... impurities are blocked outside,so as to achieve permeability,filtration,drainage once. Features: 1.Pore diameter is small,all-round ... prevent slump; 2.Airports,railways,roads,sports grounds,parks greening drainage; 3.Mine last dam,power plant ash dam,landfill plant ... tunnel wall,the back of retaining wall,embankment,road,slope drainage. Product technical index:Diameter of steel wire mmSpace for spring ...