Flat cardboard blank, of a general rectangular shape, designed for the formation of a final packaging of a pack of cartons, of the tubular envelope type, with the pack including at least one base carton layer comprising four wedging cartons that are two by two, side by side, and opposite one another, positively spaced and wedged on their side walls in the vicinity of their bottom walls, comprising: ▪ Two top panels (10, 10a, 10b) connected to two side panels (11, 11a, 11b), two connecting panels (12, 12a, 12b), a base panel connected to the side panels via the connecting panels, and a connecting means for the closing on itself of the blank that is expanded in volume, ▪ Cutout lines, and grooved lines in a transverse direction, of the blank, capable of folding and designed to fold panels, in order to expand the blank in volume, for putting together the packaging and the pack, ▪ A receiving part, extending over a part of the base panel, for receiving wedging cartons by their bottom walls, and if necessary extending over the connecting panels (12, 12a, 12b), ▪ And a spacing/wedging part, coming from the base panel with cutout lines, able to be expanded in volume relative to the receiving part, in such a way as to form stopping edges for the wedging cartons acting on their side walls in the vicinity of their bottom walls, characterized in that: ▪ The spacing/wedging part is continuous and is formed by a first median portion formed in the base panel and two (23a,23b) second median portions, formed respectively in the two connecting panels (12, 12a, 12b), ▪ A continuity arrangement exists between, on the one hand, the spacing/wedging part, and, on the other hand, the receiving part and the portions of connecting panels (12, 12a, 12b) other than the one of the spacing/wedging part, ▪ wherein four grooved lines (15a, 16a) arranged at the spacing/wedging part form two irreversible-pivot double hinges, such that the first median transverse portion of the base panel can be separated from the receiving part along an axis that is perpendicular or essentially perpendicular to the receiving part, ▪ The spacing/wedging part is delimited in the transverse direction of the blank by two continuous and curved edge cutout lines extending generally in a longitudinal direction of the blank, segments of which form the stopping edges. ▪ Two top panels (10, 10a, 10b) connected to two side panels (11, 11a, 11b), two connecting panels (12, 12a, 12b), a base panel connected to the side panels via the connecting panels, and a connecting means for the closing on itself of the blank that is expanded in volume, ▪ Cutout lines, and grooved lines in a transverse direction, of the blank, capable of folding and designed to fold panels, in order to expand the blank in volume, for putting together the packaging and the pack, ▪ A receiving part, extending over a part of the base panel, for receiving wedging cartons by their bottom walls, and if necessary extending over the connecting panels (12, 12a, 12b), ▪ And a spacing/wedging part, coming from the base panel with cutout lines, able to be expanded in volume relative to the receiving part, in such a way as to form stopping edges for the wedging cartons acting on their side walls in the vicinity of their bottom walls, ▪ The spacing/wedging part is continuous and is formed by a first median portion formed in the base panel and two (23a,23b) second median portions, formed respectively in the two connecting panels (12, 12a, 12b), ▪ A continuity arrangement exists between, on the one hand, the spacing/wedging part, and, on the other hand, the receiving part and the portions of connecting panels (12, 12a, 12b) other than the one of the spacing/wedging part, ▪ wherein four grooved lines (15a, 16a) arranged at the spacing/wedging part form two irreversible-pivot double hinges, such that the first median transverse portion of the base panel can be separated from the receiving part along an axis that is perpendicular or essentially perpendicular to the receiving part, ▪ The spacing/wedging part is delimited in the transverse direction of the blank by two continuous and curved edge cutout lines extending generally in a longitudinal direction of the blank, segments of which form the stopping edges.