Predictive Equations of Shear Wave Velocity for Bay of Campeche Clay

Abstract

One of the most important soil parameters required in the analyses of the piles of oil platforms subjected to lateral earthquake loading is the shear wave velocity (V S ) of the soil. Since in-situ measurements of V S is part of the scope of work of a limited amount of platform sites, there is the need to develop site specific correlations to estimate V S based on basic soil properties. To cover this need a database with in-situ measurements of V s and basic soil properties of clay has been established. Data were collected from eleven offshore geotechnical investigations performed on behalf of PEMEX for the design and installation of fixed offshore platforms in the Bay of Campeche. The database was tailored to developed empirical correlations between the shear wave velocity and undrained shear strength, effective vertical stress, water content, void ratio, overconsolidation ratio and net cone resistance, using simple regression analyses and multiple regression analyses. Three of the most prominent empirical correlations developed using multiple regression analyses are recommended to provide a mean of determining the best estimate V S in clay, along with a three step procedure to perform site response analyses in the Bay of Campeche when in-situ measurements of V S at a site are not available.

Integration of SH seismic reflection and Love-wave dispersion data for shear wave velocity determination over quick clays

“…This was confirmed by the analysis of a number of landslides occurring without external causes and by laboratory data (Bjerrum 1954). Empirical correlations between Vs and undrained shear strength determined in triaxial or direct shear tests and with empirical interpretations of geotechnical in situ testing have been established (Dickenson 1994;Andersen 2004;Taboada et al 2013). Specific correlations have also been proposed for Norwegian clays (NGI 2015;L'Heureux & Long 2017).…”

“…Bjerrum (1954) showed that leaching could cause a shear strength reduction in the order of 40 per cent from the original material and, by collecting different Norwegian clay samples, observed relatively constant density values which showed no particular correlation with material sensitivity. Depending on the proposed correlations (Dickenson 1994;Andersen 2004;Taboada et al 2013;NGI 2015;L'Heureux & Long 2017) between Vs and undrained shear strength different ranges of reduction could be attended in the shear wave velocity from non-leached clay to quick clays.…”

Relationship Between Shear Wave Velocity and Piezocone Penetration Tests on the Brazilian Continental Margin

“…In this study, four relatively recent published correlations are analyzed using the local CPTu data: two generic correlations (Robertson, 2009;Tong et al, 2018), and two for specific soil types (Long & Donohue, 2010;Taboada et al, 2013). This selection was based on a preliminary fit analysis for the generic correlations and for the correlations with similar offshore conditions for the specific soil type.…”

“…6 was chosen for further analysis. Taboada et al (2013) analysed P-S logging data for the Bay of Campeche, Mexico, aiming to evaluate the geohazards involved in offshore petroleum exploration. Their study can be directly related to the present work, as it was developed under similar site conditions.…”

“…Data scatter is a factor to be considered for this type of correlation (Wair et al, 2012), and in order to minimize its influence, correlation studies are usually separated into three categories: • Correlations for clay -undrained behavior (e.g., Mayne & Rix, 1995;Long & Donohue, 2010;Taboada et al, 2013;Zhang & Tong, 2017); • Correlations for sands -drained behavior (e.g., Baldi et al, 1989;Hegazy & Mayne, 1995;Taboada et al, 2015); • Correlations for soils in general (e.g., Hegazy & Mayne, 1995Robertson, 2009;McGann et al, 2015). The use of empirical correlations is an easy and straightforward method for estimating shear wave velocity profiles for numerous applications based on parameters obtained through in-situ tests, or more simply, from vertical effective stresses.…”