PB Energy Storage Services, Inc.
AAI conducted a variety of design and project management tasks for PB Energy Storage Services, Inc., of Houston, Texas, related to the design and construction of a large underground gas storage complex located in Singapore. The facility included five storage caverns, each having a total volume of approximately 11 million barrels and located 110 to 140 m deep. The design included a sophisticated network of access shafts and connecting drifts to support construction and the unique requirements of gas storage containment. The caverns were constructed in a metamorphosed shale and limestone under a bay with shaft access on adjacent land. During the design phase, AAI evaluated the rock mass classification and ground support requirements and conducted numerical modeling analyses of overall cavern stability, alternative opening profile shapes, and appropriate pillar widths. AAI played a key role in the design process by providing advice to PB Energy regarding appropriate excavation and support practices and evaluating the viability of detailed construction plans. Throughout the construction phase, AAI provided senior personnel on-site to review construction activities and ensure long-term cavern stability by verifying that proper excavation and ground support methods were employed and by monitoring changing ground conditions and modifying support plans as needed during construction. The total project duration was about 7 years (2007–2014).