The impact of a PEER funded research project “Remediation of Liquefaction Effects on Embankments Using Soil-Cement Reinforcements” is highlighted below. The project Principal Investigator is Ross W. Boulanger, Professor of Civil Engineering, UC Davis. The research team includes Mohammad Khosravi, Post-doc, UC Davis, Ali Khosravi, Visiting Scholar, Sharif University of Technology, Dan Wilson, Associate Director of CGM, UC Davis, W. Yunlong, Visiting Scholar, China Earthquake Administration, and A. Pulido, Undergraduate researchers, UC Davis.
Centrifuge tests and two-dimensional nonlinear dynamic analyses were performed for an embankment on a liquefiable foundation layer treated with soil-cement walls. The model corresponded to a 28 m tall embankment underlainby a 9 m thick saturated loose sand layer. Soil-cement walls were constructed through the loose sand layer over a 30 m long section near the toe of the embankment with a replacement ratio of 24%. The model was shaken with scaled earthquake motions having peak horizontal base accelerations of 0.26g and 0.54 g. The experimental data were archived as a lasting resource for validation of numerical modeling procedures. Nonlinear deformation analyses were performed using the platform FLAC with the user-defined constitutive model PM4Sand for the liquefiable materials and area-averaged properties for the treatment zone. The numerical simulations were in reasonable agreement with the recorded dynamic responses, including the triggering of liquefaction in the loose sand layer during both events. The simulations reasonably approximated the observed deformation magnitudes and patterns, and correctly predicted that the soil-cement walls would shear through their full length in the second event.
The results of these comparisons provide support for the use of these numerical modeling procedures, including the representation of the treatment zone with area-weighted properties, for analyses of embankments with soil-cement treatment of liquefiable soils in their foundations.