, the guide bracket 8 'guides the cut-off temporary body 1 while settling or press-fitting (lowering), so there is no need to assemble a large scaffold, and when the cut-off temporary body 1 is landed, the cut-off temporary body 1 is temporarily set by water flow. There is little possibility that the body 1 tilts, and it is extremely safe and the work period can be reduced.

  Further, when the deadline temporary body 1 is pressed into the underwater ground by the press-fit jack 4, it is guided by the lower guide bracket 9, so that the press-fitting of the deadline temporary body 1 into the underwater ground can be accurately guided and guided vertically downward. It is possible to press-fit smoothly without receiving unnecessary resistance. For this reason, a work period can be reduced and construction cost can be reduced.

  In addition, according to the temporary closing method of the existing underwater structure according to the present embodiment, the initial assembly of the temporary closing body 1 can be performed using the temporary receiving bracket 8. For this reason, it is easy to assemble the cut-off temporary structure 1 even in a narrow place where the head is limited or even when the suspended load is rotated by wind or the like. In addition, the tip of the temporary support bracket 8 can be changed to a guide bracket 9 to accurately guide the position of the deadline temporary body 1 upon landing, thereby further reducing the work period and reducing the construction cost. Can do.

  Furthermore, since the cut-off temporary body 1 can be pulled out by the pull-out jack 11 using the steel material 10 for drawing, the dismantling / removal work of the cut-off temporary body 1 can be easily performed in a short time. For this reason, the work period can be further reduced to reduce the construction cost.

  As mentioned above, although the temporary closing method of the existing underwater structure which concerns on embodiment of this invention was demonstrated in detail, all the embodiment mentioned above or illustrated was implemented in implementing this invention. However, the technical scope of the present invention should not be construed in a limited manner.

  In particular, the various brackets are not limited to those having a cane, and may be strips provided on a simple wall surface. The press-fit jack 4 and the pull-out jack 11 are not limited to hydraulic jacks, and may be other power mechanisms such as an electric cylinder. It is clear that even such a mechanism or member has the above-described effects.

P: Pier P1: Column P2: Beam P3: Reinforcement member F: Footing 1: Closing temporary body 2: Closing member 2a: Pull-out piece 3: Reaction force bracket 4: Press-in jack 5: Waterproof concrete 6: Assembling type float 7: Overhead crane 8: Temporary receiving bracket 8a: Temporary receiving member 8 ': Guide bracket 8a': Roller member 9: Lower guide bracket 9a: Roller member 10: Pulling steel 11: Pulling jack

Claims (5)

A temporary closing method for an existing underwater structure such as a bridge pier and the like that is closed by a temporary cut-off body and draining the inside of the underwater structure to perform the main work.
A reaction force bracket installation step of installing a reaction force bracket on the upper part of the existing underwater structure to obtain a reaction force from the existing underwater structure when the deadline temporary structure is press-fitted into the underwater ground;
While receiving reaction force from the existing underwater structure with the reaction force bracket, press-fit the deadline temporary body into the underwater ground with a press-fitting jack, and excavate the underwater ground inside the deadline temporary body. A drilling process,
A temporary cutoff method for an existing underwater structure, wherein the cutoff temporary structure is lowered while being guided by a guide bracket having a roller member or a sliding contact member at a tip abutting against the temporary cutoff body. A provisional bracket installation step of installing a provisional bracket as a provisional base for initial assembly of the deadline provisional body;
An initial assembly step of a cutoff temporary structure for assembling one or more stages from the lowest level of the cutoff temporary structure on the temporary bracket;
A bracket tip replacement step in which the tip of the provisional bracket is replaced with a roller member or a sliding contact member to change the provisional bracket to the guide bracket;
The temporary closing method for an existing underwater structure according to claim 1, further comprising: a sinking step of a cutoff temporary body that sinks while guiding the cutoff temporary body with the guide bracket. A lower guide bracket attaching step for attaching a lower guide bracket having a roller member or a sliding contact member at a tip abutting on the deadline temporary body at a lower portion of the deadline temporary body;
The temporary undercutting method for an existing underwater structure according to claim 1 or 2, wherein the lower cutout temporary structure is guided by the lower guide bracket when being pressed into the underwater ground by a press-fit jack. The existing underwater according to claim 3, further comprising: a water stopping treatment step of placing water stopping concrete on a lower end of the cutoff temporary body while holding the temporary suspension body so as not to move by the lower guide bracket. A temporary cut-off method for structures. And withdrawing steel material placing step of placing a pulling steel material for pull out the deadline temporary body to obtain a reaction force from the footing of the existing underwater structures,
The temporary undercutting method for an existing underwater structure according to any one of claims 1 to 4, further comprising: a pulling-out process of a cut-off temporary body that pulls out the temporary cut-off temporary body using the steel material for drawing.