Gabion Works. The quality of stone for gabion shall be as specified in Clause 4.01. The stone size ranges from 200 mm to 350 mm. Small stones should be avoided. The stones used should have a minimum size of not less than “D” (mesh width) and not greater than 3.5 times “D”, where D is the specified mesh width as given below. Larger stones can be used provided that their total volume does not exceed 5% of the cell volume. Gabions shall be of the types and sizes shown on the Drawings. The cages shall be constructed from mild steel wire complying with BS 1052, "Specification for mild steel wire for general engineering purposes", galvanised in accordance with BS 443, "Specification for testing zinc coatings on steel wire and for quality requirements". Wire used for the formation of the mesh panel will have a diameter of 3.0 mm.
Gabion Works. Gabion works shall comply with the requirements as specified in the Technical Specifications. Filter materials used in drains shall comply with the requirements. Geomembrane shall be made of PVC or polythene sheets of at least 0.8 mm thickness, duly protected from ultra-voilet exposure with 2.5 per cent carbon black, in black colour, supplied in roll form with a minimum of 3 m width. The joints of these sheets shall be heatbonded or seamed for effective permeation cut off. While fixing on to a slope, they shall not be punctured or stappled to impair their use.
