JP2019143295A - Method for construction of oil protective barrier and installation jig - Google Patents

Abstract

To provide a method for constructing an oil protective barrier excellent in economy, and to provide an installation jig used for the method.SOLUTION: Provided are the method for constructing a liquid barrier comprising: an inner form forming step for forming an inner form by connecting a plurality of segments; an outer form forming step for installing an outer form on the outer side of the inner form with a gap from the inner form; and a placing step for placing concrete between an inner form and an outer form to form a concrete wall part, and an installation jig 4 for use in the method. A plurality of bolt holes through which a fixing bolt 43 for fixing to a foundation is inserted are formed on a lower part of the installation jig 4, and an adjustment bolt 44 screwed to the back surface of the segment is provided on the upper end part so as to be capable of advancing and retracting.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a method for constructing a breakwater and an installation jig.

As a method of constructing a breakwater (wall body) for above-ground LNG tanks and underground LNG tanks, an inner frame (steel liner plate, precast concrete segment, etc.) is installed at a position that becomes the inner peripheral surface of the wall body There is known a method in which an outer mold is installed at a position to be an outer peripheral surface of a wall, and concrete is placed between the inner mold and the outer mold (for example, see Patent Document 1). The inner mold is a so-called remaining mold and is left as it is after the concrete is hardened.
The inner formwork (segment) is assembled by an operator in a temporary scaffold while supporting the segment with a temporary support member or the like. However, it takes time to install the temporary scaffold and the temporary support member. Further, since the temporary scaffold and the temporary support member are assembled from the ground part, it is necessary to secure a sufficient space around the wall body.
For this reason, as shown in Patent Document 1, the present applicant has developed a method for constructing a breakwater using a multipurpose post that remains in the wall and has been put to practical use. In this construction method of the breakwater, the segment and the scaffold are supported by a multipurpose post erected in advance at a predetermined position, thereby eliminating the time and labor required for installing and removing the temporary scaffold and the temporary support member. Moreover, in this construction method of a breakwater, it is not necessary to secure a site for installing a temporary member around the wall body.

JP 2014-58793 A

Since the multipurpose post remains in the wall, the amount of steel for the multipurpose post increases, which is expensive. In addition, since the wall thickness increases as multipurpose posts are placed, the amount of concrete in the breakwater increases (that is, the weight of the breakwater increases). May increase.
An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to propose a construction method of a breakwater excellent in economy and an installation jig used therefor.

In order to solve the above-mentioned problem, the construction method of a breakwater according to the present invention includes an inner mold forming step of connecting a plurality of segments to form an inner mold, and a gap from the inner mold, An outer mold forming step for installing an outer mold outside the inner mold, and a placing step for forming a concrete wall by placing concrete between the inner mold and the outer mold. ing. In the inner mold forming step, the standing work for standing the segment on the existing inner mold left on the inner surface of the existing part of the concrete wall, and the installation treatment fixed to the existing inner mold The inner mold is formed by repeating a supporting operation for supporting the segments with a tool and a connecting operation for connecting adjacent segments. In the placing step, concrete is placed after the installation jig is removed from the inner mold.
According to the construction method of the liquid breakwater, since the temporary steel material (support member) used when forming the inner mold is not left inside the wall body, the amount of steel material can be reduced. . Further, since the installation jig is attached to the inner mold, it is not necessary to secure a site for installing the temporary member around the wall body. In addition, by using the installation jig, the inner mold can be assembled with high accuracy. If an aluminum alloy or the like is used as a material constituting the installation jig, the installation jig can be reduced in weight. If the installation jig is lightweight, it can be attached and detached manually on the scaffold.

In the supporting operation, it is desirable to adjust the inclination of the segment using the installation jig after the installation jig is fixed to the existing inner formwork. According to the construction method of such a breakwater, since the inclination of the segment can be easily adjusted, the workability is excellent.
Further, in the inner mold forming step, after connecting a predetermined number or more of the segments, the installation jig is removed from one of the segments and the installation jig is supported by the new segment. It is desirable to use it. In such a construction method of a breakwater, after a plurality of segments are connected to stabilize the shape, an installation jig used to support an existing segment is used to support another segment. By doing so, it is possible to reduce the number of installation jigs, and to reduce the material cost.

The installation jig of the present invention is used when a plurality of segments are connected to form an inner mold, and a plurality of fixing bolts for fixing the segments to a base on which the segments are mounted are inserted. Bolt holes are formed in the lower part, and an adjusting part for adjusting the inclination of the segment is formed in the upper part. If the lower part of the installation jig is fixed to the base, the segment can be supported and the inclination of the segment can be adjusted. Therefore, compared with the case where a temporary support member is separately installed, the labor required for the segment installation work can be omitted.
The configuration of the adjustment unit is not limited. For example, an adjustment bolt that can be advanced and retracted with respect to the adjustment unit and screwed to the back surface of the segment may be provided, and a jack is attached. For this purpose, a jack base or a locking part for attaching the chain block may be formed. Moreover, since the installation jig is detachably attached to the segment, it can be removed after the segment is fixed. Therefore, it is not necessary to leave the steel material used as the support member in the wall. In addition, if the bracket for scaffolding is being fixed to this installation jig, it can also be used as a support member of a temporary scaffold, and the effort and expense at the time of providing a temporary scaffold separately can be reduced.

  According to the construction method and installation jig of the breakwater according to the present invention, the breakwater can be constructed at low cost.

(A) is sectional drawing which shows the structure of a wall body, (b) is the elements on larger scale of (a). (A) is a top view which shows an inner mold form, (b) is the sectional view on the AA line of FIG.1 (b). It is a perspective view which shows a segment. It is a perspective view which shows the attachment condition of the installation jig to a segment. It is a figure which shows an installation jig | tool, Comprising: (a) is a side view, (b) is BB sectional drawing of (a). (A) And (b) is a side view which shows the adjustment part of an installation jig. (A)-(c) is a front view which shows the construction condition of an inner formwork. It is sectional drawing which shows the construction condition of an inner formwork. It is sectional drawing which shows the construction condition of the internal formwork which concerns on another form.

The wall body W according to the embodiment of the present invention is a liquid breakwater of a ground LNG tank and has a cylindrical shape in plan view. As shown in FIG. 1A, the wall body W includes a concrete wall portion 1 made of cast-in-place concrete, and a remaining mold (inner mold frame 2) left on the inner surface of the concrete wall 1. ing.
As shown in FIG. 1 (b), wall bars 11 and 11 are embedded in the concrete wall portion 1. The wall line 11 is a combination of vertical and horizontal lines in a grid pattern. Moreover, the circumferential direction PC steel material 12, the longitudinal direction PC steel material 14, etc. are embed | buried in the concrete wall part 1 as needed.

  The inner mold 2 is formed by connecting a plurality of segments 3, 3... In the circumferential direction and the vertical direction (see FIGS. 2A and 2B). As shown in FIG. 3, the segment 3 is a precast concrete product having a rectangular shape in front view and an arc shape in plan view. In addition to the joint box 32 opened to the concrete wall 1 side, the segment 3 is embedded with an insert nut (for outer tank liner plate and separator), a shear transmission member for integration with the concrete wall 1 and the like. ing. Further, a plurality of installation jig nuts (insert nuts with plates) 31 for attaching the installation jig 4 are provided on the upper portion of the segment 3 (above the center in the height direction). The installation jig nut 31 is open to the outer surface of the segment 3. In the present embodiment, two upper and lower installation jig nuts 31, 31 are provided on the left and right ends of the segment 3. In other words, the segment 3 of this embodiment is provided with a total of four installation jig nuts 31, 31,. The number and arrangement of the installation jig nuts 31 are not limited. Further, the jig for attaching the installation jig 4 does not necessarily need to be an insert nut with a plate.

When building the wall body W, it is divided into a plurality of lots and started up several meters at a time. That is, the construction of the wall body W includes an inner mold forming process, an outer mold forming process, and a placing process for each lot.
The inner mold forming process is a process of forming the inner mold 2 by connecting a plurality of segments 3, 3,. As shown in FIG. 2A, the inner mold 2 (residual mold) has a ring shape in plan view. In the inner mold forming process, the inner mold 2 is formed by repeating the standing work, the supporting work, and the connecting work.
In the standing work, first, installation jigs 4 and 4 are attached to the back surface of the segment 3 placed flat on the ground (work yard) (see FIG. 4).

Here, as shown in FIGS. 5A and 5B, the installation jig 4 of the present embodiment includes a main body portion 41 and an adjustment portion 42 formed at the upper end of the main body portion 41.
The main body 41 of the present embodiment is formed of an H-shaped steel having a length that is greater than the height of the segment 3. The cross-sectional dimension of the main body 41 is set to a size that can support the segment 3. In addition, the member which comprises the main-body part 41 is not limited to H-section steel, For example, a groove-shaped steel and L-shape steel may be sufficient. Moreover, the material which comprises the main-body part 41 is not limited to steel materials, For example, comparatively lightweight materials, such as an aluminum alloy, may be sufficient.
As shown in FIG. 5B, upper and lower two-stage bolt holes (not shown) are formed in the lower portion of the main body 41. A fixing bolt 43 for fixing the installation jig 4 to the existing internal mold 2a (base) on which the segment 3 is mounted is inserted into the bolt hole. The number of bolt holes is not limited. The interval between the bolt holes is the same as the interval between the installation jig nuts 31 formed at the center of the segment 3 in the vertical direction.
At the upper end portion of the main body portion 41, a part of the flange on the segment 3 side (the right side portion in FIG. 5B) is removed.

The adjustment unit 42 includes an adjustment plate 45 that is integrally fixed to the upper end of the main body 41 and an adjustment bolt 44 that is provided on the adjustment plate 45 so as to be able to advance and retreat.
The adjustment plate 45 is joined to the central portion of one surface of the web (the right side surface in FIG. 5B) at the upper end of the main body 41. In the present embodiment, among the two flanges of the main body 41, a reinforcing plate is horizontally placed between the flange on the opposite side of the segment 3 of the main body 41 and the adjustment plate 45. As shown in FIG. 6A, a nut (fixing nut 46) for screwing the adjustment bolt 44 is fixed to the adjustment plate 45. The adjustment plate 45 is firmly fixed to the upper end portion of the main body 41 by appropriately disposing a reinforcing material. The adjustment bolt 44 is provided so as to be able to advance and retreat with respect to the adjustment plate 45.
The installation jig 4 is attached to the segment 3 by screwing an adjustment bolt 44 to an installation jig nut 31 formed on the upper left and right ends of the outer surface of the segment 3. The adjusting bolt 44 is screwed with a fixing nut 47 at the front end side of the bolt and two adjusting nuts 48, 48 disposed between the fixing nut 47 and the adjusting plate 45 with a gap therebetween. . When the adjustment bolt 44 is screwed to the segment 3, the fixing nut 47 is brought into close contact with the back surface of the segment 3. As shown in FIG. 4, when the installation jig 4 is attached to the segment 3, the lower portion (portion where the bolt hole is formed) of the main body portion 41 protrudes from the lower end of the segment 3. The configuration of the adjustment unit 42 is not limited. For example, it may be a jack base or a locking portion to which a chain block is attached.

When the installation jig 4 for the segment 3 is attached, the segment 3 is lifted using a lifting machine (not shown). In the present embodiment, as shown in FIG. 7A, a hanging object 6 is fixed to the installation jig 4, and a wire (not shown) of a lifting machine is locked to the hanging object 6. The hanger 6 includes a pair of left and right vertical members 61, 61, a cross member 62, and a wire that locks a hook of a lifting machine. The upper ends of the longitudinal members 61 are connected to the end portions of the transverse members 62, respectively. The wire is attached to the upper surface of the cross member 62. After fixing the lower part of the vertical member 61 to the installation jig 4, the wire is lifted by a lifting machine. In addition, the structure of the hanging object 6 and the fixing method to the installation jig 4 of the hanging object 6 are not limited.
Next, the segment 3 is moved to a predetermined position using a lifting machine. Then, the segment 3 is erected on the existing internal formwork 2a (base) left on the inner surface of the existing part of the concrete wall 1 in a state where the segment 3 is suspended.
The segment 3 may be erected on the existing inner formwork 2a using a lifting machine without attaching the installation jig 4. The hanging object 6 in this case is attached to the segment 3 directly or via a jig.

In the support operation, as shown in FIG. 8, the segment 3 is supported (temporarily fixed) by fixing the lower part of the installation jig 4 fixed to the segment 3 to the existing inner mold 2a. The installation jig 4 is fixed by screwing a fixing bolt 43 through which a bolt hole is inserted into an installation jig nut 31 formed on the existing inner mold 2a (upper left and right of the existing segment 3). By fixing the installation jig 4 to the existing inner mold 2a, the segment 3 is supported by the installation jig 4. Here, a bracket 5 for scaffolding is fixed to the installation jig 4. When the installation jig 4 is fixed to the existing inner mold 2a, a scaffold 51 is formed by horizontally placing a scaffold plate on the bracket 5. In addition, when the scaffold bracket 5 is not fixed to the installation jig 4, as shown in FIG. 9, the assembly-type scaffold and the portable scaffold 52 are installed.
In the present embodiment, as shown in FIGS. 7A to 7C, the segments 3 are arranged in a row (so-called “joint arrangement”).
When the installation jig 4 is attached after the segment 3 is placed on the existing inner mold 2a, the bolt (fixed) is placed with the installation jig 4 straddling the segment 3 and the existing segment 3. The bolt 43 and the adjusting bolt 44) are tightened. At this time, work is performed on the assembly-type scaffold or the portable scaffold 52 (see FIG. 9).

  In the supporting operation, after fixing the installation jig 4 to the existing inner mold 2a, the inclination of the segment 3 is adjusted using the installation jig 4. By fixing the lower part of the installation jig 4 to the existing inner mold 2a, the installation jig 4 is erected along the outer surface of the existing inner mold 2a. In the supporting operation, as shown in FIGS. 6A and 6B, the adjustment bolt 44 attached to the segment 3 in the upper part of the installation jig 4 is moved forward and backward with respect to the adjustment plate 45, so that the inclination of the segment 3 is increased. Adjust (angle with respect to vertical). In the present embodiment, the inclination is adjusted so that the outer surface of the segment 3 has a predetermined angle (vertical in the present embodiment). The operator on the scaffold 51 performs the operation (advance and retreat) of the adjustment bolt 44.

  In the connecting operation, adjacent segments 3 are connected. After adjusting the inclination, the segments 3 adjacent to each other in the circumferential direction supported by the installation jig 4 are bolted together using the joint box 32 provided in each segment 3. In this embodiment, as shown in FIG. 7 (b), after three or more of the segments 3 are connected, one of the connected segments 3 (the leftmost segment 3 in the drawing) and the existing internal The installation jig 4 is removed (removed) from the mold 2a. The removed installation jig 4 is attached to the newly installed segment 3 and used to support the segment 3 in the work yard (see FIG. 7C). That is, in this embodiment, the segments 3 are connected to each other while supporting the segments 3 via the installation jig 4, and when a predetermined number of segments 3 are connected in an arc shape and stabilized, the installation jigs are connected to the connected segments 3. 4 is removed and used for construction of the newly established segment 3. If it does in this way, it can support so that the segment 3 may not fall down in unstable conditions, such as the beginning of the assembly of the segments 3 (inner formwork 2). In addition, by using the installation jig 4, the inner mold 2 can be formed with the minimum necessary installation jig 4, and the construction cost can be reduced.

The outer mold forming step is a process of installing the outer mold 7 (see FIG. 8) outside the inner mold 2 with a gap from the inner mold 2.
When the inner mold 2 is installed, necessary wall reinforcement 11 and circumferential PC steel material 12 and longitudinal PC steel material 14 are installed. The wall bars 11 are preferably assembled in a reinforcing bar processing site in the construction site and built in the state of a reinforcing bar net or a reinforcing bar rod. The lower end portion of the wall reinforcement 11 is connected to the existing wall reinforcement 11 protruding from the existing portion of the concrete wall 1 through an appropriate reinforcing steel joint (lap joint, mechanical joint, etc.). The circumferential PC steel material 12 is inserted into the transverse sheath 13 disposed along the outer wall reinforcement 11 after the reinforcement of the wall reinforcement 11. A fixing tool fixed to a pilaster (not shown) is attached to the end of the circumferential direction PC steel material 12. Moreover, the lower end part of the longitudinal direction PC steel material 14 is connected to the existing longitudinal direction PC steel material which protrudes from the existing part of the concrete wall part 1 through a suitable mechanical coupling. The installation position of the longitudinal PC steel material 14 is confirmed by measuring the offset amount from the inner mold 2.
The outer mold 7 is connected to the inner mold 2 via a separator (not shown). In this embodiment, the upper and lower two-stage separators are provided, but the number of separator stages, the arrangement pitch, and the like are not limited. The outer mold 7 has a strength that does not deform due to the side pressure of the concrete. The outer mold 7 is fixed to the upper surface of the existing outer mold 7. The outer mold 7 is installed by using a scaffold 51 disposed outside the outer mold 7.

The placing process is a process of forming concrete wall 1 by placing concrete between the inner mold 2 and the outer mold 7.
In the placing process, first, the installation jig 4 is removed from the inner mold 2. Next, concrete is placed from two locations facing each other across the central axis of the tank (inner mold 2) (see FIG. 2A). The concrete is placed by using a concrete pumping tube to drive the concrete to a position lower than the top edge of the outer mold 7. The method for placing concrete is not limited. When the concrete has been placed, the concrete is cured. When all the lots are completed, the circumferential PC steel material 12 and the longitudinal PC steel material 14 are applied with tensile force, and prestress is introduced into the wall body W.

According to the construction method of the wall body W (construction method of the breakwater) and the installation jig 4 according to the present embodiment, the following operational effects are obtained.
Since the installation jig 4 used as a temporary support member is not left behind, the amount of steel can be reduced. Moreover, the steel material can be further reduced by sequentially diverting the installation jig 4. Further, since the temporary support member does not remain in the wall body W, the wall thickness can be minimized, and consequently the amount of concrete in the wall body W and the foundation portion can be reduced. Further, since the installation jig 4 is attached to the inner mold 2, it is not necessary to secure a site for installing a temporary member around the wall body W.

Since the support of the segment 3 is completed only by fixing the installation jig 4 attached to the segment 3 to the existing inner mold 2a, the workability is excellent. Moreover, by using the installation jig 4, the assembly of the inner mold 2 (e.g., tilt adjustment of the segment 3) can be performed with high accuracy. Furthermore, the tilt adjustment can be easily performed only by moving the adjustment bolt 44 provided on the head of the installation jig 4 forward and backward.
Since the concrete side pressure acts uniformly on the inner mold 2 in the center direction of the tank, ring compression acts on the inner mold 2 and the movement and deformation of the inner mold 2 are suppressed. Therefore, the construction of the wall body W can be performed with high quality.

The embodiment according to the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and the above-described components can be appropriately changed without departing from the spirit of the present invention.
In the above-described embodiment, the installation jig 4 is attached to the segment 3 and transferred to a predetermined position in the standing work, but the installation jig 4 is a segment on the existing inner formwork (base) 2a. 3 may be attached. If the installation jig 4 is made of a lightweight material such as an aluminum alloy, an operator on the scaffold 51 can be attached and detached by human power.
Further, the inclination adjustment of the segment 3 may be performed as necessary. For example, when the segment 3 is vertical while standing on the existing inner mold 2a, the tilt adjustment may be omitted.
In the said embodiment, although the length of the installation jig 4 (main-body part 41) was made more than the height of the segment 3, the length of the installation jig 4 is not limited. That is, the length of the installation jig 4 (main body portion 41) may be equal to or less than the height of the segment 3.
In the embodiment, the segment 3 is a continuous arrangement, but the segment 3 may be a so-called staggered arrangement.
In the embodiment, the case where the inclination of the segment is adjusted using the adjustment bolt has been described, but the method of adjusting the inclination of the segment is not limited. For example, the inclination may be adjusted by using a jack or a chain block provided in the adjustment portion 42 of the installation jig fixed to the existing inner mold 2a.

DESCRIPTION OF SYMBOLS 1 Concrete wall part 2 Internal formwork 2a Existing internal formwork 3 Segment 31 Nut for installation jigs 4 Installation jigs 41 Main body part 42 Adjustment part 43 Fixing bolt 44 Adjustment bolt 45 Adjustment plate 5 Bracket 51 Scaffold 6 Suspension 7 External mold frame

Claims (6)

An inner mold forming step for forming an inner mold by connecting a plurality of segments;
An outer mold forming step of providing an outer mold on the outside of the inner mold with a gap from the inner mold; and
A method of constructing a breakwater comprising: placing concrete between the inner mold and the outer mold to form a concrete wall;
In the inner mold forming step,
Standing work for standing the segment on the existing inner formwork left on the inner surface of the existing part of the concrete wall,
A support operation for supporting the segment by an installation jig fixed to the existing internal formwork;
A connecting operation for connecting the adjacent segments;
To form the inner mold by repeating
In the placing step, the concrete is placed after the installation jig is removed from the inner formwork, and the construction method of a breakwater is provided.   2. The liquid breakwater according to claim 1, wherein, in the supporting operation, after the installation jig is fixed to the existing inner formwork, the inclination of the segment is adjusted using the installation jig. How to build.   In the inner mold forming step, after connecting a predetermined number or more of the segments, when removing the installation jig from one of the segments and supporting the installation jig to the new segment The construction method of a breakwater according to claim 1 or 2, characterized by being used. An installation jig used when connecting a plurality of segments to form an inner mold,
A plurality of bolt holes for inserting fixing bolts for fixing the base on which the segments are mounted are formed in the lower part,
An installation jig, wherein an adjustment portion for adjusting the inclination of the segment is formed at an upper portion. The adjustment portion is provided with an adjustment bolt that is screwed onto the back surface of the segment,
The installation jig according to claim 4, wherein the adjustment bolt is provided so as to be movable forward and backward with respect to the adjustment portion.   The installation jig according to claim 4 or 5, wherein a scaffold bracket is fixed.

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