Functions of geosynthetics drainage

Drainage (Fluid transmission) - transportation of liquid or gas within its own plane to an outlet - transmissivity 

Impermeable soil base 8.4 Geotextile drainage function. 

Similar to the filtration function, the requirements for drainage are soil retention, adequate flow capacity, and long term soil-to-geotextile flow equilibrium, in respect of minimum clogging of the pore spaces. Apart from the flow capacity within the plane of the geosynthetic material, the other aspects have been dealt with above. We will therefore now consider the inplane flow characteristics. 

For fluid flow along the plane within the thickness of the geosynthetic. Equation [8.5] can be rewritten as  

Water supply, 2. Water collection, 3. Specimen, 4. Foam, 5. Load, 6. Loading platen, 7. Overflow weirs at hydraulic gradient 0.1 and 1.0. 

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