Dynamic Centrifuge Tests to Evaluate the Seismic Performance of an Embankment Resting on Liquefiable Ground Improved by Unreinforced and Reinforced Soil-Cement Columns

A series of centrifuge experiments were conducted to identify different internal failure modes of a group of soil-cement (SC) columns (e.g., shearing and tension due to bending) under combined effects of embankment loading and liquefaction-induced lateral spreading. The results were also used to investigate how an increase in the flexural/shear strength of SC columns (using high-strength steel reinforcement bars) can affect their ability to limit settlements or deformations. The centrifuge experiments included two centrifuge tests of liquefiable foundation reinforced by SC columns with and without high-strength steel reinforcement cores during strong earthquake loading. It was found that during and after cracking of the SC columns, shear and tilting failure is the prominent failure mechanism. The test results showed that increasing the flexural capacity of SC columns can reduce the potential for earthquake-induced liquefaction and associated damage. Compared with conventional SC columns, reinforced soil-cement (RSC) columns are more effective in providing confinement for the soil under the embankment during strong shaking events, resulting in lower shaking-induced pore-water pressure and a reduction in the lateral deformation of the soil and embankment.