| 摘要 |
A perforated interlocking concrete slab, for example moulded from cement, intended for use for example for consolidating turfed areas or sloping banks, has an outline which includes portions that project and portions that are withdrawn with respect to a notional base line that forms a rectangle with sides twice as long as its ends are wide; the projections and withdrawn portions being arranged so that it is possible to lay against half the length of a side of the slab (regarded as extending from a corner) another like slab oriented at will either with its end abutting that half length or with half the length of its side abutting that half length, so that by their interengagement relative displacement longitudinally with respect to that half length is prevented; the perforations passing from the face to the back of the slab and being disposed in first rows that extend parallel to each other and in second rows that extend at right angles to the first rows and parallel to each other, the first and second rows extending obliquely with respect to the rectangular base line. The first rows of perforations can extend in the same direction as the diagonal of the rectangular base line (one of the first rows being situated on that diagonal). Recesses at the corners and midway of the longitudinal sides, combine in an array of such slabs to form perforations of like shape and area as the perforations of the slab. |
