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Probabilistic simulation of rock quality designation (RQD)

Simulation probabiliste du R.Q.D.

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Bulletin of the International Association of Engineering Geology - Bulletin de l'Association Internationale de Géologie de l'Ingénieur Aims and scope Submit manuscript

Abstract

Rock quality designation (RQD) parameter distributions are obtained by Monte Carlo simulation techniques to describe the excellent, good, fair, poor and very poor rock percentages within a given rock mass. In the simulations, the intact length distributions are chosen either as the negative exponential or logarithmic-normal distribution.

Rock quality designation is dependent on a predetermined level of truncation and therefore the simulation procedure is repeated for different levels and their effects are presented in various charts.

RQD distributions are given in detail for different average number of discontinuities. The logarithmic normal distribution is unique in the sense that it preserves in the simulation the variance of intact lengths independently from the mean value. The greater the variance the better is the rock quality.

Résumé

La distribution des valeurs de RQD (Rock Quality Designation) obtenues par les techniques de simulation de Monte Carlo est utlisée pour décrire les pourcentages de roche de qualité excellente, bonne, moyenne, faible ou très faible dans un massif rocheux donné. Dans les simulations, la loi de distribution des longueurs est choisie soit comme une exponentielle négative soit comme une loi de log normal.

Le R. Q. D. dépend d'une longuer prédéterminée de coupure et en conséquence la procédure de simulation est répétée pour différents niveaux et les résultats sont présentés sur différentes abaques.

Les distributions du RQD sont données de façon détaillée pour différents nombres moyens de discontinuités. La distribution logarithmique normale est intéressante car dans la simulation la variance des longueurs apparaît indépendante de la valeur moyenne. Plus la variance est élevée, meilleure est la qualité de la roche.

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Authors and Affiliations

  1. Faculty of Earth Sciences, King Abdulaziz University, P.O. Box 1744, 21441, Jeddah, Saudi Arabia

    Eissa Elsayed A. & Zekâi Sen

Authors
  1. Eissa Elsayed A.
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  2. Zekâi Sen
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Eissa Elsayed, A., Sen, Z. Probabilistic simulation of rock quality designation (RQD). Bulletin of the International Association of Engineering Geology 43, 31–40 (1991). https://doi.org/10.1007/BF02590168

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  • DOI: https://doi.org/10.1007/BF02590168

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