Adaptive phase-field modelling of fracture propagation in poroelastic media using the scaled boundary finite element method
- Authors: Wijesinghe, Dakshith , Natarajan, Sundararajan , You, Greg , Khandelwal, Manoj , Dyson, Ashley , Song, Chongmin , Ooi, Ean Tat
- Date: 2023
- Type: Text , Journal article
- Relation: Computer Methods in Applied Mechanics and Engineering Vol. 411, no. (2023), p.
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- Description: A scaled boundary finite element-based phase field formulation is proposed to model two-dimensional fracture in saturated poroelastic media. The mechanical response of the poroelastic media is simulated following Biot's theory, and the fracture surface evolution is modelled according to the phase field formulation. To avoid the application of fine uniform meshes that are constrained by the element size requirement when adopting phase field models, an adaptive refinement strategy based on quadtree meshes is adopted. The unique advantage of the scaled boundary finite element method is conducive to the application of quadtree adaptivity, as it can be directly formulated on quadtree meshes without the need for any special treatment of hanging nodes. Efficient computation is achieved by exploiting the unique patterns of the quadtree cells. An appropriate scaling is applied to the relevant matrices and vectors according the physical size of the cells in the mesh during the simulations. This avoids repetitive calculations of cells with the same configurations. The proposed model is validated using a benchmark with a known analytical solution. Numerical examples of hydraulic fractures driven by the injected fluid in cracks are modelled to illustrate the capabilities of the proposed model in handling crack propagation problems involving complex geometries. © 2023 The Author(s)
Image based probabilistic slope stability analysis of soil layer interface fluctuations with Brownian bridges
- Authors: Wijesinghe, Dakshith , Dyson, Ashley , You, Greg , Khandelwal, Manoj , Ooi, Ean Tat
- Date: 2023
- Type: Text , Journal article
- Relation: Engineering Failure Analysis Vol. 148, no. (2023), p.
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- Description: Accurate interpretation of stratigraphic profiles, the phreatic surface and the spatial variability of geomaterials are essential to produce representative behaviour of geomechanical systems through numerical simulations. When considering slope stability, variations in soil layer boundaries and the phreatic surface may result in misleading metrics such as the Factor of Safety (FoS) and the Probability of Failure (PoF). This paper presents an image-based technique for generating continuous stratigraphic profiles, including random fluctuations based on Brownian motion. Brownian bridges are used to produce random walks between known points on both soil layer boundaries and the phreatic level that overlap with the slope profile image. Quadtree decomposition is used to discretise the stratigraphy and the phreatic level through an automatic process using generated digital images for mesh generation while also integrating material properties. The Scaled Boundary Finite Element (SBFEM) is used to analyse the slope stability problem. Images based on random walks along an unknown stratigraphic material boundary and the phreatic surface are randomly generated and have many random possibilities, which are used to undertake probabilistic analysis to obtain PoF. This process is complex when using numerical methods, such as the Finite Element Method, as it requires mesh generation from different slope profiles with alternating material interfaces at each probabilistic instance. When the Scaled Boundary Finite Element Method is applied, probabilistic numerical analyses can be fully automated for randomly generated material interfaces. The feasibility of the proposed method is illustrated through several cases of a slope with multiple material layers, in addition to a slope incorporating a Brownian bridge phreatic surface formulation. © 2023 Elsevier Ltd
Development of the scaled boundary finite element method for image-based slope stability analysis
- Authors: Wijesinghe, Dakshith , Dyson, Ashley , You, Greg , Khandelwal, Manoj , Song, Chongmin , Ooi, Ean Tat
- Date: 2022
- Type: Text , Journal article
- Relation: Computers and Geotechnics Vol. 143, no. (2022), p.
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- Description: This paper presents a numerical technique for geotechnical slope stability analysis, integrating digital image meshing with the scaled boundary finite element method, allowing site conditions such as complex stratigraphies, surface and internal geometry evolution to be simulated in a robust and straightforward procedure. The quadtree decomposition technique is used to automatically discretise the geometry directly from digital images using pixel information to accurately capture boundaries with fine-scale elements. The process allows complex numerical models to be generated from cross-section images of slopes, capitalising on the combination of the scaled boundary finite element method and quadtree meshing. The spatial distribution of the soil material properties can be represented by the colour of each pixel. A mapping technique is developed to integrate these parameters into the computational mesh. The feasibility of the proposed method is presented through case study simulations of an active large Australian open-pit mine, considering various aspects of complex features such as geometry, stratigraphy and material behaviour. © 2021
Simultaneous slope design optimisation and stability assessment using a genetic algorithm and a fully automatic image-based analysis
- Authors: Wijesinghe, Dakshith , Dyson, Ashley , You, Greg , Khandelwal, Manoj , Song, Chongmin , Ooi, Ean Tat
- Date: 2022
- Type: Text , Journal article
- Relation: International Journal for Numerical and Analytical Methods in Geomechanics Vol. 46, no. 15 (2022), p. 2868-2892
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- Description: Mine slope design is a complex task that requires consideration of geotechnical analysis, structural stability, economics and the environment. Economic factors usually drive mine slope design, particularly in the case of open-pit designs, where the process of steepening slope walls by several degrees can have profound financial implications. Due to the risks associated with catastrophic slope collapse, slope stability analysis is an integral component of open-pit engineering projects. However, initial design concepts and geotechnical assessments are often considered separately. In this study, a technique is developed that combines the scaled boundary finite element method (SBFEM) with genetic algorithms (GAs) to simultaneously perform slope stability analysis and optimise the slope profile. The iterative design approach optimises characteristics of the slope profile such as the slope height, width, angle and number of benches while ensuring the factor of safety (FoS) remains above a threshold value. A salient feature of the technique is the ability to automatically address the modifications to the geometry of the slope by updating the digital images used in the analysis to assess the stability of each instance in the optimisation process and determine the optimum slope geometry. The results highlight the application of the developed technique to determine appropriate slope excavation designs as well as slope backfilling scenarios. The method is exemplified in several cases where complex stratigraphies and spatially variable materials are considered. As such, the GA-driven slope design process conveys an optimised, automated tool, combining mine slope design and slope stability analysis. © 2022 John Wiley & Sons Ltd.
Rainfall affected stability analysis of Maddingley brown coal eastern batter using plaxis 3D
- Authors: Zhao, Lei , You, Greg
- Date: 2020
- Type: Text , Journal article
- Relation: Arabian Journal of Geosciences Vol. 13, no. 20 (2020), p.
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- Description: Rainfall is a common factor that triggers the instability of Victorian Brown Coal (VBC) open pits which facilitate some of the largest brown coal mining operations. There has been no relevant study on rainfall-induced slope instability of VBC open pits in literature. In this paper, a three-dimensional (3D) two-phase (fluid-solid) coupled finite element method (FEM) was employed to investigate the stability of Maddingley Brown Coal (MBC) eastern batter under different rainfall conditions. It was found that the batter tends to lead a circular failure path during large rainfall. With the increase in either precipitation period or rainfall intensity, the deformation, excess pore pressure and active pressure increased, while the matric suction decreased. The hydrostatic force in the confined aquifer underlying the brown coal seam increased during rainfall; meanwhile, the resisting force decreased. As a result, the shear strength decreased and thereby the stability of the batter decreased. The safety factor and the critical failure path of the eastern batter simulated in this study were consistent with the previous study on the Northern batter. This study is a strong supplement to the literature on rainfall-induced instability of VBC batters. In the meantime, it is significant to provide a reference to the application of sophisticated 3D numerical modelling for studying slope instability of brown coal and similar mineral deposits. © 2020, Saudi Society for Geosciences.
- Description: The study is supported by the Australian Research Training Program (RTP) Scholarship and Federation University Australia George Collins Memorial Scholarship
Statistical analysis the characteristics of extraordinarily severe coal mine accidents (ESCMAs) in China from 1950 to 2018
- Authors: Zhang, Jinjia , Xu, Kaili , Reniers, Genserik , You, Greg
- Date: 2020
- Type: Text , Journal article
- Relation: Process Safety and Environmental Protection Vol. 133, no. (2020), p. 332-340
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- Description: Extraordinarily severe coal mine accidents (ESCMAs) are characteristized by thirty fatalities or more in one accident. In this paper, such ESCMAs are analyzed using 188 cases which occurred in Chinese underground coal mines. The analysis shows that the number of ESCMAs and the death toll have decreased steadily over time. Gas explosions, mine water inrushes, and coal dust explosions are the three major types of ESCMAs. Among the causes of ESCMAs, inadequate implementation of safety measures, deliberate violations and electromechanical equipment faults are the three top causes of ESCMAs, accounting for 27.13 %, 21.81 %, and 15.96 % of incidences, respectively. Meanwhile, ESCMAs frequently occur in the heading face, especially gas explosions, mine water inrushes and coal and gas outbursts. Furthermore, ESCMAs reoccur often in certain provinces, such as Shanxi, Henan and Heilongjiang, and mostly during November and December in each year. The results of statistical studies have presented useful information for the prevention of ESCMAs in order to reduce the probability of such disastrous accidents. © 2019 Institution of Chemical Engineers
Study on the stability of brown coal batter with opened cracks on Maddingley brown coal mine
- Authors: Zhao, Lei , You, Greg
- Date: 2020
- Type: Text , Journal article
- Relation: Sn Applied Sciences Vol. 2, no. 6 (Jun 2020), p. 14
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- Description: After a 26-mm precipitation in February 2014, noticeable ground movements were recorded on the north batter of Maddingley brown coal open pit, Victoria. To investigate the rainfall effect on the stability of the brown coal batter with opened cracks, a three-dimensional geologic model was developed, and the finite element program encoded in Plaxis 3D was employed to conduct a complex two-phase (fluid-solid) coupled numerical simulation. It was found that the simulated deformations were well agreed with the field survey data. There were ground movements along the length of cracks on both sides of the crack with larger movement towards the pit bottom. The coupled effect of hydrostatic forces from the crack in the rear of the batter and from the clay layer underlain the batter caused the block to slide, or batter failure. From the results, it revealed that both short-term high rainfall intensity precipitation and long enduring low rainfall intensity precipitation could cause the brown coal batter with opened cracks instable.
- Description: Australian Research Training Program (RTP) Scholarship Federation University Australia George Collins Memorial Scholarship.
Analysis of a combined circular–toppling slope failure in an open–pit
- Authors: Al Mandalawi, Maged , You, Greg , Dahlhaus, Peter , Dowling, Kim , Sabry, Mohannad
- Date: 2019
- Type: Text , Conference paper
- Relation: 2nd GeoMEast International Congress and Exhibition on Sustainable Civil Infrastructures, Egypt 2018 - The official international congress of the Soil-Structure Interaction Group in Egypt, SSIGE 2018 p. 10-30
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- Description: Most studies of rock slope failures on open–pit mines have considered either toppling or circular failure stability analysis. By comparison, complex circular–toppling failure has received much less attention in the published literature. This paper presents a study using a range of methods to investigate a failure that occurred in July 2008 in Handlebar Hill, an open–pit base metal mine, near Mt Isa, Australia. Circular failure is the typical slope failure mechanism in slopes with low–strength rocks, although direct/flexural toppling of jointed columns can also occur. The study reviews circular–toppling failure mechanisms in the context of the local geotechnical and geo–hydrological conditions, which include the interaction between fault contacts and the existing deformed rocks. General limit equilibrium methods are used to evaluate the sensitivity of slope models to rock strength parameters and the trigger mechanisms. Finite element methods are used to assess the failure mechanisms and slope displacement, and a kinematic approach is used to evaluate structurally controlled slope instability mechanisms. The results demonstrate that the most credible failure mechanism was shearing along a circular path through the upper weaker rocks (leached Magazine Shale) that in turn initiated secondary block toppling, and the progressive nature of the slope failure mechanism. The use of conventional and numerical techniques for back–analysis of the combined circular–toppling failure provided key insights into the failure mechanisms and factors controlling slope instability. © 2019, Springer Nature Switzerland AG.
Causation analysis of risk coupling of gas explosion accident in chinese underground coal mines
- Authors: Zhang, Jinjia , Xu, Kaili , You, Greg , Wang, Beibei , Zhao, Lei
- Date: 2019
- Type: Text , Journal article
- Relation: Risk Analysis Vol. 39, no. 7 (2019), p. 1634-1646
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- Description: The coal mine production industry is a complex sociotechnical system with interactive relationships among several risk factors. Currently, causation analysis of gas explosion accidents is mainly focused on the aspects of human error and equipment fault, while neglecting the interactive relationships among risk factors. A new method is proposed through risk coupling. First, the meaning of risk coupling of a gas explosion is defined, and types of risk coupling are classified. Next, the coupled relationship and coupled effects among risk factors are explored through combining the interpretative structural modeling (ISM) and the NK model. Twenty-eight representative risk factors and 16 coupled types of risk factors are obtained through analysis of 332 gas explosion accidents in coal mines in China. Through the application of the combined ISM-NK model, an eight-level hierarchical model of risk coupling of a gas explosion accident is established, and the coupled degrees of different types of risk coupling are assessed. The hierarchical model reveals that two of the 28 risk factors, such as state policies, laws, and regulations, are the root risk factors for gas explosions; nine of the 28 risk factors, such as flame from blasting, electric spark, and local gas accumulation, are direct causes of gas explosions; whereas 17 of the risk factors, such as three-violation actions, ventilation system, and safety management, are indirect ones. A quantitative analysis of the NK model shows that the probability of gas explosion increases with the increasing number of risk factors. Compared with subjective risk factors, objective risk factors have a higher probability of causing gas explosion because of risk coupling.
Characterising and structural review of the rock mass and its geological structures at open pit mine in Queensland-Australia
- Authors: Al Mandalawi, Maged , Sabry, Manar , You, Greg , Sabry, Mohannad
- Date: 2019
- Type: Text , Conference paper
- Relation: 3rd GeoMEast International Congress and Exhibition on Sustainable Civil Infrastructures, GeoMEast 2019, Egypt, 10-15 November 2019, Latest advancements in underground structures and geological engineering : proceedings of the 3rd GeoMEast International Congress and Exhibition, Egypt 2019 on sustainable civil infrastructures - the official international congress of the Soil-Structure Interaction Group in Egypt p. 29-51
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- Description: Rock characterisation is important to the feasibility of the Handlebar Hill open cut mine at Mt Isa, Queensland-Australia, because of the complex structural geology and the diversity of slope formations. The different rocks are affected by complete and moderate oxidisations coupled with mining works, giving rise to potential slope instability. Through the characterisation of these rocks, there is more confidence in the prediction of their behaviors in terms of failure mechanisms and slope stability. The objective of this research was to evaluate the properties of the pit rock masses. The geotechnical engineering practice approach was based on defining the parameters of the Hoek-Brown, Barton-Bandis and Mohr-Coulomb failure criteria. A program involving investigation that included field measurements, laboratory tests, hydrogeological settings, empirical indices and findings using the RocLab program was applied. The inputs help to analysis of pit slope stability and to understand the effects of different pit configurations on slope performance to allow safe and economic mining operations. © Springer Nature Switzerland AG 2020.
Effect of cross-sectional shape of pillar strength
- Authors: You, Greg , Zhao, Dake , Liu, Shuo , Gao, Zhou
- Date: 2019
- Type: Text , Conference paper
- Relation: 9th International Conference on Geotechnique, Construction Materials and Environment, 20-22 November 2019, Tokyo Japan
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Effect of faults on stability of partially saturated rock slope
- Authors: You, Greg , Jaggi, Nav , Al Mandalawi, Maged , Dowling, Kim , Dahlhaus, Peter
- Date: 2019
- Type: Text , Book
- Relation: Deep Rock Mechanics : From Research to Engineering
- Full Text: false
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- Description: The effect of three faults on the slope stability was studied for the Stage 1 open pit in an open cut mine in Australia. The faults were treated as joints using Barton's method, and the slope was under dry and partially saturated conditions. A finite element program in RocScience was used in the study, where the generalized Hoek-Brown criterion was employed for rock mass and the Mohr-coulomb criterion for the faults. It is found that the factor of safety of the slope decreased with the introduction of the fault structures. Furthermore, the fault structures created higher stress concentrations zones at the ends of the faults.
Modelling and analyses of rock bridge fracture and step-path failure in open-pit mine rock slope
- Authors: Al Mandalawi, Maged , You, Greg , Dahlhaus, Peter , Dowling, Kim , Sabry, Mays
- Date: 2019
- Type: Text , Conference paper
- Relation: 2nd GeoMEast International Congress and Exhibition on Sustainable Civil Infrastructures, Egypt 2018 - The official international congress of the Soil-Structure Interaction Group in Egypt, SSIGE 2018, 24-28 November 2018 p. 198-226
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- Description: Rock Bridge fracturing and coalescence with pre-existing discontinuities in rock mass due to the initiation, propagation and interaction of these fractures refers to instability mode of step-path failure. Step-path failure is a typical type of instable mode of man-made and natural rock slopes. The continuum finite element method was applied to work on deeper insight into the propagation of tensile cracks which developing in the intact rock bridges that can finally coalesce to form step-path failure. In this paper, based on the intact rock fracturing hypothesis, two selected slope simulations from the Handlebar Hill open - pit mine near Mt. Isa in Queensland, Australia, modeled the process of fracturing and step-path failure through different pre-existing discontinuities. The empirical models of Bobet and Einstein (1998) and the progressively cracks development are observed within crack initiation, propagation and coalescence in the intact rock bridges. Proposed slope models of the mine included four joint-net distributions through the rock masses considering the geometry of structures (dip angles, spacing, lengths and orientation) illustrated the extension cracks from the flaw tips and propagated to the slope surface. Modes of intact rock bridges fracturing (shear, tensile and a combination of shear and tensile) have been observed. Tensile fracture is usually generated when the rock bridge angle is sub-vertical. Shear fracture can be initiated in less steep rock bridge angles. A combination of shear and tensile failure is normally generated in slopes with. Slope with explicit large-scale structures of steeper dip angles increased the yielding. Larger structures show much higher potential for yielding as the tensile stresses increasing. Major joint plane spacing resulted in less potential for relative deformations between neighboring structures and consequently reduced slope instability. The changes of length and spacing have more influence on slope stability than a change in the dip angle of the structures. © 2019, Springer Nature Switzerland AG.
Rainfall-induced deformation behavior of cracks on brown coal open pit batter in Australia
- Authors: Zhao, Lei , You, Greg
- Date: 2019
- Type: Text , Conference paper
- Relation: 9th International Conference on Geotechnique, Construction Materials and Environment, 20-22 November 2019, Tokyo Japan p. 458-463
- Full Text: false
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- Description: After a 26mm rainfall in 24 hours, noticeable ground movements were observed on the north batter at Maddingley Brown Coal Open Pit Mine, Victoria, Australia in February 2014. The batter is brown coal sandwiched by confining beds. Cracks manifested on the north batter months before the rainfall event, and then an emergency buttress was immediately constructed to maintain the batter stability. A three-dimensional geologic model is developed to study the rainfall-induced ground movement in this paper. The finite element program encoded in Plaxis 3D is employed to conduct the complex two-phase (fluid-solid) coupled numerical simulation. It is found that the simulated deformation is well agreed with the observed data from field survey markers. There are ground movements along the length of cracks on both sides with larger movement towards the pit bottom. These movements are the results of the combined reactions of surface run-off and sudden increased underground water level. The 26mm rainfall event did not cause instability of the batter.
Sensitivity analysis, determination and optimization of granite RHT parameters
- Authors: Li, Hongchao , Chen, Yong , Liu, Dianshu , Zhao, Lei , You, Greg
- Date: 2019
- Type: Text , Journal article
- Relation: Journal of Beijing Institute of Technology (English Edition) Vol. 28, no. 1 (2019), p. 94-102
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- Description: The RHT model has 34 parameters, among which 19 parameters can be obtained by experiments or theoretical calculations and the remaining 15 parameters are difficult to acquire. In this study, firstly, 10 Hopkinson impact tests were conducted to acquire the typical stress-strain curves of granite under dynamic loads. Through the sensitivity analysis, it is found that 13 of the 15 difficultacquired parameters are effective to affect the shape of the stress-strain curve, and the other two parameters have no effect. Following the initial determination of model parameters with reference to the concrete RHT model, a new approach is proposed to optimize the 13 influential parameters through the LS-DYNA numerical simulation and orthogonal experiments. Finally, the determined granite RHT model parameters are verified by the results of Hopkinson impact tests conducted in this study and the bullet penetration test by Wang et al. Both results of the numerical simulations are in a good agreement with the tested results, which validates the suitability of the proposed method to acquire RHT model parameters for granite and the other rocks.
Cracking mechanism along the north batter of Maddingley Brown Coal Open Pit Mine, Victoria, Australia
- Authors: Zhao, Lei , You, Greg
- Date: 2018
- Type: Text , Book chapter
- Relation: Engineering Geology and Geological Engineering for Sustainable Use of the Earth's Resources, Urbanization and Infrastructure Protection from Geohazards, Proceedings of the 1st GeoMEast International Congress and Exhibition, Egypt 2017 on Sustainable Civil Infrastructures (Part of the Sustainable Civil Infrastuctures book series) 8 p. 115-129
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- Description: Cracks manifested on the north batter at Maddingley Brown Coal Open Pit Mine, Victoria, Australia in November 2013. The crack opened varies from trace to approximately 150 mm wide was located at about 20 m back from the coal face and extended for approximately 50 m on the eastern side and terminated 10 m away from the access road. Site investigations and remedy measures were implemented immediately after the cracking. This study involves in a three dimensional modeling on the cracking mechanism using finite element method (FEM) encoded in Plaxis 3D software program. From the study, it was found that the initial model based on north batter being stable for many decades tended to lead a circular critical path while the model after overburden removal showed a trend of block sliding. The safety factor of initial north batter was 1.38 through safety analysis while it was decreased to 1.17 for the coal batter after overburden removal. But the simulated shear and tensile strains indicated that the coal batter after overburden removal in fact experienced block failure. Furthermore, the simulated location of cracking was in good agreement with the actual location, and the simulated heave of the coal seam was in good agreement with the experience in Victoria brown coal open pit mining The observed vertical crack would be a combined action of the overburden removal and the groundwater flow in the unconfined aquifer.
Focusing on the patterns and characteristics of extraordinarily severe gas explosion accidents in Chinese coal mines
- Authors: Zhang, Jinjia , Cliff, David , Xu, Kaili , You, Greg
- Date: 2018
- Type: Text , Journal article
- Relation: Process Safety and Environmental Protection Vol. 117, no. (2018), p. 390-398
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- Description: Extraordinarily severe gas explosion accidents (ESGEAs) (thirty fatalities or more in one accident) have a high occurrence frequency in Chinese coal mines. There are 126 ESGEAs that occurred in China from 1950 to 2015, and they were investigated through statistical methods in this study to review the overall circumstances and to provide quantitative information on ESGEAs. Statistical characteristics about accident-related factors, such as gas accumulation, ignition sources, operating locations, accident time, coal mine regions and coal mine ownership, were assessed in this paper. The statistical analysis shows that disorganized ventilation fan management was the most frequent cause of gas accumulation in ESGEAs, while illegal blasting was the most prominent cause of the ignition source in ESGEAs. Furthermore, ESGEAs were found to occur frequently in certain provinces (e.g., Shanxi, Henan and Heilongjiang) and during November and December of the year. Moreover, most accidents and the largest death tolls generally occur in state-owned coal mines. Based on the results of statistical studies, some countermeasures were proposed in this study.
Reliability analysis of shear strength parameters of rock mass derived using the Hoek-Brown criterion
- Authors: Wen, Yiming , Wang, Chun , Zhao, Lei , You, Greg , Yang, Jianzhong , Zeng, Xiaoyan , Yang, Ze , Sun, Wei , Cheng, Yong , Lin, You
- Date: 2018
- Type: Text , Journal article
- Relation: Journal of Mines, Metals and Fuels Vol. 66, no. 8 (2018), p. 438-443
- Full Text: false
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- Description: Determining the mechanical parameters of a rock mass is a difficult but crucial matter in studies pertaining to stability. In this study, the Hoek-Brown criterion is used to derive the shear strength parameters of a rock mass; the parameters are subsequently optimized through reliability analyses, including the nonlinear Mohr-Coulomb envelope, optimized slopes, and least square variance methods. Further, through a case study of the Jianshan open pit mine, the c and ϕ values of the orebody were comparatively studied using the proposed method. The nonlinear Mohr-Coulomb envelope method and the optimized slopes method can attain reliability values exceeding 80%, as required by Chinese standards.
Shallow seismic investigation of the Yangtze River Fault at Zhenjiang, Jiangsu Province, China
- Authors: Wang, Guang-ya , You, Greg , Chen, Ming-zhu , Zhou, Guo-xing , Jian, E.
- Date: 2018
- Type: Text , Book chapter
- Relation: Engineering Geology and Geological Engineering for Sustainable Use of the Earth's Resources, Urbanization and Infrastructure Protection from Geohazards, Proceedings of the 1st GeoMEast International Congress and Exhibition, Egypt 2017 on Sustainable Civil Infrastructures (Part of the Sustainable Civil Infrastuctures book series) 13 p. 192-205
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- Description: Debates on the Yangtze River Fault at Zhenjiang, Jiangsu Province, China have lasted for a long time. In order to clarify the stratigraphy, characteristics and activity of the fault, a large-scale shallow seismic investigation was conducted on the site. It involved 10 onsite field experiments, 5715 m long shallow seismic exploration and five geological drill holes, and consequent data processing and interpretation of the shallow seismic time profiles in combination with one geological profile and a satellite image. It was found that the loose Quaternary strata present good continuity in the area. Four pre-Cenozoic faults present in the bedrock (including the Yangtze River Fault), and two Quaternary faults cut the Quaternary sediments. Therefore, the existence of the Yangtze River Fault is verified, and its activity and characteristics are analyzed in this study.
Stability study on the northern batter of MBC Open Pit using Plaxis 3D
- Authors: Zhao, Lei , You, Greg
- Date: 2018
- Type: Text , Journal article
- Relation: Arabian Journal of Geosciences Vol. 11, no. 6 (2018), p. 1-11
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- Description: Cracks appeared on the northern batter at Maddingley Brown Coal Open Pit Mine, Victoria, Australia, on 8 November 2013 and a 2-day rainfall event happened 5 days later. This study models the stability of the northern batter considering the effect of the rainfall event and an emergency buttress using finite element method (FEM) encoded in Plaxis 3D. It is found that the batter tended to lead to block sliding after overburden removal. The observed vertical crack would be a combined action of the overburden removal and groundwater flow. The simulated location of cracks agrees well with the actual location, and the simulated heave of the coal seam is in good agreement with the experience in Victoria brown coal open pit mining. The rainfall accelerated the development of the cracks. With the construction of the emergency buttress, the batter became stable that is in good agreement with the monitored data.