Spatial modeling of discontinuity intensity from borehole observations at El Teniente mine, Chile
Author
dc.contributor.author
Hekmatnejad, Amin
Author
dc.contributor.author
Emery, Xavier
Author
dc.contributor.author
Brzovic, Andrés
Author
dc.contributor.author
Schachter, Paulina
Author
dc.contributor.author
Vallejos Massa, Javier
Admission date
dc.date.accessioned
2018-06-07T20:32:00Z
Available date
dc.date.available
2018-06-07T20:32:00Z
Publication date
dc.date.issued
2017
Cita de ítem
dc.identifier.citation
Engineering Geology 228 (2017) 97–106
es_ES
Identifier
dc.identifier.other
http://dx.doi.org/10.1016/j.enggeo.2017.07.012
Identifier
dc.identifier.uri
https://repositorio.uchile.cl/handle/2250/148719
Abstract
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This work addresses the problem of predicting the discontinuity intensity P32 (discontinuity area per unit volume
of rock mass) in space and of quantifying the uncertainty in the true P32 values, using information from observed
discontinuities intersecting boreholes. This problem is relevant in various fields of engineering, including mining
applications, hydrocarbon extraction, groundwater modeling and civil works. The main idea is to calculate
experimental P32 values for borehole segments (composites), based on a Terzaghi weighting of the discontinuities
that intersect the boreholes. A validation exercise performed on simulated discrete fracture networks
demonstrates that the calculated P32 values provide unbiased predictions of the true P32, at both global
and local scales, and can therefore be used as experimental data for spatial interpolation purposes.
By using geostatistical simulation techniques, the spatial prediction of the P32 and the corresponding measures
of uncertainty can be obtained on a block-by-block basis. This methodology is applied to a data set from the
El Teniente copper mine, Codelco-Chile. The objective is to map the expected values of the intensity of stockwork
veins with a weak infill mineral assemblage and a typical thickness greater than 1 mm, which are referred to as
weak veins. Confidence limits on this intensity and its probability of exceeding given critical values are also
estimated. The quality of the prediction and of the uncertainty quantification is checked by leave-one-out crossvalidation.
The resulting confidence limits and probability maps can be used as indicators to define geotechnical
domains in the rock mass.