Evaluation of One-Dimensional Multi-Directional Site Response Analyses Using Geotechnical Downhole Array Data in California and Japan

Abstract

This study presents a comprehensive investigation of one-dimensional (1-D) site response analysis (SRA) to predict the dynamic response of soil deposits under earthquake loading utilizing the recordings at selected borehole arrays. Seven instrumented downhole arrays in California and Japan were studied using 41 recorded ground motions that cover a broad range of intensities. The arrays were initially assessed in terms of effectiveness of 1-D SRA using taxonomy screening. Furthermore, LS-DYNA, an advanced Finite Element (FE) program, was employed to develop the 1-D soil column models for the SRA of these arrays. The soil stress-strain behavior was characterized with three different models including one linear elastic and two nonlinear backbone curve formulations. All predictions were compared to the measured ground motions to quantify the model biases and uncertainties. Lastly, the practical limitations of 1-D SRA models considered herein are identified, and recommendations are provided to assess the usefulness of the predictions in engineering practice.

Estimating epistemic uncertainty in soil parameters for nonlinear site response analyses: Introducing the Latin Hypercube Sampling technique

“…A detailed description of the utilized soil profile (e.g., geologic section, location of sensors, and Vs logging data) was provided by TEPCO. Taxonomy screening was previously carried out at this site to assess the extent of site complexity, which demonstrated its suitability for one-dimensional bi-directional SRA (Li et al, 2018) following the procedure outlined in Thompson et al (2012). Liquefaction and basin effects are not believed to be significant at the SHA.…”

“…In recent years, several studies have highlighted the importance of downhole arrays to verify the accuracy of SRA methodologies using either a single site (Groholski et al, 2015;Motamed et al, 2016;Tsai and Hashash, 2008;Yee et al, 2013) or a large inventory of sites (Afshari and Stewart, 2019;Kaklamanos and Bradley, 2018;Kaklamanos et al, 2013Kaklamanos et al, , 2015Kim and Hashash, 2013;Li et al, 2018;Pilz and Cotton, 2019;Stewart and Kwok, 2008;Thompson et al, 2012). Although these densely instrumented downhole arrays are usually well-documented, numerical modeling of these arrays still shows some deviation from the recordings.…”

Can modeling soil heterogeneity in 2D site response analyses improve predictions at vertical array sites?

“…Afshari and Stewart, 2019; Pilz and Cotton, 2019; Tao and Rathje, 2020a; Thompson et al, 2009, 2012), determining the most influential parameters to site response, assessing the aleatory variability of site response given variability of soil properties and input motions (e.g. Griffiths et al, 2016a; Hallal and Cox, 2021a; Kaklamanos et al, 2013, 2015; Li et al, 2018; Rathje et al, 2010; Tao and Rathje, 2019; Teague et al, 2018; Zalachoris and Rathje, 2015), and estimating epistemic uncertainty associated with uncertain input parameters (e.g. Rodriguez-Marek et al, 2021; Ulmer et al, 2021) and modeling uncertainty (e.g.…”

How much are sites affected by 2-D and 3-D site effects? A study based on single-station earthquake records and implications for ground motion modelling

“…Multiple empirical studies have illustrated that 1-D siteresponse approaches, despite their broad usage in practice, often fail to be accurate (e.g. Thompson et al 2012;Kaklamanos et al 2013;Kim & Hashash 2013;Zalachoris & Rathje 2015;Kaklamanos & Bradley 2018;Li et al 2018;Pilz & Cotton 2019;Tao & Rathje 2020;Zhu et al 2020) and more sophisticated approaches Assessing 2-D/3-D site response 1993 are needed to capture 2-D/3-D site effects (i.e. topographic effects, slopes along with impedance contrasts, the geometry of the soft soil layers, basin-edge induced surface waves, 2-D basin resonance effects).…”