Visakhapatnam underground LPG storage cavern, India

One of the world's deepest underground liquefied petroleum gas (LPG) storage cavern projects has been built near the city of Visakhapatnam in India. Storage is based on the hydraulic containment principle using water pressure. This paper discusses the design aspects and various phases involved in construction. The general outline, significance of the facility and basic principles of storage are described, including the initial exploration works, complementary site investigations, basic engineering design and the design changes made during construction. Health, safety and environment as well as quality aspects are considered. The sequence and methods adopted to construct diaphragm walls for the foreshafts, sinking for the rock shafts, installation of the water curtain tunnel and excavation for the main storage cavern are described. The scope and construction methodologies are explained and the challenges and complexities of the underground project, a first for south Asia, are considered. Achievements and areas where there is scope for improvements are discussed. Finally, the advantages of such projects, critical success factors and special issues needing attention are presented.