Rainwater storage and infiltration facility

Abstract

A unit member A includes a square flat plate (31) with a given thickness and hollow legs (32, 33) in a truncated cone shape being opened to contact surfaces (34) formed on the four corners and the flat plate. The contact surface is provided with an engaging convex portion (321) and an engaging concave portion (331) for mutually connecting with another unit member A. The engaging convex portion 321 of one unit member A and the engaging concave portion 331 of the other unit member A is placed facing each other to make a pair of unit members, and given numbers of the pair of unit members are assembled in the horizontal and vertical directions to construct a rainwater storage/infiltration facility. Since the contact surface has a step thereon, load can be supported by virtue of the step of the two lateral sides of the contact surfaces.

1 . A rainwater storage/infiltration facility for creating space to storage rainwater structured by assembling a plurality of unit members in both horizontal and vertical directions and placing the assembled unit members under the ground wherein
 the unit member comprises:   an either square or rectangular flat plate having a given thickness,   connecting portions formed on four corners of one side of the flat plate and provided with contact surfaces adapted to connect to four corners of a flat plate of an other unit member, and   hollow cylindrical legs integrally formed with the flat plate on the four corners of said flat plate, projecting toward the other side of said flat plate and being opened to said one side, and   said contact surfaces are rectangular planar bottom surfaces each having been formed to be dented from said other side toward said one side by the length of half a thickness of said flat plate, and sides adapted to contact to lateral sides of any of the four corners of the flat plate of the other unit member.   
     
     
         2 . (canceled) 
     
     
         3 . The rainwater storage/infiltration facility of  claim 1 , wherein
 each of the connecting portions is provided with an engaging portion and an engaged portion for engaging with the connecting portions of the other unit member,   tip portions of the legs positioning at diagonal positions of the flat plate consist of a projecting convex portion and the tip portions of the legs positioning at the other diagonal positions of the flat plate consist of a projecting concave portion for connecting with the legs of the other unit member, and   each of the legs is formed in either round or truncated pyramid shape, and a diameter of each of the legs is made to be gradually reduced in a direction of from said one side toward said other side.   
     
     
         4 . The rainwater storage/infiltration facility of  claim 3 , wherein
 the convex portions and the concave portions of the legs are connected to structure a pair of the unit members, the engaging portions, the engaged portions and the contact surfaces of said pair of unit members and an other pair of unit members are engaged and assembled alternately in the horizontal direction and the vertical direction and followed by placing the assembled unit members under the ground to construct the rainwater storage space.   
     
     
         5 . The rainwater storage/infiltration facility of  claim 4 , wherein
 top portion of an inspection port, embedded in covered soil laid over a top stage unit members group and formed between sides of the flat plates of the adjacent top stage unit members, and the earth surface are connected, and   hollow structure, into which an inspection camera may be inserted through the inspection port, is provided to the facility.   
     
     
         6 . The rainwater storage/infiltration facility of  claim 4 , wherein an inspection manhole connected to the ground is provided by removing the unit members in the vertical direction to form a cylinder-shaped space extending from a top surface of the top stage unit members group up to the ground.