| 摘要 |
<p>The invention is an earth drain, comprised of a core consisting of an elongated, flexible web (3) having an array of discrete, longitudinally and transversely spaced projections (4) on at least one surface thereof, and a filter (2) of sheet-like water permeable material encasing the core and adapted to be maintained in spaced relationship to the web (3) by the free ends of the projections (4). The projections (4) are arranged with regular spacing in parallel rows disposed transversely of the web, and projections (4) in alternating transverse rows are disposed between the projections (4) in an adjacent row. A transverse line touching the outermost periphery of at least some of the projections (4) in each row intersects part of some of the projections of an adjacent row causing an overlap (B) between at least some of the projections (4) in adjacent rows in the longitudinal direction of the web (3).</p> |
