The containment systems for landfills need to be judiciously designed, and geosynthetics can play a significant role. Along the sides, the landfill is contained within earthen dykes, which should be stable with a factor of safety higher than conventional, considering the consequences of a breach. Outer slopes of such containment can be of the order of 1V:4H. The landfill at Ghazipur is no exception. The slopes of the containment dyke constructed from local silt were adequately stable. However, the slope’s surface was lined with a geomembrane, which was required to be protected by soil cover. Soil cover, which was local silt, laid on geomembrane was subject to sliding. To compound the problem, the length along the slope was high, as much as 30 m in many sections.

The challenge was to stabilize a thick enough soil mass placed over the geomembrane to protect it against any physical damage and UV degradation. Apart from these requirements, there were strict deadlines to complete the design, supply and execution within six weeks.

A solution was engineered involving a system using StrataGrid™ and StrataWeb® geocells. Geocells are an HDPE cellular confinement system used the world over for load support, earth retention, and slope and channel protection applications. StrataWeb® effectively confines the infill material placed on a slope and prevents erosion. While guaranteeing the integrity of the soil, it simultaneously allows the growth of desired natural vegetation. The vegetation further protects the soil within the geocell from possible erosion.