Earth fissures in Jiangsu Province, China and geological investigation of Hetang earth fissure
- Wang, Guang-ya, You, Greg, Shi, Bin, Qiu, Z. L., Li, H. Y., Tuck, Michael
- Authors: Wang, Guang-ya , You, Greg , Shi, Bin , Qiu, Z. L. , Li, H. Y. , Tuck, Michael
- Date: 2009
- Type: Journal article
- Relation: Environmental Earth Sciences Vol. 60, no. 1 (2009), p. 35-43
- Full Text:
- Reviewed:
- Description: Earth fissures are a geohazard in Jiangsu Province, China. They can be caused by earthquakes and active faults, underground mining, groundwater extraction and landslides. In order to establish a provincial rehabilitation plan in Jiangsu, a range of monitoring programs, surveys, geological investigations and modeling have been implemented or planned. One of the focuses of the project is the land subsidence and earth fissures caused by excessive groundwater withdrawal in Suzhou, Wuxi and Changzhou (Su-Xi-Chang) area, southern Jiangsu Province. Hetang earth fissure within the Su-Xi-Chang area was first reported in 1995 and a series of investigation has been conducted since then. The site investigations and geophysical survey in 1997 have recognized the causative factor as the excessive groundwater drawdown coupled by the underlying bedrock ridge. An open trench excavation in 2007 and a plane strain analysis suggest that Hetang earth fissures may have cracked from the bedrock ridge to ground surface. Geological drilling in 2007 has further confirmed the existence and configuration of the ridge and extracted soil samples for laboratory tests to obtain soil parameters for numerical analyses and modeling of land subsidence and earth fissures in the Su-Xi-Chang area, Jiangsu, China. The laboratory tests are currently in progress and the result of numerical analyses and modeling is expected to be presented in the near future.
- Authors: Wang, Guang-ya , You, Greg , Shi, Bin , Qiu, Z. L. , Li, H. Y. , Tuck, Michael
- Date: 2009
- Type: Journal article
- Relation: Environmental Earth Sciences Vol. 60, no. 1 (2009), p. 35-43
- Full Text:
- Reviewed:
- Description: Earth fissures are a geohazard in Jiangsu Province, China. They can be caused by earthquakes and active faults, underground mining, groundwater extraction and landslides. In order to establish a provincial rehabilitation plan in Jiangsu, a range of monitoring programs, surveys, geological investigations and modeling have been implemented or planned. One of the focuses of the project is the land subsidence and earth fissures caused by excessive groundwater withdrawal in Suzhou, Wuxi and Changzhou (Su-Xi-Chang) area, southern Jiangsu Province. Hetang earth fissure within the Su-Xi-Chang area was first reported in 1995 and a series of investigation has been conducted since then. The site investigations and geophysical survey in 1997 have recognized the causative factor as the excessive groundwater drawdown coupled by the underlying bedrock ridge. An open trench excavation in 2007 and a plane strain analysis suggest that Hetang earth fissures may have cracked from the bedrock ridge to ground surface. Geological drilling in 2007 has further confirmed the existence and configuration of the ridge and extracted soil samples for laboratory tests to obtain soil parameters for numerical analyses and modeling of land subsidence and earth fissures in the Su-Xi-Chang area, Jiangsu, China. The laboratory tests are currently in progress and the result of numerical analyses and modeling is expected to be presented in the near future.
The harnessing of peptide-monolith constructs for single step plasmid DNA purification
- Han, Ying Chao, You, Greg, Pattenden, Leonard Keith, Forde, Gareth
- Authors: Han, Ying Chao , You, Greg , Pattenden, Leonard Keith , Forde, Gareth
- Date: 2010
- Type: Text , Journal article
- Relation: Process Biochemistry Vol. 45, no. 2 (2010), p. 203-209
- Full Text:
- Reviewed:
- Description: The availability of synthetic peptides has paved the way for their use in tailor-made interactions with biomolecules. In this study, a 16mer LacI-based peptide was used as an affinity ligand to examine the scale up feasibility for plasmid DNA purification. First, the peptide was designed and characterized for the affinity purification of lacO containing plasmid DNA, to be employed as a high affinity ligand for the potential capturing of plasmid DNA in a single unit operation. It was found there were no discernible interactions with a control plasmid that did not encode the lacO nucleotide sequence. The dissociation equilibrium constant of the binding between the 16mer peptide and target pUC19 was 5.0 ± 0.5 × 10-8M as assessed by surface plasmon resonance. This selectivity and moderated affinity indicate that the 16mer is suitable for the adsorption and chromatographic purification of plasmid DNA. The suitability of this peptide was then evaluated using a chromatography system with the 16mer peptide immobilized to a customized monolith to purify plasmid DNA, obtaining preferential purification of supercoiled pUC19. The results demonstrate the applicability of peptide-monolith supports to scale up the purification process for plasmid DNA using designed ligands via a biomimetic approach. © 2009 Elsevier Ltd. All rights reserved.
- Authors: Han, Ying Chao , You, Greg , Pattenden, Leonard Keith , Forde, Gareth
- Date: 2010
- Type: Text , Journal article
- Relation: Process Biochemistry Vol. 45, no. 2 (2010), p. 203-209
- Full Text:
- Reviewed:
- Description: The availability of synthetic peptides has paved the way for their use in tailor-made interactions with biomolecules. In this study, a 16mer LacI-based peptide was used as an affinity ligand to examine the scale up feasibility for plasmid DNA purification. First, the peptide was designed and characterized for the affinity purification of lacO containing plasmid DNA, to be employed as a high affinity ligand for the potential capturing of plasmid DNA in a single unit operation. It was found there were no discernible interactions with a control plasmid that did not encode the lacO nucleotide sequence. The dissociation equilibrium constant of the binding between the 16mer peptide and target pUC19 was 5.0 ± 0.5 × 10-8M as assessed by surface plasmon resonance. This selectivity and moderated affinity indicate that the 16mer is suitable for the adsorption and chromatographic purification of plasmid DNA. The suitability of this peptide was then evaluated using a chromatography system with the 16mer peptide immobilized to a customized monolith to purify plasmid DNA, obtaining preferential purification of supercoiled pUC19. The results demonstrate the applicability of peptide-monolith supports to scale up the purification process for plasmid DNA using designed ligands via a biomimetic approach. © 2009 Elsevier Ltd. All rights reserved.
Long-term land subsidence and strata compression in Changzhou, China
- Wang, Guang-ya, You, Greg, Shi, Bin, Yu, Jun, Tuck, Michael
- Authors: Wang, Guang-ya , You, Greg , Shi, Bin , Yu, Jun , Tuck, Michael
- Date: 1999
- Type: Text , Journal article
- Relation: Engineering Geology Vol. 104, no. (1999), p. 109–118
- Full Text:
- Description: Changzhou City, underlain by a multi-layered aquifer system in Quaternary sediments in the Great Yangtze River Delta region, experienced a maximum land subsidence rate of 147 mm/year in the early 1980s due to excessive groundwater extraction. A large-scale monitoring station of 11 borehole extensometerswas established in the city in 1983 to investigate land subsidence. Nine stratawere predetermined in the Quaternary depth interval andmonitored by borehole extensometers. Presented in this paper are the long-term observations of land subsidence, strata compression and groundwater level in four aquifers from 1984 to 2002, and discussion on strata compression based on the measured data with reference to the stratigraphy, soil properties, groundwater withdrawn and literature of similar situations. The compression of strata varies significantly and is strongly influenced by groundwater drawdown in the second confined aquifer, or CA2. The groundwater level in CA2 declined from −55 m in 1981 to −76 m in 1994 and the land subsidence rate remained high. After the city government enforced restrictions on groundwater extraction in 1995, the extraction rate sharply reduced, the groundwater level in CA2 steadily recovered to −56 m until 2003, and the land subsidence rate declined to 10 mm/year in 2002. From 1984 to 2002, the land subsidence was mainly attributed to the consolidation of the thick aquitard overlying CA2. In the future, to prevent the subsidence rate from rising, it is vital to stop groundwater drawdown in aquifers.
Long-term land subsidence and strata compression in Changzhou, China
- Wang, Guang-ya, You, Greg, Shi, Bin, Yu, Jun, Tuck, Michael
- Authors: Wang, Guang-ya , You, Greg , Shi, Bin , Yu, Jun , Tuck, Michael
- Date: 2009
- Type: Text , Journal article
- Relation: Engineering Geology Vol. 104, no. 1-2 (2009), p. 109-118
- Full Text:
- Reviewed:
- Description: Changzhou City, underlain by a multi-layered aquifer system in Quaternary sediments in the Great Yangtze River Delta region, experienced a maximum land subsidence rate of 147 mm/year in the early 1980s due to excessive groundwater extraction. A large-scale monitoring station of 11 borehole extensometers was established in the city in 1983 to investigate land subsidence. Nine strata were predetermined in the Quaternary depth interval and monitored by borehole extensometers. Presented in this paper are the long-term observations of land subsidence, strata compression and groundwater level in four aquifers from 1984 to 2002, and discussion on strata compression based on the measured data with reference to the stratigraphy, soil properties, groundwater withdrawn and literature of similar situations. The compression of strata varies significantly and is strongly influenced by groundwater drawdown in the second confined aquifer, or CA2. The groundwater level in CA2 declined from - 55 m in 1981 to - 76 m in 1994 and the land subsidence rate remained high. After the city government enforced restrictions on groundwater extraction in 1995, the extraction rate sharply reduced, the groundwater level in CA2 steadily recovered to - 56 m until 2003, and the land subsidence rate declined to 10 mm/year in 2002. From 1984 to 2002, the land subsidence was mainly attributed to the consolidation of the thick aquitard overlying CA2. In the future, to prevent the subsidence rate from rising, it is vital to stop groundwater drawdown in aquifers. © 2008 Elsevier B.V. All rights reserved.
- Authors: Wang, Guang-ya , You, Greg , Shi, Bin , Yu, Jun , Tuck, Michael
- Date: 2009
- Type: Text , Journal article
- Relation: Engineering Geology Vol. 104, no. 1-2 (2009), p. 109-118
- Full Text:
- Reviewed:
- Description: Changzhou City, underlain by a multi-layered aquifer system in Quaternary sediments in the Great Yangtze River Delta region, experienced a maximum land subsidence rate of 147 mm/year in the early 1980s due to excessive groundwater extraction. A large-scale monitoring station of 11 borehole extensometers was established in the city in 1983 to investigate land subsidence. Nine strata were predetermined in the Quaternary depth interval and monitored by borehole extensometers. Presented in this paper are the long-term observations of land subsidence, strata compression and groundwater level in four aquifers from 1984 to 2002, and discussion on strata compression based on the measured data with reference to the stratigraphy, soil properties, groundwater withdrawn and literature of similar situations. The compression of strata varies significantly and is strongly influenced by groundwater drawdown in the second confined aquifer, or CA2. The groundwater level in CA2 declined from - 55 m in 1981 to - 76 m in 1994 and the land subsidence rate remained high. After the city government enforced restrictions on groundwater extraction in 1995, the extraction rate sharply reduced, the groundwater level in CA2 steadily recovered to - 56 m until 2003, and the land subsidence rate declined to 10 mm/year in 2002. From 1984 to 2002, the land subsidence was mainly attributed to the consolidation of the thick aquitard overlying CA2. In the future, to prevent the subsidence rate from rising, it is vital to stop groundwater drawdown in aquifers. © 2008 Elsevier B.V. All rights reserved.
- Wang, Guang-ya, You, Greg, Shi, Bin, Yu, Jun, Li, H. Y., Zong, K. H.
- Authors: Wang, Guang-ya , You, Greg , Shi, Bin , Yu, Jun , Li, H. Y. , Zong, K. H.
- Date: 2008
- Type: Text , Journal article
- Relation: Environmental Geology Vol. , no. (2008), p. 1-8
- Full Text:
- Reviewed:
- Description: Earth fissures in Jiangsu Province, China have caused serious damages to properties, farmlands, and infrastructures and adversely affected the local or regional economic development. Under the geological and environmental background in Jiangsu Province, this paper presents the earth fissures caused by excessive groundwater withdrawal and coupled by distinctive geological structures such as Ancient Yellow River Fault in Xuzhou karst area, and Ancient Yangtze River Course and bedrock hills in Suzhou, Wuxi, and Changzhou area. Although all the earth fissures are triggered by groundwater exploitation, the characteristics are strongly affected by the specific geological and hydrogeological settings. In particular, in the water-thirsty Xuzhou city, the cone of depression caused by groundwater extraction enlarged nearly 20 times and the piezometric head of groundwater declined 17 m over a decade. As groundwater is extracted from the shallowly buried karst strata in the Ancient Yellow River Fault zone, the development of earth fissures is highly associated with the development of karstic cavities and sinkholes and their distribution is controlled by the Ancient Yellow River Fault with all the 17 sinkholes on the fault. On the other hand, in the rapidly developing Southern Jiangsu Province, groundwater is mainly pumped from the second confined aquifer in the Quaternary, which is distributed neither homogeneously nor isotropically. The second confined aquifer comprises more than 50 m thick sand over the Ancient Yangtze River Course, but this layer may completely miss on the riverbank and bedrock hills. With a typical drawdown rate of 4-6 m per annum, the piezometric head of groundwater in the second confined aquifer has declined 76 m at Maocunyuan since 1970s and 40 m at Changjing since mid-1980s, and a large land subsidence, e.g., 1,100 mm at Maocunyuan, is triggered. Coupled with the dramatic change of the bedrock topography that was revealed through traditional geological drilling and modern seismic reflection methods, the geological-structure-controlled differential settlement and earth fissures are phenomenal in this area. © 2008 Springer-Verlag.
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
- Full Text:
- Reviewed:
- 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.
- Authors: Zhao, Lei , You, Greg
- Date: 2018
- Type: Text , Journal article
- Relation: Arabian Journal of Geosciences Vol. 11, no. 6 (2018), p. 1-11
- Full Text:
- Reviewed:
- 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.
Land rebound after banning deep groundwater extraction in Changzhou, China
- Wang, Guang-ya, Zhu, Jin-qi, You, Greg, Yu, Jun, Gong, Xu-long, Li, Wei, Gou, Fu-gang
- Authors: Wang, Guang-ya , Zhu, Jin-qi , You, Greg , Yu, Jun , Gong, Xu-long , Li, Wei , Gou, Fu-gang
- Date: 2017
- Type: Text , Journal article
- Relation: Engineering Geology Vol. 229, no. (2017), p. 13-20
- Full Text:
- Reviewed:
- Description: More than 30 years groundwater overdraft had resulted in hydraulic head declined from near the ground surface to 85 m deep in the second confined aquifer (CA2) in Changzhou, and lead to regional land subsidence from 1970's to early 2000's. After banning deep groundwater extraction was banned in 2000, the hydraulic head of CA2 had recovered to 37.6 m in Changzhou by the end of 2013. Based on several stages first and second order leveling results and long term monitoring data from the multi-strata borehole extensometer station (BES), it was revealed that the land subsidence is attributed to the compression of both aquifers and aquitards in the porous aquifer system. The spatial characteristics of subsidence are related not only to hydraulic head pattern in the area, but also to the thickness and compressibility of different soil strata, and distance from the aquifer. Since banning deep groundwater extraction, the ground uplifted 37.22 mm (5.4% of the pre subsidence) at BES, Changzhou due to the hydraulic head recovering. Strata compression and rebound was recorded as: the upper most stratum, and the underlying aquitard of CA2, and the upper CA3 are still in the compression process, the lower CA3 layer and the upper most segment of aquitard of CA2 rebounded about 90% of the pre compression recorded since 1984, and the CA2 and its adjacent overlying aquitard rebounded 3.8%–9.7% of the pre compression. © 2017 Elsevier B.V.
- Authors: Wang, Guang-ya , Zhu, Jin-qi , You, Greg , Yu, Jun , Gong, Xu-long , Li, Wei , Gou, Fu-gang
- Date: 2017
- Type: Text , Journal article
- Relation: Engineering Geology Vol. 229, no. (2017), p. 13-20
- Full Text:
- Reviewed:
- Description: More than 30 years groundwater overdraft had resulted in hydraulic head declined from near the ground surface to 85 m deep in the second confined aquifer (CA2) in Changzhou, and lead to regional land subsidence from 1970's to early 2000's. After banning deep groundwater extraction was banned in 2000, the hydraulic head of CA2 had recovered to 37.6 m in Changzhou by the end of 2013. Based on several stages first and second order leveling results and long term monitoring data from the multi-strata borehole extensometer station (BES), it was revealed that the land subsidence is attributed to the compression of both aquifers and aquitards in the porous aquifer system. The spatial characteristics of subsidence are related not only to hydraulic head pattern in the area, but also to the thickness and compressibility of different soil strata, and distance from the aquifer. Since banning deep groundwater extraction, the ground uplifted 37.22 mm (5.4% of the pre subsidence) at BES, Changzhou due to the hydraulic head recovering. Strata compression and rebound was recorded as: the upper most stratum, and the underlying aquitard of CA2, and the upper CA3 are still in the compression process, the lower CA3 layer and the upper most segment of aquitard of CA2 rebounded about 90% of the pre compression recorded since 1984, and the CA2 and its adjacent overlying aquitard rebounded 3.8%–9.7% of the pre compression. © 2017 Elsevier B.V.
Focusing on the patterns and characteristics of extraordinarily severe gas explosion accidents in Chinese coal mines
- Zhang, Jinjia, Cliff, David, Xu, Kaili, You, Greg
- 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
- Full Text:
- Reviewed:
- 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.
- 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
- Full Text:
- Reviewed:
- 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.
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
- Full Text:
- Reviewed:
- 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.
- Authors: Zhao, Lei , You, Greg
- Date: 2020
- Type: Text , Journal article
- Relation: Sn Applied Sciences Vol. 2, no. 6 (Jun 2020), p. 14
- Full Text:
- Reviewed:
- 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.
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.
- Full Text:
- Reviewed:
- 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
- Authors: Zhao, Lei , You, Greg
- Date: 2020
- Type: Text , Journal article
- Relation: Arabian Journal of Geosciences Vol. 13, no. 20 (2020), p.
- Full Text:
- Reviewed:
- 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
Adaptive phase-field modelling of fracture propagation in poroelastic media using the scaled boundary finite element method
- Wijesinghe, Dakshith, Natarajan, Sundararajan, You, Greg, Khandelwal, Manoj, Dyson, Ashley, Song, Chongmin, Ooi, Ean Tat
- 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.
- Full Text:
- Reviewed:
- 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)
- 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.
- Full Text:
- Reviewed:
- 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)
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