Plastic material mesh structure

A method of constructing a civil engineering structure, comprising:

• providing a mass of particulate material and a reinforcing means therefor, said reinforcing means comprising at least one generally horizontally extending layer of a flexible, integral, uniaxially-molecularly orientated, plastics material mesh structure having a thickness of not less than 1.5 mm, said mesh structure having upper and lower faces and comprising molecularly orientated longitudinal strands interconnected by transverse bars, thereby defining a generally square or rectangular grid, respective orientated strands being aligned on each side of respective bars, said orientated strands and said bars defining therebetween mesh openings whose dimension in a direction parallel to said orientated strands is at least several multiples of the width of the mid-points of the orientated strands between said transverse bars, each said bar comprising a succession of alternate zones, namely first zones between and interconnecting the ends of aligned orientated strands and second zones between the first zones, the orientation of the strands penetrating into a respective said bar on each face of the mesh structure beyond a notional line which is substantially parallel to a respective said bar and is substantially tangential to respective said mesh openings, the mid-point of each said first zone being unorientated or substantially less orientated than said mid-points of said orientated strands connected thereby and said second zones not being substantial orientated;
• and
• embedding said reinforcing means in said mass of particulate material with portions of said mass of particulate material being below said mesh structure, portions of said mass of particulate material being above said mesh structure, and portions of said mass of particulate material being within the mesh openings defined by said mesh structure, so that portions of said particulate material are in direct contact with said upper and lower faces of said mesh structure and with portions of said mesh structure defining said mesh openings;
• whereby said mesh structure has good slip resistance properties with respect to said particulate material and provides good stress transmission paths in said civil engineering structure.

A method of constructing a civil engineering structure, comprising;

• providing a mass of particulate material and a reinforcing means therefor, said reinforcing means comprising at least one generally horizontally extending layer of a flexible, integral, biaxially-molecularly--orientated plastics material mesh structure formed from a sheet of starting material having a thickness of not less than 1.5 mm, said mesh structure having upper and lower faces and comprising a generally square or rectangular grid formed by respective sets of orientated strands interconnected by orientated junctions and defining mesh openings whose dimension in a direction parallel to each set of said orientated strands is at least several multiples of the widths of the mid-points of said orientated strands, the junctions interconnecting respective orientated strands having a profile which on each face of the mesh structure is formed at least in part by stretching and biaxially orientating said starting sheet, which profile comprises a central zone which is thicker than the mid-points of any of the orientated strands interconnected by the junction, and is unorientated or less orientated than said mid-points of said orientated strands, the junction having no thin lateral zones which could form tear starters, crotches extending between respective pairs of said orientated strands passing into the junction generally at right angles to each other, the edge zones of said crotches being continuously orientated in the direction running around the respective crotch;
• and
• embedding said reinforcing means in said mass of particulate material with portions of said mass of particulate material being below said mesh structure, portions of said mass of particulate material being above said mesh structure, and portions of said mass of particulate material being within the mesh openings defined by said mesh structure, so that portions of said particulate material are in direct contact with said upper and lower faces of said mesh structure and with portions of said mesh structure defining said mesh openings;
• whereby said mesh structure has good slip resistance properties with respect to said particulate material and provides good stress transmission paths in said civil engineering structure.