Continuum–discontinuum analysis of failure mechanisms around unsupported circular excavations in anisotropic clay shales

Lisjak, A.; Grasselli, Giovanni; Vietor, Tim

doi:10.1016/j.ijrmms.2013.10.006

Cited by 244 publications

(68 citation statements)

References 76 publications

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“…Munjiza [27] developed a combined finite-discrete element method (FDEM), in which elasticity calculations are based on continuum finite element methods, and discontinuous behavior is represented by a discrete method. Whereas the transition from continuous to discontinuous behavior needs proper attention [5], [29], [30], [34], FDEM capably simulates both elasticity and failure processes of geomaterials, as demonstrated through comparisons with theory and laboratory studies [26], [24]. Munjiza et al [28] cover several methods that describe physical systems using discrete entities.…”

Section: Introductionmentioning

confidence: 99%

Simulating the Poisson effect in lattice models of elastic continua

Asahina

Ito

Houseworth

et al. 2015

Computers and Geotechnics

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Lattice models provide discontinuous approximations of the displacement field over the computational domain, which facilitates the modeling of fracture and other discontinuous phenomena. By discretizing the domain with two-node elements, however, ordinary lattice models cannot simulate the Poisson effect in a local (intra-element) sense, which is problematic for some types of analyses.Furthermore, such methods are limited in the range of Poisson ratio values that can be simulated. We present a new approach to remedy such known, yet underappreciated, shortcomings of lattice models. In this approach, the Poisson effect is modeled through the introduction of fictitious stresses into a regular lattice. Capabilities of the new approach are demonstrated through compressive test simulations of homogeneous and heterogeneous materials. The simulation results are compared with theory and those of continuum finite element models. The comparisons show good agreement for arbitrary Poisson ratios (including ν ⩾ 1/3) with respect to nodal displacement, intra-element stress, and nodal stress. This form of discrete method, supplemented by the proposed fictitious measures of stress, retains the simplicity of collections of two-node elements.

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Section: Introductionmentioning

confidence: 99%

Simulating the Poisson effect in lattice models of elastic continua

Asahina

Ito

Houseworth

et al. 2015

Computers and Geotechnics

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“…A motivation is to combine advantages of both continuous and discontinuous approaches proposed by Munjiza et al (1995), Li et al (2004), Wang et al (2013), etc. These combined methods include FDEM (FEMDEM) (Munjiza et al, 1995;Munjiza, 2004;Mahabadi et al, 2010Mahabadi et al, , 2012Lisjak et al, 2014Lisjak et al, , 2015 and Continuous-Discontinuous Element Method (CDEM) (Li et al, 2004(Li et al, , 2008Ma et al, 2011;Wang et al, 2013;Li et al, 2015). In the study of Cai et al (2007), the continuum-based software FLAC was coupled with the discontinuum-based software PFC to investigate acoustic emissions in large-scale underground excavations.…”

Section: Contents Lists Available At Sciencedirectmentioning

confidence: 99%

“…Lisjak et al (2015) used the FDEM method to model the crack evolution due to the excavation of a circular tunnel in a bedded argillaceous rock. The progressive failure of rock masses was simulated by a cohesivezone approach (Munjiza et al, 1995;Munjiza, 2004;Mahabadi et al, 2010Mahabadi et al, , 2012Lisjak et al, 2014Lisjak et al, , 2015. The method of CDEM not only can deal with both continuous and discontinuous problems, but also can reproduce the progressive damage and failure evolution of materials from a continuous state to a discontinuous state .…”

Section: Contents Lists Available At Sciencedirectmentioning

confidence: 99%

Stability analysis of underground oil storage caverns by an integrated numerical and microseismic monitoring approach

Tang

Wang

et al. 2016

Tunnelling and Underground Space Technology

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a b s t r a c tUnderground storage in unlined caverns is of great significance for storing energy resources. Construction of underground storage caverns is an extremely complex process, involving extensive multi-bench excavation and strong unloading. Excavation-induced damage of surrounding rock masses may lead to instability of underground storage caverns. The aim of this paper is to put forward a method by integrating numerical simulation and microseismic monitoring for evaluation of cavern stability. A novel numerical method called Continuous-Discontinuous Element Method (CDEM) is applied to simulate micro-cracks under excavation-induced unloading conditions. Meanwhile, a microseismic (MS) monitoring system is employed to monitor real-time MS events during construction of storage caverns. Numerical results are validated using the monitoring data from the MS monitoring system. The integrated method is proved to be successful in capturing micro-cracks in underground storage caverns. Local instability, potential unstable zones and micro-crack evolution are analyzed, and cracking mechanisms are also discussed.

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“…b.2) Fraturamento hidráulico. Em vermelho, a infiltração do fluido e em preto, a fratura hidráulica [16] A utilização do MED (para o caso de elementos circulares ou esféricos) acoplado com o método de LB (MED-LB), tem sido utilizado na simulação de produção de areia em poços de petróleo [84] O acoplamento entre o MEF e o MED, permite a simulação numérica da propagação de fraturas em um meio rochoso fraturado [55,56,58,59,60].…”

Section: Modelos Numéricosunclassified

Simulação Numérica Do Processo De Propagação De Fraturas Em Materiais Rochosos Em Condições De Acoplamento Fluidomecânico

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A Carla, a minha companheira pelo seu amor e carinho, e por ter me dado um filho maravilhoso e uma família.Aos meus pais e meus irmãos, pelo imenso apoio e carinho.Ao Prof. Eurípedes do Amaral Vargas Jr., pela orientação, apoio e incentivo para a realização deste trabalho.Ao Prof. Gláucio Paulino, pela orientação, apoio e ajuda ao longo do desenvolvimento desta pesquisa durante a minha estadia na Universidade Esta pesquisa aborda o processo de fraturamento hidráulico ou processo de propagação de fraturas em rocha através da injeção de um fluido sob pressão, o que gera fissuras no material que se propagam de acordo com a quantidade de fluido injetado. Esta técnica leva a um incremento da transmissividade hidráulica da rocha e, como conseqüência, ocorre um incremento da produção deóleo. Diversos trabalhos analíticos e numéricos têm sido propostos para estudar o mecanismo de fratura, geralmente baseados em meios contínuos ou através da utilização de elementos de interface em uma trajetória de propagação conhecida. Neste trabalho, a propagação de uma fraturaé simulada utilizando o modelo potencial PPR[72] através da sua implementação extrínseca. Assim, os elementos coesivos de interface são inseridos na malha de elementos finitos de forma adapativa para capturar o processo de fraturamento.A pressão do fluidoé simulada utilizando o modelo de lattice-Boltzmann [84]. Através de um processo interativo, os contornos da fratura, computados utilizando o método dos elementos finitos, são transferidos para o modelo de lattice-Boltzmann como uma condição de contorno. Assim, a força que o fluido exerce nestes contornos, gerada pela injeção do fluido, pode ser calculada. Estas forças são utilizadas no modelo de elementos finitos como uma força externa aplicada nas faces da fratura. A nova posição das faces da fraturaé calculada e transferida novamente para o modelo de lattice-Boltzmann como condição de contorno. Este processo interativo fluido-estrutura permite modelar o processo de fraturamento hidráulico em trajetórias de propagação irregulares. This research addresses hydraulic fracturing or hydro-fracking, i.e. fracture propagation process in rocks through the injection of a fluid under pressure, which generates cracks in the rock that propagate according to the amount of fluid injected. This technique leads to an increase of the hydraulic transmissivity of the rock mass and, consequently, improves oil production. Palavras-chaveSeveral analytical and numerical models have been proposed to study this fracture mechanism, generally based in continuum mechanics or using interface elements through a known propagation path. In this work, the crack propagation is simulated using the PPR potential-based cohesive zone model [72] by means of an extrinsic implementation. Thus, interface cohesive elements are adaptively inserted in the mesh to capture the softening fracture process. The fluid pressure is simulated using the lattice Boltzmann model [84] through an iterative procedure. The boundaries of the crack, computed using the fini...

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Continuum–discontinuum analysis of failure mechanisms around unsupported circular excavations in anisotropic clay shales

Cited by 244 publications

References 76 publications

Simulating the Poisson effect in lattice models of elastic continua

Simulating the Poisson effect in lattice models of elastic continua

Stability analysis of underground oil storage caverns by an integrated numerical and microseismic monitoring approach

Simulação Numérica Do Processo De Propagação De Fraturas Em Materiais Rochosos Em Condições De Acoplamento Fluidomecânico

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