Energy-Based Liquefaction Triggering Model

Abstract

The most commonly used approach for evaluating liquefaction triggering is via stress-based simplified models. Proposed herein is a model for evaluating liquefaction triggering where the imposed loading and ability of the soil to resist liquefaction are quantified in terms of normalized dissipated energy per unit volume of soil (ΔW/σvo′), computed within a total stress framework. The proposed model overcomes limitations of many previously proposed energy-based triggering models. Additionally, the proposed energy-based model unites concepts from both stress-based and strain-based procedures, overcoming some of their limitations, and in its simplified form is implemented similarly to the simplified stress-based models. An updated field case history database is used to develop probabilistic limit-state curves. These limit-state curves express ΔW/σvo′ required to trigger liquefaction as a function of corrected cone penetration test tip resistance (qc1Ncs) for different probabilities of liquefaction (PL) and have comparable predictive abilities to stress-based limit-state curves in terms of number of correct predictions for the cases analyzed. However, because dissipated energy is a scalar quantity, multidirectional shaking and other effects such as soil–structure interaction, nonvertical wave fields, and topographic site effects can readily be accounted for. Additionally, the applicability of the proposed triggering curve is not limited to earthquake loading but, rather, can be used in relation to other sources of vibrations (e.g., construction vibrations and explosive loading, among others).