geotextiles can be used: 1 filtration layer of the dykes, 2 river canal, seacoast, 3 concrete slope, 4retaining walls. geotextiles can be the filtration layer of the dykes, river canal, seacoast, concrete slope, retaining walls. At the same time of preventing the clay granule from passing, it allows the water and the gas pass through freely.SeparationThe isolation of the railway dregs and the ...