EVALUATING ROCK MASS GEOMETRY FROM PHOTOGRAPHIC IMAGES

CROSTA G

G. Crosta, EVALUATING ROCK MASS GEOMETRY FROM PHOTOGRAPHIC IMAGES, Rock mechanics and rock engineering, 30(1), 1997, pp. 35-58

23

INGLESE

Article

Geosciences, Interdisciplinary","Engineering, Civil

Rock mechanics and rock engineering → ACNP

0723-2632

30

1

1997

35 - 58

ISI

0723-2632(1997)30:1<35:ERMGFP>2.0.ZU;2-U

The importance of discontinuities in controlling rock mass behaviour i n any engineering project involving excavations calls for a sound and spatial characterization of the discontinuity structure present. Such a characterization necessitates field work that requires sufficient ro ck exposures in order to obtain an adequate number of data, time and c onsiderable cost. Photoanalysis techniques can help in overcoming the above difficulties equally well or better than other techniques. This paper refers to simple photographic techniques and their implementatio n for computer aided analyses for the characterization of the rock mas s fracturing features. In particular attention is focused on scale pro blems and on reconstruction of fracture density stereoplots on the bas is of data collected from one or two images according to different lit hologies and outcropping conditions. The methodology for evaluating th e volumetric fracture intensity follows in a slightly modified way a t echnique previously suggested in the literature. Certain reported exam ples allow to validate the photoanalytical technique used and the prop osed method of analysis. Furthermore, analyses on planar density, spac ing, frequency, terminations in solid rock or against other discontinu ities and spatial correlation have been implemented in a software to y ield a more complete rock mass characterization. At the same time inpu t data and analysis results are produced in data files available as in put for numerical analyses.