Dynamic Tank Performance Evaluation, South Asia
The tank is built on reclaimed land in a seismically active region. While the loose hydraulically-placed fill under the tank was densified using stone columns, simplified liquefaction-triggering evaluations performed for the project showed liquefaction potential within the native deposits underlying the site and within some of the deeper layers of the reclamation fill materials. The tank is located near the edge of the land reclamation, and therefore additional deformation risks exist due to lateral spreading.
2D and 3D dynamic effective stress numerical analyses were condcuted using the Ta-Ger soil contitutive model for sands implemented in FLAC 3D by GR8 GEO.
GR8 GEO performed the following tasks to assess the dynamic performance of the tank:
• Dynamic site characterization using available in situ tests, boreholes, and laboratory tests
• Total and effective stress site response analyses to develop near-surface design ground motions
• Evaluation of dynamic stiffening effect of stone columns by conducting 3D dynamic effective stress numerical analyses explicitly modeling the stone columns. Analyses showed that the stone columns reduced the soil deformations by about 50%.
• 2D SSI analyses to evaluate the performance of the structure/foundation system for combined deformations from the inertial response of the tank and lateral spreading towards the shoreline
• 3D dynamic effective stress SSI analyses to more realistically represent the geometry of the tank foundation system and assess the distribution of liquefaction-induced deformations of the tank foundation