JP4853430B2 - Construction method of underground tank, underground tank constructed by the construction method, and formwork apparatus - Google Patents

Description

  The present invention relates to a construction method for an underground tank constructed in the ground.

  As a method of constructing cylindrical concrete structures such as silos, chimneys, tanks, etc., a formwork device comprising an inner formwork, an outer formwork, a jack and a yoke for connecting them is used, and concrete is provided between these inner and outer formwork. There is known a construction method for constructing a structure by repeating the work of raising the entire formwork device with a jack to secure the next concrete placement volume when a predetermined strength of the concrete is developed.

  For example, Patent Document 1 discloses a method of constructing a cylindrical concrete structure by attaching a roof to a formwork apparatus on the ground, raising the formwork apparatus, and simultaneously raising the roof. In this method, first, the roof is suspended on the formwork device on the ground, then concrete is placed between the inner and outer formwork, and when the predetermined strength of the concrete is developed, the formwork device and the roof are raised with a jack. Then, the side wall is constructed by placing concrete again between the inner and outer molds, and finally, the upper part of the side wall and the roof are joined to construct a cylindrical concrete structure.

  Patent Document 2 discloses a method of forming a hollow concrete part in the ground and constructing a cylindrical concrete structure using a formwork device in the hollow part. In this method, first, a hollow portion is formed in the ground, and the formwork device is disposed inwardly with an interval that allows the outer formwork of the formwork device to be raised and lowered from the inner wall of the hollow portion. Build a roof inside. Next, concrete is placed between the inner and outer molds, and when the concrete exhibits a predetermined strength, the mold apparatus is lifted with a jack, and at the same time, a roof is provided using a lifting device provided separately below the mold apparatus. To raise.

Then, concrete is cast again between the inner and outer molds to construct a side wall. When the strength of the concrete is developed, the mold apparatus is raised and the roof is also raised. This operation is repeated, and finally, the upper part of the side wall and the roof are joined to construct a cylindrical concrete structure.
Patent Publication No. 59-109656 JP 7-286449 A

  However, in the method described in Patent Document 1, the roof and the formwork device are connected to prevent the formwork device from being shaken in the horizontal direction and deformed, but basically the roof is suspended from the formwork device. Therefore, there is a limit to the deformation suppressing effect of the formwork device. For example, if the cylindrical concrete structure becomes large and the diameter of the cylinder becomes long, the roof also becomes large and the weight increases, and the deformation of the formwork device with the increase in the weight of the roof becomes larger than the deformation suppression. It is what will end up. And if the deformation | transformation of a formwork apparatus becomes large, since the construction precision of a side wall etc. will fall, it was difficult to apply to a large cylindrical concrete structure.

  Moreover, in the method described in Patent Document 2, a gap must be secured between the inner wall and the side wall of the cavity so that the outer mold can be raised and lowered during the construction of the side wall. A larger diameter cavity must be formed. In addition, after the underground tank is constructed, the gap must be backfilled with earth and sand. In particular, since the gap is formed on the outer periphery of the hollow portion, there is a problem that the excavation soil and backfill soil become large, and the excavation work and backfilling work take time and effort, and the construction period becomes long.

  Then, this invention is made | formed in view of the above conventional problems, Comprising: It aims at providing the construction method which can construct | assemble an underground tank accurately in a short time.

  In order to achieve the object, an underground tank construction method according to the present invention includes a side wall installed along an inner wall of a cavity formed in the ground and a roof installed on the upper side of the side wall. In the construction method, a mold frame disposed inward from the inner wall of the hollow portion at a predetermined interval, a yoke connected to the mold frame, a lifting means for moving the yoke up and down, and the roof Using a formwork device comprising a connecting means for connecting the steel roof structural member to the yoke, connecting the formwork device and the steel roof structural member, the inner wall and the Work to raise the formwork device and the steel roof structural member by placing concrete between the formwork and raising the yoke by the lifting means when a predetermined strength of the concrete is developed. Repeat Te building a side wall, characterized by bonding the steel roof structural member and constructed the sidewalls (first invention).

  According to the construction method of an underground tank according to the present invention, a mold frame disposed inward at a predetermined interval from the inner wall of the cavity, a yoke connected to the mold frame, and a lift for moving the yoke up and down A side wall in contact with the inner wall can be constructed using means and a formwork device having one end connected to the yoke and connecting means for connecting the steel roof structural member to the yoke.

  Further, when a side wall is constructed in the basement using a formwork apparatus for both the inner and outer molds as in the prior art, excavation work for excavating a gap for raising and lowering the outer mold between the inner wall and the side wall and backfilling are performed. Whereas a backfilling operation is required, according to the construction method of an underground tank of the present invention, an operation for providing such a gap is not required, so that the construction period can be shortened. And since it is not necessary to excavate the clearance for raising / lowering the outer formwork, the amount of excavated soil can be reduced.

  Furthermore, since the formwork apparatus and the steel roof structural member are connected, the steel roof structural member can partially bear the role of suppressing deformation of the formwork apparatus. That is, since the formwork device is not deformed, the side wall can be constructed with high accuracy.

  Moreover, since the side wall is constructed below the steel roof structural member while the steel roof structural member is safely supported by the formwork apparatus, the work of raising the steel roof structural member after the side wall is constructed is performed. It becomes possible to connect the side wall and the steel roof structural member immediately after construction of the side wall. Therefore, when the steel roof structural member is suspended above the side wall by a crane or the like after the side wall is constructed, a scaffold for connecting the side wall and the steel roof structural member is used as a steel roof. However, according to the construction method of the underground tank of the present invention, such work is not required, while the work under the high place and the work under the suspended load are required to be installed below the structural member. , Safety is greatly improved.

According to a second invention, in the first invention, the steel roof structural member has a dome shell structure.
According to the construction method of an underground tank according to the present invention, by making the steel roof structural member a dome shell structure, the steel roof structural member can effectively bear the role of suppressing deformation of the formwork device. it can. Moreover, since the weight of a roof can be lightened by making the structural member for steel roofs into a dome shell structure, a deformation | transformation of a formwork apparatus can be suppressed.

According to a third invention, in the first invention, the connecting means includes a telescopic device capable of loading a compressive force on the steel roof structural member, and the steel roof structural member is extended by extending the telescopic device. A bending moment inward of the side wall acting on the formwork device is reduced by a reaction force of the steel roof structural member generated by loading a compression force on the side wall.
According to the construction method of an underground tank according to the present invention, the connecting means includes an expansion device such as a jack, so that it is possible to load a compressive force on the steel roof structural member. By extending the expansion / contraction means and applying a compressive force to the steel roof structural member, a reaction force acts on the formwork apparatus from the steel roof structural member. Since the horizontal component of the reaction force acts on the outer side of the side wall, the weight of the steel roof structural member, the weight of the formwork device, and the frictional resistance generated between the inner formwork and the side wall when the formwork device is raised. It is possible to reduce the bending moment in the inner side direction of the side wall caused by the above. And since loads, such as a bending moment which acts on a formwork apparatus, become small, a deformation | transformation of a formwork apparatus can be suppressed and it becomes possible to construct | assemble a side wall accurately.

The underground tank of 4th invention was constructed | assembled by the construction method of the underground tank in any one of 1-3.
According to the underground tank according to the present invention, since the underground tank is constructed by the underground tank construction method described in the first to third aspects, it is possible to construct the underground tank with high accuracy in a short time.

  The formwork apparatus of 5th invention is a formwork for constructing an underground tank provided with a side wall installed along an inner wall of a hollow portion formed in the ground and a roof installed on the upper side of the side wall. An apparatus, a mold frame disposed inwardly with a predetermined distance from the inner wall of the cavity, a yoke connected to the mold frame, a lifting means for moving the yoke up and down, And a connecting means for connecting a steel roof structural member constituting the roof to the yoke.

  A sixth invention is characterized in that, in the fifth invention, the connecting means is a telescopic device capable of loading a compressive force on the steel roof structural member.

  According to the underground tank construction method of the present invention, an underground tank can be constructed with high accuracy in a short period of time.

  Hereinafter, a preferred embodiment of an underground tank construction method according to the present invention will be described in detail with reference to the drawings.

  FIG.1 and FIG.2 is the sectional side view and top view which show the state which has constructed | assembled the side wall 3 of the underground tank 2 using the formwork apparatus 1 which concerns on this invention, respectively.

  As shown in FIGS. 1 and 2, the mold apparatus 1 includes an inner mold 6 that is disposed inward from the inner wall 5 a of the cavity 5 formed in the ground 4 with a predetermined distance L, and an inner mold 6. A yoke 7 connected to the formwork 6, elevating means 8 for moving the yoke 7 up and down, a dome shell-shaped steel roof structural member whose one end is the yoke 7 and the other end is the structural material of the roof after construction 9, a connecting means 10 for connecting the steel roof structural member 9 to the yoke 7, and a work scaffold 14 that is attached to the lower side and the upper side of the yoke 7 and performs bar arrangement work. .

  The inner mold frame 6 is connected to the yoke 7 so as to maintain a predetermined distance L corresponding to the thickness of the side wall 3 from the inner wall 5a. In this embodiment, H-shaped steel is used as the yoke 7.

  The raising / lowering means 8 is comprised from the rod 8a embed | buried so that the longitudinal direction may become perpendicular | vertical in the side wall 3 under construction, and the jack 8b which can be raised / lowered using this rod 8a as a support | pillar. The jack 8b is joined to the yoke 7 by welding or the like, and the rod 8a is gripped by the jack 8b, and the yoke 7 is lifted using the rod 8a as a reaction material, thereby raising the mold apparatus 1 to a desired position. Let

  The connecting means 10 includes a telescopic device 10a for loading compressive force on the steel roof structural member 9, a strut 10b having one end connected to the telescopic device 10a and the other end connected to the yoke 7, and one end connecting material 10d. The steel roof structural member 9 is provided with a support member 10c having the other end connected to the yoke 7. In this embodiment, the screw jack which can be operated manually is used as the expansion and contraction device 10a, and the steel roof structural member 9, the strut 10b, and the H-shaped steel are used as the support member 10c.

  The telescopic device 10a and the strut 10b, the telescopic device 10a and the steel roof structural member 9, the steel roof structural member 9 and the connecting material 10d, the connecting material 10d and the supporting material 10c, and the supporting material 10c and the yoke 7 are respectively bolts 20. -The nut 21 is connected so as to be detachable. The strut 10b and the yoke 7 are joined by welding.

  In the present embodiment, a screw jack is used as the expansion and contraction device 10a. However, the present invention is not limited to this, and any other device that can load a compressive force on the steel roof structural member 9; For example, a spring or the like may be used.

  FIG. 3 is a diagram showing a schematic load state acting on the mold apparatus 1. As shown in FIG. 3, when the expansion / contraction device 10 a is extended and a compressive force F <b> 1 is loaded on the steel roof structural member 9, both ends of the steel roof structural member 9 are installed along the inner peripheral surface of the side wall 3. The reaction force F2 is generated in the axial direction of the strut 10b. The vertical downward load V3 acting on the support member 10c in this state includes a vertical downward load V2 due to the weight of the steel roof structural member 9 and a vertical force V1 which is a vertical upward component of the compressive force F1. It is canceled out and becomes a value smaller than the load V2. This load V3 is one of the factors that increase M1 in the bending moment that rotates the formwork device 1 toward the inside of the side wall 3, so that the load V3 is as small as possible, that is, F1sinθ (θ is for the component roof) The compression force F1 is adjusted so that the angle of the structural member 9 with respect to the horizontal direction at the support point by the expansion device 10a substantially coincides with the load V2.

  Since the bending moment M1 is a force for rotating the mold apparatus 1 toward the inside of the side wall 3, the inner mold frame 6 is deformed when this force is increased, and it is difficult to construct the side wall 3 with high accuracy. become. On the other hand, according to the construction method of the present invention, the bending moment M1 can be reduced, so that the side wall 3 can be constructed with high accuracy. Further, when the underground tank 2 becomes large, the weight of the steel roof structural member 9 increases and the bending moment M1 also increases. However, by using the construction method of the present invention, the bending moment M1 is reduced to reduce the inner mold. Since the deformation of the frame 6 can be suppressed, the side wall 3 can be constructed with high accuracy even when the underground tank 2 is enlarged.

  When the side wall 3 is constructed using the above-described formwork device 1, concrete is placed between the inner wall 5a and the inner formwork 6, and when the predetermined strength of the concrete is expressed, the formwork device is formed with the jack 8b. The operation of raising 1 to a desired position to secure the next concrete placement volume is repeated.

  FIG. 4 is a diagram showing a schematic load state when the mold apparatus 1 is raised. As shown in FIG. 4, when the mold apparatus 1 rises, in addition to the weight W <b> 1 of the mold apparatus 1 and the load V <b> 3, a frictional resistance W <b> 2 generated between the inner mold frame 6 and the inner peripheral surface of the side wall 3. Acts vertically downward. When the formwork device 1 tries to rotate toward the inside of the side wall 3 by these resultant forces (the bending moment generated by these resultant forces is assumed to be M2), it is compressed to the steel roof structural member 9 via the expansion / contraction device 10a. Force F3 is loaded. In such a state, the steel roof structural member 9 acts as an elastic body, and a reaction force F4 is generated in the axial direction of the strut 10b at the connecting portion between the steel roof structural member 9 and the telescopic device 10a. The horizontal component F4h of the reaction force F4 acts on the outer side of the side wall 3 to cause the mold apparatus 1 to generate a moment opposite to the bending moment M2. Therefore, the mold apparatus 1 has more than the bending moment M2. A small bending moment M3 acts. Therefore, since the bending moment M3 smaller than the bending moment M2 acts on the mold apparatus 1, the deformation of the inner mold 6 is suppressed, and the side wall 3 can be constructed with high accuracy.

  The steel roof structural member 9 has a dome shell structure composed of a beam 9a arranged in the radial direction and a beam 9b arranged in the circumferential direction, and has a three-dimensional direction in the circumferential direction, the radial direction, and the vertical direction. It has the rigidity of. For deformation due to work load such as deformation of the inner mold frame 6 due to frictional force generated between the inner mold frame 6 and the side wall 3 when the mold apparatus 1 is raised, or deformation of the inner mold frame 6 when placing concrete. On the other hand, the steel roof structural member 9 forming the dome shell structure acts so that the rigidity in the three-dimensional direction of the dome shell structure suppresses the deformation of the mold 6, so that the side wall 3 is constructed with high accuracy. Can do.

Next, the construction method of the underground tank 2 using the mold apparatus 1 will be described according to the construction procedure.
5-13 is a figure which shows the construction procedure of the underground tank 2. As shown in FIG.

  First, as shown in FIG. 5, the ground 4 is excavated in a cylindrical shape to a predetermined depth, the excavated soil is discharged, and the excavated portion is filled with concrete to construct the underground continuous wall 11.

  The underground continuous wall 11 has an external pressure load resistance performance that supports the earth pressure and groundwater pressure of the ground 4 and a water stop performance that prevents the inflow of groundwater from the ground 4 as much as possible, to a predetermined depth determined by design and the like. It is constructed with a predetermined thickness.

  And after the predetermined | prescribed intensity | strength of the underground continuous wall 11 expresses, as shown in FIG. 6, the inner earth and sand enclosed by the underground continuous wall 11 is excavated, and the cavity part 5 which upper direction opened is constructed | assembled. Although not shown, gravels, pebbles, crushed stones, and the like are laid on the bottom of the cavity 5, and a water collecting pipe and a pump are installed to construct a drainage layer.

  Next, as shown in FIG. 7, the bottom plate 12 is constructed by assembling a bottom plate reinforcing bar (not shown) on the drainage layer and placing concrete.

  Next, as shown in FIG. 8, after the desired strength of the bottom plate 12 is developed, the pedestal 13 is installed inwardly at a predetermined distance L from the inner wall 11 a of the underground continuous wall 11, and the steel is formed thereon. The structural member 9 for roof making is placed.

  And as shown in FIG. 9, the rod 8a and the side wall reinforcement 17 are arrange | positioned between the inner wall 11a of the underground continuous wall 11 and the mount 13, and concrete is laid, and the lower part 3a of the side wall 3 is constructed | assembled. In the present embodiment, the diameter of the side wall 3 is, for example, 30 m, but is not limited thereto.

  Next, as shown in FIG. 10, after the strength of the lower part 3a of the side wall 3 is developed, the mold apparatus 1 is installed on the lower part 3a of the side wall 3, and the expansion / contraction apparatus 10a of the mold apparatus 1 is extended. Then, a compressive force is loaded on the steel roof structural member 9, and then the formwork device 1 and the steel roof structural member 9 are connected. The connection is performed by tightening bolts 20 and nuts 21 for fastening the steel roof structural member 9 and the connecting member 10d that have been loosened when the compressive force is loaded. Then, after confirming that the steel roof structural member 9 is completely connected, the gantry 13 is removed.

  Next, as described above, concrete is placed between the inner wall 11a and the inner mold frame 6, and when the strength of the concrete is expressed, the jack 7, the yoke 7, the inner mold frame 6, and the steel roof structural member 9 is raised to a desired position to secure the next concrete placement volume, and concrete is again placed between the inner wall 11a of the underground continuous wall 11 and the inner mold 6 to form the side wall 3 having a thickness L. To construct.

  Next, as shown in FIGS. 11 and 12, when the construction of the side wall 3 in the underground portion is completed, the anchor 15 is driven on the side wall 3 to fix the formwork apparatus 1 to the side wall 3. And if it confirms that the formwork apparatus 1 is being completely fixed to the side wall 3, the expansion-contraction apparatus 10a will be shrunk and the compressive force loaded on the structural member 9 for steel roofs will be released, and the expansion-contraction apparatus 10a, Remove the strut 10b. The vertically downward load V2 due to the weight of the steel roof structural member 9 in this state is supported by the jack 8b and the anchor 15.

  Next, the roof ring plate 16 is installed at the place where the expansion and contraction device 10a and the strut 10b are attached, and one end of the roof ring plate 16 is embedded in the steel roof structural member 9 and the other end is embedded in the side wall 3. Each material 19 is joined by welding. After joining, the jack 8b and the part interfering in the side wall 3 of the yoke 7 are removed. Even if the part interfering in the side wall 3 of the jack 8b or the yoke 7 is removed, the formwork device 1 is fixed to the side wall 3 by the anchor 15, so it does not fall. Then, the side bars 17 are assembled to the upper end of the side wall 3, and the outer mold 18 and the inner mold 22 are installed.

  Finally, as shown in FIG. 13, concrete is placed between the outer mold 18 and the inner mold 6 to construct the upper portion 3b of the side wall 3, and the roof ring plate 16 and the side wall 3 are completely connected. Integrate. And although not shown in figure, the underground tank 2 is constructed | assembled by installing a roof board on the structural member 9 for steel roofs.

  According to the construction method of the underground tank 2 according to the present invention constructed as described above, the inner mold frame disposed inwardly with the thickness L of the side wall 3 from the inner wall 11a of the underground continuous wall 11. 6, a yoke 7 connected to the inner mold 6, lifting means 8 for moving the yoke 7 up and down, one end connected to the yoke 7, and the other end connected to the steel roof structural member 9. The side wall 3 in contact with the inner wall 11a of the underground continuous wall 11 can be constructed by using the formwork apparatus 1 including the connecting means 10 for connecting the structural member 9 to the yoke 7.

  Further, when the side wall 3 is constructed by using a formwork apparatus including the outer formwork 18 and the inner formwork 6 as in the prior art, the outer formwork lifting and lowering is performed between the inner wall 11 a and the sidewall 3. Whereas excavation work for excavating the gap and backfilling work for backfilling are required, in the present embodiment, the work for providing such a gap is not necessary, so the amount of excavated soil in the ground can be reduced. At the same time, the construction period can be shortened.

  Furthermore, since the formwork apparatus 1 and the steel roof structural member 9 are connected, the steel roof structural member 9 is partially responsible for the role of suppressing deformation of the formwork apparatus 1 and the side wall 3 is accurately obtained. Can be built. Moreover, by making the steel roof structural member 9 into a dome shell structure, the steel roof structural member 9 can be effectively burdened with the role of suppressing deformation of the mold 6 and the weight of the roof can be reduced. be able to.

  Moreover, since the side wall 3 is constructed under the steel roof structural member 9 while the steel roof structural member 9 is supported by the mold apparatus 1, the steel roof structural member 9 is constructed after the side wall 3 is constructed. As a result, the side wall 3 and the steel roof structural member 9 can be connected immediately after the side wall 3 is constructed. Therefore, when the steel roof structural member 9 is hung above the side wall 3 with a crane or the like after the side wall 3 is constructed as in the prior art, the side wall 3 and the steel roof structural member 9 are connected to each other. While it is necessary to perform the work at a high place and under a suspended load in which the scaffold 14 is installed on the upper part 3b of the side wall 3, such work is not necessary in the present embodiment, so the safety is greatly improved. To improve.

  And when the formwork apparatus 1 is raised, the reaction force F4 acts on the strut 10b from the structural member 9 for steel roof by loading the compressive force F3 on the structural member 9 for steel roof. Since the horizontal component F4h of the reaction force F4 acts in the outward direction of the side wall 3, the bending moment M2 acting on the mold apparatus 1 is reduced. Thereby, since the formwork apparatus 1 can be accurately installed at a predetermined position, the side wall 3 can be constructed with high accuracy.

It is a sectional side view which shows the state which has constructed | assembled the side wall using the formwork apparatus which concerns on this invention. It is a top view which shows the state which has constructed | assembled the side wall using the formwork apparatus which concerns on this invention. It is a figure which shows the general load state which is acting on the formwork apparatus. It is a figure which shows the general load state when a formwork apparatus raises. It is a figure which shows the construction procedure of an underground tank. It is a figure which shows the construction procedure of an underground tank. It is a figure which shows the construction procedure of an underground tank. It is a figure which shows the construction procedure of an underground tank. It is a figure which shows the construction procedure of an underground tank. It is a figure which shows the construction procedure of an underground tank. It is a figure which shows the construction procedure of an underground tank. It is a figure which shows the construction procedure of an underground tank. It is a figure which shows the construction procedure of an underground tank.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Formwork apparatus 2 Underground tank 3 Side wall 3a Lower part of side wall 3b Upper part of side wall 4 Ground 5 Cavity part 5a Inner wall 6 Inner form frame 7 Yoke 8 Lifting means 8a Rod 8b Jack 9 Steel roof structural members 9a, 9b Beam 10 Connection Means 10a Stretching device 10b Strut 10c Support material 10d Linking material 11 Underground continuous wall 11a Inner wall 12 Bottom plate 13 Mounting base 14 Scaffold 15 Anchor 16 Roof ring plate 17 Rebar for side wall 18 Outer frame 19 Extension material 20 Bolt 21 Nut 22 Inner mold L Predetermined interval

Claims (6)

In the construction method of the underground tank comprising a side wall installed along the inner wall of the cavity formed in the ground and a roof installed on the upper part of the side wall,
A mold frame that is arranged inward from the inner wall of the hollow portion at a predetermined interval, a yoke that is connected to the mold frame, lifting means for moving the yoke up and down, and steel that constitutes the roof Using a formwork apparatus provided with a connecting means for connecting the structural member for roof making to the yoke,
Connecting the formwork device and the steel roof structural member;
Concrete is placed between the inner wall and the formwork, and when a predetermined strength of the concrete is developed, the yoke is raised by the lifting means to thereby form the formwork device and the steel roof structural member. Build the side walls by repeating the work of raising,
A construction method of an underground tank, characterized in that the constructed side wall and the steel roof structural member are joined.   The construction method for an underground tank according to claim 1, wherein the steel roof structural member has a dome shell structure.   The connecting means includes a telescopic device capable of loading a compressive force on the steel roof structural member, and the steel roof is formed by extending the telescopic device and loading the steel roof structural member with the compressive force. 2. The construction method of an underground tank according to claim 1, wherein a bending moment inwardly of the side wall acting on the formwork device is reduced by a reaction force acting on the formwork device from a structural member. .   An underground tank constructed by the underground tank construction method according to any one of claims 1 to 3. A formwork device for constructing an underground tank comprising a side wall installed along an inner wall of a hollow portion formed in the ground and a roof installed on the upper side of the side wall,
A mold that is disposed inward from the inner wall of the hollow portion at a predetermined interval;
A yoke connected to the formwork;
Elevating means for moving the yoke up and down;
A formwork apparatus comprising: a connecting means for connecting a steel roof structural member constituting the roof to the yoke.   6. The formwork apparatus according to claim 5, wherein the connecting means includes an expansion / contraction device capable of loading a compressive force on the steel roof structural member.

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