Design of water retaining embankment using geosynthetics for hydraulic conditions

Sand is often used in chimney and blanket drain to control the seepage inside the water retaining embankment. On many sites it is not economical to find a sufficient quantity of good quality sand. The objective of the present study is to minimize use of sand in design of water-retaining embankment by using geosynthetics material to control the seepage. Accordingly, two alternative designs of water retaining embankment with internal drainage system have been proposed. These designs are ‘water retaining embankment with vertical drainage composite’ and ‘water retaining embankment with horizontal drainage composite’. The functions of geosynthetics in both the designs are filtration and drainage, and the geosynthetics material used are geotextile, drainage composite (geonet sandwiched by geotextile) and perforated pipe. The performance of geosynthetics for drainage and filtration in various structures like earth dam, retaining wall, highway drains and landfills provides confidence to use geosynthetics effectively in place of sand in water retaining embankment. A detailed methodology is set to determine the drainage and filtration requirement of geosynthetics material in each component of proposed alternative designs. The specifications required for geosynthetics material in each component of the proposed alternative design are also given. Depending upon the requirement any one of the alternatives can be used in place of the conventional system.