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1. Efficacy of Aging Correction for Liquefaction Assessment of Case Histories Recorded During the 2010 Darfield and 2011 Christchurch Earthquakes in New Zealand

   Rahimi, S. (August 2020, Journal of geotechnical and geoenvironmental engineering)

   null (Ed.)

   Data from 58 high-quality liquefaction case histories from the Darfield and Christchurch earthquakes are utilized to investigate the efficacy of current liquefaction aging correction procedures. Toward this end, liquefaction case histories are analyzed in which aging corrections are and are not applied, and the resulting predictions are compared to the actual liquefaction response of the deposits. An error index is calculated to quantify the efficacy of aging corrections. While all the sites located in the Christchurch area are classified as Holocene, based on their geological age, their liquefaction response is influenced more by the geotechnical age of the soil deposits. Aging correction was determined to be beneficial for the liquefaction assessment of soils that experienced recurrent liquefaction (i.e., geotechnical young deposits). However, aging corrections were determined to exacerbate the liquefaction assessment of relatively old (greater than ∼62–580 years) soil deposits. 

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2. Select liquefaction case histories from the 2001 Nisqually, Washington, earthquake: A digital data set and assessment of model performance

   https://doi.org/10.1177/87552930231174244  

   Rasanen, Ryan A; Geyin, Mertcan; Maurer, Brett W (January 2023, Earthquake Spectra)

   While soil liquefaction is common in earthquakes, the case-history data required to train and test state-of-practice prediction models remains comparatively scarce, owing to the breadth and expense of data that comprise a single case history. The 2001 Nisqually, Washington, earthquake, for example, occurred in a metropolitan region and induced damaging liquefaction in the urban cores of Seattle and Olympia, yet case-history data have not previously been published. Accordingly, this article compiles 24 cone-penetration-test (CPT) case histories from free-field locations. The many methods used to obtain and process the data are detailed herein, as is the structure of the digital data set. The case histories are then analyzed by 18 existing liquefaction response models to determine whether any is better, and to compare model performance in Nisqually against global observations. While differences are measured, both between models and against prior global case histories, these differences are often statistically insignificant considering finite-sample uncertainty. This alludes to the general inappropriateness of championing models based on individual earthquakes or otherwise small data sets, and to the ongoing needs for additional case-history data and more rigorous adherence to best practices in model training and testing. 

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3. Select CPT-Based Liquefaction Case Histories from the 2001 Nisqually, Washington, Earthquake

   https://doi.org/10.17603/ds2-nsf8-7944  

   Rasanen, Ryan; Geyin, Mertcan; Maurer, Brett (January 2022, Designsafe-CI)

   While soil liquefaction is common in earthquakes, the case history data required to train and test state-of-practice prediction models remains comparatively scarce, owing to the breadth and expense of data that comprise a single case history. The 2001 Nisqually, Washington, earthquake, for example, occurred in a metropolitan region and induced damaging liquefaction in the urban cores of Seattle and Olympia, yet case history data has not previously been published. Accordingly, we compile 24 cone-penetration-test (CPT) case histories from free-field locations. The many methods used to obtain and process the data are detailed in the accompanying manuscript, as is the structure of the digital dataset. The case histories are then analyzed by 18 existing liquefaction response models to determine whether any is better, and to compare model performance in Nisqually against global observations. While differences are measured, both between models and against prior global case histories, these differences are often statistically insignificant considering finite-sample uncertainty. This alludes to the general impropriety of championing models based on individual earthquakes or otherwise small datasets, and to the ongoing need for additional case history data and more rigorous adherence to best practices in model training and testing. 

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4. Assessing the Limitations of Liquefaction Manifestation Severity Index Prediction Models

   Green, R.A. (July 2022, Proc. 4th Intern. Conf. Performance-based Design in Earthquake Geotechnical Engineering (PBD-IV 2022))

   L. Wang, J.-M. Zhang (Ed.)

   The severity of surface manifestation of liquefaction is commonly used as a proxy for liquefaction damage potential. As a result, manifestation severity index (MSI) models are more commonly being used in conjunction with simplified stress-based triggering models to predict liquefaction damage potential. This paper assesses the limitations of four MSI models. The different models have differing attributes that account for factors influencing the severity of surficial liquefactionmanifestations, with the newest of the proposed models accounting more factors than the others. The efficacies of these MSI models are evaluated using well-documented liquefaction case histories from Canterbury, New Zealand, with the deposits primarily comprising clean to non-plastic silty sands. It is found that the MSI models that explicitly account for the contractive/dilative tendencies of soil did not perform as well as the models that do not account for this tendency, opposite of what would be expected based on the mechanics of liquefaction manifestation. The likely reason for this is the double-counting of the dilative tendencies ofmedium-dense to dense soils by theseMSI models, since the liquefaction triggering model, to some extent, inherently accounts for such effects. This implies that development of mechanistically more rigorous MSI models that are used in conjunction with simplified triggering models will not necessarily result in improved liquefaction damage potential predictions and may result in less accurate predictions. 

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5. Numerical Simulations of Sand Elements Based on Constant-Volume versus True-Undrained Data from Cyclic Direct Simple Shear Tests

   https://doi.org/10.1061/9780784485996.028  

   Nguyen, Catherine T; Kwan, Wing_Shun; Leal, Cesar (February 2025, American Society of Civil Engineers)

   Numerical simulation of liquefiable soil under cyclic undrained loading is essential for predicting earthquake-induced deformation of geotechnical structures in liquefaction hazard evaluation. Successful simulation of soil response requires constitutive models that can reasonably predict soil behavior under dynamic loading. Many advanced constitutive models have been developed for soil liquefaction hazard evaluation in the past four decades. These advanced models are built on plasticity theories with different modifications and assumptions. Nevertheless, the core part of all models was mainly developed based on observations from constant-volume (CV) cyclic direct simple shear (DSS) tests. While CV tests are standardized in the widely recognized ASTM D8296-19, true-undrained (TU) cyclic DSS tests wherein pore water pressure (PWP) is directly measured have also been performed in academic research. CV and TU cyclic DSS data were successfully generated at California State University, Los Angeles (Cal State LA), from the same apparatus. In this paper, the PM4Sand plasticity model is calibrated using CV and TU data. The performance of CV- and TU-calibrated models is cross-compared with TU and CV data, respectively. While results suggest trends in liquefaction capacity predictions, further data is required for comprehensive validation. The outcomes of this paper also provide insight into the calibration of PM4Sand over a range of relative densities and loading conditions. 

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