This Paper presents a case study for the design of a parking lot using geocells and geogrids.  The parking lot is essentially for standby heavy container carriers at one of the container yards at Nhava-Sheva Port in Navi Mumbai, India, operated by the Jawaharlal Nehru Port Trust (JNPT).  The site is along the West Coast of India adjacent to the Thane Creek and experiences the full brunt of the South West monsoons.  The average annual rainfall is as high as 1,800mm, with a historical maximum rainfall of 548mm over 24 hours in the recent past.

The subsoil comprises of reclaimed soil fill overlying the typical Bombay residual Marine Clay to a greater depth.  Conventionally, a pavement section comprising of dry paver blocks followed by dry lean concrete and granular subbase was proposed.  To facilitate fast construction along with an economic solution, a flexible pavement including geosynthetic reinforcements was provided below the surface paver blocks.  The geosynthetics included High Density Polyethylene (HDPE) geocells for load bearing and Polypropylene (PP) geogrids for traction forces.

The HDPE geocells are rhomboidal cellular confinement systems fabricated from ultrasonically welded, textured and perforated strips.  Geocells have the characteristics of spreading heavy vertical force over a wider area, thereby reducing the bearing pressures on the subgrade.  Geocell perforations also help in providing drainage to the pavement section below the surface.  A layer of biaxial rigid geogrid was also incorporated in the sand layer, a component of the flexible pavement section.  The geogrid was provided to address deformations that can be brought about due to traction when the heavily loaded vehicles take turns, accelerate and brake on the pavement.  The geogrid develops resistance to horizontal traction forces through tension within the geogrid which gets its anchorage through interaction with the fill material.  French drains have also been provided to cover uninterruptedly paved vast area which experiences heavy rainfall.

The construction of 33 hectares of the parking area commenced on November 2017 and the areas were released for use in phases.