DIOGRID AND ITS MANUFACTURE

摘要

PURPOSE: To increase the strength per a unit wt. of a geogrid to a large extent by setting a plastic starting material to a specific thickness at the thickest part thereof and making the crosssectional area of a longitudinal part larger than that of a connection part and continuing stretching until the thickness of the central part of an imaginary connecting area reduces at least in a specific ratio. CONSTITUTION: A geogrid is formed from a starting material 1 having a thickness of at least 6 mm at the thickest part thereof and the average thickness of the longitudinal part 2 of the starting material 1 is substantially larger than that of a connection part 3 as the cross section along the axis of the central line of the connection part 3. Further, the cross-sectional area of the longitudinal part 2 is at least 2.5 times that of the connection part. Stretching is continued until the central part of an imaginary connection area reduces to a thickness of at least about 9.6% and completed before the thickness reducing ratio of the center of the imaginary connection area becomes substantially smaller than that of the strand reaching the imaginary connection area when it is measured at the intermediate part of the imaginary connection area.