Abstract:
A stacked structure especially useful for storing water in the underground is formed of a plurality of skeleton members. Each skeleton member includes a plurality of skeleton parts extending in one direction and situated side by side in a lateral direction perpendicular to the one direction. Each skeleton part has one top portion, and two bottom portions extending from the top portion, wherein one bottom portion in one skeleton part is connected to one bottom portion in the adjacent skeleton part. Also, each skeleton part includes top recesses formed at the top portion to be spaced apart from each other at a predetermined interval, and bottom recesses formed at the bottom portions to be spaced apart from each other at a predetermined interval. The skeleton members form upper and lower skeleton members to be vertically stacked together. The skeleton parts of the upper and lower skeleton members extend perpendicularly to each other. The bottom recesses of the upper skeleton member are located in the top recesses of the lower skeleton member so that the upper and lower skeleton members are securely assembled together.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a stacked structure used as a structure for, e.g., storing water in the underground. 
     2. Description of the Related Art 
     There is known a conventional structure for storing water in the underground as disclosed in, e.g., Japanese Unexamined Patent Publication No. 8-184080. The disclosed structure is constructed by excavating in the ground, forming a hollowed portion surrounded by a water-proof layer and a water-proof-layer protective material in the underground, installing a number of perforated pipes within the hollowed portion to fit with one another in close contact relation, and supporting from below an upper floor concrete and a water-proof layer by the perforated pipes. The disclosed structure also includes a water supply pipe and a water discharge pipe both communicating with the hollowed portion and the aboveground. 
     The conventional structure for storing water in the underground, however, requires a great space in operation of transporting and keeping the perforated pipes, which are to be installed in the hollowed portion, to and in the work site. Also, arranging the perforated pipes so as to fit with one another is not easy and positioning the perforated pipes in place takes time. Another problem is that manufacture of the perforated pipes pushes up a cost due to a complicated configuration thereof. 
     SUMMARY OF THE INVENTION 
     The present invention has been made in view of the problems stated above, and its object is to provide a stacked structure which is lightweight and strong in strength, the structure being not limited in applications to storing of water in the underground. 
     To achieve the above object, according to a first aspect of the present invention, there is provided a stacked structure comprising skeleton members each having mountain-shaped portions or skeleton part with substantially mountain-like shapes successively repeated in one section and substantially the same sectional form extending in a direction perpendicular to the section, the skeleton members being stacked together to form the stacked structure, wherein when stacking the skeleton members together, bottom ends of the mountain-shaped portions with substantially mountain-like shapes successively repeated in one of two adjacent skeleton members are arranged to cross top ends of the mountain-shaped portions of the other skeleton member. 
     According to a second aspect, there is provided a stacked structure comprising skeleton members each having mountain-shaped portions with substantially mountain-like shapes successively repeated in an X-axis direction and substantially the same sectional form extending in a Y-axis direction orthogonal to the X-axis direction, the skeleton members being stacked together in a Z-axis direction orthogonal to the X-axis direction and the Y-axis direction to form the stacked structure, wherein when stacking the skeleton members together, bottom ends of the mountain-shaped portions with substantially mountain-like shapes successively repeated in one of two skeleton members adjacent each other in the Z-axis direction are arranged to cross top ends of the mountain-shaped portions of the other skeleton member. 
     According to a third aspect, there is provided a stacked structure comprising skeleton members each having mountain-shaped portions with substantially mountain-like shapes successively repeated in section cut along a Z-axis orthogonal to the X-axis, and substantially the same sectional form extending along a Y-axis orthogonal to both the X-axis and the Z-axis, the skeleton members being stacked together along the Z-axis to form the stacked structure, wherein when stacking the skeleton members together, bottom ends of the mountain-shaped portions with substantially mountain-like shapes successively repeated in one of two skeleton members adjacent each other along the Z-axis are arranged to cross top ends of the mountain-shaped portions of the other skeleton member. 
     According to a fourth aspect, in the stacked structure according to the first, second or third aspect, the rear side of the mountain-shaped portions is shaped in conformity with the configuration of the mountain-shaped portions on the front side, and individual rear-side spaces are defined on the rear side of the mountain-shaped portions. 
     According to a fifth aspect, in the stacked structure according to the first, second or third aspect, the rear side of the mountain-shaped portions is shaped in conformity with the configuration of the mountain-shaped portions on the front side, individual rear-side spaces are defined on the rear side of the mountain-shaped portions, and reinforcing members are provided in the individual rear-side spaces to interconnect opposed slopes of the mountain-shaped portions on the rear side for reinforcing the mountain-shaped portions. 
     According to a sixth aspect, in the stacked structure according to the second or third aspect, bottom recesses provided at the bottom ends of the mountain-shaped portions in one of two adjacent skeleton members stacked in the Z-axis direction are engaged with top recesses provided at the top ends of the mountain-shaped portions of the other skeleton member, the bottom recesses are portions recessed when looking at the bottom ends from the rear side of the skeleton member, and the top recesses are portions recessed when looking at the top ends from the front side of the skeleton member. 
     According to a seventh aspect, in the stacked structure according to the second or third aspect, bottom recesses provided at the bottom ends of the mountain-shaped portions in one of two adjacent skeleton members stacked in the Z-axis direction are engaged with top recesses provided at the top ends of the mountain-shaped portions of the other skeleton member; the top recesses are portions recessed when looking at the top ends from the front side of the skeleton member, and provide hollow spaces each surrounded by first and second top slopes inclined in respective directions to cross the top end of the mountain-shaped portion, and a third top flat surface connected at both ends to the first and second top slopes and extended parallel to the top end of the mountain-shaped portion; the bottom recesses are portions recessed when looking at the bottom ends from the rear side of the skeleton member, and provide hollow spaces each surrounded by first and second bottom slopes inclined in respective directions to cross the bottom end of the mountain-shaped portion, and a third bottom flat surface connected at both ends to the first and second bottom slopes and. extended parallel to the bottom end of the mountain-shaped portion; each of the top end of the mountain-shaped portion and. the bottom end of the mountain-shaped portion has an included angle θ; the first and second top slopes intersect at an angle θ such that the first and second top slopes are inclined to separate away from each other outward and approach closer inward; the first and second bottom slopes intersect at an angle θ such that the first and second bottom slopes are inclined to separate away from each other outward and approach closer inward; and in a state where the bottom recess is engaged with the top recess, the third top flat surface and the third bottom flat surface lie in opposed relation to each other, the first and second bottom slopes lie in opposed relation to the front side of the mountain-shaped portion of one adjacent skeleton member, and the first and second top slopes lie in opposed relation to the rear side of the mountain-shaped portion of another adjacent skeleton member. 
     According to an eighth aspect, in the stacked structure according to the first, second or third aspect, the rear side of the mountain-shaped portions is shaped in conformity with the configuration of the mountain-shaped portions on the front side, individual rear-side spaces are defined on the rear side of the mountain-shaped portions, and openings are provided to penetrate the mountain-shaped portions from the front side to the rear side, whereby water is allowed to pass through the openings and a space including the individual rear-side spaces defined between the skeleton members stacked one above another is utilized to store water in the underground. 
     According to a ninth aspect, in the stacked structure according to the first, second or third aspect, the rear side of the mountain-shaped portions of the lowermost skeleton member is shaped in conformity with the configuration of the mountain-shaped portions on the front side, and individual rear-side spaces are defined on the rear side of the mountain-shaped portions, and lowermost reinforcing members which are flat at lower surfaces are provided in contact relation to the opposed slopes of the mountain-shaped portions on the rear side, thereby filling the individual rear-side spaces of the lowermost skeleton member. 
     According to a tenth aspect, in the stacked structure according to the first, second or third aspect, a front-side space is defined between two adjacent mountain-shaped portions of the uppermost skeleton member, and a flat surface member having an upper flat surface is provided in contact relation to opposed slopes of the adjacent mountain-shaped portions on the front side so as to fill the front-side space, the upper surface of the flat surface member lying flush with the top ends of the mountain-shaped portions. 
     Further, according to an eleventh aspect of the present invention, there is provided a stacked structure comprising skeleton members each having mountain-shaped portions with substantially mountain-like shapes successively repeated in an X-axis direction, top recesses and bottom recessed provided respectively in top ends and bottom ends of the mountain-shaped portions, and substantially the same sectional form extending in a Y-axis direction orthogonal to the X-axis direction, the skeleton members being juxtaposed in a plane extending in the X-axis direction and the Y-axis direction orthogonal to the X-axis direction, the skeleton members being stacked and juxtaposed on the juxtaposed skeleton members in a Z-axis direction orthogonal to the X-axis direction and the Y-axis direction, thereby forming stages of the stacked structure successively in the Z-axis direction, wherein the mountain-shaped portions of the skeleton members each stacked in the Z-axis direction on two adjacent skeleton members in the above plane are arranged in crossed and straddling relation to the mountain-shaped portions of the two adjacent skeleton members in the above plane; the bottom recesses of the skeleton member stacked in the Z-axis direction on the two adjacent skeleton members in the above plane are engaged with the top recesses of the two adjacent skeleton members in the above plane; the top recesses are portions recessed when looking at the top ends from the front side of the skeleton member; and the bottom recesses are portions recessed when looking at the bottom ends from the rear side of the skeleton member. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic sectional view of an underground water-storing structure using a stacked structure according to one embodiment of the present invention. 
     FIG. 2 is a schematic perspective view of a skeleton member used in FIG.  1 . 
     FIG. 3A is a schematic front view of the skeleton member of FIG.  2  and FIG. 3B is a schematic plan view of the skeleton member of FIG.  2 . 
     FIG. 4 is a schematic view showing a state where the skeleton members each shown in FIG. 2 are stacked in crossed relation. 
     FIGS. 5A to  5 G are schematic sectional views showing various examples of mountain-shaped portions of the skeleton member of FIG.  2 . 
     FIG. 6 is a schematic view showing a state where the skeleton members each shown in FIG. 2 are stacked one above another in the same direction. 
     FIG. 7 is a schematic view of a skeleton member which is formed in foldable fashion, the skeleton member being in a folded state. 
     FIG. 8 is a schematic perspective view of the stacked structure according to one embodiment of the present invention. 
     FIG. 9 is a schematic perspective view of a modification of the skeleton member shown in FIG.  8 . 
     FIG. 10A is a schematic partly-enlarged plan view showing part of FIG. 3 in enlarged scale and FIG. 10B is a schematic sectional view taken along line  10 B— 10 B in FIG.  10 A. 
     FIG. 11A is a schematic partly-enlarged plan view showing a modification of the skeleton member :shown in FIG.  10 A and FIG. 11B is a schematic sectional view taken along line  11 B— 11 B in FIG.  11 A. 
     FIG. 12 is a schematic perspective view showing a modification of the skeleton member shown in FIG.  9 . 
     FIG. 13 is a schematic sectional view showing a modification of the underground water-storing structure shown in FIG.  1 . 
     FIG. 14A is a schematic plan view of a state where the skeleton members each shown in FIG. 2 are arranged in juxtaposed relation to form a first stage, FIG. 14B is a schematic plan view of a state where the skeleton members each shown in FIG. 2 are arranged in juxtaposed relation to form a second stage on the first stage, and FIG. 14C is a schematic plan view of a state where the skeleton members each shown in FIG. 2 are arranged in juxtaposed relation to form a third stage on the second stage. 
     FIG. 15 is a schematic plan view of a state where in a process of stacking the second stage on the first stage, one of the skeleton members of the second stage is laid in crossed and straddling relation to the mountain-shaped portions of two skeleton members juxtaposed in the first stage. 
     FIG. 16 is a schematic perspective view showing the stacked structure in the case where lowermost reinforcing members and flat surface members are disposed respectively under and over the stacked structure. 
     FIG. 17 is a schematic perspective view showing another modification of the skeleton member shown in FIG.  2 . 
     FIG. 18 is a schematic view showing a state where the skeleton members each shown in FIG. 17 are stacked one above another in the same direction. 
     FIG. 19 is a schematic view of a state where the skeleton members each shown in FIG. 17 are arranged in juxtaposed relation. 
     FIG. 20 is a schematic sectional view of a state where the stacked structure according to one embodiment of the present invention is heaped up on the ground. 
     FIG. 21 is a schematic sectional view of a waterway in which the stacked structure according to one embodiment of the present invention is installed. 
     FIG. 22 is an enlarged view of part of FIG.  4 . 
     FIG. 23 is a schematic sectional view taken along line  23 — 23  in FIG.  22 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the present invention will be described below with reference to the drawings. As one embodiment of a stacked structure according to the present invention, a sectional view of FIG. 1 shows an underground water-storing structure wherein the stacked structure is used to provide a structure for storing water in the underground. A space  10  is formed by excavating in the ground, and side walls  11  of the space  10  have sloped surfaces. The side walls  11  and a floor surface  12  of the space  10  are is subjected to a conventional water-shielding treatment, thereby defining a water-shielding space. Thus permeation of water between the interior and exterior of the space is cut off. 
     Incidentally, the term “water-shielding treatment” used herein means that a water-shielding sheet S is disposed to cover peripheries of a stacked structure  40 , which is formed by, e.g., stacking skeleton members  50  (or plate-like members) shown in FIGS. 2,  3 A and  3 B in such a state as shown in FIGS. 1 and 4, i.e., bottom, side and top surfaces of the stacked structure  40 , thereby defining a water-shielded space within the surrounding sheet S, the space being utilized to store water in the underground. 
     Further, as shown in FIG. 1, a receiving reservoir  21  for collecting rainwater, etc. is provided in the ground surface. A water conduit  20  (water introducing portion) for introducing rainwater, etc. from the receiving reservoir  21  to an upper portion of the water-shielded space is provided to, for example, penetrate the water-shielded space S. Accordingly, rainwater, etc. are supplied from the receiving reservoir  21  to the water-shielded space through the water conduit  20 . 
     In the water-shielded space, the skeleton members  50  are stacked one above another. Each of the skeleton members  50  has top cut-out recesses  55  and bottom cut-out recesses  57 , described later, formed therein to function as openings allowing water to pass through them. With water allowed to pass through the openings (top recesses  55  and bottom recesses  57 ), the space including individual rear-side spaces  52   a  formed between the stacked skeleton members  50 , as described later, is utilized as an underground water-storing tank. 
     In addition, a discharge unit  30  is provided to discharge rainwater, etc. from the interior of the water-shielded space to the exterior of the water-shielded space, e.g., a tank (not shown) on the ground surface. The discharge unit  30  comprises, for example, a discharge pipe  31  provided to penetrate the water-shielding sheet S, a pump  32  and a water delivery pipe  33 . The discharge pipe  31  is arranged in a lower portion of the water-shielded space to interconnect the interior and exterior of the water-shielded space. Rainwater, etc. in the water-shielded space are sent by the pump  32  from the discharge pipe  31  to the water delivery pipe  33 . 
     Provided within the water-shielded space is the stacked structure  40  which comprises the skeleton members  50  (or plate-like members) stacked in crossed, e.g., orthogonal, relation and has a vacant space therein. 
     As shown in FIGS. 2,  3 A and  3 B, the skeleton members  50  are substantially rectangular in plan view and have such a form as obtained by folding a flat plate, which is substantially uniform in thickness, parallel to a long side (extending in a Y-axis direction Y) alternately while advancing along a short side (i.e., in an X-axis direction X), the form including mountain-shaped portions  51  with mountain-like shapes successively repeated in the X-axis direction. A perspective view of the skeleton member  50  is shown in FIG.  2 . 
     In other words, each skeleton member  50  (or plate-like member) has; 
     the mountain-shaped portions or skeleton parts  51  with substantially mountain-like shapes successively repeated in one section and substantially the same sectional form extending in a direction perpendicular to the above section, 
     specifically, the mountain-shaped portions  51  with substantially mountain-like shapes successively repeated in the X-axis direction X and substantially the same sectional form extending in the Y-axis direction Y orthogonal to the above X-axis direction X, and 
     more specifically, the mountain-shaped portions  51  with substantially mountain-like shapes successively repeated in section cut along both an X-axis and a Z-axis orthogonal to the X-axis, and substantially the same sectional form extending along a Y-axis orthogonal to both the X-axis and the Z-axis. 
     Further, the skeleton member  50  (or plate-like member) has the top recesses  55  and the bottom recesses  57  through which the skeleton members  50  to be stacked are engaged with each other. The top recesses  55  and the bottom recesses  57  are formed to function not only as means for holding the skeleton members  50  in place, but also as openings penetrating the mountain-shaped portions  51  from the front side to the rear side so that water is allowed to pass through the top recesses  55  and the bottom recesses  57 . Incidentally, the bottom recesses  57  imply cut-out portions recessed when looking at a bottom end  56  from the rear side of the skeleton member  50 , and the top recesses  55  imply cut-out portions recessed when looking at a top end  54  from the front side of the skeleton member  50 . 
     The skeleton member  50  is substantially uniform in thickness, and the mountain-like shape on the front side is substantially the same as the mountain-like shape on the rear side. Stated otherwise, the rear side of the mountain-shaped portions  51  is shaped in conformity with the form of the mountain-shaped portions  51  on the front side and the individual rear-side spaces  52   a  are defined on the rear side of the mountain-shaped portions  51 , as shown in FIGS. 2 and 3B. Accordingly, when the skeleton members  50  are stacked successively in the same orientation, they are placed together in closely contact relation. On the other hand, when the skeleton members  50  are stacked successively to extend in orthogonal directions as shown in FIG. 4, there is defined a space between one skeleton member  50  and another skeleton member  50  (the space including the individual rear-side spaces  52   a  defined on the rear side of the mountain-shaped portions  51  and individual front-side spaces  52   b  defined on the front side of the mountain-shaped portions  51 , as shown in FIGS.  3 B and  4 ). By transporting and keeping the skeleton members  50  while stacking them in the same orientation as shown in FIG. 6, therefore, a required space can be reduced. Also, the stacked structure  40  shown in FIG. 4 can be constructed as a structure having spaces therein and a relatively small density. 
     Although the stacked structure  40  can be held as an integral structure by using, e.g., fasteners (not shown) or the like after stacking the skeleton members  50  one above another, it can also be kept integral by merely fitting the top recesses  55  and the bottom recesses  57  (in the form of, e.g., cut-out portions) with each other. 
     When forming the stacked structure  40  by stacking the skeleton members  50  together in the Z-axis direction orthogonal to both the X-axis direction and the Y-axis direction, the skeleton members  50  are arranged to extend in orthogonal relation, but not limited to the orthogonal arrangement. The skeleton members  50  may be stacked (in the Z-axis direction Z) such that the upper and lower mountain-shaped portions at least cross each other. 
     In other words, as shown in FIG. 4, two skeleton members  50  adjacent to each other in the Z-axis direction Z are stacked in such an arrangement that the bottom ends  56  of the successive mountain-shaped portions  51  of one skeleton member  50  (shown at, by way of example, character A) cross (more desirably perpendicularly intersect) the top ends  54  of the successive mountain-shaped portions  51  of the other skeleton member  50  (shown at, by way of example, character B). 
     Here, the entire density (weight) of the stacked structure  40  can be appropriately designed depending on applications, and materials of the skeleton members  50  constituting the stacked structure  40  can be properly selected from, e.g., synthetic resins and metals. 
     The skeleton members  50  can also be manufactured by molding a resin with a mold. The molding process can contribute to reducing a cost and a further reduction in weight. The skeleton member  50  may be integrally molded to be incapable of extending and contracting (or pivoting) such that it does not open at folds (the top ends  54  and the bottom ends  56 ), or may be formed such that it can extend and contract (or pivot through a hinge structure) in the X-axis direction X at the folds (the top ends  54  and the bottom ends  56 ). 
     In the latter case, the skeleton member  50  is spread into an extended state when used, but can be folded into a contracted state as shown in FIG. 7 when transported to and kept in the work site. This enables the skeleton member  50  to be easily handled in transporting and keeping it, and also contributes to reducing a required space. There is no problem in holding the skeleton member  50  in a state having the predetermined mountain-like shape. In case the folds cannot hold the skeleton member  50  in the predetermined mountain-like shape and the skeleton member  50  is fully extended into a flat state, the stacked structure  40  can be obtained as a stable structure by providing means for restricting the skeleton member  50  from being extended and contracted in the X-axis direction X when stacked, e.g., later-described cutouts through which the skeleton members  50  are fitted with each other. 
     The scope of “the mountain-shaped portions  51  with substantially mountain-like shapes” which constitute the skeleton member  50  in the present invention is not limited to a mountain-like shape successively repeated in one direction as shown in FIG. 5A, but may include a shape having a flat top in the mountain-like shape as shown in FIG. 5B, a shape with vertical walls as shown in FIG. 5C, and a wavy shape as shown in FIG.  5 D. In addition, it may also include a shape having a flat portion between the mountain-like shapes adjacent to each other, as well as a flat portion in each mountain-shaped portion, these flat portions being equidistantly or inequidistantly spaced, as shown in FIGS. 5E,  5 F and  5 G. The type and size of the mountain-shaped portions can be determined case by case in consideration of various conditions in use. 
     In this embodiment, the outer configuration of each skeleton member  50  is rectangular in plan view as shown in FIGS. 2,  3 A and  3 B, but it may be suitably shaped corresponding to the form of the water-shielded space intended without being limited to the rectangular shape. 
     Also, while the skeleton member  50  is substantially uniform in thickness, the thickness may be partly changed to some extent, or the stack height may be changed in the direction in which the skeleton members  50  are stacked one above another. 
     It is thus only required for the outer configuration of the skeleton member  50  that the rear surfaces of the mountain-shaped portions  51  having successive mountain-like shapes on the front side are formed in conformity with the configuration of front surfaces of the mountain-shaped portions  51  having the successive mountain-like shapes, and the individual rear-side spaces  52   a  are defined on the rear side of the mountain-shaped portions  51 . 
     Engagement between the skeleton members  50  stacked together to construct the stacked structure  40  will be described below. As shown in FIGS. 2,  3 A and  3 B, the top recesses  55  and the bottom recesses  57  are provided in plural number respectively at the top ends  54  and the bottom ends  56  of the mountain-shaped portions  51  along the folds (the top ends  54  and the bottom ends  56 ) with predetermined intervals therebetween. Because the top recesses  55  and the bottom recesses  57  are in the form of cutouts, a reduction in space required for transporting and keeping the skeleton members is not impaired. 
     As shown in FIG. 4, a predetermined interval a between the top recesses  55 , and between the bottom recesses  57  is set smaller than an open end interval b between the adjacent top ends  54  an  54  (or adjacent bottom ends  56  and  56 ) in the mountain-shaped portions  51  each having a first leg portion  58  and a second leg portion  59  coupled to each other at the top end  54 . 
     Of two adjacent skeleton members  50  stacked in the Z-axis direction Z, therefore, the bottom recesses  57  formed at the bottom ends  56  of the mountain-shaped portions  51  of one skeleton member  50  (shown at, by way of example, character A in FIG. 4) are respectively engaged with the top recesses  55  formed at the top ends  54  of the mountain-shaped portions  51  of the other skeleton member  50  (shown at, by way of example, character B in FIG.  4 ). 
     Particularly, as shown in FIG. 4, the top recesses  55  are each defined as a hollow space surrounded by first and second top slopes  55 K,  55 L inclined in respective directions to cross the top end  54  of the mountain-shaped portion  51 , and a third top flat surface  55 M connected at both ends to the first and second top slopes  55 K,  55 L and extended parallel to the top end  54  of the mountain-shaped portion  51 . The bottom recesses  57  are each defined as a hollow space surrounded by first and second bottom slopes  57 K,  57 L inclined in respective directions to cross the bottom end  56  of the mountain-shaped portion  51 , and a third bottom flat surface  57 M connected at both ends to the first and second bottom slopes  57 K,  57 L and extended parallel to the bottom end  56  of the mountain-shaped portion  51 . 
     Further, the top end  54  and the bottom end  56  of the mountain-shaped portion  51  have each an included angle θ. The first and second top slopes  55 K,  55 L also intersect at an angle θ such that they are inclined to separate away from each other outward and approach closer inward. Likewise, the first and second bottom slopes  57 K,  57 L intersect at an angle θ such that they are inclined to separate away from each other outward and approach closer inward. 
     Accordingly, in a state where the bottom recess  57  is engaged with the top recess  55 , the third top flat surface  55 M and the third bottom flat surface  57 M lie in opposed (more desirably contact) relation to each other, the first and second bottom slopes  57 K,  57 L of one skeleton member  50  (shown at, by way of example, character A in FIG. 4) lie in opposed (more desirably contact) relation to the front side of the mountain-shaped portion  51  of the other skeleton member  50  (shown at, by way of example, character B in FIG.  4 ), and the first and second top slopes  55 K,  55 L of one skeleton member  50  lie in opposed (more desirably contact) relation to the rear side of the mountain-shaped portion  51  of another adjacent skeleton member  50 . Then, the bottom recess  57  and the top recess  55  are tightly engaged (more desirably fitted) to each other such that the tightly engaged skeleton members  50  are prevented from moving in the X-axis and Y-axis directions while being allowed to move only in the Z-axis direction Z (when loosely fitted, the skeleton members  50  are movable in the X-axis and Y-axis directions as well). 
     The bottom recesses  57  each have a substantially hexagonal shape in plan view as shown in FIGS. 2 and 3A. Note that the top recesses  55  and the bottom recesses  57  can also serve as openings allowing water to pass therethrough because they are formed to penetrate the skeleton member  50  from the front side to the rear side. 
     The intervals between the adjacent top recesses  55  and between the adjacent bottom recesses  57  along the folds (the top ends  54  and the bottom ends  56 ) are selected, as explained above, such that the top recesses  55  and the bottom recesses  57  are engaged with each other when the skeleton members  50  are stacked in orthogonal directions. 
     The optimum intervals between the adjacent top recesses  55  and between the adjacent bottom recesses  57  can be therefore determined depending on the size and configuration of the mountain-shaped portions  51  of the skeleton members  50 . 
     The top recesses  55  and the bottom recesses  57  are provided in positions shifted a half pitch from one another in the Y-axis direction Y. With that relative positional relationship, it is possible to stack the structure in the upright direction (Z-axis direction Z) by using one type of skeleton members  50 , reduce types of skeleton members  50  to be used, and hence lower a cost. Additionally, the stacked structure  40  can be formed into various shapes by changing the relative positional relationship as required. 
     In the case of folding the flat skeleton member  50  to form the mountain-shaped portions  51  as stated above, the top recesses  55  and the bottom recesses  57  can be provided in similar fashion. 
     FIG. 4 shows a state where the skeleton members  50  are stacked and engaged with each other between adjacent two. Engagement between the top recesses  55  and the bottom recesses  57  enables the skeleton members  50  to be stacked together in orthogonal direction with no need of positioning, makes easier the work of stacking the skeleton members  50 , and increases the working efficiency. 
     Further, by tightly fitting the top recesses  55  and the bottom recesses  57  with each other in the stacked state, the skeleton members  50  are restricted from moving in the X-axis and Y-axis directions. With a load applied to the stacked structure from above, therefore, the skeleton members  50  are kept from disengaging from the fitted state and the need of fixing the skeleton members  50  in place by fasteners or the like is eliminated. This results in even easier stacking work, the reduced number of parts, an improvement of the working efficiency, a reduction in cost, and so on. 
     For the skeleton member  50  capable of extending and contracting along the folds (the top ends  54  and the bottom ends  56 ) as stated above, extension and contraction of the skeleton member  50  are restricted by the top recesses  55  and the bottom recesses  57  fitting with each other. Incidentally, hinge-like extension and contraction of the skeleton member  50  (movement of the leg portions thereof) in the lowermost stage can be restricted by using, e.g., an auxiliary member  61  (lower flat plate) shown in FIG.  8 . 
     When neither cutouts nor recesses are provided in the skeleton members  50 , the stacked structure rises in the Z-axis direction Z in increment corresponding to the height of the individual rear-side spaces  52   a  on the rear side of the mountain-shaped portions  51  for each stage when the skeleton members  50  are stacked together such that the X-axis direction X of the skeleton member  50  crosses alternately. With the provision of cutouts or the like, the skeleton members  50  are engaged with each other when stacked and the height of the stacked structure per stage is reduced correspondingly. However, the above-stated advantages of eliminating the need of positioning, making easier the stacking work, etc. can be achieved. 
     In this embodiment, the skeleton members  50  are all provided with cutouts in the same pattern and stacked together while meshing with each other at the cutouts so that the skeleton members  50  are restricted from moving in the X-axis and Y-axis directions. However, the cutouts may be provided, for example, such that the skeleton members  50  are allowed to move only in any one direction. By so providing the cutouts, the stacked structure  40  can be easily stacked to have an inclined surface and hence can be adapted for the water-shielded space having an inclined surface. 
     After laying the individual skeleton members  50  over a plane extending in the X-axis direction X and the Y-axis direction Y while stacking them in the Z-axis direction Z until the stacked structure  40  is stacked up to a position near the ground surface, a ceiling portion  13  capable of shielding penetration of water therethrough is placed to cover the water-shielded space and level with the ground surface, as shown in FIG.  1 . Since the skeleton members  50  are stacked together with the cutouts fitted to each other, water passages can be secured by the presence of the top recesses  55  and the bottom recesses  57 . Further, the flat working surface can be achieved by providing a top plate  62  (upper flat plate), shown in FIG. 8, over the skeleton members  50  in the uppermost stage and a bottom plate  61  (lower flat plate), shown in FIG. 8, under the skeleton members  50  in the lowermost stage. 
     In the above-explained embodiment, the top recesses  55  and the bottom recesses  57  of the mountain-shaped portions  51  are formed as openings which penetrate the skeleton member  50  from the front side to the rear side and have functions to not only hold the skeleton members  50  through mutual engagement but also allow water to pass therethrough. However, if the top recesses  55  and the bottom recesses  57  are made open entirely, the strength of the skeleton members  50  may not be held at a satisfactory level in some cases. 
     In such a case, each skeleton member  50  may have top recesses  55  and bottom recesses  57  which are dented, but have no through holes, for example, as shown in FIG.  9 . This case requires that openings K penetrating the mountain-shaped portions  51  from the front side to the rear side are separately provided as holes allowing water to pass therethrough in appropriate positions such as the top ends, bottom ends or slopes of the mountain-shaped portions  51 . For example in FIG. 9, the openings K are provided at the top ends. 
     More specifically, the top recesses  55  and the bottom recesses  57  may be entirely closed as shown in FIG.  9 . As an alternative, as shown in FIGS. 10A and 10B, the top recesses  55  and the bottom recesses  57  may be partly closed by reinforcing members H which are provided in the individual rear-side spaces  52   a  to interconnect the slopes on the rear side of the mountain-shaped portions  51  while reinforcing the mountain-shaped portions  51  (with the openings K left in the top recesses  55  and the bottom recesses  57 ). Further, as shown in FIGS. 11A and 11B, reinforcing members H may be provided in the individual rear-side spaces  52   a  to interconnect the slopes on the rear side of the mountain-shaped portions  51  awhile the top recesses  55  and the bottom recesses  57  are entirely closed, thereby enhancing the strength of the mountain-shaped portions  51 . 
     Furthermore, a stacked structure  40  shown in FIG. 13 can be formed by using skeleton members  50 ,  50 ′ shown in FIGS. 9 and 12, respectively. Each of the skeleton members  50 ,  50 ′ has the mountain-shaped portions  51  with substantially mountain-like shapes successively repeated in the X-axis direction X, the top recesses  55  provided in the top ends  54  of the mountain-shaped portions  51 , and substantially the same sectional form extending in the Y-axis direction Y orthogonal to the X-axis direction X. For example, the mountain-shaped portions  51  of the skeleton members  50  are provided in four lines (see FIG. 9) and the mountain-shaped portions  51  of the skeleton members  50 ′ are provided in two lines (see FIG.  12 ). 
     Then, as shown in FIG. 14A, the skeleton members  50  are arranged in juxtaposed relation over a plane extending in the X-axis direction X and the Y-axis direction Y orthogonal to the X-axis direction to form a first stage (lowermost layer). Over the juxtaposed skeleton members  50 , as shown in FIGS. 14B and 14C, the skeleton members  50 ,  50 ′ are juxtaposed and stacked in the Z-axis is direction Z orthogonal to both the X-axis direction X and the Y-axis direction Y. Second, third and further stages of the skeleton members  50  are thus stacked successively in the Z-axis direction Z, thereby forming the stacked structure  40  in the form of a rectangular parallelepiped shown in FIG.  13 . 
     In the above process, one skeleton member (shown at, by way of example, character E in FIGS. 14 and 15) is placed in the Z-axis direction Z on two adjacent skeleton members (shown at, by way of example, characters C, D in FIGS. 14 and 15) in a plane extending in the X-axis direction X and the Y-axis direction Y orthogonal to the X-axis direction such that the mountain-shaped portions of the former skeleton member lie in crossed and straddling relation to the mountain-shaped portions of the latter two skeleton members. Further, bottom recesses (the bottom recesses  57  in FIG. 9) provided in the bottom ends  56  of the mountain-shaped portions  51  of one skeleton member (shown at, by way of example, character E in FIGS.  14  and  15 ), which is placed in the Z-axis direction Z on two adjacent skeleton members (shown at, by way of example, characters C, D in FIGS. 14 and 15) in the above plane, are engaged with top recesses (the top recesses  55  in FIG. 9) provided in the top ends  54  of the two adjacent skeleton members in the above plane. The two adjacent skeleton members (shown at, by way of example, characters C, D in FIGS. 14 and 15) in the above plane are thereby coupled to each other. 
     The above-explained embodiment has a disadvantage that a load imposed on the stacked structure  40  is concentratedly applied to the lowermost skeleton member  50 . To solve such a disadvantage, lowermost reinforcing members  41 , each being flat at a lower surface and substantially triangular, are provided in contact relation to the opposed slopes of the mountain-shaped portions on the rear side, respectively, so as to fill the individual rear-side spaces  52   a  defined on the rear side of the mountain-shaped portions of the lowermost skeleton member  50 . Thus, the lowermost reinforcing members  41  bear the load imposed on the stacked structure  40 , thereby reducing the load applied to the lowermost skeleton members  50  and improving the strength of the stacked structure  40 . 
     Also, the top plate  62  is provided in the above-explained embodiment. Instead of the top plate  62 , however, a flat surface member  42  having an upper flat surface may be provided in contact relation to the opposed slopes of two adjacent mountain-shaped portions (shown at characters F, G in FIG. 16) on the front side so as to fill each front-side space  52   b  defined between two adjacent mountain-shaped portions  51  of the uppermost skeleton member  50  on the front side. The upper surfaces of the flat surface members  42  lie flush with the top ends  54  of the mountain-shaped portions. 
     Further, the above embodiment has been explained as being applied to the water-shielded space. The stacked structure of the present invention can also be employed in a space where rainwater, etc. are temporarily stored and then allowed to gradually permeate into the ground. Such a space may be formed by excavating in the ground, or surrounding a certain area by soil and sand or the like to define an enclosed space. 
     While in the above-explained embodiment the skeleton member  50  has the mountain-shaped portions with substantially mountain-like shapes successively repeated in the X-axis direction X, a skeleton member  50  (plate-like member) modified as described below has the mountain-shaped portion  51  with a single mountain-like shape in the X-axis direction X. In this modification, the skeleton member  50  has an appearance as shown in FIG.  17 . Thus, the skeleton member  50  of this modification is obtained by dividing the skeleton member  50  shown in FIG. 2 from each other in units of the mountain-shaped portion. 
     When stacking the skeleton members  50  together to form the stacked structure  40 , therefore, the skeleton members  50  are first arranged side by side to form an assembly with mountain-like shapes successively repeated in the X-axis direction X. Then, the skeleton members  50  are stacked to form successive stages in orthogonal relation. The stacked structure  40  is thus widely adapted for a desired outer configuration size. 
     When the skeleton members  50  as shown in FIG. 12 are placed in the same orientation one above another, they can also be stacked in closely contact relation as shown in FIG.  18 . Further, in an intermediate portion of the stacked structure, the skeleton members  50  may be arranged at every other top recess or several top recesses apart. The stacked structure  40  can be thus formed in many variations in consideration of various conditions including installation places. 
     In addition to the assembly comprising the skeleton members  50  arranged side by side continuously without spacings, an assembly may be formed by (though not shown) arranging the skeleton members  50  at every other top recess, for example. By using the skeleton members  50  each having one mountain-shaped portion  51 , the stacked structure can be appropriately adapted for installation places. Also, by arranging those skeleton members  50  in alternately inverted orientations to form an assembly  72  as shown in FIG. 19, the stacked structure  40  can have a higher degree of strength as a whole and can be adapted for a variety of environments in use. 
     In the above embodiment, the present invention has been explained as the underground water-storing structure using the stacked structure  40 ; namely in the stacked structure  40 , water is allowed to pass through the openings in the skeleton members  50  and a space including the individual rear-side spaces  52   a  defined between the skeleton members  50  stacked together is utilized to store water in the underground. However, the present invention is not limited to the above embodiment. For example, as shown in FIG. 20, a level of the ground surface  81  can be raised by using the stacked structure  40  in which the skeleton members  50  are stacked together in crossed relation, and covering only outer surfaces of the stacked structure  40  with earth and sand or the like  82 . 
     Generally, heavy materials such as soil and sand or concrete are used to raise the ground level, but work of reinforcing the foundation is required in places where the foundation is not firm, resulting in a longer term of scheduled work and an increased cost. By using the stacked structure  40  having a space therein, it is possible to omit the work of reinforcing the foundation even in places where the foundation is soft, shorten the term of scheduled work, and cut down a cost. In such a case, to prevent soil and sand or the like from entering the interior of the stacked structure  40 , the stacked structure  40  is first surrounded by a sheet  83  and soil and sand or the like  82  is then covered over the sheet  83 . Since a load acts on the stacked structure  40  from above due to the surrounding soil and sand, the skeleton members  50  can be maintained in the fitted condition explained above under the load, and therefore the stacked structure  40  can be firmly kept as an integral structure. 
     In addition, the stacked structure  40  in which the skeleton members  50  are stacked together in crossed relation can also be applied to other structures serving as, for example, gathering blocks for fish, wave canceling blocks, waterways, water gates, and walls. When applied to gathering blocks for fish, the stacked structure  40  can be handled as one integral structure by stacking and coupling the skeleton members  50  and the top plate  62  (upper flat plate), as shown in FIG.  8 . If a relatively heavy plate is used as the top plate  62 , the skeleton members  50  are kept from disengaging from the fitted condition at the cutouts thereof because of the weight of the stacked structure  40  itself and hence fasteners are not required. If the skeleton members  50  are manufactured by, e.g., a synthetic resin other than metals, there is no fear of rusting even with the stacked structure  40  immersed in sea water. Further, since metal-made fasteners are not required, the stacked structure  40  having high durability can be provided without a fear of corrosion such as rusting. A larger number of water introducing holes may be provided, if necessary, to reduce resistance against water flow. 
     When applied to waterways, the ecology of fish, etc. can be maintained by providing the stacked structure  40  at each of opposite lower ends of a concrete-made waterway. This results in such advantages as making work easier, reducing the term of scheduled work and the cost, and facilitating maintenance. In that case, materials of the plate-like members, the configuration and size of the mountain-shaped portions of each plate-like member, the positions, number and size of the openings, etc. may be determined as required. 
     With the stacked structure according to the first (second or third) aspect, the skeleton members are relatively light since a space is left between adjacent mountain-shaped portions of each of the skeleton members. Further, when stacking the skeleton members together, bottom ends of the mountain-shaped portions with substantially mountain-like shapes successively repeated in one of two adjacent skeleton members are arranged to cross top ends of the mountain-shaped portions of the other skeleton member. Therefore, the stacked structure having a high degree of strength can be achieved. 
     With the stacked structure according to the fourth aspect, since the rear side of the mountain-shaped portions is shaped in conformity with the configuration of the mountain-shaped portions on the front side, the skeleton members can be formed to be thinner and lighter in addition to the above-stated advantages obtainable with the first aspect. 
     With the stacked structure according to the fifth aspect, since reinforcing members are provided to interconnect opposed slopes of the mountain-shaped portions on the rear side for reinforcing the mountain-shaped portions, the stacked structure having a higher degree of strength can be achieved in addition to the above-stated advantages obtainable with the first aspect. 
     With the stacked structure according to the sixth aspect, the stacked structure can be assembled just by engaging bottom recesses provided at the bottom ends of the mountain-shaped portions in one of two adjacent skeleton members stacked in the Z-axis direction with top recesses provided at the top ends of the mountain-shaped portions of the other skeleton member. In addition to the above-stated advantages obtainable with the first aspect, therefore, the stacked structure can be assembled easily, can firmly hold a stacked state of the skeleton members stacked in the Z-axis direction, and has a higher degree of strength. 
     With the stacked structure according to the seventh aspect, the stacked structure having a higher degree of strength than obtainable with the fourth aspect can be achieved. 
     With the stacked structure according to the eighth aspect, the following advantage can be obtained in addition to the above-stated advantages obtainable with the first aspect. When the stacked structure is covered along its peripheries by a shield sheet, for example, to be used as a structure for storing water, water received by the upper skeleton member is introduced to the lower skeleton member through openings provided in the mountain-shaped portions, and individual spaces defined between the adjacent mountain-shaped portions of the skeleton member can be utilized to store water. 
     With the stacked structure according to the ninth aspect, since lowermost reinforcing members are provided to bear a load imposed on the stacked structure, the load imposed on the mountain-shaped portions of the lowermost skeleton member can be reduced and the stacked structure having a higher degree of strength can be achieved in addition to the above-stated advantages obtainable with the first aspect. 
     With the stacked structure according to the tenth aspect, a flat surface member having an upper flat surface is provided to be contacted at slopes thereof with opposed slopes of the adjacent mountain-shaped portions on the front side while the upper surface of the flat surface member is lying flush with the top ends of the mountain-shaped portions, thereby providing an upper flat surface of the stacked structure. In addition to the above-stated advantages obtainable with the first aspect, therefore, it is possible to fill front-side recessed spaces which are formed at a top of the stacked structure when it is constructed by stacking the skeleton members one above another. 
     Further, with stacked structure according to the eleventh aspect, the mountain-shaped portions of the skeleton members each stacked in the Z-axis direction on two adjacent skeleton members in a plane are arranged in crossed and straddling relation to the mountain-shaped portions of the two adjacent skeleton members in the above plane. In addition to the above-stated advantages obtainable with the first aspect, therefore, the skeleton members can be stacked in the Z-axis direction while coupling the two adjacent skeleton members in the above plane to each other, and the stacked structure having a higher degree of strength can be achieved.