PURPOSE: To expand a stormwater-permeable area by providing a paved surface course over an underlayer, providing sand filtration layer under the underlayer, and providing a stormwater-permeable layer, in which globe-shaped molded items are superposed in layers, under the sand filtration layer.
CONSTITUTION: An asphalt layer 1 is formed over an underlayer 2 and a stormwater-permeable layer 4 is provided under the underlayer 2, a concrete layer 30, as a sand filtration layer, being interposed therebetween. The layer 4 is formed over an underground premeable layer 5 under the road, in which globe-shaped molded items 40 with nearly equal diameters are laid in the layer 4 and the opposite edge thereof are connected to each side drain 6, 6 and further the under side thereof are downwardly inclined toward the center of the road. Stormwater flowing through the side drain 6 passes through a filter 64 and flows through lateral holes 63 into the layer 4, thence into the layer 5. As a result, stormwater can penetrate through a wide area under the road, without causing high resistance to the flow of water by the provision of the molded items 40.
YAMAGUCHI JUNKO
YANAGAWA YASUSHI
MATSUKAZE YUUJI
