Nonparametric Liquefaction Triggering and Postliquefaction Deformations

Abstract

This study evaluates granular liquefaction triggering case-history data using a nonparametric approach. This approach assumes no functional form in the relationship between liquefied and nonliquefied cases as measured using cone penetration test (CPT) data. From a statistical perspective, this allows for an estimate of the threshold of liquefaction triggering unbiased by prior functional forms, and also provides a platform for testing existing published methods for accuracy and precision. The resulting threshold exhibits some unique trends, which are then interpreted based on postliquefaction deformation behavior. The range of postliquefaction deformations are differentiated into three zones: (1) large deformations associated with metastable conditions; (2) medium deformations associated with cyclic strain failure; and (3) small deformations associated with cyclic stress failure. Deformations are further defined based on the absence or presence of static driving shear stresses. This work presents a single simplified framework that provides quantitative guidance on triggering and qualitative guidance on deformation potential for quick assessment of risks associated with seismic soil liquefaction failure.

Incorporating Shear Stiffness into Post-Fire Debris Flow Triggering Models

“…Post-event earthquake reconnaissance similarly strives to determine if YES the soil failed or NO it did not. These class models are then used to forecast the outcome for future events (e.g., [Moss et al, 2006;Yazdi and Moss, 2017], Smith and Moss, 2021). In concept the shear stiffness should then also provides some utility for debris flow triggering.…”

Prior and future earthquake effects in Valdivia, Chile

“…The questions then becomes, which mechanism controls and how much deformation is expected? For liquefaction deformations Yazdi and Moss (2016) can be used to estimate deformations. For sloping ground or free face conditions it is typical to use a lateral spreading model (Youd et al, 2002).…”

A New Equation to Evaluate Liquefaction Triggering Using the Response Surface Method and Parametric Sensitivity Analysis

“…Next to that, due to the magnitude range of the attenuation equations, the seven data samples from the Tohoku earthquake, with a moment magnitude of nine, are eliminated from the dataset. From all of the parameters in the source, only eight are selected according to studies reported in the literature [7,13,15,16,27,28,30,31,[46][47][48][49][50]: momentum magnitude (Mw), PGA(g), thickness of liquefiable soil (m) (measured from critical depth interval)(T), ground water table GWT (m), overburden stress (σ) (kPa), effective overburden stress (σ') (kPa), normalized con penetration test result tip (q c1N ), mean grain size (D 50 ), and fine content (FC) (%). The two extra parameters of CAV and r rup are added to the dataset through Equations (9) and (10), Therefore, the study considers some of the essential aspects of the earthquakes, such as the near-fault earthquake zone and causative fault type of the earthquake.…”

“…In this study, the most essential parameters to evaluate the potential of liquefaction are selected according to background research studies [7,13,15,16,27,28,30,31,[46][47][48][49][50]. Then, two new earthquake parameters added to the dataset to create a comprehensive database: CAV 5 and the closest distance from the site to the rupture surface (r rup ).…”