Characterization and utilization of noisy displacement signals from simple shear device using linear and kernel regression methods

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• 作者：Eric Yee ; Jonathan P. Stewart ; Frederic P. Schoenberg
• 刊名：Soil Dynamics and Earthquake Engineering
• 出版年：2011
• 出版时间：January 2011
• 年：2011
• 卷：31
• 期：1
• 页码：25-32
• 全文大小：712 K

文摘

Small strain testing of dynamic soil properties such as threshold strains, γ_tv, are often conducted using specialized devices such as dual-specimen simple-shear, as devices configured for large strain testing produce noisy signals in the small strain range. Working with a simple shear device originally developed for large-strain testing, we extend its low-strain capabilities by characterizing noisy signals and utilizing several statistical methods to extract meaningful responses in the small strain range. We utilize linear regression of a transformed variable to estimate the cyclic shear strain from a noisy signal and the confidence interval on its amplitude. We utilize Kernel regression with the Nadaraya–Watson estimator and a Gaussian kernel to evaluate vertical strain response. A practical utilization of these techniques is illustrated by evaluating threshold shear strains for volume change with a procedure that takes into account uncertainties in the measured shear and vertical strains.