JP2003160944A - Construction method for precast concrete reservoir - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to efficiently construct a reservoir having the interior space with a large height in a short construction period without requiring skilled workers. <P>SOLUTION: The precast concrete reservoir is constructed in a excavated space 6, in which an earth-retaining wall support 5 is assembled, the support 5 comprising a plurality of strut frameworks 3 arranged vertically by putting together struts 2a running sidewise and struts 2b running front to rear in a latticed arrangement in plan view. Each sidewise strut 2a and front-to-rear strut 2b is arranged to be overlapped to each other in plan view. Supports 9 are stood on the bottom 8 of the excavated space, and the upper ends of the supports 9 are positioned below the upper-most struts, and the upper ends of adjacent supports 9, 9 are connected together by a connecting beam 11, respectively. Respective sections 7a, 7b formed by the strut frameworks include one support 9, and the one within the section 7a formed by the front-to-rear struts is erected at the same corner of rectangular sections. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a water tank made of precast concrete, which is suitable for constructing an underground buried type water tank made of precast concrete having a large inner height.

[0002]

2. Description of the Related Art In urban areas, cases of constructing rainwater storage tanks and multipurpose storage tanks underground have been increasing in recent years for the purpose of preventing urban flood damage or using water for multiple purposes.

On the other hand, from the aspect of urban environment, there is a demand for shortening the construction period in order to minimize noise and pollution. In recent years, due to labor shortage due to lack of skilled workers, there is a demand for a construction method capable of realizing such shortening of the work period without skilled workers.

[0004] Against this background, various precast concrete water tank construction methods (hereinafter referred to as precast methods) have been proposed so that construction can be performed without skilled workers and the construction period can be shortened. For example, a precast method in which box-shaped blocks a as shown in FIG. 49 are arranged side by side at a required interval, and their upper ends are connected to each other by a top slab block b, and L-shaped blocks at the ends as shown in FIG. c and an intermediate I-shaped block d are arranged side by side at a required interval, and their upper ends are connected by a top plate block e, or an L-shaped wall block f as shown in FIG. 51. Column block g, connecting beam block h,
A precast method or the like has been put to practical use in which the top blocks j and the like are used to connect the upper ends of the pillar blocks g adjacent to each other in one direction with the connecting beam block h.

Such a precast method has a depth of 5-6.
It is for the construction of a small-scale water tank with a relatively small inner space height, which is constructed in an excavation space of about m, and the earth retaining wall used for this is steel sheet pile if the ground is good. It was possible to deal with the self-supporting earth retaining wall that was just driven in. And when the ground is not good, the retaining wall was supported by the support work with a single beam. In the case of supporting the single-stage cut beam, various precast concrete members can be installed below the cut beam, so that the water tank for joining the members can be constructed without any trouble.

[0006] However, if the inner height of the water tank becomes large, for example, 5 m or more, the excavation depth will inevitably become deeper. Therefore, the support work for the self-supporting earth retaining wall and the single-level girder simply by driving the steel sheet pile is performed. Can't handle it. Therefore, the earth retaining wall formed by driving the steel sheet pile has to be supported by the supporting work in which the cross beams are provided in the upper and lower stages.

However, when such a construction method is used,
The crossbeam framework in which the crossbeams in the left-right direction and the front-rear direction intersect in a grid pattern is present in the excavation space in a plurality of upper and lower stages. Therefore, when applying the above-mentioned conventional type precast method to construct a water tank with such a large inner air height, the beams in the middle and bottom steps become an obstacle, and the above-mentioned blocks are extended vertically and horizontally. It was difficult to do. Also, when installing the wallboard in the horizontal or vertical direction, the crossbeams existing in the middle and the lowest steps become an obstacle, which makes it difficult to install the wallboard continuously in the horizontal or vertical direction. did.

As for the precast method (FIG. 51) in which the upper ends of the pillar blocks g, which are adjacent to each other in one direction, are connected by the connecting beam block h, this is a relatively small scale with an inner height of up to 5 m. When it is intended for the water storage tank of No. 1, it can be dealt with by the support work by the above-mentioned one-step beam. In the case of such support work, connecting beam block h
In order to secure a working space and to easily connect the column blocks to each other, the column block is formed into a rectangular section formed by a grid-shaped cut beam k, as shown in FIG. It was common to stand upright at the center of one side p of n. When the precast method is used, the construction of the water tank can be completed under the beam, and after the completion of the construction, the backfilling and the work of dismantling and removing the supporting structure including the beam can be done without any problems. I was able to do it.

However, when the inner air height of the water storage tank is increased to 5 m or more, the crossbeams k have a plurality of stages as described above.
Then, the upper end of the pillar block is normally positioned on the slightly lower side of the upper cross beam k. In this way, when the crossbeams k have a plurality of stages, even if the water tank is constructed with these crossbeams existing, as described above, the middle and the lowest crossbeams become obstacles. Therefore, such construction becomes extremely difficult. In order to solve this, with the attachment of the wall plate from the bottom to the top, backfilling is performed between the wall plate and the retaining wall, and after the backfilling, the cutting beam immediately above is dismantled, It is necessary to proceed with water tank construction while removing it. When the construction is performed in this manner, the technique according to claims 10 and 11 of the present invention is applied to stabilize the strut block that supports the wall plate that receives the pressure from the backfill soil, so It is conceivable to connect all of them with the connecting beam block. That is, it is necessary to provide the connecting beam blocks not only in one direction as described above but also in two directions orthogonal to each other.

In that case, as described above, since the pillar block is erected at the center of the rectangular section in close proximity to one side p, the connecting beam block is unidirectional as described above (see FIG. 52). Even if the work of connecting in the direction indicated by the arrow F1) can be easily performed, when the connection is made in the direction orthogonal thereto (the direction indicated by the arrow F2 in FIG. 52), the crossbeam will be an obstacle. Will occur. This will be described in more detail below with reference to the drawings.

That is, in the step of connecting the upper ends of the pillar blocks g to each other by the connecting beam block h, first, as shown in FIG. 53, both ends q and q are fixed to both ends r and r of the connecting beam block h. The central part of the hanging rope s composed of a wire is hooked on the hook t of the crane and lifted. The angle between the inclined pieces u, u of the suspension rope s is set to, for example, 60 degrees. When the upper ends of the pillar blocks g adjacent to each other in the one direction F1 are to be connected by the connecting beam block h, the connecting beam block h suspended in the section n is used.
As shown in FIG. 54, the lateral movement can be performed in a state where the slanted side u of the suspension rope s does not contact the cross beam k. However, when the upper ends of the pillar blocks g, g adjacent to each other in the orthogonal direction F2 are to be connected to each other, the partition n
When laterally moving the connecting beam block h suspended by
The slanting piece u of the hanging rope s hits the cross beam k as shown in FIG. Therefore, as shown in FIG. 56, it is extremely difficult to connect the upper ends of the column blocks g in the front-rear direction with the connecting beam block h unless the end q of the suspension rope s is replaced. . As shown in FIG. 56, when replacing the end portion of the suspension rope s, the work is performed while the connecting beam block g is suspended. Therefore, the replacement is extremely difficult. The problem that it is troublesome and forced to do dangerous work,
Not practical at all. As described above, when the upper ends of the pillar blocks are connected to each other in the direction F2 which is orthogonal to the one direction, there arises a problem that the cutting beam becomes an obstacle.

For this reason, conventionally, a water tank having a large inner air height (inner air height is, for example, 5 to 10 m) has been constructed by cast-in-place construction. In the case of such cast-in-place construction, even if a crossbeam frame assembly in which the crossbeams intersect in a grid pattern is provided in a plurality of upper and lower stages, the material is placed in the excavation space through the rectangular enclosure formed by the front, rear, left, and right cut beams. Since it can be introduced and the lateral movement of the material is also free, there was an advantage that the desired water tank could be constructed relatively easily. However, in order to prevent the pillars and walls from being destabilized by earth pressure when they are backfilled during the process of extending the pillars and walls upward,
It was necessary to support them with a horizontal support beam portion in the middle. However, in order to support the supporting beam portion in this way, it is necessary to specially assemble a formwork for forming the supporting beam part and a supporting work for supporting the formwork, and therefore, it is necessary to construct a water tank. Therefore, there was a problem that the construction period was prolonged and the construction cost was increased. Further, since the supporting beam portion is provided in this manner, there is a problem that the internal volume of the water storage tank is reduced by that amount.

[0013]

SUMMARY OF THE INVENTION The present invention has been developed in view of the above-mentioned problems of the prior art, and facilitates the connection of columns with each other by a connecting beam, and further advances the wall between the columns existing on the outer periphery. The problem is to provide a construction method for a water tank made of precast concrete that makes it possible to efficiently construct a water tank with a large inner air height by making it possible to attach plates easily in a short construction period and without requiring skilled workers. To do.

[0014]

In order to solve the above problems, the present invention adopts the following means. That is, the first aspect of the construction method of the precast concrete water storage tank according to the present invention (hereinafter referred to as the construction method) is assembling so that the cross beams in the left-right direction and the cross beams in the front-rear direction intersect in a grid pattern in a plan view. It is a construction method to construct a water tank made of precast concrete in the excavation space where the earth retaining wall support is provided in the upper and lower stages of the timber frame structure. The left and right horizontal beams and the front and rear vertical beams arranged in a plurality of upper and lower stages are formed so as to substantially overlap each other in a plan view. Further, a pillar is erected in a required arrangement at the bottom of the excavation space, the upper end of the pillar is located below the uppermost beam, and the upper ends of the adjacent pillars are connected to each other by a connecting beam, which exists on the outer circumference. The pillars shall support the wall plates sequentially attached from the bottom to the top so as to cover the spaces between the pillars on the outer circumference, and the pillars arranged inside the pillars on the outer circumference are the front, rear, left and right beams. The columns are made to exist one by one in the rectangular section formed by, and the columns are erected at the same corner portion of the rectangular section.

In the above-mentioned construction method, among the rectangular compartments formed by the front, rear, left and right beams, the required ones of the compartments on the outer periphery are combined with the pillars which do not support the wall board, and also the pillars which support the wall board. May be present.

A more specific aspect (second aspect) of the construction method according to the present invention comprises a left-right beam and a front-back beam which are assembled so as to intersect in a grid pattern in a plan view. A construction method for constructing a water tank made of precast concrete in an excavation space provided with earth retaining wall support, wherein in the earth retaining wall support, horizontal beams and vertical upper and lower stages arranged in a plurality of upper and lower stages. The cross beams in the front-rear direction, which are arranged in the above, respectively, are formed so as to substantially overlap each other in a plan view. Further, a pillar is erected in a required arrangement at the bottom of the excavation space, the upper end of the pillar is located below the uppermost beam, and the upper ends of the adjacent pillars are connected to each other by a connecting beam, which exists on the outer circumference. The pillars shall support the wall plates sequentially attached from the bottom to the top so as to cover the spaces between the pillars on the outer circumference, and the pillars arranged inside the pillars on the outer circumference are the front, rear, left and right beams. One of each of the columns is present in the rectangular section formed by, and the pillars are erected at the same corner portion of the rectangular section, and are located outside the rectangular section formed by the front, rear, left, and right cutting beams. The pillars to be installed on the corners are installed standing close to the crossbeam in a state of being opposed to the pillars standing at the corner portion in the front-rear direction or in a state of being opposed to the left-right direction. The distance between adjacent left and right crossing beam intersections The distance between the centers of the columns adjacent to each other when viewed in the front-rear direction is set to be substantially equal to the distance between the adjacent front and rear intersections of the cross beam intersections intersecting in a cross shape. To do.

In the first and second aspects, when the upper ends of the adjacent columns are connected to each other by the connecting beam, both ends of the hanging rope are fixed to both ends of the connecting beam by a hook. Hoisting, the connection beam is hung in the rectangular section in a state of being inclined with respect to the left-right direction and the front-rear direction, and the direction of the connection beam is changed in the left-right direction or the front-rear direction below the uppermost cut beam. Direction, and then the connecting beam is laterally moved in the left-right direction or the front-back direction, before the slanted side of the suspending rope comes into contact with the cross beam existing between the adjacent columns, or It is preferable that both end portions of the connecting beam are placed on the upper ends of the adjacent columns in a state where the inclined side of the rope is not bent and deformed even when the inclined side comes into contact with the cutting beam.

Further, in the first and second aspects, the earth retaining wall support work includes a support pile for supporting the cutting beam from below, which is the same at an intersection portion of the cutting beam in the left-right direction and the cutting beam in the front-rear direction. It is preferable that the pillars are formed by being erected at the corner portions (not necessarily erected at all of the same corner portions), and the pillars are erected in a diagonal arrangement with the support piles.

In each of the construction methods described above, it is preferable that the pillar has a support projection formed at the upper end thereof so as to project laterally, and the end portion of the connecting beam is placed on the support projection. . In this case, in plan view, the distance between the side end of the support protrusion and the girder facing it is 10 to 40c.
It is better to set to m.

In addition, in the first and second aspects, when attaching the wall plate so as to cover between the adjacent columns existing on the outer periphery, both ends of the hanging rope fixed to both end sides of the wall plate. The central part is hung up with a hook, and the wall plate is hung in the section in which the stanchions are present with the wall plate inclined with respect to the left-right direction and the front-rear direction, and the direction of the wall plate is changed to the left-right direction or the front-rear direction. , The wall plate is laterally moved in the left-right direction or the front-rear direction, and before the slanted side of the hanging rope comes into contact with a beam which exists between adjacent columns, or the slanted side of the hanging rope is It is preferable that both end portions of the wall plate are supported on the outer surface side of the adjacent columns in a state where the inclined side does not bend and deform even when the pillar is contacted.

Further, in each of the construction methods, the pillar is
It is preferable that the wall plate receiving portion is formed so as to project laterally on the outer surface side, and the end portion of the wall plate is supported by the wall plate receiving portion.

In addition, in the first and second aspects, when the wall plates are sequentially attached from the bottom to the top so as to cover between the columns of the outer periphery, the wall plates are attached at each stage or at a plurality of stages. Each time a wall plate is attached to the wall plate, backfill is performed between the wall plate and the retaining wall, and after the backfill is performed, the vertical arrangement of the cut beams is considered so that the cut beam directly above can be removed. It is advisable to attach a wall plate having a vertical height set by the above method. Alternatively,
When the wall plates are sequentially attached from the bottom to the top so as to cover between the columns of the outer periphery, the wall plates and the earth retaining wall are provided for each stage of the wall plates attached or for each of the stages of the wall plates attached. It is preferable to set the vertical arrangement of the beams in consideration of the vertical height of the wall plate so that the vertical beams of the wall boards can be removed so that the vertical beams of the wall beams can be removed after performing the backfilling after the backfilling. .

In the present invention, the water storage tank includes a rainwater temporary storage tank for temporarily storing a large amount of rainwater, and a water tank which can be used in combination for various purposes such as planting and snow melting.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In the construction method according to the present invention, when constructing the water storage tank 1 shown in FIG. 1 having a large inner height, as shown in FIG. 2, a cut in the left-right direction F1 assembled so as to intersect in a grid pattern in a plan view. In the excavation space 6 in which the earth retaining wall support 5 having the beams 2a and the beams 2b extending in the front-rear direction F2 are provided in a plurality of upper and lower stages, each of which is divided into a lattice shape in a plan view. In each of the compartments 7, its bottom 8
The pillar 9 is erected on the upper side, and the upper ends 10, 1 of the adjacent pillars 9, 9 are
0s are connected to each other by a connecting beam 11, and a wall plate 12 is attached so as to cover between the columns 9a existing on the outer periphery, as shown in FIG. This will be described below in more detail in the order of steps.

First, as shown in FIGS.
The steel sheet pile 16 is driven into a continuous wall shape by connecting the joints 15 and 15 to each other so as to surround the ground 13 to be dug in order to bury it underground (usually, as shown in FIG. The upper end 17 is located on the ground surface 19), and a soil retaining wall 20 having a rectangular shape in plan view is formed.
At the same time, the support piles 21 that constitute the earth retaining wall support 5 for supporting the earth retaining wall 20 when the earth is dug down are provided with the required intervals in the front-rear direction and the left-right direction as shown in FIG. Type in 13.

Then, the retaining wall 2 constructed as described above.
Dig inside 0. This digging is, for example, 10
Perform to a depth of about 11 m. At the time of this digging, each time the digging to a predetermined depth is completed, as shown in FIG.
a, 3b, 3c are formed. The forming height of each girder frame is
It is set in consideration of stable support of the retaining wall 20. For example, the uppermost girder framework 3a is formed in a state of being dug down to a depth D shown in FIG.

As shown in FIG. 2, FIG. 5, and FIG. 7, the cross beam frames 3a, 3b, and 3c face an uprising 22 that is fixedly installed at a predetermined height position on the inner surface of the steel sheet pile 16. Right and left angry 2
2a, 22a, for example, a left-right beam girder 2a installed in parallel at intervals of 5 m, and a front-rear ridge 2 facing each other fixed at a position higher than the left-right ridge 22a.
A front and rear direction cutting beam 2b is provided between 2b and 22b in parallel at a distance of 5 m, for example, and the front and rear direction cutting beam 2b is placed on the left and right direction cutting beam 2a. Then, the right and left uprising 22a and the front and rear uprising 22b
The end side of each of them is connected by a flint 23, and is raised with the end side of the required ones 2a1 and 2b1 of the beam.
2b and reinforced by being connected by fire 25. The top, middle, and bottom girder frames 3a, 3 configured in this way
The left and right cutting beams 2a and the front and rear cutting beams 2b forming b and 3c substantially overlap each other in plan view as shown in FIG.
The support piles 21 are formed so as to be erected at required parts of the same corner portion 27 (FIG. 7) of the cross-shaped crossing portion 26 formed by the left and right cutting beams 2a and the front and rear cutting beams 2b. The cutting beams 2a and 2b are supported by the support pile 21 via a bracket (not shown). As a result, the excavation space 6 formed inside the rectangular earth retaining wall 20 is divided into a lattice shape in plan view, and a large number of rectangular sections 7 are formed. In the partition 7 thus formed, as shown in FIG. 7, a first partition 7a having four sides formed by front, rear, left, and right beams, and one or two sides of the uprising 22a, 22b. A second section 7b formed by the second section 7b, and the second section 7b is arranged on the outer periphery of the first section 7a.

As described above, the top, middle, and bottom 3
After forming the girder frames 3a, 3b, 3c at the points, as shown in FIG.
As shown in FIG. 6, on the bottom portion 8 of the excavation space 6, by concrete-casting on site, concrete is cast to a thickness of, for example, about 1 m to construct the bottom plate portion 30. Then, as shown in FIG. 6, for example, as shown in FIG. 6, a support member 28 is provided between the bottom plate portion 30 and the soil retaining wall 20 so that the built bottom plate portion 30 can support the soil retaining wall 20.
After the interposition, as shown in FIG. 8, cut beams 2a in the left-right direction and in the front-rear direction, which form the cut beam framework 3c in the lowermost stage,
2b is dismantled and removed. Note that, in FIG. 2, for the sake of convenience of explaining the entire structure of the retaining wall support work 5, the lowermost beam girder framework 3 is shown.
Although c is illustrated, this girder framework 3c does not exist in a state in which the column 9 is erected.

Next, for each of the rectangular sections 7, as shown in FIGS. 8 to 9, one column 9 is erected at the bottom 8 (the bottom plate 30) of the excavation space. These stanchions 9
In the first section 7a formed by the front, rear, left and right beams, as shown in FIGS.
2, the centers 33 of the columns arranged in the left-right direction F1 are arranged on the same straight line 35, and the centers 33 of the columns arranged in the front-rear direction F2 are also arranged on the same line 3.
6 to exist. Then, the distance L1 between the centers 33, 33 of the columns viewed in the left-right direction is set substantially equal to the distance L2 between the adjacent left and right intersections 37, 37 of the cross beam intersections intersecting each other in the cross direction, and Center 3 of the pillar seen in
The distance L3 between 3 and 33 is set to be approximately equal to the distance L4 between the front and rear intersections 37, 37 that are adjacent to each other among the cross beam intersections that intersect in a cross shape. When the support piles 21 are erected at the cross-shaped intersections, the erected supports 9 and the support piles 21 are diagonally arranged.

In this embodiment, as shown in FIG. 10, the sections (the second sections) 7b and 7b existing on both outer sides of the row of the first sections 7a as viewed in the left-right direction and in the front-rear direction. One strut 9 is erected in each of the compartments (second compartments) 7b, 7b existing on both outer sides of the first compartment 7a seen, but the center 33 of the outer pillar 9b is , On the extension line of the straight line 35 in the left-right direction and on the extension line of the straight line 36 in the front-rear direction. In addition, in the present embodiment, the interval between the columns in the left-right direction and the interval between the columns in the front-rear direction are set to be equal. Therefore, the columns 9b existing in the second section 7a are present in the same corner portion 39 of the section 7a or are close to the left and right cutting beams 2a or the front and rear cutting beams 2b in a plan view. As shown in FIG. 8, the upper ends 10 of the stanchions 9 thus erected are located below the beams 2 that form the uppermost beam framework 3a.

Although it is not considered that the upper end 10 of the upright pillar 9 is located above the uppermost beam structure 3a, the uppermost beam structure 3a is usually
70 to 80 cm from the upper end (ground 19) 17 of the steel sheet pile
Because of the arrangement below, when the upper ends of the erected columns are connected by the connecting beam 11, the connecting beam 11
In the case of a large one, the vertical height is as large as 120 to 150 cm, so that the connecting beam 11 largely projects from the ground 19. Due to such inconvenience,
The overwhelming majority of the water tanks currently constructed are the connecting beams 1.
1 is a type that does not project onto the ground 19.

Since the present invention is a construction method for constructing this kind of water storage tank, the upper end 10 of the column 9 is positioned below the uppermost beam structure 3a in consideration of the vertical height of the connecting beam. It is supposed to be done.

Explaining the structure of the support column 9 here, the support column 9a in the first section 7a is a corner in which the support column 38 has a square cross section as shown in FIG. 12 in the present embodiment. It has a columnar shape. The second section 7b
As shown in FIG. 27 and FIG. 29, the pillar 9b present in FIG. 27 has a trapezoidal cross section so that its outer surface side 40 spreads on both sides, and supports the end portions 41, 41 of the wall plate 12. The wall plate receiving portions 42, 42 are formed so as to project laterally on both sides of the outer surface of the column 9b. It should be noted that, although vertical rebars 64 project upward from the columns 9 as shown in FIGS. 14 and 22, for convenience of description, the vertical rebars 64 are omitted in other figures.

As shown in FIG. 13, for example, the supporting column 9 having such a structure is constructed by inserting the connecting main bar 43, which is erected at a required portion of the bottom plate portion 30, into the joint sleeve 45 provided at the lower end portion of the supporting column 9, and then the bottom plate. It is erected on the section 30. And, as shown in FIGS. 12 and 14, at the upper end of the column 9,
A support protrusion 47 that supports both end portions 46, 46 of the connecting beam 11 is formed to project laterally.

In the present embodiment, in plan view,
The support column 9 is arranged so that the side end 49 of the support protrusion 47 is separated from the facing girder 2 by about 10 to 40 cm.
Is to be installed upright on the corner portion 39. This interval is indicated by L5 in FIG. The erected state in which the columns 9 are separated by such a degree is that the columns 9 can be hung in the first section 7a without contacting the beams 2, and the upper ends of the columns 9 adjacent to each other can be mutually suspended. This is to minimize the amount of movement of the connecting beam 11 that is laterally moved to connect the two as described later.

Next, the upper ends of the adjacent columns 9 are connected to each other by the connecting beam 11. In this embodiment, as shown in FIGS. 14 and 1, the connecting beam 11 has a rectangular cross section that is vertically long, and supports a side portion 51 of a lid plate 50, which will be described later, from below. There are two types of ridges 52, one provided on the side surface portions 38, 38 so as to be continuous in the length direction of the connecting beam, and one not having such support ridges 52. Further, protruding reinforcing bars 63 are provided on both end surfaces 62, 62. The connecting beam 11 may be composed of one type in which the supporting protrusion 52 is provided.

The connecting step by the connecting beam 11 is performed by the upper end 1 of the columns 9, 9 existing in the adjacent first sections 7a, 7a.
The case of connecting 0 and 10 with each other will be described. First, as shown in FIG.
The center portion of the hanging rope 56 made of wires fixed to both ends 55 of the No. 1 is hooked on the hook 57 of the crane and lifted. The angle of the inclined sides 59, 59 of the suspension rope 56 is set to 40 to 60 degrees, preferably 60 degrees as shown in FIG. After that, the connecting beam 11 is tilted in a horizontal plane with respect to the left-right direction and the front-back direction,
It is suspended in the first compartment 7a. In addition, if the connecting beam 11 can be hung in a state where the connecting beam 11 is left or right or in the front-rear direction, the connecting beam 11 may be hung in such a manner. Therefore, it is not always necessary to hang it in an inclined state in a horizontal plane. Although not necessary, the tilted state has an advantage that the hanging operation can be performed easily and safely.

In this suspended state, the height of the lower end 60 of the connecting beam 11 is set to be substantially equal to the height of the upper end 10 of the pillar 9 in the upright state. In this state, the connecting beam 11 is located below the uppermost beam 2 as shown in FIG. After that, for example, as shown by the arrow in FIG.
The connection beam 11 is laterally moved in the left-right direction or the front-rear direction by adjusting the length direction of the connection beam 11 to the left-right direction or the front-back direction, and the both end portions 46, 46 of the connection beam 11 are adjacent to each other. The support protrusions 47, 4 formed at the upper end of the
Put on 7.

The lateral movement of the connecting beam 11 is as follows because the pillar 9 is erected at the corner portion 39 of the first section 7a.
The movement can be performed in a state where the slanted side 59 of the suspension rope 56 does not come into contact with the truss 2. Alternatively, even if the slanted side 59 of the suspension rope 56 comes into contact with the girder 2, the slanted side 56 can be reasonably performed in a state in which the slanted side 59 does not bend and deform.

If, as shown in FIG. 18, the adjacent columns 9, 9 are viewed in the left-right direction or the front-back direction, the first section 7
If it is assumed that the side portions 61 of a and 7a are placed close to each other and are erected at the central portion thereof, the connecting beam 11 suspended in the section is divided into two beams.
When the upper ends of the columns 9A and 9B that are equidistant from each other are moved in the arrow direction in order to connect them, the inclined side 59 of the suspension rope 56 hits the beam 2 as shown in FIG. Therefore, unless the end portion 53 of the suspension rope 56 is replaced, it becomes extremely difficult to connect the upper ends of the columns 9 with the connecting beam 11. As shown in FIG. 20, when the end portion of the suspension rope 56 is replaced, the work is performed while the connecting beam 11 is suspended. Therefore, the replacement is very troublesome. However, there is a problem of being forced to perform dangerous work, which is not practical at all. In the present invention, the girder 2 does not become an obstacle,
There is an advantage that the upper ends of the columns 9, 9 can be easily connected by the connecting beam 11.

Further, the pillar 9a existing in the first compartment 7a and the pillar 9b existing in the second compartment 7b on the outer periphery thereof.
When connecting the upper ends of each other, or when connecting the upper ends of the columns 9b, 9b existing in the adjacent second sections 7b, 7b on the outer periphery, as shown in FIG. After suspending the connecting beam 11 on the side of the section 7b1 having a large distance from the column 9, the connecting beam 11 is directed leftward or rightward or backward toward the pillar 9 on the side of the section 7b2 having a small distance between the cutting beam 2 and the pillar 9. 21, the upper ends of the columns 9, 9 are connected to each other by a connecting beam 11, as shown by a chain line in FIG. In this case, the lateral movement of the connecting beam 11 can also be performed in a state where the slanted side 59 of the suspension rope 56 does not come into contact with the cutting beam 2. Alternatively, it can be reasonably performed in a state in which the inclined side 59 of the suspension rope 56 does not bend and deform even when the inclined side 59 contacts the beam girder 2.

Then, the end portions 46 of the column 9 and the connecting beam 11 are
In order to integrate and, the connecting beams 11 and 1 supported by the supporting protrusions 47 of the column 9 are integrated as shown in FIG.
The protruding reinforcing bars 63, 63 horizontally projected at the facing end surfaces 62, 62 of 1, 11, 11 are welded to each other, and the vertical reinforcing bars 64 are projected upward at the upper end 10 of the column 9, and then, Figure 2 after placing the formwork and placing concrete
3 and the pillar joint part 65 shown in FIG. 1 are formed.

Thereafter, as shown in FIGS. 24 to 25 and FIG. 1, a wall plate 12 made of precast concrete is attached between the columns 9b, 9b located on the outer circumference. In the present embodiment, the wall plates 12 are attached in upper and lower four stages. As shown in FIG. 26, the construction process for that purpose is as follows. First, in the second section 7b located on the outer periphery, the wall plate 12 is tilted in the horizontal plane with respect to the left-right direction and the front-back direction, Suspend to the required position in 7b. In this state, as shown in FIG. 24, the wall plate 12 is positioned below the middle beam frame 3b to be disassembled and removed thereafter. Then Figure 2
As shown in FIG. 6, by aligning the length direction of the wall plate 12 with the left-right direction and the front-rear direction, the wall plate 12 is cut between the columns facing each other in the left-right direction and the front-back direction with the cross beam 2 interposed therebetween. The wall plate 1 is moved laterally toward the pillar 9b1 in the state of being close to the beam 2.
Both end portions 41, 41 of 2 are supported by the wall plate receiving portions 42, 42 provided on the adjacent columns 9b, 9b.

In this embodiment, as shown in FIGS. 27 and 29, U-shaped protruding reinforcing bars 67 are provided on the end surface 66 of the wall plate 12 in the vertical direction at a predetermined interval. Therefore, the support is provided by the projecting rebar 67 projecting at the end faces 66, 66 of the wall plates 12, 12 facing each other, and the projecting rebar 68 projecting at the outer surface side of the column 9b on the outer periphery.
Are engaged with each other (FIG. 28). In this case, the protruding amount of the protruding reinforcing bar 68 is increased to make the protruding reinforcing bar 6
There may be a case where the 8, 68 mesh with each other. Alternatively, the protruding reinforcing bars 67 protruding on the end surface 66 of the wall plate 12 and the protruding reinforcing bars 68 protruding on the outer surface side of the corner strut 9b are engaged with each other (FIG. 30). in this case,
The protruding amount of the protruding reinforcing bar 68 may be made larger than that shown in the drawing. After that, the annular reinforcing bars 69 having a rectangular annular shape or a triangular annular shape are attached in a required overlapping state, and the longitudinal main reinforcing bars 70 are arranged as required. After that, the formwork is assembled at the joints between the wall plates and concrete is poured to form the wall plate joints 71.

Thereafter, as shown in FIG. 24, the wall plate 12
A slightly lower position (for example, 30 to 40) of the upper end 72 of (12a).
Backfilling is performed between the wall plate 12 and the retaining wall 20 up to about a cm lower position. The earth retaining wall 20 is supported by the backfill soil 68. Similarly, as shown in FIG. 25, the second-stage wall plate 12 is attached between the columns, and the frame is assembled at the joints between the wall plates to pour the concrete into the wall plate 12 and the retaining wall. The soil retaining wall 20 is supported by the backfilling soil 68 by performing backfilling with the soil 20. By repeating this, the wall surface 73 of the water storage tank 1 is formed. Note that the space 75 (FIG. 25) between the upper and lower wall plates is filled with grout, and the upper and lower wall plates 12, 12 are connected to each other via the connecting rod 74 shown in FIG. The wall plate 12 may be attached to the outer surface side between the pillars, or may be attached to the inner surface side of the pillar or in the middle of the width of the pillar.

The required number of steps of the wall plate, for example, the first step wall plate 1
After attaching 2a, the cross beams 2a, 2b in the left-right direction and the front-rear direction which form the middle-level cross beam framework 3b are disassembled and removed. As described above, since the earth retaining wall 20 is supported by the backfill soil 68, even if the cutting beam is dismantled and removed, the earth retaining wall 2
A stable state of 0 can be maintained. Also, after installing the uppermost wall plate 12b between the columns and performing necessary backfilling, the left and right cutting beams 2a and 2b forming the uppermost cutting beam framework 3a are disassembled and removed. . After that, the support pile 21
Is melted off on the upper surface of the bottom plate portion 30 and removed. As a result, all the retaining wall support works 5 are dismantled and removed.

Then, as shown in FIG. 31 and FIG. 1, both side portions 51, 51 of the lid plate 50 are separated by the supporting protrusions 52, 52 provided so as to face the side surfaces of the adjacent connecting beams 11, 11. The slab 76 is formed by supporting it horizontally. As a result, the required water storage tank 1 is constructed. After that, concrete is placed on the slab 76 and the concrete is placed to form the ceiling 77 of the water tank. Thereby, for example, the inner sky height is 9 to
A water storage tank 1 of about 10 m will be constructed. After that, as shown by the alternate long and short dash line in FIG. 31, backfilling is performed on the entire upper part of the water storage tank, and after completion of the backfilling, the steel sheet pile 1
Pull out 6. The steel sheet pile 16 may be buried.

[Other Embodiments] The present invention is by no means limited to those shown in the above embodiments, and various design modifications are possible within the scope of the claims. Needless to say. An example is as follows. (1) FIGS. 32 to 33 show another aspect of the construction method according to the present invention, and the pillars 9b at the four corners shown in FIG.
1, 9b2, 9b3, 9b4 are omitted, and instead, a wall plate 12 having a triangular shape in a plan view, or an L shape, etc.
This is related to the case where A is arranged instead of the column. In FIG. 33, the wall plate 12A has a triangular shape. In this case, the both end surfaces 80, 80 of the triangular wall plate 12A,
A flat plate-shaped wall plate 12B is arranged between the adjacent pillars 9a, and a joint portion is formed between the end face 79 of the flat plate-shaped wall plate 12B and the end face 80 of the triangular shaped wall plate 12A by in-situ casting. To form 78. The other construction is the same as the construction method shown in the above-mentioned embodiment, and therefore its explanation is omitted.

(2) In the construction method according to the present invention,
As shown in FIG. 34 and FIG. 35, a column 9b for supporting the wall plate and a column 9a not supporting the wall plate should be present in the first section 7a or the second section 7b located on the outer periphery. There is also. With such a configuration, when the pillars 9b1, 9b2, 9b3, 9b4 at the four corners shown in FIG. 1 are erected, as shown in the figure, when the corner portion is covered with the L-shaped wall plate 12c, There is an advantage that the L-shaped wall plate 12c can be formed in a small size and can be easily transported. FIG. 36 shows a case where one column 9 is erected in each section 7, and when the corner portion is covered with the L-shaped wall plate 12c, the L-shaped wall plate 12c is considered to be large. There is a problem that becomes.

(3) FIG. 37 shows the bottom portion 8 on which the column 9 is erected.
It shows another embodiment of the.

(4) The cross-sectional shape of the pillar is not limited to the circular shape described above. Further, the support protrusion 47 for mounting the end portion of the connecting beam 11 is not limited to the one shown in the above-mentioned embodiment as long as the end portion can be stably mounted. 38 to 42 show an example of these.

(5) The wall plate receiving portion 42 for supporting the end portion 41 of the wall plate 12 is the one shown in the above embodiment as long as it can stably support the end portion. However, it may be configured as a continuous ridge as shown in FIG. 43, or may be discontinuous in the vertical direction as shown in FIG. 45 to 46 show an example of a state in which the wall plate receiving portion 42 supports the end portion 41 of the wall plate 12 in these cases and the like.

(6) FIG. 47 is a partial plan view showing another embodiment of the soil retaining wall 20, in which the ground is drilled in the vertical direction and the agitated mixture of the drilled soil and cement milk is hardened therein. Soil-cement-shaped pillars 81 thus formed are continuously formed in the circumferential direction in such a manner that their side portions overlap each other, and if necessary, a reinforcing material 82 made of, for example, H-shaped steel, is formed on the pillars 81. Is buried vertically.

(7) In the above embodiment, the retaining wall 2
Although 0 is formed in a rectangular shape, the earth retaining wall 20 is formed in various shapes according to the site shape of the water storage tank to be constructed, such as that shown in FIG. In this case, the second section 7b arranged on the outer circumference includes not only a rectangular shape but also a trapezoidal shape or a triangular shape.

(8) The lowermost beam structure 3c has a bottom portion 8
In some cases, after the pillar 9 is erected upright, the pillar 9 may be disassembled and removed until the wall plate 12 is attached.

(9) In the construction method according to the present invention, when the wall plates are sequentially attached from the bottom to the top so as to cover the columns of the outer periphery, the wall plates are attached at each stage or at a plurality of stages. Each time the wall board is attached, backfilling is performed between the wallboard and the retaining wall, and after performing the backfilling, the vertical height of the wallboard is adjusted so that the cutting beam directly above it can be removed. It is also possible to configure the vertical arrangement of the beams in consideration.

[0057]

The present invention has the following excellent effects. (1) A construction method according to the present invention is a retaining wall support work that includes a cross beam frame structure that is assembled so that the cross beams in the left-right direction and the cross beams in the front-rear direction intersect in a grid pattern in plan view in a plurality of upper and lower stages. Is a construction method for constructing a water tank made of precast concrete in the excavation space provided with, and in the earth retaining wall support work, horizontal beam beams arranged in upper and lower stages and upper and lower stages are arranged. The cross beams in the front-rear direction are arranged so as to substantially overlap each other in a plan view, and the columns are erected in a required arrangement at the bottom of the excavation space, and the upper ends of the columns are positioned on the lower side of the uppermost beam. , Connect the upper ends of adjacent columns with connecting beams,
The pillars existing on the outer circumference shall support the wall plates sequentially attached from the bottom to the top so as to cover the spaces between the pillars on the outer circumference. A structure is employed in which each of the columns is present in a rectangular section formed by a truss and the columns are erected at the same corner of the rectangular section.

Therefore, according to the present invention, even when the cross beams are arranged vertically and horizontally in a plurality of stages, when the upper ends of the adjacent columns are connected by the connecting beams, both ends of the suspension rope are connected to each other. When suspending the suspension rope by fixing it to both ends of the suspension rope with a crane, do not allow the inclined side of the suspension rope to come into contact with the crossbeam, or if the inclined side of the suspension rope comes into contact with the crossbeam. Even in the state where the inclined side is not flexibly deformed, both end portions of the connecting beam can be placed on the upper ends of the adjacent columns while reducing the lateral movement amount of the connecting beam. Accordingly, there is an advantage that the connecting beams can be laterally moved without replacing the hanging ropes and the upper ends of the adjacent columns can be easily connected by the connecting beams. Therefore, according to the present invention, there is an advantage that even a large precast concrete water storage tank having an inner air height of more than 5 to 10 m can be constructed without hindering the retaining wall support.

As described above, the large precast concrete water tank having a large inner air height had to be constructed by the cast-in-place construction in the past, but according to the present invention, the construction efficiency is increased. It will be well built. In addition, in the case of the water tank that is constructed in-situ, the intermediate supporting beam portion is required as described above. However, according to the present invention, since the upper ends of the adjacent columns can be connected by the connecting beam, No intermediate support beam is needed. Further, since the supporting work for forming the supporting beam portion is not necessary, it is possible to reduce the construction cost, and the intermediate supporting beam portion is not necessary. Therefore, the volume of the water tank can be increased accordingly. Therefore, it is possible to construct a water storage tank with high capacity efficiency.

(2) When the pillar is constructed such that a supporting projection is provided at the upper end thereof, and the end portion of the connecting beam is placed on the supporting projection, the pillar body 38 (FIG. 10) is used. The pillar portion 83 (FIG. 10) supporting the end portions of the connecting beams can be moved closer to the cutting beams 2a and 2b while being separated from the cutting beams 2a and 2b. There is an advantage that the lateral movement amount of the connecting beam can be minimized.

(3) By constructing the support pillars so that the wall plate receiving portion projects on the outer surface side thereof, the support pillar portion that supports the end portion of the wall board when the outer peripheral support pillars are covered with the wall board. 8
4 (FIG. 10) can be made closer to each other by the trusses 24, so that there is an advantage that the lateral movement amount of the wall plates can be made as small as possible when covering the pillars existing on the outer periphery with the wall plates.

(4) Among the rectangular partitions formed by the front and rear and left and right trusses, when the columns that support the wall plate as well as the columns that do not support the wall plate are present in the partition existing on the outer periphery,
In particular, when a pillar is erected on the corner portion of the water tank, when covering the corner portion with an L-shaped wall plate, for example, as shown in FIG.
As is clear from comparison between FIGS. 4 to 35 and FIG. 36, the L-shaped wall plate can be made smaller, which facilitates the transportation and improves the transportation efficiency.

(5) When the wall plates are sequentially attached from the bottom to the top so as to cover the space between the columns on the outer periphery, when the wall plates are attached at each stage or the wall plates are attached at a plurality of stages, A wall having a vertical height set in consideration of the vertical arrangement of the cutting beams so that the back beams can be backfilled with the retaining wall and the cutting beams immediately above can be removed after the backfilling. Attach a board, or
When setting the layout of the cutting beams in consideration of the vertical height of the wallboard, the cutting beams can be disassembled and removed sequentially from the bottom while stably supporting the retaining wall by the backfill soil. As a result, even if the water tank has a large inner height,
There is an advantage that the water storage tank can be efficiently constructed by, for example, attaching the wall plate upward in the open space formed after removing the cutting beam without difficulty. Then, in the case of constructing in this way, it is necessary to connect all the adjacent columns with connecting beams in order to stabilize the columns that support the wall plate that receives pressure from the backfill soil. However, according to the present invention, as described above, the connecting work of the connecting beams in the left-right direction and the front-rear direction can be easily performed due to the ease of lateral movement of the hanging connecting beams.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing a water tank constructed according to the present invention.

FIG. 2 is a partial perspective view showing a state in which columns are erected in an excavation space provided with a retaining wall support and the columns are connected to each other by connecting beams.

FIG. 3 is a plan view showing a retaining wall formed by driving steel sheet piles together with driven support piles.

FIG. 4 is a cross-sectional view showing a driven state of a steel sheet pile.

FIG. 5 is a partial perspective view showing a state where the ground is dug down to form the uppermost beam girder framework.

FIG. 6 is a sectional view showing a retaining wall support work.

FIG. 7 is a plan view showing a retaining wall support work.

FIG. 8 is a cross-sectional view showing a state in which columns are erected in an excavation space provided with a retaining wall support and columns are connected to each other by connecting beams.

FIG. 9 is a perspective view showing a state in which a column is erected in an excavation space provided with a retaining wall support.

FIG. 10 is a plan view thereof.

FIG. 11 is an explanatory view for explaining a manner of standing upright columns in an excavation space provided with a retaining wall support.

FIG. 12 is a perspective view showing pillars provided upright in a first section and a second section.

FIG. 13 is a partial side view showing a state in which a column is erected on the bottom plate portion.

FIG. 14 is a perspective view showing an upper portion of a support column together with a connecting beam connecting the support columns to each other.

FIG. 15 is a front view showing a suspended state of a connecting beam.

FIG. 16 is a plan view illustrating a step of suspending a connecting beam in the first section and connecting the columns to each other by the connecting beam.

FIG. 17 is a front view showing a state where the connecting beam is hung so as to connect the columns to each other.

FIG. 18 is a plan view showing a state in which a column is erected in the vicinity of the central portion of the side of the first section.

FIG. 19 is a front view illustrating a problem in that case.

FIG. 20 is a front view illustrating another problem in that case.

FIG. 21 is a plan view illustrating a step of connecting the upper ends of the columns existing in the adjacent second sections with each other by a connecting beam.

FIG. 22 is a cross-sectional view showing a bar arrangement state for integrating the end portion of the connecting beam placed on the upper end of the column and the upper end of the column.

FIG. 23 is a plan view showing the integrated state.

FIG. 24 is a cross-sectional view showing a state in which a lowermost wall plate is attached between columns on the outer circumference.

FIG. 25 is a cross-sectional view showing a state in which wall plates are attached to the entire upper and lower portions between columns on the outer periphery.

FIG. 26 is a plan view illustrating a step of attaching a wall plate between support posts on the outer circumference.

FIG. 27 is a perspective view illustrating a step of linearly joining wall plates to each other.

FIG. 28 is a partially cutaway perspective view showing a state where the wall plates are linearly joined together.

FIG. 29 is a perspective view illustrating a step of joining wall plates to each other at a right angle.

FIG. 30 is a partially cutaway perspective view showing a state where the wall plates are joined at a right angle.

FIG. 31 is a cross-sectional view illustrating the structure of the ceiling portion of the water storage tank.

FIG. 32 is a plan view showing a state in which the pillars at the four corners are labor-saving when the pillars are erected in the excavation space provided with the retaining wall support.

FIG. 33 is a cross-sectional view showing an attached state of L-shaped wall plates at the four corners thereof.

FIG. 34 shows a state in which a column supporting a wall plate and a column not supporting a wall plate are both erected in a second section located on the outer periphery.
It is sectional drawing shown with the attachment state of the L-shaped wall board of a corner part.

FIG. 35 shows a state in which a column supporting a wall plate and a column not supporting a wall plate are both erected in a first section located on the outer periphery,
It is sectional drawing shown with the attachment state of the L-shaped wall board in a corner part.

FIG. 36 is a cross-sectional view illustrating a problem in the case where one column is erected in all the sections.

FIG. 37 is a partial perspective view showing another aspect of the bottom portion on which the support columns are erected.

FIG. 38 is a partial cutaway perspective view showing another aspect of the support column.

FIG. 39 is a partial perspective view showing another aspect of the column.

FIG. 40 is a partial perspective view showing another aspect of the support column.

FIG. 41 is a partial perspective view showing another aspect of the column.

FIG. 42 is a partial perspective view showing another aspect of the column.

FIG. 43 is a partial perspective view showing another aspect of the support column.

FIG. 44 is a partial perspective view showing another aspect of the column.

FIG. 45 is a plan view showing another mode in which the end portion of the wall plate is supported by the wall plate receiving portion.

FIG. 46 is a plan view showing another aspect in which the end portion of the wall plate is supported by the wall plate receiving portion.

FIG. 47 is a partial plan view showing another aspect of the retaining wall.

FIG. 48 is a plan view showing another form of the retaining wall together with the retaining wall support.

FIG. 49 is a partial cross-sectional view showing an example of a conventional precast method.

FIG. 50 is a partial cross-sectional view showing another aspect of the conventional precast method.

FIG. 51 is a partial perspective view showing another aspect of the conventional precast method.

52 is a plan view explaining a problem of the precast method according to FIG. 51. FIG.

FIG. 53 is a front view showing a suspended state of the connecting beam in the precast method.

[Fig. 54] In the precast method, connecting beams are
FIG. 6 is a front view showing a state in which the columns are suspended so as to be connected to each other.

FIG. 55 is a front view for explaining a problem in the precast construction method when the pillar is erected in the vicinity of the central portion of the side of the section.

FIG. 56 is a front view illustrating another problem in that case.

[Explanation of symbols]

1 water tank 2 beams 2a Horizontal beam 2b Front and rear beams 3 Girder frame 5 Soil retaining wall support 6 excavation space 7 divisions 8 bottom 9 props 10 Upper end of column 11 connecting beams 12 wall boards 13 ground 20 earth retaining wall 21 Support pile 22 upset 26 Cross-shaped intersection 27 Same corner 30 Bottom plate 33 Center of pillar 37 Cross beam intersection 39 corners with the same corner 41 Edge of wallboard 42 Wall plate receiving part 46 End part of connecting beam 47 Support protrusion 50 lid version 52 Support ridges 56 hanging rope 59 Inclined side

Claims (11)

[Claims] 1. In an excavation space provided with a retaining wall support structure having a plurality of upper and lower stages of a crossbeam frame assembly assembled so that the crossbeams in the left-right direction and the crossbeams in the front-rear direction intersect in a grid pattern in a plan view. , A construction method for constructing a water tank made of precast concrete, in the earth retaining wall support work, horizontal crossbeams arranged in a plurality of upper and lower steps and front and rear cut beams in a plurality of upper and lower steps Are arranged so as to substantially overlap each other in a plan view, and the pillars are erected in a required arrangement at the bottom of the excavation space, and the upper ends of the pillars are positioned below the uppermost beams, and the upper ends of the adjacent pillars are arranged. The pillars that are connected to each other by connecting beams, and the pillars existing on the outer circumference are supported by the wall plates that are sequentially attached from the bottom to the top so as to cover the pillars on the outer circumference. The pillars to be placed in the One are allowed to be present by one, a strut, construction method of precast concrete reservoir, characterized in that the upright in the same corners of the rectangular compartments within. 2. The precast according to claim 1, characterized in that among the rectangular sections formed by the front, rear, left and right beams, a column for supporting the wall plate is provided in a required section of the outer section. Construction method of concrete water tank. 3. A water tank made of precast concrete is provided in an excavation space provided with earth retaining wall supports having left and right cutting beams and front and rear cutting beams assembled so as to intersect each other in a grid pattern in a plan view. It is a construction method to build, in the earth retaining wall support work, the horizontal beams which are arranged in a plurality of upper and lower steps and the longitudinal beams which are arranged in a plurality of upper and lower steps are substantially overlapped in plan view. As a result, the pillars are erected in a required arrangement at the bottom of the excavation space, the upper ends of the pillars are located below the uppermost cross beam, and the upper ends of the adjacent pillars are connected to each other by a connecting beam. The pillars existing in the above shall support the wall plates sequentially attached from the bottom to the top so as to cover the spaces between the pillars on the outer periphery, and the pillars arranged inside the pillars on the outer periphery are Make sure there are one in each of the rectangular sections formed by the beams. The pillars are erected at the same corner portion of the rectangular section, and the pillars that are arranged outside the rectangular section formed by the front, rear, left, and right beam beams are erected at the corner sections. Standing close to the cross beam in a state of facing the front and rear or facing left and right, the distance between the centers of the adjacent posts as seen in the left and right direction is the The distance between the right and left intersecting intersections is set to be approximately equal, and the distance between the centers of the columns that are adjacent to each other when viewed in the front-rear direction is approximately equal to the distance between the adjacent front and rear intersections of the cross beam intersection that intersects each other. Construction method of precast concrete water tank characterized by setting. 4. The method for constructing a water tank made of precast concrete according to claim 1 or 3, wherein both end portions are fixed to both end sides of the connecting beam when the upper ends of adjacent columns are connected to each other by the connecting beam. The central portion of the hanging rope is hung with a hook, and the connecting beam is hung in the rectangular section in a state of being inclined with respect to the left-right direction and the front-back direction,
Below the uppermost cut beam, after the connecting beam is oriented in the left-right direction or the front-rear direction, the connecting beam is laterally moved in the left-right direction or the front-rear direction, and the slanted sides of the suspension rope are adjacent to each other. Before contacting the cutting beam existing between the supporting columns, or in a state where the slanted side of the suspension rope does not bend and deform even when the slanted side of the hanging rope contacts the cutting beam, both end portions of the connecting beam are A construction method for a water tank made of precast concrete that is placed on the upper ends of adjacent columns. 5. The retaining wall support work is formed by vertically arranging support piles for supporting the cutting beam from below at the same corner portion at the intersection of the cutting beam in the left-right direction and the cutting beam in the front-rear direction. The method for constructing a precast concrete water storage tank according to claim 1 or 3, characterized in that the pillars are erected in a diagonal arrangement with the support piles. 6. A support projection is laterally formed on the upper end of the column, and an end portion of the connecting beam is placed on the support projection. The construction method for a precast concrete water storage tank according to any one of the above. 7. The water storage made of precast concrete according to claim 6, wherein a distance between a side end of the support protrusion and a girder facing the support protrusion is set to 10 to 40 cm in plan view. Construction method of tank. 8. The method for constructing a water tank made of precast concrete according to claim 1 or 3, wherein both end portions are located at both end sides of the wall plate when the wall plate is attached so as to cover between adjacent columns existing on the outer circumference. The central part of the fixed hanging rope is hung up with a hook, and the wall board is hung in the section in which the pillars are present with the wall board inclined with respect to the left-right direction and the front-back direction, and the direction of the wall board is changed to the left-right direction. Direction or front-back direction, then move the wallboard laterally or in the front-back direction,
Before the slanted side of the suspension rope comes into contact with the crossbeam existing between adjacent columns, or even when the slanted side of the suspension rope contacts the crossbeam, the slanted side does not flex and deform. A construction method for a water tank made of precast concrete, characterized in that, in this state, both end portions of the wall plate are supported by the outer surfaces of adjacent columns. 9. The pillar has a wall plate receiving portion formed on the outer surface side thereof so as to project in the lateral direction, and an end portion of the wall plate is supported by the wall plate receiving portion. 1-5
The method for constructing a water tank made of precast concrete according to any one of 1. 10. When the wall plates are sequentially attached from the bottom to the top so as to cover between the columns of the outer periphery, the wall plates are attached at each stage of the wall plates or at each stage of the wall plates. Perform the backfilling between the plate and the retaining wall, and after performing the backfilling, the vertical height set in consideration of the vertical arrangement of the cutting beams so that the cutting beams immediately above can be removed. The precast concrete water storage tank construction method according to claim 1 or 2, wherein a wall plate having the same is attached. 11. When the wall plates are attached sequentially from the bottom to the top so as to cover between the columns of the outer periphery, the wall plates are attached for each stage of the wall plates or for each stage of the wall plates. Perform backfilling between the board and the retaining wall, and after performing the backfilling, consider the vertical height of the wallboard so that the cut beams above and below can be removed vertically. The method for constructing a water tank made of precast concrete according to claim 1 or 2, which is set.