Reassessing the Joint Roughness Coefficient (JRC) Estimation Using Z2
About: This article is published in Rock Mechanics and Rock Engineering.The article was published on 2001-08-01. It has received 159 citations till now. The article focuses on the topics: Fractal dimension & Rock mechanics.
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TL;DR: In this paper, the authors present the techniques, advances, problems and likely future developments in numerical modelling for rock mechanics and discuss the value that is obtained from the modelling, especially the enhanced understanding of those mechanisms initiated by engineering perturbations.
976 citations
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...(2001) [643–653]....
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213 citations
TL;DR: In this paper, the peak shear strength of tensile rock joints with surface roughness parameters is estimated by using a rational dilatancy angle function, which is based on the Mohr-Coulomb type of formulation.
Abstract: The prime objective of this work is to improve our understanding of the shear behavior of rock joints. Attempts are made to relate the peak shear strength of rock joints with its three-dimensional surface morphology parameters. Three groups of tensile joint replicas with different surface morphology are tested with direct shear tests under constant normal load (CNL) conditions. Firstly, the three-dimensional surface characterization of these joints is evaluated by an improved roughness parameter before being tested. Then, a new empirical criterion is proposed for these joints expressed by three-dimensional quantified surface roughness parameters without any averaging variables in such a way that a rational dilatancy angle function is used instead of $${\text{JRC}} \cdot \log_{10} \left( {{{\text{JCS}} \mathord{\left/ {\vphantom {{\text{JCS}} {\sigma_{\text{n}} }}} \right. \kern-
ulldelimiterspace} {\sigma_{\text{n}} }}} \right)$$
by satisfying the new peak dilatancy angle boundary conditions under zero and critical-state normal stress (not physical infinite normal stress). The proposed criterion has the capability of estimating the peak shear strength at the laboratory scale and the required roughness parameters can be easily measured. Finally, a comparison among the proposed criterion, Grasselli’s criterion, and Barton’s criterion are made from the perspective of both the rationality of the formula and the prediction accuracy for the three groups of joints. The limitations of Grasselli’s criterion are analyzed in detail. Another 37 experimental data points of fresh rock joints by Grasselli are used to further verify the proposed criterion. Although both the proposed criterion and Grasselli’s criterion have almost equal accuracy of predicting the peak shear strength of rock joints, the proposed criterion is easier and more intuitive from an engineering point of view because of its Mohr–Coulomb type of formulation.
194 citations
Cites background from "Reassessing the Joint Roughness Coe..."
...…proposed by Grasselli and his colleagues can be considered as the best roughness evaluation technique, since the surface is assessed according to the exact geometrical shape of asperities and the actual potential contact areas, without any average value of surface variables (Yang et al. 2011)....
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...This roughness function can be considered as the best roughness evaluation technique since the surface is assessed by the exact geometrical shape of asperities and the actual potential contact areas, and not by any average value of surface variables (Yang et al. 2011)....
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TL;DR: In this paper, a set of empirical equations are proposed to estimate the joint roughness coefficient (JRC) of a rock fracture based on its fractal dimension (D ), which is found that great variation exists among the previously proposed equations, and partially because of the inconsistency in the methods for determining D.
141 citations
Cites methods from "Reassessing the Joint Roughness Coe..."
...The development of objective methods was gradually advanced by researchers considering statistical parameters and the fractal dimension of the rock joint profiles [4–8]....
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TL;DR: In this article, the porosity and permeability models used for reservoir and geomechanical coupled simulation have been established in order to simulate the influence of these alterations in predicting or evaluating coalbed methane (CBM) production.
137 citations