... different specifications as customers`s request.1 FiltrationThe filtration layer of the dykes,river canal, seacoast, concrete slope, retaining walls ... water and the gas pass through freely.2 Separation:The isolation of the railway dregs and the roadbed, roadbed and the ... , railway, soil-stone dam, breakwater, airport, backfill soil of retaining wall, slope protection, etc in which distributes the earth ...