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1. Assessing Numerical Simulations of Liquefiable Geosystems Using Time History-Based Validation Metrics

   https://doi.org/10.1061/9780784485996.035  

   Mivehchi, Maziar; Ziotopoulou, Katerina (February 2025, American Society of Civil Engineers)

   Non-linear dynamic analyses (NDAs) can capture the complex dynamic behavior of the soil using properly calibrated constitutive models. However, the quality of results from an NDA tudy hinges on several factors. Validation, which involves comparing numerical results to physical measurements, can assess the ability of an NDA to capture key responses through selected metrics. This study presents the application of a time history-based validation metric for evaluating the performance of numerical simulations. The centrifuge experiment conducted at UC Davis under the LEAP-2017 project, along with simulations performed using the PM4Sand constitutive model, provides the experimental and numerical data, respectively. The validation of the simulations against experimental measurements using the proposed metric is followed by a discussion on the potential experimental and numerical sources causing the quantified discrepancies. Conclusions are drawn on the effectiveness of the investigated metrics in facilitating the performance evaluation of numerical simulations and enhancing their reliability. 

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2. Probabilistic Calibration and Prediction of Seismic Soil Liquefaction using quoFEM

   Satish, AB; Yi, S; Nair, AS; Arduino, P (September 2022, Springer, Cham)

   Wang, L; Zhang, JM; Wang, R (Ed.)

   Liquefaction under cyclic loads can be predicted through advanced (liquefaction-capable) material constitutive models. However, such constitutive models have several input parameters whose values are often unknown or imprecisely known, requiring calibration via lab/in-situ test data. This study proposes a Bayesian updating framework that integrates probabilistic calibration of the soil model and probabilistic prediction of lateral spreading due to seismic liquefaction. In particular, the framework consists of three main parts: (1) Parametric study based on global sensitivity analysis, (2) Bayesian calibration of the primary input parameters of the constitutive model, and (3) Forward uncertainty propagation through a computational model simulating the response of a soil column under earthquake loading. For demonstration, the PM4Sand model is adopted, and cyclic strength data of Ottawa F-65 sand from cyclic direct simple shear tests are utilized to calibrate the model. The three main uncertainty analyses are performed using quoFEM, a SimCenter open-source software application for uncertainty quantification and optimization in the field of natural hazard engineering. The results demonstrate the potential of the framework linked with quoFEM to perform calibration and uncertainty propagation using sophisticated simulation models that can be part of a performance-based design workflow. 

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3. Probabilistic Calibration and Prediction of Seismic Soil Liquefaction Using quoFEM

   Bangalore Satish, A.; Yi, S.-ri; Nair, A.S.; Arduino, P. (September 2022, Proceedings of the 4th International Conference on Performance Based Design in Earthquake Geotechnical Engineering (Beijing 2022))

   Liquefaction under cyclic loads can be predicted through advanced (liquefaction-capable) material constitutive models. However, such constitutive models have several input parameters whose values are often unknown or imprecisely known, requiring calibration via lab/in-situ test data. This study proposes a Bayesian updating framework that integrates probabilistic calibration of the soil model and probabilistic prediction of lateral spreading due to seismic liquefaction. In particular, the framework consists of three main parts: (1) Parametric study based on global sensitivity analysis, (2) Bayesian calibration of the primary input parameters of the constitutive model, and (3) Forward uncertainty propagation through a computational model simulating the response of a soil column under earthquake loading. For demonstration, the PM4Sand model is adopted, and cyclic strength data of Ottawa F-65 sand from cyclic direct simple shear tests are utilized to calibrate the model. The three main uncertainty analyses are performed using quoFEM, a SimCenter open-source software application for uncertainty quantification and optimization in the field of natural hazard engineering. The results demonstrate the potential of the framework linked with quoFEM to perform calibration and uncertainty propagation using sophisticated simulation models that can be part of a performance-based design workflow. 

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4. Modeling the cyclic response of sands for liquefaction analysis

   Manzari, M.T.; El Ghoraiby, M.A.; Kutter, B.L.; Zeghal, M. (July 2019, Earthquake Geotechnical Engineering for Protection and Development of Environment and Constructions – Silvestri & Moraci (Eds) © 2019 Associazione Geotecnica Italiana, Rome, Italy, ISBN 978-0-367-14328-2)

   Constitutive relations used to describe the stress-strain-strength behavior of soils in cyclic loading are known to play a critical role on our ability to predict the response of geo-structures to seismic loading. The extent and intricacies of this role, however, are highly problem-dependent and often difficult to discern from the effects of other ingredients of a numerical simulation. Moreover, realistic assessments of constitutive models and numerical analysis techniques require detailed comparisons of their performances with reliable experimental observations. The experimental data that have been produced in the course of recent Liquefaction Experiments and Analysis Projects (LEAP-2015 and LEAP-2017) provide an opportunity for a more thorough assessment of the capabilities and limitations of constitutive models for sands over a wide range of strains. The LEAP experimental data along with a large number of cyclic element tests are used here to explore the performance of several constitutive models in numerical simulation of soil liquefaction and its effects on lateral spreading of mildly sloping grounds. 

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5. Modeling the cyclic response of sands for liquefaction analysis

   Manzari, M.T. (June 2019, 7th lnternational Conference on Earthquake Geotechnical Engineering (VII ICEGE))

   Constitutive relations used to describe the stress-strain-strength behavior of soils in cyclic loading are known to play a critical role on our ability to predict the response of geo-structures to seismic loading. The extent and intricacies of this role, however, are highly problem-dependent and often difficult to discern from the effects of other ingredients of a numerical simulation. Moreover, realistic assessments of constitutive models and numerical analysis techniques require detailed comparisons of their performances with reliable experimental observations. The experimental data that have been produced in the course of recent Liquefaction Experiments and Analysis Projects (LEAP-2015 and LEAP-2017) provide an opportunity for a more thorough assessment of the capabilities and limitations of constitutive models for sands over a wide range of strains. The LEAP experimental data along with a large number of cyclic element tests are used here to explore the performance of several constitutive models in numerical simulation of soil liquefaction and its effects on lateral spreading of mildly sloping grounds. 

   more » « less