Estimating the mean length of discontinuity traces

Pahl, Peter Jan

doi:10.1016/0148-9062(81)90976-1

Cited by 125 publications

(52 citation statements)

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“…5). In order to derive the mean trace length of the distribution, the method of Pahl (1981) was used, which considers sampling bias. Pahl (1981) classified the joints in the sampling window into three types, depending on whether they intersect, transect or contain the joint trace.…”

Section: Fracture Lengthmentioning

confidence: 99%

“…In order to derive the mean trace length of the distribution, the method of Pahl (1981) was used, which considers sampling bias. Pahl (1981) classified the joints in the sampling window into three types, depending on whether they intersect, transect or contain the joint trace. Dividing the joints into these categories and substituting these values to Pahl's equation (Pahl 1981;Lee and Farmer 1993;Priest 1993), the mean fracture trace length for all trace maps is 1.7 m. However, horizontal exposures reveal that systematic joints have straight traces and are more continuous.…”

Section: Fracture Lengthmentioning

confidence: 99%

“…However, there is no reliable information on the fracture length of the systematic joints (set I) due to lower truncation and censoring effects. Hence, in the present study the mean fracture length from Pahl's method was used (Pahl 1981). In order to enable the generation of systematic joints, which are more continuous as observed in the field (Fig.…”

Section: Fracture Network Generationmentioning

confidence: 99%

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Evaluation of the representative elementary volume (REV) of a fractured geothermal sandstone reservoir

2010

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The objective of this study is to evaluate a representative elementary volume (REV) in a fractured geothermal sandstone reservoir in Germany using the discrete fracture network (DFN) model approach. Due to the lack of in situ data from the deep geothermal reservoir, field measurements of outcrop reservoir analogues were conducted to get a quantitative description of the DFN. Field measurements reveal that the geometry of the DFN is largely influenced by the lithological layering (e.g. relationship between joint spacing and bed thickness). Thus, DFN models have to be completed individually for each layer since each bed is distinct compared to its neighbouring beds. Various DFNs were generated using statistical-derived fracture input data. The two-dimensional universal distinct element code UDEC was used for fracture flow simulations. In order to determine the minimum REV, the equivalent average conductivity tensors were obtained with increasing block size. Plots of conductivity tensor coefficients versus block size exhibit only minor variation of the hydraulic properties with increasing block size. Hence, an REV size of 10 m 9 10 m could be determined for all studied stochastically derived discrete fracture networks.

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Section: Fracture Lengthmentioning

confidence: 99%

Section: Fracture Lengthmentioning

confidence: 99%

Section: Fracture Network Generationmentioning

confidence: 99%

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Evaluation of the representative elementary volume (REV) of a fractured geothermal sandstone reservoir

2010

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“…L'évaluation de cette équation exige une distribution supposée de r. En pratique, nous supposons que le rayon r suit la même loi que la longueur de trace I. Les études expérimentales montrent que 1 suit habi-tuellement la loi log-normale ou exponentielle (BAE-CHER, 1983) dont l'estimation des paramètres est bien étudiée et peut être réalisée par des procédés traditionnels (PRIEST et HUDSON, 1981 ;PAHL, 1981 …”

Section: Simulation Tridimensionnelle De Discontinuitésunclassified

Simulation tridimensionnelle de la blocométrie naturelle de massifs rocheux

Cojean

Arnould

1992

Rev. Fr. Geotech.

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RésuméCet article présente un modèle général de simulation à trois dimensions de la blocométrie naturelle des massifs rocheux. Il est constitué de quatre parties : 1. analyse statistique et simulation à trois dimensions des discontinuités ; 2. analyse de la connectivité des discontinuités simulées ; 3. identification des blocs discrets intersectés par des discontinuités connectées ; 4. caractérisation de la blocométrie de massifs rocheux. Trois types de représentation (distribu tion de taille, distribution de taille pondérée, distribution de l'orientation des blocs) sont utilisés. Les résultats des exemples réels sont donnés dans les sec tions correspondantes de l'article. AbstractThis paper presents a general model for simulating three dimensional natural rock mass granulometry. It consists of four parts : 1. statistic analysis and three dimensional simulation of rock mass fractures ; 2. connectivity study of simu lated fractures ; 3. identification of distinct blocks intersected by the fractu res : 4. characterization of rock mass granulometry. Three representative methods, such as size distribution, weighted size distribution and orientation distribution of blocks, are used. The results of some real examples are given in the correspondent sections of the paper.* 60, bd Saint-Michel, 75272 Paris, Cedex 06. N° 58 REVUE FRANÇAISE DE GÉOTECHNIQUE

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“…Similar ideas based on counting the number of traces within a sampling domain have also been employed to estimate the distribution of trace lengths in rock outcrops (see e.g. Pahl 1981;Mauldon 1998;Zhang and Einstein 1998;Lyman 2003a). …”

Section: Introductionmentioning

confidence: 99%

A Simple Genetic Algorithm for Calibration of Stochastic Rock Discontinuity Networks

Jimenez

Jurado-Piña

2012

Rock Mech Rock Eng

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We present a novel approach for calibration of stochastic discontinuity network parameters based on genetic algorithms (GAs). To validate the approach, examples of application of the method to cases with known parameters of the original Poisson discontinuity network are presented. Parameters of the model are encoded as chromosomes using a binary representation, and such chromosomes evolve as successive generations of a randomly generated initial population, subjected to GA operations of selection, crossover and mutation. Such backcalculated parameters are employed to make assessments about the inference capabilities of the model using different objective functions with different probabilities of crossover and mutation. Results show that the predictive capabilities of GAs significantly depend on the type of objective function considered; and they also show that the calibration capabilities of the genetic algorithm can be acceptable for practical engineering applications, since in most cases they can be expected to provide parameter estimates with relatively small errors for those parameters of the network (such as intensity and mean size of discontinuities) that have the strongest influence on many engineering applications.

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Estimating the mean length of discontinuity traces

Cited by 125 publications

References 2 publications

Evaluation of the representative elementary volume (REV) of a fractured geothermal sandstone reservoir

Evaluation of the representative elementary volume (REV) of a fractured geothermal sandstone reservoir

Simulation tridimensionnelle de la blocométrie naturelle de massifs rocheux

A Simple Genetic Algorithm for Calibration of Stochastic Rock Discontinuity Networks

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