Robust algorithms for polyhedral modelling of fractured rock mass structure

Elmouttie, Marc; Krahenbuhl, Greg; Poropat, George

doi:10.1016/j.compgeo.2013.05.001

Cited by 16 publications

(4 citation statements)

References 24 publications

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“…The fractures within intact rock but not presently associated with the formation of the outer boundaries of complex blocks can be important in many analysis, such as modeling the fluid or hydro-mechanical behaviors of rock masses. 24 These fracture polygons are defined as the interior fracture boundaries of complex-blocks. In this section, the procedures of determining the interior fracture boundaries of the complex-blocks identified using the element blockassembling approach are presented.…”

Section: Constructing Interior-fracture Boundariesmentioning

confidence: 99%

Section: Constructing Boundary Structuresmentioning

confidence: 99%

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Constructing boundary structures of rock blocks

Zheng

Xia

2019

Num Anal Meth Geomechanics

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Summary Determining rock‐block structures is important for modeling jointed rock masses. This paper presents a method to construct the boundary structures of complex blocks by eliminating fictitious surfaces. The planes involved in forming a complex block are retrieved, and the boundary polygons on each plane are determined using a series of Boolean operations. A regulation method is used to adjust the resulting polygons so that the regulated outer boundary structures can be used directly in the contact‐detection algorithms. The interior fracture boundaries that are not explicitly associated with the formation of blocks are also constructed. These boundary surfaces are valued in hydraulic models to provide conductive channels of fluids in rock masses. The proposed method extends previous developments on block‐identification algorithms, and the constructed boundary structures can be used directly in the modeling process of most discrete models. The program implemented based on this method has been used to study the stability and morphology of blocks in the Three Gorges Project, and several examples are given to further demonstrate the ability and performance of the proposed method.

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Section: Constructing Interior-fracture Boundariesmentioning

confidence: 99%

Section: Constructing Boundary Structuresmentioning

confidence: 99%

Constructing boundary structures of rock blocks

Zheng

Xia

2019

Num Anal Meth Geomechanics

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“…In this study, an investigation is made of the validity of these approaches and therefore of relevance is the mean and variance of block volumes and a representative linear measure of fracture frequency for estimation of a characteristic rock mass RQD. The use of polyhedral block modelling (Elmouttie, Poropat and Hamman 2009) has shown that the average block volume calculation proposed by Cai et al (2004) is valid with their assumption of joint persistence, i.e. fully or semi-persistent joints but significantly underestimates volumes for jointing with a more realistic assumption of joint size.…”

Section: Application For Rock Strength Characterisationmentioning

confidence: 99%

Rapid characterisation of fracture network realisations for hydrogeological, slope stability and geomechanical modelling

Elmouttie

Poulsen²,

Krahenbuhl³

et al. 2015

Mining Technology

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For fractured rock masses, Monte Carlo simulation can be used to generate a multitude of fracture network realisations to support the estimation of the uncertainties in the fracture network properties and behaviour. However, the approach is limited by the computation time associated with performing fluid flow, slope stability or geomechanical analysis on each realisation, where it is often only feasible to analyse a small subset of these. The work presented in this paper facilitates the selection of fracture network realisations, representing conservative and aggressive scenarios, by using fast-to-compute geometry-based metrics. For hydrogeological analyses, we find that the success of such metrics depends on the complexity of the fracture network and we present an analysis of multiple scenarios to demonstrate this. Finally, we propose a similar approach for slope stability analyses and rock mass strength characterisation.

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“…(2015) preformed a probabilistic block theory analysis and used the developed procedure to study a rock slope at a hydropower station in China. Because of the efforts of various researchers (Leung and Lo 1993;Mauldon and Ureta 1996;Jimenez-Rodriguez and Sitar 2008;Elmouttie et al 2010;Cho et al 2012;Elmouttie et al 2012), considerable progress has been made, which has improved the applicability of block theory. The shape of blocks in a block system may be complex, and concave blocks are common in practical engineering projects.…”

Section: Introductionmentioning

confidence: 99%

Analysis of removability and stability of rock blocks by considering the rock bridge effect

Zheng

Xia

2016

Can. Geotech. J.

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In traditional block theory, the removability and stability of rock blocks are analyzed independently; that is, the stability of a removable block is analyzed in detail, and nonremovable blocks are regarded as stable. However, in practical situations, nonremovable blocks may pose more danger than removable blocks. This paper presents a unified method for analyzing the removability and stability of rock blocks. In this method, the cracking of rock bridges is considered and nonremovable blocks are not assumed to be stable. First, possible cracking rock bridges are identified by extending finite-sized fractures and comparing the boundary surfaces of the resulting blocks with those of the original blocks. Then, the sliding direction associated with each possible moving block is determined by solving an optimization problem. The normal force acting on each sliding surface is determined, and the resisting force on each rock bridge is calculated and integrated into the total resisting force when calculating the safety factor of a possible moving block. Procedures to determine all possible moving blocks are introduced, and the possible moving block with the minimum safety factor is regarded as the actual moving block. The corresponding minimum safety factor is defined as the actual safety factor of the block. The proposed method is verified by considering a few examples. The results show that nonremovable blocks may be unstable if the cracking of rock bridges is considered.

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Robust algorithms for polyhedral modelling of fractured rock mass structure

Cited by 16 publications

References 24 publications

Constructing boundary structures of rock blocks

Constructing boundary structures of rock blocks

Rapid characterisation of fracture network realisations for hydrogeological, slope stability and geomechanical modelling

Analysis of removability and stability of rock blocks by considering the rock bridge effect

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