Soil Improvement Through Rammed Aggregate Piers to Mitigate Liquefaction Risk in Storage Tanks-Video

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Juan Pablo Rodriguez presented a ground-improvement project for four storage tanks in Tabasco, Mexico, focusing on the largest, a 30-meter-diameter tank. Silty sand layers created significant liquefaction risk: analyses predicted post-earthquake settlements of roughly 40–57 cm, exceeding the 30 cm allowance. The design used rammed aggregate piers spaced about two meters apart, extending to 12.5 meters deep, with closer spacing beneath the tank’s ring wall. The project installed 980 piers. Static analyses showed settlement and differential-settlement requirements were approximately met, while the estimated liquefaction-induced settlement after improvement fell to about 1.5–4 cm. Post-installation CPT and SPT results indicated increased resistance and soil densification in susceptible sandy layers. Rodriguez noted that these performance estimates have not yet been verified by a design-level earthquake at the site, but cited the favorable performance of an aggregate-pier-supported embankment during the 2016 Ecuador earthquake.

Keywords

ground improvement

liquefaction mitigation

rammed aggregate piers

settlement analysis

Tabasco Mexico