Numerical Investigation of the E ects of Soil Densi cation on the Reduction of Liquefaction-Induced Settlement of Shallow Foundations


Department of Civil Engineering,Sharif University of Technology


Abstract. The liquefaction phenomenon is usually accompanied by a large amount of settlement.
Based on the observations made in past earthquakes, ground improvement by densi cation is one of
the most useful approaches to reduce the liquefaction-induced settlement. Currently, there is no analytical
solution for evaluation of the amount of settlement and tilting of footings that are constructed on densi ed
ground surrounded by lique able soil. A number of factors, such as underlying soil properties, dimensions
of the footing and earthquake loading characteristics, cause the problem to become complicated. In this
paper, the dynamic response of shallow foundations on both lique able and non-lique able (densi ed) soils
is studied using a 3D fully-coupled dynamic analysis. A well-calibrated critical state two-surface plasticity
model has been used in the numerical analysis, which is capable of accounting for the volumetric/shear
response of the soil skeleton at a wide range of densities (void ratios) and con ning pressures. The
OpenSEES platform is used to conduct the numerical simulations. The proposed numerical model has
been applied in simulating a series of centrifuge experiments. Comparison of the numerical results and
the centrifuge experiment measurements reveals that the numerical model is capable of capturing the
important aspects of the dynamic response of footings on lique able and densi ed subsoils, and can be
used as a valuable tool for investigating the amount of liquefaction-induced settlement, tilting of footings
and their reduction due to densi cation.