Calibration of Finn Model and UBCSAND Model for Simplified Liquefaction Analysis Procedures

Der-Guey Lin,Jui-Ching Chou,Hsueh-Tusng Yang

doi:10.3390/app11115283

Abstract

Soil-liquefaction-related hazards can damage structures or lead to an extensive loss of life and property. Therefore, the stability and safety of structures against soil liquefaction are essential for evaluation in earthquake design. In practice, the simplified liquefaction analysis procedure associated with numerical simulation analysis is the most used approach for evaluating the behavior of structures or the effectiveness of mitigation plans. First, the occurrence of soil liquefaction is evaluated using the simplified procedure. If soil liquefaction occurs, the resulting structural damage or the following mitigation plan is evaluated using the numerical simulation analysis. Rational and comparable evaluation results between the simplified liquefaction analysis procedure and the numerical simulation analysis are achieved by ensuring that the liquefaction constitutive model used in the numerical simulation has a consistent liquefaction resistance with the simplified liquefaction analysis procedure. In this study, two frequently used liquefaction constitutive models (Finn model and UBCSAND model) were calibrated by fitting the liquefaction triggering curves of most used simplified liquefaction analysis procedures (NCEER, HBF, JRA96, and T-Y procedures) in Taiwan via FLAC program. In addition, the responses of two calibrated models were compared and discussed to provide guidelines for selecting an appropriate liquefaction constitutive model in future projects.

Highlights

IntroductionSoil-liquefaction-related hazards (lateral spreading, settlement of shallow foundations, uplift of underground structures, etc.) can severely damage structures or result in a considerable loss of life and property
Soil-liquefaction-related hazards can severely damage structures or result in a considerable loss of life and property
The evaluation is usually performed in three steps: (1) a simplified liquefaction analysis procedure or a cyclic test is used to evaluate the occurrence of soil liquefaction at a site during the design earthquake; (2) if the site is liquefied, effects of liquefaction hazards on structures are evaluated via an empirical procedure, a numerical simulation analysis, or a physical model test; and

Summary

Introduction

Soil-liquefaction-related hazards (lateral spreading, settlement of shallow foundations, uplift of underground structures, etc.) can severely damage structures or result in a considerable loss of life and property. When numerical analysis is needed for subsequent evaluations, many engineers assign the input parameters of the liquefaction constitutive model following the model’s default values without performing a proper model calibration. This practice results in an inconsistent liquefaction resistance (cyclic resistance ratio, CRR) between the simplified liquefaction analysis procedure and the liquefaction constitutive model, leading to numerical simulation results that are not representable and comparable. Results of this study provide engineers with a valuable reference for evaluating liquefaction hazards

Finn Model

UBCSAND Model

Methodology of Model Calibration

Comparisons of Undrained Cyclic DSS Responses

Overburden

Conclusions