Accuracy of the spectral method in estimating fractal/spectral parameters for self-affine roughness profiles

T. Shirono, P. H.S.W. Kulatilake

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

Self-affine fractals seem to have the potential to represent rock joint roughness profiles. Both stationary and non-stationary fractional Brownian profiles (self-affine profiles) with known values of fractal dimension, D, and input standard deviation, σ, were generated at different generation levels. A few smoothing techiques were used. The following conclusions were obtained: (a) To obtain accurate estimates for D, Ks (spectral parameters) and CD (cross-over profile dimension), it seems necessary to have at least 10 data points per unit length for a profile having a total length of 100 units. (b) For accurate estimation of D, Ks and CD, the non-stationarity of profiles should be removed, if it exists. (c) The parameter combinations D and Ks, and D and CD are recommended for quantification of stationary roughness; in addition, extra parameters are required to quantify the non-stationarity. (d) Both the Parzen and Hanning smoothing techniques seem suitable to use with the spectral technique to obtain accurate estimates for D, Ks and CD. (e) To obtain accurate estimates for D, Ks, and CD, it is necessary to use a suitable bandwidth for the Parzen window and a suitable number of iterations for the Hanning window; this paper provides guidelines to choose these suitable values. (f) Seed value has negligible effect on the accuracy of estimated D, Ks and CD.

Original languageEnglish (US)
Pages (from-to)789-804
Number of pages16
JournalInternational journal of rock mechanics and mining sciences & geomechanics abstracts
Volume34
Issue number5
DOIs
StatePublished - Jul 1997

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology
  • Engineering(all)

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