A Numerical Study of Pillar Failure Based on a Cusp-Type Catastrophe Model

2005 ◽  
Vol 297-300 ◽  
pp. 2628-2635 ◽  
Author(s):  
Shan Yong Wang ◽  
S.K. Au ◽  
K.C. Lam ◽  
Chun An Tang
Keyword(s):  
Numerical Study ◽  
Progressive Failure ◽  
Failure Process ◽  
Numerical Code ◽  
Stiffness Ratio ◽  
Catastrophe Model ◽  
Deformation Jump ◽  
Proposed Model ◽  
Unstable Failure ◽  
Rock Model

Based on cusp-type catastrophe theory, a sample rock-rock (hypocenter surrounding the rock) model for studying the pillar rockburst mechanism is presented in this paper. It is expounded theoretically that the stiffness ratio, K, of the roof and floor to the pillar plays an important role in the outbreak of instability. Using a newly developed numerical code, RFPA2D, the progressive failure process and associated microseismic behavior of the twin rock samples are simulated. The numerically simulated results also confirm that a soft roof and floor promotes an unstable failure or collapse of pillars. Additionally, the simulated results reproduced the deformation jump and the energy release that occur during a pillar rockburst. It is demonstrated that the proposed model properly simulates the pillar failure process.

Numerical Study of Elastic-Brittle Failure of Notched Openings in Rocks

2005 ◽  
Vol 297-300 ◽  
pp. 2605-2611
Author(s):  
Shan Yong Wang ◽  
S.K. Au ◽  
K.C. Lam ◽  
Chun An Tang
Keyword(s):  
Numerical Study ◽  
Progressive Failure ◽  
Process Analysis ◽  
Failure Process ◽  
Confining Pressure ◽  
Numerical Code ◽  
Tunnel Wall ◽  
Model Studies ◽  
Borehole Breakout ◽  
Rock Failure Process

Borehole breakout is the process by which portions of borehole or tunnel wall fracture or spall when subjected to compressive stresses. The stress-strain characteristics of rock during loading and unloading confining pressure are studied firstly. To overcome the difficulties in analytical model studies, a numerical code, RFPA2D (Rock Failure Process Analysis), developed by CRISR, Northeastern University, China, is used to investigate the progressive failure of breakout around tunnel. The heterogeneity of rock was also taken into account in the software. The numerical simulation reproduces the formation notch in rocks by the growth, interaction and coalescence of randomly distributed macrocracks. It is illustrated from the numerical simulated results that breakout direction of tunnel is parallel with the minor stress tensor in the plane perpendicular to the borehole axis. Specifically due to the inclusion of heterogeneity, some peculiarities are studied both in the evolution of fracture and the influence of borehole on the peak intensity of specimen as well as the AE event patterns.

Failure of a linear Voussoir arch: a laboratory and numerical study

1992 ◽  
Vol 29 (2) ◽  
pp. 188-194 ◽  
Author(s):  
B. Stimpson ◽  
M. Ahmed
Keyword(s):  
Numerical Study ◽  
Progressive Failure ◽  
Load Capacity ◽  
Failure Process ◽  
Physical Models ◽  
Ultimate Load Capacity ◽  
Element Analysis ◽  
Underground Openings ◽  
Physical Model Tests ◽  
Discrete Crack

The design of underground openings in horizontally layered strata on the basis of classical linear arching theory assumes the ultimate load capacity of the roof is limited by crushing or compressional failure at the centre of the arch or at the abutments. In this study, physical model tests on limestone, granite, and potash beams revealed a progressive failure mechanism dominated by discrete tensile fracturing, a quite different failure process to that assumed by classical theory. Subsequently, discrete crack propagation finite element analysis successfully simulated the failure mechanisms observed in the physical models. Key words : rock mechanics, underground design, roof stability, Voussoir arch, fracture.

Failure Analysis of Laminate on Influence of the Hole

2012 ◽  
Vol 450-451 ◽  
pp. 590-593
Author(s):  
Yin Huan Yang
Keyword(s):  
Failure Analysis ◽  
Composite Structures ◽  
Parametric Design ◽  
Numerical Study ◽  
Laminated Composites ◽  
Progressive Failure ◽  
Failure Process ◽  
Laminated Composite ◽  
Progressive Failure Analysis ◽  
Ultimate Failure

Failure process of laminated composites is performed by progressive failure analysis method. A modified form of Hashin’s failure criterion by Shokrieh is used to investigate the failure, where a sudden degradation model is proposed to reduce engineering material constants. The numerical study of laminated composites is implemented in ANSYS Parametric Design Language (APDL). The initiation and propagation of local damage and response of laminated composite structures from initial loading and ultimate failure are predicted. The model has been validated by comparing numerical results with existing experimental results. And then failure analysis of specimen fabricated from M40J/Ag80 on influence of the hole has been performed by the proposed model.

Numerical Study on the Fracture Evolution around Cavities in Rock

2005 ◽  
Vol 297-300 ◽  
pp. 2598-2604
Author(s):  
Shan Yong Wang ◽  
S.K. Au ◽  
K.C. Lam ◽  
Chun An Tang
Keyword(s):  
Shear Fracture ◽  
Model Simulation ◽  
Numerical Study ◽  
Process Analysis ◽  
Failure Process ◽  
Confining Pressure ◽  
Numerical Code ◽  
Tensile Fracture ◽  
Fracture Evolution ◽  
Rock Failure Process

By using numerical code RFPA2D (Rock Failure Process Analysis), the evolution of fracture around cavities subjected to uniaxial and polyaxial compression is examined through a series of model simulation. It is shown from the numerical results that the chain of events leading to the collapse of the cavity may involve all or some of the fractures designated as primary tensile, shear and remote fracture. Numerical simulated results reproduce the evolution of three types of fractures. Under the condition of no confining pressure, the tensile mode dominates with collapse coinciding with the sudden and explosive appearance of the secondary tensile fracture; at moderate higher confining pressure, the tensile mode is depressed, comparatively, the shear effect is strengthened. Nevertheless, tensile fractures especially in remote fractures stage still play a role; at higher pressure, the shear fracture dominates the remote fractures. In addition, the evolution and interact of fractures between multiple cavities is investigated, considering the stress redistribution and transference in compressive and tensile stress field.

scholarly journals 3D Anisotropic Elastoplastic-Damage Model and its Application in Simulating the Behavior of Rock Materials

2006 ◽  
Vol 324-325 ◽  
pp. 579-582
Author(s):  
Jun Feng Zhang ◽  
Tao Qi
Keyword(s):  
Damage Evolution ◽  
Damage Mechanics ◽  
Rock Sample ◽  
Progressive Failure ◽  
Failure Process ◽  
Damage Model ◽  
Tensor Decomposition ◽  
Continuum Damage Mechanics ◽  
Proposed Model ◽  
Elastoplastic Damage

A 3D anisotropic elastoplastic-damage model was presented based on continuum damage mechanics theory. In this model, the tensor decomposition technique is employed. Combined with the plastic yield rule and damage evolution, the stress tensor in incremental format is obtained. The derivate eigenmodes in the proposed model are assumed to be related with the uniaxial behavior of the rock material. Each eigenmode has a corresponding damage variable due to the fact that damage is a function of the magnitude of the eigenstrain. Within an eigenmodes, different damage evolution can be used for tensile and compressive loadings. This model was also developed into finite element code in explicit format, and the code was integrated into the well-known computational environment ABAQUS using the ABAQUS/Explicit Solver. Numerical simulation of an uniaxial compressive test for a rock sample is used to examine the performance of the proposed model, and the progressive failure process of the rock sample is unveiled.

3-D Micromechanics Model for Progressive Failure Analysis of Laminated Cylindrical Composite Shell

2005 ◽  
Vol 297-300 ◽  
pp. 1113-1119 ◽  
Author(s):  
Zheng Zhao Liang ◽  
Chun An Tang ◽  
De Shen Zhao ◽  
Yong Bin Zhang ◽  
Tao Xu ◽  
...  
Keyword(s):  
Composite Shell ◽  
Progressive Failure ◽  
Failure Process ◽  
Compressive Loading ◽  
Three Dimensional ◽  
Constitutive Law ◽  
Numerical Code ◽  
Damage And Failure ◽  
Progressive Failure Analysis ◽  
Cylindrical Composite Shell

A newly developed numerical code MFPA3D is applied to simulate the progressive damage and failure process of laminated cylindrical composite shell. Heterogeneities in meso-scale are taken into account by randomly distributing the material properties throughout the model by following a Weibull statistical distribution. The cylindrical composite shell is discretized into 3-D block elements with the fixed size and is subjected to a lateral compressive loading, applied with a constant displacement control manner. The numerical simulation results show that not only the process of crack initiation, propagation and coalescence but also the failure process can be numerically obtained in three dimensional. The MFPA3D modeling demonstrates that the code can simulate non-linear behavior of brittle materials with a simple mesoscopic constitutive law with a strength and elastic modulus reduction of the weaken elements.

Failure Prediction of Laminated Composites with the Hole under in-Plane Compressive Loading

2012 ◽  
Vol 476-478 ◽  
pp. 2539-2542
Author(s):  
Yin Huan Yang
Keyword(s):  
Failure Analysis ◽  
Composite Structures ◽  
Parametric Design ◽  
Numerical Study ◽  
Laminated Composites ◽  
Progressive Failure ◽  
Failure Process ◽  
Compressive Loading ◽  
Laminated Composite ◽  
Progressive Failure Analysis

Failure process of laminated composites with the hole under in-plane compressive loading is performed by progressive failure analysis method. A modified form of Hashin’s failure criterion by Shokrieh is used to investigate the failure, where a sudden degradation model is proposed to reduce engineering material constants. The numerical study of laminated composites is implemented in ANSYS Parametric Design Language (APDL). The initiation and propagation of local damage and response of laminated composite structures from initial loading and ultimate failure are predicted. The model has been validated by comparing numerical results with existing experimental results. And then failure analysis of specimen fabricated from M40J/Ag80 on influence of the hole under compressive loading has been performed by the proposed model.

Digital Image Based Simulation on Failure Process of Heterogeneous Brittle Materials

2006 ◽  
Vol 324-325 ◽  
pp. 315-318
Author(s):  
Wan Cheng Zhu ◽  
Jin Chao Duan ◽  
Chun An Tang ◽  
Shan Yong Wang
Keyword(s):  
Digital Image ◽  
Progressive Failure ◽  
Process Analysis ◽  
Failure Process ◽  
Brittle Materials ◽  
Heterogeneous Material ◽  
Numerical Code ◽  
Mechanical Responses ◽  
Macro Scale ◽  
Rock Failure Process

Rock and concrete are typical heterogeneous material that the meso-scale heterogeneity may have a significant effect on their macro-scale mechanical responses. In this work, a digital image-based (DIB) technique is employed to characterize and quantify the heterogeneity of concrete, and the obtained data is directly imported into a numerical code named RFPA (Rock Failure Process Analysis) to study the effect of heterogeneity on the failure process of concrete. The upgraded RFPA is capable to simulate the progressive failure of brittle materials such as rock and concrete, representing both the growth of existing fractures and the formation of new fractures, obviating the need to identify crack tips and their interaction explicitly. The simulated results are in reasonable agreement with experimental measurements and phenomenological observations reported in previous studies.

scholarly journals A 3DEC Numerical Analysis of the Interaction Between an Uneven Rock Surface and Shotcrete Lining

2021 ◽  
Author(s):  
Ping Zhang ◽  
Ering Nordlund
Keyword(s):  
Numerical Study ◽  
Support Effect ◽  
Influential Factors ◽  
Numerical Analyses ◽  
Numerical Code ◽  
Rock Surface ◽  
Stress Concentrations ◽  
Circular Tunnel ◽  
Rock Tunnels ◽  
Shotcrete Lining

AbstractRock tunnels excavated using drilling and blasting technique in jointed rock masses often have a very uneven and rough excavation surface. Experience from previous studies shows that the unevenness of a rock surface has a large impact on the support effect of shotcrete lining. However, clear conclusions regarding the effect of 2D and 3D uneven surfaces were not obtained due to limited studies in the literature. The numerical analyses reported in this paper were made to investigate the influence of the surface unevenness of a circular tunnel opening on the support effect of shotcrete using a 3D numerical code (3DEC). The models were first calibrated with the help of observations and measured data obtained from physical model tests. The influential factors were investigated further in this numerical study after calibration had been achieved. The numerical analyses show that, in general, the unevenness of a tunnel surface produces negative support effects due to stress concentrations in recesses (compressive) and at apexes (tensile) after excavation. However, shotcrete sprayed on a doubly waved uneven surface has better support effect compared to shotcrete sprayed on a simply waved tunnel surface. The development of shear strength (specifically frictional strength) on the uneven interface between the shotcrete and the rock contributes to this effect, in the condition where bonding of the shotcrete does not work effectively. The interface is a crucial element when the interaction between the rock and shotcrete is to be simulated. When an entire tunnel surface is covered by shotcrete with high modulus, more failures will occur in the shotcrete especially when rock surface is uneven. Based on the numerical model cases examined, some recommendations on how to incorporate tunnel surface conditions (2D or 3D unevenness) in the design of a shotcrete lining are given.

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