High shear strength clay liner, method and apparatus for its production

摘要

PCT No. PCT/IT95/00127 Sec. 371 Date Apr. 24, 1996 Sec. 102(e) Date Apr. 24, 1996 PCT Filed Jul. 24, 1995 PCT Pub. No. WO96/06987 PCT Pub. Date Mar. 7, 1996A high shear strength clay liner comprising two synthetic geotextiles (1a, 1b) and a semihydrated layer (1c) of swellable clay therebetween with fastening means (5) arranged in such a pattern of connecting threads to form pockets (7) through the clay layer. The pattern comprises rows of independent fasteners arranged according two intersecting directions. The fasteners have knots (8) at their ends protruding from the surface of the liner. The invention also comprises a method and a machine for forming the independent fasteners by means of two parallel needle bars (104a, b) each carrying a row of needles (105) reciprocating in opposed directions and cooperating with a reciprocating needle plate (109) having a plurality of parallel fingers (110) and a looper bar (117) with a plurality of parallel looper plates (118) rocking on its axis to form loops (5a, 5b) which can be melted into protruding knots (8). The independent fasteners carry the major part of the shear forces on the liner avoiding failure of the fabrics and giving a much greater interfacial shear strength with a high internal friction angle.