Title: Robust assessment of shear parameters from direct shear tests

Authors: Wolfgang Fellin; Michael Oberguggenberger

Addresses: Institute of Geotechnical and Tunnel Engineering, University of Innsbruck, A-6020 Innsbruck, Austria. ' Unit of Engineering Mathematics, University of Innsbruck, A-6020 Innsbruck, Austria

Abstract: In the geotechnical determination of the cohesion c and the angle of internal friction ? of a soil from shear tests, a linear regression model is fitted to normal and shear stress data, and confidence bounds are computed. The applicability of standard linear regression is limited by the physical requirement of non-negative cohesion and the statistical requirement of normality. We propose two methods from computational statistics that are able to overcome both obstacles: a bootstrap resampling method in case the experimental data set is sufficiently large, and a Bayesian approach for small samples. The methods are demonstrated at the hand of a real data set for glacial silt.

Keywords: shear parameters; non-normal regression; Bayesian methods; bootstrap confidence intervals; computational statistics; glacial silt; geotechnical engineering; soil parameters.

DOI: 10.1504/IJRS.2012.044294

International Journal of Reliability and Safety, 2012 Vol.6 No.1/2/3, pp.49 - 64

Received: 25 Nov 2010
Accepted: 04 Apr 2011
Published online: 27 Dec 2014 *

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