JP2015183418A - Water pool and construction method of water pool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a concrete water pool and a construction method of the concrete water pool capable of preventing flow-out of water out of the water pool while reducing the construction time.SOLUTION: The concrete water pool includes: a water pool 11 that has a space capable of pooling water being enclosed by concrete walls; a manhole 12 constituting a gateway of the water pool 11; a water-resistant layer 2 formed along the inner face of the water pool 11; and a grid-like structure 3 which is assembled to fill the inside of the water pool 11 inside the water-resistant layer 2. The grid-like structure 3 is arranged so that a certain gaps Δgx1, Δgx2, Δgy1, Δgy2 and Δgz are ensured between a side wall 11a and a ceiling 11b of the water pool 11.

Description

  The present invention relates to a water tank and a water tank construction method, and more particularly to a water tank and a water tank construction method suitable for reuse of an existing water tank.

  In urban areas, concrete water tanks are often installed on the ground or underground in case the fire hydrant can no longer be used or when there is a shortage of drinking water during a disaster. A water tank for storing a quantity of water necessary for a minimum digestion activity in order to minimize damage in the event of a fire is generally called a fire prevention water tank. A water tank for storing water for drinking and digestion activities in case of a shortage of drinking water during a large-scale disaster such as an earthquake is generally called a water storage tank. In the present specification, the “water tank” includes at least both a fireproof water tank and a water tank.

  Concrete tanks are known to deteriorate due to exposure to the atmosphere, rainwater, underground moisture, etc. over many years, or corrosion of reinforcing bars embedded in concrete. Or refurbishment is required. In recent years, there is also a demand for reinforcement in order to improve the seismic performance of concrete water tanks in preparation for a large earthquake.

  For example, Patent Document 1 includes a base plate and a leg in a method for reinforcing an underground fire prevention water tank including a water tank part buried in the ground and a manhole part communicating with the water tank part and opening to the ground. Prepare a large number of frame units, lay the frame units on the bottom wall of the water tank part and stack them up to the vicinity of the ceiling wall of the water tank part, interposing a filler in the gap between the ceiling wall and the uppermost frame unit, There is disclosed a method for reinforcing an underground fire prevention water tank in which a ceiling wall is supported by a frame unit and a filler.

Japanese Patent No. 4795120

  In the reinforcing method described in Patent Document 1 described above, since a filler is interposed in the gap between the frame unit and the side walls and the ceiling wall of the fire prevention water tank, the construction work is difficult and the construction time is long. There was a problem that it would be prolonged. Moreover, in the method described in Patent Document 1, since the existing fire prevention water tank is merely reinforced, when cracks occur in the wall surface and the filler of the fire prevention water tank, the water in the fire prevention water tank is externally removed. There was also a problem of being leaked.

  The present invention was devised in view of the above-described problems, and provides a water tank and a water tank construction method capable of reducing the construction time and suppressing the outflow of water in the water tank. With the goal.

  According to the present invention, in a water tank comprising a water tank part having a space capable of storing water, and a manhole part constituting an entrance / exit of the water tank part, a waterproof layer formed along the inner surface of the water tank part, A lattice-like structure constructed so as to bury the inside of the water tank inside the waterproof layer, and the lattice-like structure has a certain gap between the side wall and the ceiling of the water tank. A water tank is provided, which is characterized in that it is arranged in

  The water tank may have a gap adjusting member that is disposed on the outer periphery of the lattice structure and adjusts the size of the gap. The gap adjusting member is constituted by, for example, a plate material, a frame structure, an extendable rod member, or a combination thereof.

  The said waterproof layer is a prevention sheet affixed on the inner surface of the said water tank part, for example. Further, the lattice structure is formed by combining a plurality of resin blocks each having a substantially flat substrate and a plurality of legs standing on the substrate, for example.

  Further, according to the present invention, there is provided a method for constructing a water tank comprising a water tank part having a space capable of storing water and a manhole part constituting an entrance / exit of the water tank part, and is waterproof along the inner surface of the water tank part. A lattice-like structure is constructed so that a waterproof step of forming a layer and the inside of the water tank portion are buried inside the waterproof layer, and a certain gap is provided between the side wall and the ceiling of the water tank portion There is provided a method for constructing a water tank, comprising: constructing an internal water tank comprising the waterproof layer and the lattice structure inside the water tank portion.

  The construction method of the water tank may include a gap adjusting step of arranging a gap adjusting member for adjusting the size of the gap on the outer periphery of the lattice structure.

  According to the above-described water tank and the method for constructing the water tank according to the present invention, for example, repair is performed by disposing a waterproof layer and a lattice structure inside a water tank (external water tank) made of concrete, metal, resin, or the like. Or a new water tank (internal water tank) can be formed inside the external water tank to be repaired. Therefore, even if a crack occurs in the wall surface of the external water tank due to deterioration of the external water tank or an earthquake, the outflow of water can be suppressed by the internal water tank. In addition, since no filler is arranged between the internal water tank and the external water tank, the work effort at the time of constructing the internal water tank can be reduced, and the construction time can be shortened.

  In addition, by forming a certain gap between the wall surface of the external water tank and the lattice structure, when the external water tank is distorted beyond this gap due to an earthquake or the like, the load applied to the external water tank is latticed. It can be transmitted to the structure, and the subsidence and deformation of the ground around the external water tank can be suppressed. Furthermore, the reduction of space due to distortion can be suppressed, and the planned water storage amount can be secured.

It is a figure which shows the concrete water tank which concerns on 1st embodiment of this invention, (A) is a longitudinal cross-sectional view, (B) is BB arrow sectional drawing in FIG. 1 (A). It is explanatory drawing regarding a lattice-shaped structure, (A) is a perspective view of a resin block, (B) is a perspective view which shows the state which combined the resin block. It is a figure which shows the concrete water tank which concerns on 2nd embodiment of this invention, (A) is a longitudinal cross-sectional view, (B) is BB arrow sectional drawing in FIG. 3 (A). It is a longitudinal cross-sectional view which shows the construction method of the concrete water tank which concerns on embodiment of this invention, (A) has shown the state before construction, (B) has shown the waterproofing process. It is a longitudinal cross-sectional view which shows the construction method of the concrete water tank which concerns on embodiment of this invention, (A) has shown the frame | skeleton formation process, (B) has shown the clearance gap adjustment process.

  Hereinafter, an embodiment of a water tank and a water tank construction method according to the present invention will be described with reference to FIGS. Here, FIG. 1 is a figure which shows the concrete water tank which concerns on 1st embodiment of this invention, (A) is a longitudinal cross-sectional view, (B) is BB arrow sectional drawing in FIG. 1 (A). . 2A and 2B are explanatory diagrams relating to the lattice-like structure, in which FIG. 2A is a perspective view of a resin block, and FIG. 2B is a perspective view showing a state in which the resin blocks are combined. FIG. 3: is a figure which shows the concrete water tank which concerns on 2nd embodiment of this invention, (A) is a longitudinal cross-sectional view, (B) is a BB arrow directional cross-sectional view in FIG. 3 (A). .

  As shown in FIGS. 1A and 1B, a concrete water tank 1 according to an embodiment of the present invention has a water tank part 11 having a water-storable space surrounded by a concrete wall, and an entrance / exit of the water tank part 11. A manhole portion 12, a waterproof layer 2 formed along the inner surface of the water tank portion 11, and a lattice structure 3 constructed so as to fill the inside of the water tank portion 11 inside the waterproof layer 2. The lattice structure 3 is arranged so as to have constant gaps Δgx1, Δgx2, Δgy1, Δgy2, Δgz between the side wall 11a and the ceiling 11b of the water tank unit 11.

  The concrete water tank 1 is, for example, a fire prevention water tank or a water storage tank disposed underground or on the ground, and is a water tank for storing water for fire extinguishing or drinking. Concrete has features such as high degree of freedom of modeling, high fire resistance, strong compression, excellent durability, and large mass, and is often used for installation-type fire prevention water tanks and water storage tanks. Since the concrete water tank 1 is required to have water tightness (resistance to water penetration and permeation), the concrete water tank 1 is made of so-called water tight concrete. In addition, although the case where the concrete water tank 1 is used as an example of the water tank is described in this embodiment, the water tank forming the external water tank may be made of metal or resin.

  The water tank portion 11 generally has a substantially rectangular parallelepiped shape, but may be a cylindrical shape or a spherical shape. The manhole portion 12 is an entrance for an operator to enter and exit the water tank portion 11 for maintenance and the like. When the concrete water tank 1 is installed underground, the manhole part 12 is extended until it reaches the ground surface. Further, a ladder 13 is disposed from the manhole part 12 to the inside of the water tank part 11.

  The waterproof layer 2 is formed of a resin waterproof sheet mainly composed of, for example, vinyl chloride, vulcanized rubber, EVA (ethylene-vinyl acetate copolymer resin), or the like. The waterproof layer 2 is preferably attached to the inner surface of the water tank unit 11. For example, the waterproof sheet forming the waterproof layer 2 may be attached with an adhesive, or may be attached using a metal fitting such as a stud pin or a rivet. At this time, the entire surface of the waterproof sheet may be affixed to the inner surface of the water tank part 11, or only a part may be affixed to the inner surface of the water tank part 11. In addition, if a waterproof sheet can be arrange | positioned in the position close | similar to the inner surface of the water tank part 11, it does not necessarily need to stick.

  Thus, by sticking the waterproof sheet forming the waterproof layer 2 to the inner surface of the water tank part 11, a bag body having the maximum volume in the water tank part 11 can be easily formed. In addition, the waterproof layer 2 is not limited to a waterproof sheet, For example, you may make it form with a coating, a waterproof material, concrete, steel materials, etc.

  The lattice structure 3 forms a skeleton that three-dimensionally holds the space formed by the waterproof layer 2. In particular, when the waterproof layer 2 is formed of a waterproof sheet, even if the waterproof sheet is peeled off from the inner surface of the water tank portion 11 by disposing the lattice structure 3 inside the waterproof layer 2, A substantially rectangular parallelepiped tank shape can be maintained. Here, “lattice shape” means a structure composed of vertical members and cross members as a whole, and is intended to include diagonal materials and plate materials as necessary. Note that the lattice-like structure 3 may be made of resin, wooden, or metal, for example.

  For example, as shown in FIG. 2A, the lattice-like structure 3 is formed by combining a plurality of resin blocks 33 each having a substantially flat plate-like substrate 31 and a plurality of legs 32 standing on the substrate 31. Is done. The board | substrate 31 and the leg part 32 are formed of the resin-made planes and curved surfaces formed in the substantially grid | lattice form, for example. The leg portion 32 may be formed to be detachable from the substrate 31. The illustrated shape of the resin block 33 is merely an example, and is not limited to the illustrated shape.

  As shown in FIG. 2 (B), the pair of resin blocks 33 are connected and unitized by abutting the leg portions 32 of each other. By this unitization, a base unit 34 having a substantially lattice shape is formed. By disposing a plurality of the base units 34 in the horizontal direction and the vertical direction, a lattice-like structure 3 as shown in FIGS. 1A and 1B is formed. Further, by connecting a resin-made side wall 35 to the outer periphery of the lattice structure 3, the load can be transmitted to a portion that resists the load of the lattice structure 3.

  By using the above-described resin block 33, as shown in FIGS. 1 (A) and 1 (B), even if the lattice-like structure 3 is spread inside the water tank portion 11, the missing space is reduced to 8%. %. Therefore, even if this embodiment is adopted, it is possible to suppress a decrease in the amount of stored water.

  In addition, as shown in FIG. 1A, a bottom plate 36 may be disposed under the lattice structure 3. The bottom plate 36 is disposed, for example, on the waterproof layer 2 formed on the bottom surface of the water tank unit 11 and forms a stable plane for constructing the lattice structure 3. When the bottom plate 36 is disposed inside the waterproof layer 2, it is preferable that the bottom plate 36 is formed of a resin flat plate formed in a substantially lattice shape in order to suppress an increase in the defect space. The bottom plate 36 may be disposed outside the waterproof layer 2, but in this case, the amount of water stored in the internal water tank is reduced by the volume of the bottom plate 36.

  The lattice-like structure 3 is constructed so as to be close to the side wall 11a and the ceiling 11b of the water tank unit 11. Moreover, it is necessary to ensure the space below the manhole part 12 so that a worker can pass through. Accordingly, a frame 14 formed in a substantially cylindrical shape is constructed below the manhole portion 12.

  Moreover, as shown to FIG. 1 (A) and (B), the concrete water tank 1 which concerns on this embodiment is arrange | positioned on the outer periphery of the grid-like structure 3, and the clearance gap adjustment member for adjusting the magnitude | size of a clearance gap 4. The corners of the lattice-like structure 3 are positioned, for example, at the farthest corner from the manhole part 12 and are assembled toward the manhole part 12 from there. Therefore, the lattice structure 3 has a gap Δgx1 in the X direction and a gap Δgy1 in the Y direction with respect to the two side walls 11a forming the corners of the positioned water tank portion 11.

  And when the lattice-like structure 3 is built in the water tank part 11, the gap on the opposite side to the gap Δgx1 and the gap Δgy1 may be too large. Since the lattice-like structure 3 forms a skeleton of the internal water tank formed by the waterproof layer 2, it is preferably constructed as close to the waterproof layer 2 as possible.

  Therefore, when the gap between the grid structure 3 and the inner surface of the water tank portion 11 is large, a gap adjustment member 4 for adjusting the size of the gap may be disposed on the outer periphery of the grid structure 3. Good. The gap adjusting member 4 is configured by, for example, a plate material, a frame structure, an extendable rod member, or a combination thereof. The plate material and the frame structure are made of resin or metal and are configured in a lattice shape or a truss shape. The plate material is used when finely adjusting the gap, and the frame structure when adjusting a relatively large gap. The body can be used.

  In addition, when a device having an extendable rod member such as a jack device is used, the gap between the lattice structure 3 and the inner surface of the water tank 11 is adjusted by individually adjusting the length of the rod member. The size can be adjusted. Between the side wall 11a in the X direction close to the manhole portion 12 and the lattice structure 3, a gap adjusting member 4 constituted by a plate member or a frame structure is disposed on the outer periphery of the frame 14 and the lattice structure 3, A clearance adjustment member 4 having a rod member that can be expanded and contracted is disposed on the surface thereof, and adjusted to a clearance Δgx2.

  Further, between the side wall 11a in the Y direction close to the manhole portion 12 and the lattice structure 3, the gap adjustment member 4 (plate) formed of a plate material or a frame structure on the outer periphery of the frame structure 14 and the lattice structure 3 is provided. A gap adjusting member 4 (jack-like adjusting member 42) having a rod member that can expand and contract on its surface is arranged and adjusted to the gap Δgy2. The plate-like adjusting member 41 also functions as a member that forms a plane on which the jack-like adjusting member 42 is arranged.

  The gaps Δgx1, Δgx2 in the X direction and the gaps Δgy1, Δgy2 in the Y direction are, for example, a lattice-like structure even if the concrete water tank 1 is distorted due to an earthquake or the like. Since the body 3 shares the load, it is possible to suppress the reduction of the space due to the distortion, and it is possible to suppress the settlement and deformation of the surrounding ground. Therefore, these gaps Δgx1, Δgx2, Δgy1, and Δgy2 depend on conditions such as the size of the concrete water tank 1, the thickness of the concrete, the placement location (region, underground, ground, etc.), the placement environment (soil properties, etc.), etc. It is changed appropriately.

  Further, as shown in FIGS. 1A and 1B, when the jack-shaped adjusting member 42 is disposed at a position facing the side wall 11 a of the water tank portion 11, the base unit constituting the lattice structure 3 It is preferable to arrange along 34 connecting portions. With this arrangement, even when a load is applied to the gap adjusting member 4, it can be received at a portion where the strength of the lattice structure 3 is high. Note that the gap Δgz is appropriately changed depending on conditions such as the size of the concrete water tank 1, the thickness of the concrete, the placement location (region, underground, ground, etc.), the placement environment (soil properties, etc.).

  Further, as shown in FIG. 1A, between the ceiling 11b and the lattice-like structure 3, a jack-like adjusting member 42 arranged on the upper surface of the lattice-like structure 3, and the jack-like adjusting member 42 are arranged thereon. The gap adjusting member 4 constituted by the plate-like adjusting member 41 is arranged and adjusted to the gap Δgz. You may make it arrange | position the jack-shaped adjustment member 42 directly on the upper surface of the lattice-like structure 3 according to clearance gap (DELTA) gz with the concrete water tank 1. FIG. The plate-like adjusting member 41 has a function of receiving a piece of concrete and suppressing the dropping onto the lattice-like structure 3 when, for example, a part of the concrete of the ceiling 11b is dropped and dropped. The arrangement of the jack-like adjusting member 42 and the plate-like adjusting member 41 may be switched.

  Further, when the jack-shaped adjusting member 42 is disposed on the upper surface of the lattice-like structure 3, it is preferably disposed on the legs 32 of the lattice-like structure 3. With this arrangement, even when a load is applied to the gap adjusting member 4, it can be received at a portion where the strength of the lattice structure 3 is high.

  In addition, when the lattice-like structure 3 is constructed, if a gap is generated between the frame structure 14, the filler 5 that fills the gap may be disposed. The filler 5 is composed of, for example, a plate material or a frame structure. The plate material and the frame structure are made of resin or metal and are configured in a lattice shape or a truss shape. The plate material is used when finely adjusting the gap, and the frame structure when adjusting a relatively large gap. The body can be used. By disposing the filler 5, it is possible to transmit deformation and load due to an earthquake or the like acting on the frame 14 to the lattice structure 3, and it is possible to improve earthquake resistance.

  Here, FIG. 3 (A) and (B) have shown the concrete water tank 1 which concerns on 2nd embodiment of this invention. In the concrete water tank 1 according to the second embodiment, the gap adjusting member 4 is constituted by a gap adjusting member 4 (plate-like adjusting member 41) constituted by a plate material or a frame structure. As described above, the configuration and combination of the gap adjusting member 4 can be appropriately changed according to the size of the gap to be adjusted.

  According to the concrete water tank 1 which concerns on 1st embodiment and 2nd embodiment mentioned above, the concrete water tank which wants to repair or renovate by having arrange | positioned the waterproof layer 2 and the grid-like structure 3 in the inside of the concrete water tank 1. A new water tank (internal water tank) can be formed inside 1. Therefore, even if a crack occurs in the wall surface of the concrete water tank 1 due to deterioration of concrete or an earthquake, the outflow of water can be suppressed by the internal water tank. Moreover, since the filler is not arrange | positioned between an internal water tank and an external water tank (concrete water tank 1), the work effort at the time of an internal water tank construction can be reduced, and construction time can be shortened.

  Further, by forming certain gaps Δgx1, Δgx2, Δgy1, Δgy2, Δgz between the wall surface (side wall 11a and ceiling 11b) of the concrete water tank 1 and the lattice structure 3, the concrete water tank 1 is caused by an earthquake or the like. Can be transmitted to the grid-like structure 3 when the ground is distorted to more than the gaps Δgx1, Δgx2, Δgy1, Δgy2, Δgz. Subsidence and deformation can be suppressed. Furthermore, the reduction of space due to distortion can be suppressed, and the planned water storage amount can be secured.

  Next, the construction method of the concrete water tank 1 according to the embodiment of the present invention will be described with reference to FIGS. 4 and 5. Here, FIG. 4 is a longitudinal sectional view showing a method for constructing a concrete water tank according to an embodiment of the present invention, wherein (A) shows a state before construction, and (B) shows a waterproofing step. FIG. 5 is a longitudinal sectional view showing a method for constructing a concrete water tank according to an embodiment of the present invention, in which (A) shows a skeleton formation step and (B) shows a gap adjustment step.

  A concrete water tank 1 according to the present embodiment includes a water tank part 11 having a water-storable space surrounded by a concrete wall, and a manhole part 12 constituting an entrance / exit of the water tank part 11. 1, a waterproofing step of forming the waterproof layer 2 along the inner surface of the water tank unit 11, a side wall 11 a of the water tank unit 11 so as to bury the inside of the water tank unit 11 inside the waterproof layer 2. And a skeleton forming step for constructing the lattice-like structure 3 so as to have a certain gap between the ceiling 11b and a gap adjusting member 4 for adjusting the size of the gap are arranged on the outer periphery of the lattice-like structure 3 The internal water tank comprised by the waterproof layer 2 and the grid | lattice-like structure 3 is constructed | assembled in the inside of the water tank part 11.

  As shown to FIG. 4 (A), the concrete water tank 1 has the water tank part 11, the manhole part 12, the ladder 13, etc. similarly to a normal fire prevention water tank and a water storage tank. The concrete water tank 1 may be an existing fire prevention water tank or water storage tank, or may be a new fire prevention water tank or water storage tank.

  As shown in FIG. 4B, the waterproofing step is a step of attaching a waterproof sheet for forming the waterproof layer 2 to the entire inner surface of the water tank 11 (excluding the lower portion of the manhole 12). A waterproof sheet is affixed on the inner surface of the water tank part 11 with an adhesive agent or metal fittings. Thus, by attaching (fixing) the waterproof sheet to the inner surface of the water tank portion 11, the waterproof layer 2 can be easily formed, and the subsequent work such as carrying in and assembling the lattice-like structure 3 can be performed. It can be done easily.

  In the skeleton formation process, as shown in FIG. 5A, the resin block 33 shown in FIG. 2A is carried into the water tank unit 11, and the base unit 34 shown in FIG. 2B is assembled. The lattice structure 3 is constructed by arranging a plurality of the base units 34 in the horizontal direction and the vertical direction. In such a skeleton formation step, it is preferable to lay the bottom plate 36 and the frame 14 before constructing the lattice structure 3. In addition, when the gap between the lattice structure 3 and the frame 14 is open, the filler 5 may be disposed.

  In such a skeleton formation process, the lattice-like structure 3 is constructed so as not to contact the inner surface of the water tank portion 11. Moreover, the corner | angular part of the grid-like structure 3 is positioned so that it may be located in the corner | angular part of the water tank part 11 furthest from the manhole part 12, and it may be constructed so that the inside of the water tank part 11 may be filled toward the manhole part 12 from there. .

  In the gap adjusting step, as shown in FIG. 5B, the gap adjusting member 4 composed of the plate-like adjusting member 41 and the jack-like adjusting member 42 is arranged on the outer periphery of the lattice-like structure 3, and the water tank This is a step of adjusting the gap with the part 11. Thus, by forming a certain gap between the wall surface (side wall 11a and ceiling 11b) of the concrete water tank 1 and the lattice structure 3, the concrete water tank 1 is distorted more than this gap due to an earthquake or the like. In this case, the load applied to the external water tank (concrete water tank 1) can be transmitted to the lattice structure 3, and the settlement and deformation of the ground around the external water tank can be suppressed. Furthermore, the reduction of space due to distortion can be suppressed, and the planned water storage amount can be secured.

  Moreover, according to the construction method of the concrete water tank 1 which concerns on this embodiment, since the waterproof layer 2 and the grid | lattice-like structure 3 are arrange | positioned inside the concrete water tank 1, the inside of the concrete water tank 1 which wants to repair or renovate. A new water tank (internal water tank) can be formed. Therefore, even if a crack occurs in the wall surface of the concrete water tank 1 due to deterioration of concrete or an earthquake, the outflow of water can be suppressed by the internal water tank.

  In addition, when it is not necessary to adjust the clearance gap between the inner surface of the water tank part 11 as a result of constructing the lattice-like structure 3 by the skeleton formation process, the clearance adjustment process can be omitted.

  The present invention is not limited to the above-described embodiment. For example, the same resin wall material may be used for the filler 5, the base unit 34, the side wall 35, and the plate-like adjustment member 41. It goes without saying that various modifications can be made without departing from the scope of the invention.

DESCRIPTION OF SYMBOLS 1 Concrete water tank 2 Waterproof layer 3 Grid-like structure 4 Gap adjustment member 5 Filler 11 Water tank part 11a Side wall 11b Ceiling 12 Manhole part 13 Ladder 14 Frame 31 Substrate 32 Leg part 33 Resin block 34 Base unit 35 Side wall 36 Bottom plate 41 Plate -Shaped adjusting member 42 Jack-shaped adjusting member

Claims (7)

In a water tank comprising a water tank part having a space capable of storing water, and a manhole part constituting an entrance and exit of the water tank part,
A waterproof layer formed along the inner surface of the water tank,
A lattice-like structure constructed so as to bury the inside of the water tank inside the waterproof layer, and
The lattice structure is arranged so as to have a certain gap between the side wall and the ceiling of the water tank part,
An aquarium characterized by that.   The water tank according to claim 1, further comprising a gap adjusting member that is disposed on an outer periphery of the lattice-like structure and adjusts the size of the gap.   The water tank according to claim 2, wherein the gap adjusting member is configured by a plate material, a frame structure, an extendable rod member, or a combination thereof.   The water tank according to any one of claims 1 to 3, wherein the waterproof layer is a waterproof sheet attached to an inner surface of the water tank part.   5. The grid structure according to claim 1, wherein the lattice structure is formed by combining a plurality of resin blocks each having a substantially flat substrate and a plurality of legs standing on the substrate. The water tank according to one item. A water tank construction method comprising a water tank part having a space capable of storing water, and a manhole part constituting an entrance / exit of the water tank part,
A waterproofing step of forming a waterproof layer along the inner surface of the water tank,
A skeleton forming step of constructing a lattice structure so as to bury the inside of the water tank part inside the waterproof layer and to have a certain gap between the side wall and the ceiling of the water tank part. And
Constructing an internal water tank constituted by the waterproof layer and the lattice structure inside the water tank part,
A method for constructing a water tank. The method for constructing an aquarium according to claim 6, further comprising a gap adjusting step of arranging a gap adjusting member for adjusting the size of the gap on an outer periphery of the lattice structure.