JP7309629B2 - Construction method of oil dike and oil dike structure - Google Patents

Description

The present invention relates to a method for constructing an oil dike surrounding a storage tank for petroleum (and an oil dike structure).

When an oil storage tank for petroleum is installed in a factory or the like, the Fire Service Act stipulates that an oil dike having an oil storage capacity equivalent to 110% of the oil storage amount should be installed around the tank.

The cross-sectional shape of an oil barrier is generally an inverted T-shape or an L-shape, and is composed of a lower base slab portion and an upper vertical wall portion. The foundation slab is often buried in the ground, and the height of the vertical wall is often about 1 to 3m. Reinforced concrete (RC) is often used as the material.

In addition, the plan view shape (overall shape) of the oil barrier is generally a polygon (usually a rectangle) having straight portions and corner portions.

Conventionally, reinforced concrete oil barriers are constructed by casting concrete in place.
Specifically, excavate with a floor width of about 3m plus the width of the foundation slab, and apply crushed stone and leveled concrete to the bottom of the excavated trench. Then, on top of that, the foundation slab is constructed by arranging reinforcement for the foundation slab, setting the formwork, and pouring concrete. , constructing a vertical wall to construct an oil dike.

In addition, in Patent Document 1, precast concrete pieces are arranged at predetermined intervals as a cylindrical liquid barrier made of prestressed concrete (PC) that is integrally provided with a large above-ground low-temperature tank that stores low-temperature liquefied gas such as LNG. , and the precast concrete pieces are connected with cast-in-place concrete.

Japanese Patent No. 5348559

However, construction of an oil barrier by the conventional cast-in-place construction method requires time for on-site construction, and is not suitable for urgent construction. In addition, since the foundation slab is made of cast-in-place concrete, a wide floor width is required during excavation.

Moreover, it is difficult to directly apply the method of constructing a dike using precast concrete pieces and cast-in-place concrete described in Patent Document 1 to construction of an oil dike.

This is because the dike for LNG tanks is integrally formed with the LNG tank, which is circular in plan view, and the dike itself is also circular in plan view, whereas the dike for oil storage tanks is generally polygonal (usually rectangular) in plan view, and has linear portions and corner portions.
Therefore, it is necessary to devise a way to apply it to an oil breakwater.

In view of such actual circumstances, the present invention provides a reinforced concrete oil barrier that surrounds an oil storage tank and has straight portions and corner portions in a plan view, and is made of precast concrete pieces and cast-in-place concrete. An object is to provide a suitable construction method (and a dike structure).

The oil barrier targeted by the present invention is a reinforced concrete (RC) oil barrier provided to surround an oil storage tank and having a straight portion and corners in a plan view,
The construction method is
Precast concrete pieces having an inverted T-shaped or L-shaped cross section perpendicular to the extending direction of the oil barrier and having a predetermined length in the extending direction of the oil barrier are spaced apart in the extending direction of the oil barrier. spacing and arranging;
placing concrete between the precast concrete pieces;
including
The cast-in-place concrete section between the precast concrete pieces of the straight sections is placed so that the horizontal reinforcing bars protruding from the end faces of the precast concrete pieces on both sides are connected by lap joints, and the cast-in-place concrete section on both sides The joint with the precast concrete piece forms a construction joint connected by the lateral reinforcing bar,
The cast-in-place concrete part between the corner precast concrete piece and the straight part precast concrete piece is cast in a state in which the lateral reinforcing bars do not protrude from the end face of the corner precast concrete piece, and the cast-in-place concrete The junction between the corner and the precast concrete piece at the corner forms a structural joint that is not connected by the transverse reinforcing bars.

The structural joint portion preferably includes a sheath pipe pre-embedded in the end portion of the corner precast concrete piece, and a slip bar having one end inserted into the sheath pipe and the other end protruding toward the cast-in-place concrete side. .

Further, the construction joint and the structural joint may be provided with a liquid stop plate that is previously embedded in the end of the precast concrete piece and protrudes toward the cast-in-place concrete.

The term “corner” used in this specification means a portion where the extending direction of the oil barrier changes so as to surround the oil storage tank. It is a concept that includes

According to the present invention, construction period can be shortened by constructing with precast concrete pieces and cast-in-place concrete parts.
In the straight part, the joint between the precast concrete piece and the cast-in-place concrete is used as a construction joint part that connects with the horizontal reinforcing bar to obtain sufficient connection strength, while in the corner, the precast concrete piece and the cast-in-place concrete part Deformation and the like during expansion and contraction can be tolerated by forming joints as hemmed structural joints that are not connected by horizontal rebars.

1 is a plan view of an oil barrier shown as one embodiment of the present invention; FIG. Diagram showing external shape of precast concrete piece Diagram showing the shape of reinforcing bars in precast concrete pieces Detailed view of X1 part in FIG. Detailed view of X2 section in FIG. The figure which shows the modification of the X3 part of FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a plan view of an oil barrier shown as one embodiment of the present invention.

The oil barrier 1 is provided so as to surround an oil storage tank 100 for petroleum. The oil storage tank 100 has a circular shape in plan view, and the oil barrier 1 in this example has a rectangular shape in plan view. Therefore, the oil barrier 1 of this example is composed of four straight portions and four corner portions in a plan view. In this example, a rectangle is used for simplification of explanation, but depending on the restrictions of the site around the oil storage tank 100, a complex polygon including unevenness and oblique lines may be formed. corners.

The cross-sectional shape of the oil barrier 1 (the shape of the cross section orthogonal to the extending direction of the oil barrier 1) is an inverted T, as shown in FIG. It consists of a lower base slab portion 1a and an upper vertical wall portion 1b. In addition, in the present embodiment, the inverted T-shape is used, but an L-shape may be used.

The oil barrier 1 is also divided in its extending direction, and is composed of precast concrete pieces (hereinafter referred to as "PCa pieces") 10 and cast-in-place concrete 50, which are alternately arranged. be.

That is, PCa pieces 10 having a predetermined length (for example, 4200 mm) in the extending direction of the oil barrier 1 are arranged at predetermined intervals (for example, 800 mm). Adjacent PCa pieces 10, 10 are connected by placing cast-in-place concrete 50 so as to have the same cross-sectional shape.

2 shows the external shape of the PCa piece 10, FIG. 2(A) is a cross-sectional view of the PCa piece 10 (cross-sectional view taken along line AA in FIG. 1), and FIG. 2(B) is a front view of the PCa piece 10 ( 2(A)), and FIG. 2(C) is a plan view of the PCa piece 10 (view along arrow C in FIG. 2(B)).

Therefore, as shown in FIG. 2(A), the PCa piece 10 has the same cross-sectional shape as the oil barrier 1, that is, the cross section perpendicular to the extending direction of the oil barrier 1 has an inverted T shape. , a lower base slab portion 10a and an upper vertical wall portion 10b, and has a predetermined length (for example, 4200 mm) in the direction in which the oil barrier 1 extends.

3A and 3B show the shape of the bar arrangement of the PCa piece 10, where FIG. 3A is a cross-sectional view and FIG. 3B is a front view.

As can be seen from FIG. 3, in the base slab portion 10a of the PCa piece 10, reinforcing bars 11 and 12 (horizontal reinforcing bars 11 and right-angled reinforcing bars 12) are embedded in a horizontal plane in a grid pattern, and in the vertical wall portion 10b Reinforcing bars 13 and 14 (horizontal reinforcing bars 13 and vertical reinforcing bars 14) are embedded in a grid pattern in a vertical plane.

Further, from both end surfaces of the PCa piece 10, the horizontal reinforcing bars 11 in the base slab portion 10a and the horizontal reinforcing bars 13 in the vertical wall portion 10b protrude as lap joint reinforcing bars 11j and 13j. The protruding length should be slightly shorter (eg 720 mm) than the spacing between the PCa pieces 10, 10 (eg 800 mm). This is to connect the horizontal reinforcing bars between adjacent PCa pieces 10 by lap joints.

Reinforcing bars 12k and 14k are attached to one side of the protruding portions (lap joint reinforcing bars) 11j and 13j of the horizontal reinforcing bars 11 and 13 after the PCa piece 10 is installed or before the PCa piece 10 is carried. The reinforcing bar 12k crosses the reinforcing bar 11j and is arranged in parallel with the perpendicular reinforcing bar 12 in the base slab portion 10a, and the reinforcing bar 14k crosses the reinforcing bar 13j and is arranged in the longitudinal direction reinforcing bar in the vertical wall portion 10b. Arrange reinforcement parallel to 14.

The PCa piece 10 has a corner PCa piece (corner piece) 10K as shown in FIG.
The corner PCa piece 10K is L-shaped in plan view and has a bent portion (or curved portion).
Further, unlike the PCa pieces 10 at the straight portions, the PCa pieces 10K at the corners do not have internal horizontal reinforcing bars protruding from both end faces. This will be detailed later.

Next, the cast-in-place concrete 50 and joints (joints) between the PCa pieces 10, 10K and the cast-in-place concrete 50 will be described.

FIG. 4 is a detailed view (enlarged plan view) of part X1 in FIG. is shown. FIG. 4 shows only the cast-in-place concrete 50 between the vertical wall portions 10b, 10b, which will be mainly described, but the same applies to the cast-in-place concrete 50 between the foundation slab portions 10a, 10a.

An internal horizontal reinforcing bar 13 protrudes as a lap joint reinforcing bar 13j from the end face of the left PCa piece 10 (vertical wall portion 10b) in FIG. 4, and a vertical reinforcing bar 14k is assembled to this.
In addition, the internal horizontal reinforcing bar 13 protrudes as a lap joint reinforcing bar 13j from the end face of the PCa piece 10 (vertical wall portion 10b) on the right side in FIG. It is not fitted with longitudinal reinforcing bars 14k.

Therefore, by installing the left and right PCa pieces 10, 10, the transverse reinforcing bars form a lap joint. That is, by placing the cast-in-place concrete 50 between the left and right PCa pieces 10, 10, the reinforcing bars 13j, 13j, which are the protruding portions of the horizontal reinforcing bars 13, 13, are in a lap joint state in the cast-in-place concrete 50. connected with Although not shown in the drawing, between the base slab portions 10a, 10a, the reinforcing bars 11j, 11j, which are projecting portions of the horizontal reinforcing bars 11, 11, are connected in a lap joint state.

Therefore, in the cast-in-place concrete 50 between the PCa pieces 10, 10 between the straight portions, the lateral reinforcing bars 13j, 13j (and 11j, 11j) protruding from the end faces of the PCa pieces 10, 10 on both sides are connected by lap joints. The joints between the cast-in-place concrete 50 and the PCa pieces 10, 10 on both sides form construction joints SM that are rigidly connected by the lateral reinforcing bars 13j (and 11j).

In addition, one end edge of a PVC liquid stop plate 20 extending vertically along the vertical wall portion 10b is embedded in the end portion of the PCa piece 10 on the left side in FIG. protrudes from the end face of the PCa piece 10 toward the cast-in-place concrete 50 side.
In addition, one end edge of a PVC liquid stop plate 20 extending vertically along the vertical wall portion 10b is embedded in the end portion of the PCa piece 10 on the right side in FIG. also protrudes from the end face of the PCa piece 10 toward the cast-in-place concrete 50 side.

Therefore, each construction joint SM is provided with a liquid stop plate 20 that is embedded in the end of the PCa piece 10 in advance and protrudes toward the cast-in-place concrete 50 side.

FIG. 5 is a detailed view (enlarged plan view) of section X2 in FIG. The detail of the part connected with the concrete 50 is shown. FIG. 5 shows only the cast-in-place concrete 50 between the vertical wall portions 10b, 10b, which will be mainly described, but the same applies to the cast-in-place concrete 50 between the foundation slab portions 10a, 10a.

The transverse reinforcing bars 13 in the left corner PCa piece 10K in FIG.
On the other hand, from the end face of the PCa piece 10 in the straight part on the right side in FIG. ) are assembled.

Therefore, when the cast-in-place concrete 50 is placed between the PCa piece 10K on the left corner in FIG. 5 and the PCa piece 10 on the right straight portion in FIG. The cast-in-place concrete 50 and the PCa piece 10K at the left corner are not connected to each other by the lateral reinforcing bars (substantially edge-cut). ) form the structural joint KM. This KM is also called an expansion joint.

Also, an elastite 30 having a thickness of about 20 mm, which is a plate-like asphalt-based joint material, is attached to the end face of the PCa piece 10K at the corner.
Thus, the structural joint KM comprises elastite 30 interposed between the corner PCa piece 10K and the cast-in-place concrete 50 .

A PVC sheath tube (sheath tube) 31 is embedded in the end of the corner PCa piece 10K, and the open end of the sheath tube 31 is exposed at the end face of the corner PCa piece 10K. there is One end of a slip bar 32 made of round steel or the like is inserted into the sheath tube 31, and the other end of the slip bar 32 protrudes toward the cast-in-place concrete 50 side.
Therefore, the structural joint KM consists of a sheath pipe 31 embedded in advance at the end of the corner PCa piece 10K and a slip bar having one end inserted into the sheath pipe 31 and the other end protruding toward the cast-in-place concrete 50 side. 32.

Further, the structural joint portion KM is also provided with a liquid stop plate 20 that is embedded in advance in the end portion of the PCa piece 10K and protrudes toward the cast-in-place concrete 50 side. That is, one end edge of a PVC liquid stop plate 20 extending vertically along the vertical wall portion 10b is also embedded in the end portion of the PCa piece 10K at the corner. also protrudes from the end face of the PCa piece 10K toward the cast-in-place concrete 50 side.

In addition, the joint portion between the PCa piece 10 and the cast-in-place concrete 50 in the straight portion on the right side of FIG. The joint portion composed of such a one-side structural joint portion KM and one-side construction joint portion SM is not necessarily limited to a corner portion, and may be arranged in a straight portion.

Therefore, the oil protection dike 1 of the present embodiment is provided so as to surround the oil storage tank 100, and is a reinforced concrete oil protection dike 1 having straight portions and corner portions in a plan view. The cross section orthogonal to the direction of extension is inverted T-shaped (or L-shaped), has a predetermined length in the extending direction of the oil barrier 1, and is arranged at intervals in the extending direction of the oil barrier 1. and a cast-in-place concrete 50 placed between the PCa pieces 10,10.
In the cast-in-place concrete 50 (see FIG. 4) between the PCa pieces 10, 10 of the straight portions, the horizontal reinforcing bars 11, 13 protruding from the end faces of the PCa pieces 10, 10 on both sides are lap joints (11j, 13j). The joints between the cast-in-place concrete 50 and the PCa pieces 10, 10 on both sides form construction joints SM connected by the lateral reinforcing bars 11, 13.
Also, the cast-in-place concrete 50 (see FIG. 5) between the corner PCa piece 10K and the straight PCa piece 10 is in a state in which the horizontal reinforcing bars 11 and 13 do not protrude from the end face of the corner PCa piece 10K. The joints between the cast-in-place concrete 50 and the PCa pieces 10K at the corners form structural joints KM that are not connected by the lateral reinforcing bars 11 and 13 .

Next, a method for constructing the oil breakwater 1 will be described step by step.
First, the location where the oil barrier 1 is to be constructed is excavated with a floor width of about 50 cm (25 cm on each side) plus the width of the foundation slab 1a. set up.

Next, PCa pieces 10 having a predetermined length (eg, 4200 mm) are placed at predetermined intervals (eg, 800 mm) in the extending direction of the oil barrier 1 on leveled concrete in the excavated trench. Also, a PCa piece (corner piece) 10K for the corner is installed at the corner.

At this time, a liner plate of about 100 mm x 100 mm is placed on the leveled concrete, and the PCa pieces 10 and 10K are installed while adjusting the height.
Also, mortar is filled under the base slab portion 10a of the PCa pieces 10 and 10K.

In this state, the reinforcing bars 11j and 13j for the lap joint protrude from the end face of the PCa piece 10, which is the construction joint SM, by a predetermined length (for example, 720 mm). The specified lap joint length (e.g. 640 mm) is ensured.

A slip bar 32 loosely fitted in the sheath tube 31 protrudes from the end face (elastite 30 face) of the PCa piece 10K at the corner that serves as the structural joint KM.

Further, the other end edge of the liquid stop plate 20 having one end embedded protrudes from the end face of the PCa piece 10, 10K that becomes the construction joint portion SM or the structural joint portion KM.

After the PCa pieces 10 (and 10K) are installed, prior to pouring the cast-in-place concrete between the PCa pieces 10, 10, reinforcement work and formwork installation work are performed.
That is, reinforcing bars 12k and 14k are additionally arranged in the direction perpendicular to the horizontal reinforcing bars (lap joint reinforcing bars) 11j and 13j protruding from the PCa piece 10 . It should be noted that these reinforcing bars 12j and 14j can be attached to the PCa piece 10 in advance.

Next, formwork is placed on both sides of the foundation slab portion of the cast-in-place concrete portion between the PCa pieces 10, 10, and concrete is placed in this formwork to form the cast-in-place concrete between the PCa pieces 10, 10. Build the foundation slab for the department. After one day, a formwork is installed on both sides of the vertical wall part of the place of cast-in-place concrete between the PCa pieces 10, 10, concrete is poured into this formwork, and the place between the PCa pieces 10, 10 is placed. Construct the vertical wall of the poured concrete section.

When installing the formwork to the place of cast-in-place concrete, embedded anchors such as cap nuts for mounting the formwork are installed in advance on the side surface of the foundation slab portion 10a of the PCa piece 10 and the side surface of the vertical wall portion 10b. This will make installation of the formwork easier.

In addition, if the formwork is arranged on both sides of the foundation slab portion of the cast-in-place concrete portion and the formwork is arranged as floating formwork on both sides of the vertical wall portion of the cast-in-place concrete portion, the foundation slab portion and the vertical It is also possible to pour the wall concrete continuously.

After placing the cast-in-place concrete, the forms for the foundation slab and vertical wall are removed from the cast-in-place concrete. Then, backfill the dike installation location (see Fig. 2).

FIG. 6 shows a modification of the X3 section (corner of the oil barrier) in FIG.
In FIG. 1, the corner PCa piece (corner piece) 10K is integrally formed into an L-shape in plan view, but in FIG. It is divided from the piece 10K-2.
That is, the end of the second piece 10K-2 is connected to the side of the first piece 10K-1 via the cast-in-place concrete 50K.

In this case, the joints between the first piece 10K-1, the second piece 10K-2, and the cast-in-place concrete 50K between them are constructed joints SM.
The joints between the first piece 10K-1, the second piece 10K-2, and the straight PCa piece 10 are structural joints KM.
With such a configuration, the corner piece can be further simplified.

According to the above embodiment, for example, it is possible to install 5 to 10 PCa pieces per day. The construction period can be greatly shortened.
Moreover, since there is no need to install a large formwork, the excavation floor width can be reduced, and the amount of excavated soil and the amount of backfilled soil can be reduced.

However, since precast products are used, transportation costs increase construction costs. In this regard, it is better to manufacture precast products as close to the site as possible. This is because the closer to the site, the more efficiently the precast products can be brought in, and the lower the transportation cost. Therefore, it would be best if the land adjacent to the construction yard could be used as a manufacturing site for precast products.

In addition, since the PCa pieces 10 and 10K are connected by the cast-in-place concrete 50, the PCa pieces 10 and 10K do not require accuracy in units of mm.
For this reason, the formwork for manufacturing the PCa piece may be a normal formwork such as metal foam, and unlike the shield tunnel segment, it is not necessary to use a mold at a factory. As for the curing of the precast product, wet curing with a curing sheet is sufficient, and accelerated curing with steam is not necessary. These can be manufactured in the construction yard adjoining land.

In addition, regarding the PCa piece 10 in the straight part of the oil barrier 1, the joint part with the cast-in-place concrete 50 is formed as a construction joint part SM connected by a horizontal reinforcing bar to obtain sufficient connection strength, while the PCa piece 10K in the corner part As for , the joint with the cast-in-place concrete 50 can be formed as an edge-cut structural joint KM that is not connected by a horizontal reinforcing bar, and deformation, etc. during expansion and contraction can be allowed.

It should be noted that the illustrated embodiment is only a schematic illustration of the present invention, and that the present invention, in addition to what is directly indicated by the described embodiment, can also be made by those skilled in the art within the scope of the claims. Needless to say, it includes the improvement and change of

1 oil barrier 1a foundation slab 1b vertical wall 10 precast concrete piece (PCa piece)
10a Foundation slab portion 10b Vertical wall portion 10K Precast concrete pieces (PCa pieces) at corners
11 to 14 reinforcing bars 11j, 13j lap joint reinforcing bars 20 liquid stop plate 30 elastite 31 sheath pipe 32 slip bar 50 cast-in-place concrete 100 oil storage tank

Claims (4)

A method for constructing a reinforced concrete oil barrier provided to surround an oil storage tank and having a straight portion and a corner portion in a plan view,
Precast concrete pieces having an inverted T-shaped or L-shaped cross section perpendicular to the extending direction of the oil barrier and having a predetermined length in the extending direction of the oil barrier are spaced apart in the extending direction of the oil barrier. spacing and arranging;
placing concrete between the precast concrete pieces;
including
The cast-in-place concrete part between the precast concrete pieces of the straight parts is cast so that the horizontal reinforcing bars protruding from the end faces of the precast concrete pieces on both sides are connected by lap joints, and the cast-in-place concrete and the precasts on both sides are placed. The joint with the concrete piece forms a construction joint connected by the horizontal reinforcing bar,
The cast-in-place concrete part between the corner precast concrete piece and the straight part precast concrete piece is cast in a state in which the lateral reinforcing bars do not protrude from the end face of the corner precast concrete piece, and the cast-in-place concrete A method of constructing an oil dike, characterized in that a joint portion between a corner portion and a precast concrete piece forms a structural joint portion that is not connected by the lateral reinforcing bars. The structural joint portion comprises a sheath pipe embedded in advance in the end of the precast concrete piece at the corner, and a slip bar having one end inserted into the sheath pipe and the other end protruding toward the cast-in-place concrete. A method for constructing an oil dike according to claim 1. The construction joint and the structural joint according to claim 1 or 2, characterized in that they are provided with a liquid stop plate embedded in advance in the end of the precast concrete piece and protruding toward the cast-in-place concrete side. How to build an oil dike. A reinforced concrete oil barrier provided to surround an oil storage tank and having a straight portion and a corner portion in a plan view,
The cross section perpendicular to the extension direction of the dike has an inverted T-shape or L-shape, has a predetermined length in the extension direction of the dike, and is arranged at intervals in the extension direction of the dike. a precast concrete piece to be
a cast-in-place concrete portion placed between the precast concrete pieces;
including
The cast-in-place concrete part between the precast concrete pieces of the straight parts is cast so that the lateral reinforcing bars protruding from the end faces of the precast concrete pieces on both sides are connected by lap joints, and the cast-in-place concrete and the precasts on both sides are placed. The joint with the concrete piece forms a construction joint connected by the horizontal reinforcing bar,
The cast-in-place concrete part between the corner precast concrete piece and the straight part precast concrete piece is cast in a state in which the lateral reinforcing bars do not protrude from the end face of the corner precast concrete piece, and the cast-in-place concrete and a joint of the precast concrete piece at the corner forms a structural joint that is not connected by the lateral reinforcing bars.