Deterministic Analysis for Liquefaction and Its Mitigation by Suitable Foundation Type in Bangladesh-Paper

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The study evaluates liquefaction risk and foundation options for a proposed 750 MW power plant near the Meghna River in Bangladesh, where silty fine sand extends to approximately 55 m depth. The investigation included 24 boreholes, cone penetration tests, pressuremeter and cyclic plate-load tests, seismic cross-hole testing, and laboratory analyses.<br /><br />Field observations indicated loose or deformable saturated sand in parts of the site, including low pressuremeter and cone resistance values and substantial plate-load settlements. Liquefaction potential was assessed using Geologismiki software and established methods, including NCEER, Eurocode 8, Seed, and Boulanger–Idriss procedures. The SPT-based assessment identified liquefiable layers, particularly in the upper soil profile, under the assumed earthquake conditions (peak acceleration of 0.15g and magnitude 7.5).<br /><br />Given the site conditions and the project’s cost constraints, the paper recommends driven precast solid square concrete piles, 400 mm wide and approximately 36 m long, for power-plant structures. Pile driving is proposed both to transfer structural loads to more competent soil and to densify surrounding sand, thereby improving resistance to liquefaction. The authors consider this option more practical than other ground-improvement methods for the project.<br /><br />The paper concludes that deep foundations are necessary at the site and presents driven precast piles as a combined foundation and mitigation measure.

Keywords

liquefaction risk

foundation options

Meghna River

Bangladesh

silty fine sand

SPT assessment

driven precast piles

ground improvement

power plant

seismic testing