TREND REMOVAL IN SOIL PROPERTY
DOI:
https://doi.org/10.11113/mjce.v22.15801Keywords:
Soil properties, trend removal, standard deviationAbstract
It is often that trend in the form of linear or curvature appears in soil properties. Trend removal is necessary in many engineering applications where the residuals obtained would be used for further analyses. If trend in the data is not removed, a larger inherent soil variability compare to the actual one would be obtained. In this paper, a guideline relates the necessity of trend removal to the magnitude of R 2 (coefficient of determination) is established. A parametric study is also done in order to investigate the effect of trend removal on the accuracy of standard deviationReferences
Asaoka, A. and A-Grivas, D. (1982) Spatial variability of the undrained strength of clays. Journal of the Geotechnical Engineering Division, ASCE, 108(GT5): 743 – 756.
Baecher, G.B. and Christian, J.T. (2003) Reliability and Statistics in Geotechnical Engineering. John Wiley & Sons, West Sussex.
Cafaro, F. and Cherubini, C. (2002) Large sample spacing in evaluation of vertical strength variability of clayey soil. Journal of Geotechnical and Geoenvironmental Engineering, ASCE, 128(7): 558 – 568.
Jaksa, M.B., Brooker, P.I. and Kaggwa, W.S. (1997) Inaccuracies associated with estimating random measurement errors. Journal of Geotechnical and Geoenvironmental Engineering, 123(5): 393 – 401.
Lacasse, S. and Nadim, F. (1996) Uncertainties in characterizing soil properties. In Uncertainty in the geologic environment: From theory to practice (eds C.D.
Shackleford, P.P. Nelson and M.J.S. Roth), 49 – 75. ASCE Geotechnical Special Publication No. 58.
Lumb, P. (1974) Applications of statistics in soil mechanics. In Soil mechanics – new horizons, I.K. Lee, ed., Newnes-Butterworths, London, p.44 - 111.
Mendenhall, W. and Sincich, T. (2003) A Second Course in Statistics - Regression Analysis. Prentice Hall, New Jersey.
Phoon, K.K. and Kulhawy, F.H. (1999) Characterization of geotechnical variability.
Canadian Geotechnical Journal, 36: 612 – 624.
Phoon, K.K., Quek, S.T. and An, P. (2003) Identification of statistically homogeneous soil layers using modified Bartlett statistics. Journal of Geotechnical and Geoenvironmental Engineering, 129(7): 649 – 659.
Ravi, V. (1992) Statistical modelling of spatial variability of undrained strength. Canadian Geotechnical Journal, 29: 721 – 729.
Ryan, T. P. (1997) Modern Regression Methods. John Wiley & Sons, Inc, New York.
Uzielli, M., Vannucchi, G. and Phoon, K.K. (2005) Random field characterisation of stress-normalised cone penetration testing parameters. Geotechnique, 55(1): 3 – 20.
