Montgomery, Jack

Numerical Modeling of Earthquake-Induced Liquefaction Effects on Shallow Foundations

Abstract eng:
Liquefaction continues to be a major source of damage to structures during earthquakes (e.g., Canterbury earthquake sequence, New Zealand [1]). Liquefaction and subsequent reconsolidation can lead to settlement, ground cracking and loss of bearing capacity all of which can cause damage to structures. The ability of engineers to design against this type of damage requires methods which can evaluate the potential for liquefaction-induced damages and how these will be affected by varying field conditions (e.g., seismic motion, soil profile and building properties). Current practice primarily relies on empirically developed charts which correlate post-liquefaction settlement to the relative density of sand or the surface manifestation of liquefaction to the relative thickness of non-liquefiable crust layer to the liquefiable one. Despite their widespread use, these charts are based on a small number of case histories and do not directly account for other factors such as the thickness of the liquefiable layer, properties of the non-liquefiable crust and effects of a building. The limited ability of current design procedures to predict and account for such effects emphasizes the need to develop a more rational approach towards accounting for these phenomena and incorporating them into the design of shallow foundations. This paper evaluates the effects of post-liquefaction reconsolidation settlements on shallow foundations using numerical simulations. Two-dimensional, fully coupled dynamic analyses are used to simulate the response of shallow foundations on liquefiable soil deposits. The baseline analysis is first validated against two selected cases of a centrifuge test and the efficacy or our current tools (numerical platform and constitutive model for liquefiable soil) in capturing the trends observed in the centrifuge tests is investigated. The validated analysis is then used to investigate more factors which may have an effect on the settlement patterns such as the crust layer thickness, soil properties, and bearing pressure. Implications for practice are discussed.

Contributors:

Ziotopoulou, Katerina

Conference Title:

Proceedings of the 16th World Conference on Earthquake Engineering

Conference Title:

16th World Conference on Earthquake Engineering

Conference Venue:

Santiago (CL)

Conference Dates:

2017-01-09 / 2017-01-13

Rights:

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