Over the last one hundred years, tailings dams have failed globally at a rate of 2 to 5 per annum. This failure rate is considered unacceptable by the community and by the mining industry. The conventional transport of slurry or thickened tailings and their storage in a tailings dam, requires low capital and operational expenditure, as slurry tailings can be transported by pipeline using relatively inexpensive and robust centrifugal pumps. Recently, the filtration of tailings, their transport by conveyor or truck, and “dry” stacking have been seen as an alternate method of tailings management. However, filtration and dry stacking are considered expensive. Over the full life cycle, including post-closure, of filtration and a dry stack facility, the potential to increase water recovery for recycling and increased options post-closure can lead to a reduction in the total expense of a dry stack facility. This study aimed to contribute to understanding of the cost-effectiveness of tailings dewatering and dry stacking as a tailings management method. Various tailings samples from different locations and with different characteristics were tested for their filtration potential. The potential for monetary savings through the reuse/recycling of the water recovered from the tailings through filtration was a particular focus. While tailings with higher clay mineral contents had more potential for water recovery than coarser-grained tailings, they were also more difficult to dewater. Tailings with lower clay mineral contents were relatively easy to dewater, requiring a short residence time, leading to increased water recovery and volume reduction potential. The results identified that there is significant potential for water recovery, leading to monetary savings through the reuse/recycling of water, potential for storage volume reduction, and potential for higher value post-closure uses.
{"title":"Cost-Effectiveness Of Tailings Dewatering And Stacking","authors":"Sophie Flottmann, David Williams, Danish Kazmi","doi":"10.56295/agj5814","DOIUrl":"https://doi.org/10.56295/agj5814","url":null,"abstract":"Over the last one hundred years, tailings dams have failed globally at a rate of 2 to 5 per annum. This failure rate is considered unacceptable by the community and by the mining industry. The conventional transport of slurry or thickened tailings and their storage in a tailings dam, requires low capital and operational expenditure, as slurry tailings can be transported by pipeline using relatively inexpensive and robust centrifugal pumps. Recently, the filtration of tailings, their transport by conveyor or truck, and “dry” stacking have been seen as an alternate method of tailings management. However, filtration and dry stacking are considered expensive. Over the full life cycle, including post-closure, of filtration and a dry stack facility, the potential to increase water recovery for recycling and increased options post-closure can lead to a reduction in the total expense of a dry stack facility. This study aimed to contribute to understanding of the cost-effectiveness of tailings dewatering and dry stacking as a tailings management method. Various tailings samples from different locations and with different characteristics were tested for their filtration potential. The potential for monetary savings through the reuse/recycling of the water recovered from the tailings through filtration was a particular focus. While tailings with higher clay mineral contents had more potential for water recovery than coarser-grained tailings, they were also more difficult to dewater. Tailings with lower clay mineral contents were relatively easy to dewater, requiring a short residence time, leading to increased water recovery and volume reduction potential. The results identified that there is significant potential for water recovery, leading to monetary savings through the reuse/recycling of water, potential for storage volume reduction, and potential for higher value post-closure uses.","PeriodicalId":43619,"journal":{"name":"Australian Geomechanics Journal","volume":null,"pages":null},"PeriodicalIF":0.2,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44358074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In a standard deterministic analysis discrete scenarios are considered, and a moderately conservative “characteristic” value is used as a design basis. However, fixed or exact values in a real-world geotechnical site seldom occurs. Deterministic approaches may not explicitly consider the ground uncertainty. Simulations using various probabilities provides for this uncertainty as each parameter input is treated as a random variable within certain measured ranges or ability to evaluate. Monte Carlo (MC) sampling is a traditional technique for generating random numbers to sample from a probability distribution. When low probability events occur, a small number of MC iterations might not sample sufficient quantities of these outcomes for inclusion in the simulation model. Latin Hypercube (LH) sampling uses stratification of the input probability distributions, to overcome the limitations of Monte Carlo sampling. The simulation results show low probability outcomes are included in the sampling for the simulation model. At a high number of simulation iterations both provide similar outputs, but at low simulation iterations the LH is more reliable. However, both the MC and LH sampling suffer from impractical values at low or high probability events when the normal probability density function (PDF) is adopted. The normal PDF is commonly used in statistical modelling. Non-normal PDFs often represent the best fit PDF when a goodness of fit test is carried out. The errors associated with using the common normal PDF are shown with the above-mentioned simulation models. This best fit PDF applies whether simulation models as described above is used or even with simple “what if” sensitivity models in traditional analysis.
{"title":"Managing Geotechnical Uncertainty With Simulation Models: An Introduction","authors":"B. Look","doi":"10.56295/agj5741","DOIUrl":"https://doi.org/10.56295/agj5741","url":null,"abstract":"In a standard deterministic analysis discrete scenarios are considered, and a moderately conservative “characteristic” value is used as a design basis. However, fixed or exact values in a real-world geotechnical site seldom occurs. Deterministic approaches may not explicitly consider the ground uncertainty. Simulations using various probabilities provides for this uncertainty as each parameter input is treated as a random variable within certain measured ranges or ability to evaluate. Monte Carlo (MC) sampling is a traditional technique for generating random numbers to sample from a probability distribution. When low probability events occur, a small number of MC iterations might not sample sufficient quantities of these outcomes for inclusion in the simulation model. Latin Hypercube (LH) sampling uses stratification of the input probability distributions, to overcome the limitations of Monte Carlo sampling. The simulation results show low probability outcomes are included in the sampling for the simulation model. At a high number of simulation iterations both provide similar outputs, but at low simulation iterations the LH is more reliable. However, both the MC and LH sampling suffer from impractical values at low or high probability events when the normal probability density function (PDF) is adopted. The normal PDF is commonly used in statistical modelling. Non-normal PDFs often represent the best fit PDF when a goodness of fit test is carried out. The errors associated with using the common normal PDF are shown with the above-mentioned simulation models. This best fit PDF applies whether simulation models as described above is used or even with simple “what if” sensitivity models in traditional analysis.","PeriodicalId":43619,"journal":{"name":"Australian Geomechanics Journal","volume":null,"pages":null},"PeriodicalIF":0.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49458233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ralph E Cammack, R. Bertuzzi, Adrian P. L. Smith, R. Brehaut
Rock mass parameters are presented for the typical range of rock conditions encountered in the Brisbane CBD and surrounding area. Rock mass units are classified based on lithology, weathering, intact rock strength and degree of disturbance. The rock mass parameters are based on the Author’s combined experience from Brisbane infrastructure projects including the M7 Clem Jones Tunnel, Airport Link and Cross River Rail. The parameters may be useful for design and construction of future ground engineering projects in Brisbane.
{"title":"Rock Mass Parameters For The Brisbane CBD","authors":"Ralph E Cammack, R. Bertuzzi, Adrian P. L. Smith, R. Brehaut","doi":"10.56295/agj5742","DOIUrl":"https://doi.org/10.56295/agj5742","url":null,"abstract":"Rock mass parameters are presented for the typical range of rock conditions encountered in the Brisbane CBD and surrounding area. Rock mass units are classified based on lithology, weathering, intact rock strength and degree of disturbance. The rock mass parameters are based on the Author’s combined experience from Brisbane infrastructure projects including the M7 Clem Jones Tunnel, Airport Link and Cross River Rail. The parameters may be useful for design and construction of future ground engineering projects in Brisbane.","PeriodicalId":43619,"journal":{"name":"Australian Geomechanics Journal","volume":null,"pages":null},"PeriodicalIF":0.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41398663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Metro Tunnel Project is delivering twin nine-kilometre rail tunnels in Melbourne, Australia. In addition to the tunnels, five new underground stations are being constructed. Two of the new stations – State Library and Town Hall – are complex cavern and adit excavations located in Melbourne’s City Centre which will directly connect to the existing City Loop Stations. The State Library station, located predominantly underneath Swanston Street and a busy tram route, was surrounded by a mixture of modern, educational and heritage developments requiring the excavation sequence and primary support to be designed to ensure minimal surface impacts. To simulate the anisotropic rock mass response to the excavation of the State Library Station, FLAC3D numerical analysis was undertaken. The analysis adopted the ubiquitous joint constitutive model approach and was used to assess the performance of the primary lining design and to determine the impacts the predicted ground displacements may have on the surrounding structures.
{"title":"Melbourne Metro Tunnel Project - Numerical Analysis Of Anisotropic Rock Mass For State Library Station","authors":"Ben Coombes, R. Storry, D. Sainsbury","doi":"10.56295/agj5743","DOIUrl":"https://doi.org/10.56295/agj5743","url":null,"abstract":"The Metro Tunnel Project is delivering twin nine-kilometre rail tunnels in Melbourne, Australia. In addition to the tunnels, five new underground stations are being constructed. Two of the new stations – State Library and Town Hall – are complex cavern and adit excavations located in Melbourne’s City Centre which will directly connect to the existing City Loop Stations. The State Library station, located predominantly underneath Swanston Street and a busy tram route, was surrounded by a mixture of modern, educational and heritage developments requiring the excavation sequence and primary support to be designed to ensure minimal surface impacts. To simulate the anisotropic rock mass response to the excavation of the State Library Station, FLAC3D numerical analysis was undertaken. The analysis adopted the ubiquitous joint constitutive model approach and was used to assess the performance of the primary lining design and to determine the impacts the predicted ground displacements may have on the surrounding structures.","PeriodicalId":43619,"journal":{"name":"Australian Geomechanics Journal","volume":null,"pages":null},"PeriodicalIF":0.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42998012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Rozelle Interchange Project (RIC) in Sydney is an underground motorway interchange connecting multiple underground and surface arterial roads as well as the future Western Harbour Tunnel and Beaches Link. RIC completes the WestConnex program of works and is a complex array of approximately 22 km of multiple level tunnels, all constructed in an area 2.5 km long and 1.5 km wide. RIC is located within complex ground conditions that include deep soils, regional faults, structural zones and igneous intrusions. Deep natural soils infilling a valley near Rozelle Bay are mostly recent Holocene alluvial, marginal marine and marine deposits. These soils are interlayered, discontinuous, normally to slightly over consolidated and capped by sand and coarse rockfill from 19th century reclamation. There is a strong contrast in the level of detail between borehole and CPT data. Distilling this to provide a geological and geotechnical model for a project wide interpretive report for designers of multiple structures required a hybrid approach to model presentation. This included providing a simplified graphical model and including details from specific investigations and laboratory testing allowing designers flexibility to adopt appropriate parameters for their specific application. Similarly, the rock structural model evolved from development of structural domains to identification and inclusion of regional geological structures overprinting the structural model. Regional scale thrust faults, corridors of structural complexity and igneous intrusions were identified and refined prior to and throughout the design process. These were considered in the design by modification of excavation sequencing and changes to tunnel support. Tunnel excavations encountered these regional features at the locations predicted and with similar character as those described in the model allowing the safe construction of the tunnels.
{"title":"Characterisation Of Complex Ground Conditions For The Rozelle Interchange Project","authors":"B. Estrada, T. Nash, Andrew de Ambrosis, I. Chan","doi":"10.56295/agj5746","DOIUrl":"https://doi.org/10.56295/agj5746","url":null,"abstract":"The Rozelle Interchange Project (RIC) in Sydney is an underground motorway interchange connecting multiple underground and surface arterial roads as well as the future Western Harbour Tunnel and Beaches Link. RIC completes the WestConnex program of works and is a complex array of approximately 22 km of multiple level tunnels, all constructed in an area 2.5 km long and 1.5 km wide. RIC is located within complex ground conditions that include deep soils, regional faults, structural zones and igneous intrusions. Deep natural soils infilling a valley near Rozelle Bay are mostly recent Holocene alluvial, marginal marine and marine deposits. These soils are interlayered, discontinuous, normally to slightly over consolidated and capped by sand and coarse rockfill from 19th century reclamation. There is a strong contrast in the level of detail between borehole and CPT data. Distilling this to provide a geological and geotechnical model for a project wide interpretive report for designers of multiple structures required a hybrid approach to model presentation. This included providing a simplified graphical model and including details from specific investigations and laboratory testing allowing designers flexibility to adopt appropriate parameters for their specific application. Similarly, the rock structural model evolved from development of structural domains to identification and inclusion of regional geological structures overprinting the structural model. Regional scale thrust faults, corridors of structural complexity and igneous intrusions were identified and refined prior to and throughout the design process. These were considered in the design by modification of excavation sequencing and changes to tunnel support. Tunnel excavations encountered these regional features at the locations predicted and with similar character as those described in the model allowing the safe construction of the tunnels.","PeriodicalId":43619,"journal":{"name":"Australian Geomechanics Journal","volume":null,"pages":null},"PeriodicalIF":0.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45890868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bernard Shen, Strath Clarke, A. Rogan, P. McCormack
The new Roma Street underground railway station in Brisbane is being constructed as part of Cross River Rail’s Tunnel, Stations and Development (TSD) package. The joint venture of CPB Contractors, BAM International Australia, Ghella and UGL (CBGU JV) is building the 5.9km long twin tunnels from the Southern Tunnel Portal near Dutton Park station, beneath the Brisbane River and CBD to the Northern Tunnel Portal in Spring Hill. The Cross River Rail project includes excavation and construction of four new underground stations. Roma Street station comprises a 280m long cavern, five smaller connecting tunnels (adits) and three shafts. The station cavern has an excavated span of up to 24.4m with approximately 15m rock cover. It has been excavated within the Neranleigh-Fernvale Group (NFG) rock mass, which comprises weakly metamorphosed sandstone (meta-greywacke and arenite), phyllite and subordinate quartzite and meta-basalt. The station lies within the regional Normanby Fault Zone, characterised by a major fault up to 20m wide comprising a combination of intact rock, rock breccia and clay gouge. The fault zone encountered during the station cavern excavation required heavier primary support and localised foundation treatment. The initial primary (temporary) support of the cavern and adits comprised rock bolts, cable bolts and a thin synthetic fibre-reinforced shotcrete lining. In some areas a passive shotcrete arch lining was required. Overlying piled footings from an existing busway overpass structure were within a metre of the adits’ excavated profile which necessitated a complex load transfer structure at the surface and verification of pile toe levels during tunnel construction. The cavern permanent lining typically comprises steel fibre-reinforced concrete in the crown, bar reinforced concrete for the sidewalls, and bar and steel fibre-reinforced concrete invert slabs. Bar reinforcement is used in the cavern crown where it intersects the adits. Ground loads for the permanent structure had to consider the influence of future developments. This paper presents some of the challenges of the primary support and permanent lining design of the station cavern and adits. It summarises the as-encountered ground conditions, aspects of the primary support and permanent lining design that were geotechnically challenging and the solutions developed to meet the project requirements.
{"title":"Design And Construction Of Roma Street Station Cavern, Cross River Rail, Brisbane","authors":"Bernard Shen, Strath Clarke, A. Rogan, P. McCormack","doi":"10.56295/agj5744","DOIUrl":"https://doi.org/10.56295/agj5744","url":null,"abstract":"The new Roma Street underground railway station in Brisbane is being constructed as part of Cross River Rail’s Tunnel, Stations and Development (TSD) package. The joint venture of CPB Contractors, BAM International Australia, Ghella and UGL (CBGU JV) is building the 5.9km long twin tunnels from the Southern Tunnel Portal near Dutton Park station, beneath the Brisbane River and CBD to the Northern Tunnel Portal in Spring Hill. The Cross River Rail project includes excavation and construction of four new underground stations. Roma Street station comprises a 280m long cavern, five smaller connecting tunnels (adits) and three shafts. The station cavern has an excavated span of up to 24.4m with approximately 15m rock cover. It has been excavated within the Neranleigh-Fernvale Group (NFG) rock mass, which comprises weakly metamorphosed sandstone (meta-greywacke and arenite), phyllite and subordinate quartzite and meta-basalt. The station lies within the regional Normanby Fault Zone, characterised by a major fault up to 20m wide comprising a combination of intact rock, rock breccia and clay gouge. The fault zone encountered during the station cavern excavation required heavier primary support and localised foundation treatment. The initial primary (temporary) support of the cavern and adits comprised rock bolts, cable bolts and a thin synthetic fibre-reinforced shotcrete lining. In some areas a passive shotcrete arch lining was required. Overlying piled footings from an existing busway overpass structure were within a metre of the adits’ excavated profile which necessitated a complex load transfer structure at the surface and verification of pile toe levels during tunnel construction. The cavern permanent lining typically comprises steel fibre-reinforced concrete in the crown, bar reinforced concrete for the sidewalls, and bar and steel fibre-reinforced concrete invert slabs. Bar reinforcement is used in the cavern crown where it intersects the adits. Ground loads for the permanent structure had to consider the influence of future developments. This paper presents some of the challenges of the primary support and permanent lining design of the station cavern and adits. It summarises the as-encountered ground conditions, aspects of the primary support and permanent lining design that were geotechnically challenging and the solutions developed to meet the project requirements.","PeriodicalId":43619,"journal":{"name":"Australian Geomechanics Journal","volume":null,"pages":null},"PeriodicalIF":0.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46838532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Poatina Power Station Cavern was designed with a focus on the newly emerging rock mechanics theory and principles that were rapidly developing during the 1950’s and 60’s. This included measurement of the in-situ rock mass stress condition and photo-elastic analysis of the induced stress around the planned underground openings. These studies led to the adoption of many ‘firsts’ in rock mechanics that included a trapezoidal roof shape, installation of stress relieving slots and fully encapsulated grouted rebar bolts. Based on historical documentation of the construction of the cavern, a three- dimensional numerical model of the cavern construction sequence has been developed. The model is able to provide an accurate match to the observed and monitored ground conditions during construction that includes observed failure modes and instrumentation data. Based on the calibrated model outcomes, Hydro Tasmania was able to undertake a more informed review of the risks associated with the current and future ground support capacity and were able to reliably assess rehabilitation requirements for the cavern support system.
{"title":"Geotechnical Considerations Associated With The Poatina Power Station Cavern","authors":"D. Sainsbury, K. Stacey, B. Sainsbury, P. Hills","doi":"10.56295/agj5745","DOIUrl":"https://doi.org/10.56295/agj5745","url":null,"abstract":"The Poatina Power Station Cavern was designed with a focus on the newly emerging rock mechanics theory and principles that were rapidly developing during the 1950’s and 60’s. This included measurement of the in-situ rock mass stress condition and photo-elastic analysis of the induced stress around the planned underground openings. These studies led to the adoption of many ‘firsts’ in rock mechanics that included a trapezoidal roof shape, installation of stress relieving slots and fully encapsulated grouted rebar bolts. Based on historical documentation of the construction of the cavern, a three- dimensional numerical model of the cavern construction sequence has been developed. The model is able to provide an accurate match to the observed and monitored ground conditions during construction that includes observed failure modes and instrumentation data. Based on the calibrated model outcomes, Hydro Tasmania was able to undertake a more informed review of the risks associated with the current and future ground support capacity and were able to reliably assess rehabilitation requirements for the cavern support system.","PeriodicalId":43619,"journal":{"name":"Australian Geomechanics Journal","volume":null,"pages":null},"PeriodicalIF":0.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43128584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jonathon R Griffin, Z. Rice, R. Clayton, Ben Harvey, C. Leek, M. Bondietti, Ross Keeley, G. Cocks
Bitumen emulsion stabilisation of locally available Tamala Limestone was widely used by State and Local Governments from the mid-1960s through the late-1990s, however its use has declined in recent years. This paper aims to substantiate its benefits as a viable alternative material for use on heavily trafficked roads. The benefits provided through stabilisation of crushed limestone with bitumen emulsion include improved workability, reduced ravelling under construction traffic, lower moisture susceptibility and enhanced mechanical properties. Case studies are presented that show that satisfactory performance has been observed where Bitumen Stabilised Limestone (BSL) is used as a basecourse under heavily trafficked roads. The paper provides a construction methodology and discusses barriers and future opportunities. Two structural design approaches are presented for the use of BSL under sprayed seals and thin asphalt surfacings.
{"title":"Use of Bitumen Stabilised Limestone in Western Australian Road Pavements","authors":"Jonathon R Griffin, Z. Rice, R. Clayton, Ben Harvey, C. Leek, M. Bondietti, Ross Keeley, G. Cocks","doi":"10.56295/agj5732","DOIUrl":"https://doi.org/10.56295/agj5732","url":null,"abstract":"Bitumen emulsion stabilisation of locally available Tamala Limestone was widely used by State and Local Governments from the mid-1960s through the late-1990s, however its use has declined in recent years. This paper aims to substantiate its benefits as a viable alternative material for use on heavily trafficked roads. The benefits provided through stabilisation of crushed limestone with bitumen emulsion include improved workability, reduced ravelling under construction traffic, lower moisture susceptibility and enhanced mechanical properties. Case studies are presented that show that satisfactory performance has been observed where Bitumen Stabilised Limestone (BSL) is used as a basecourse under heavily trafficked roads. The paper provides a construction methodology and discusses barriers and future opportunities. Two structural design approaches are presented for the use of BSL under sprayed seals and thin asphalt surfacings.","PeriodicalId":43619,"journal":{"name":"Australian Geomechanics Journal","volume":null,"pages":null},"PeriodicalIF":0.2,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48913000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Princes Highway along Bulli Pass is a narrow, heavily trafficked two lane section of the Princes Highway that traverses steep slopes on a grade of 9H:1V on the Illawarra Escarpment, about 11 km north of Wollongong, and 75 km south of Sydney in New South Wales (NSW), Australia. It is an important arterial road for the northern suburbs of Wollongong, connecting Mt Ousley Road (M1 Princes Motorway) at the crest of the escarpment to the suburb of Thirroul on the coastal plain at the base of the escarpment. Bulli Pass has a long history of landslide and rockfall events, some of which were reported as early as 1890. One of the most significant of these events occurred on 17 August 1998 during a 1 in 100 year rainfall event. The 1998 landslide event comprised approximately 38 debris flows and slides and numerous rockfalls which partially inundated a number of cars and trapped about 15 cars on the pass. More recently, in early 2015, a small rockfall penetrated the windscreen of a car travelling up the pass. Transport for New South Wales (TfNSW) commissioned an investigation into slope instability hazards affecting the road in late 2011. This was followed in 2015 by a Risk Mitigation Options study and the detailed design of risk mitigation works in 2016. This paper provides an overview of the methods used to investigate hazards and assess risk at the site over a five year period. This has included research into the landslide history, geomorphological mapping, acquisition and review of airborne laser scanning (ALS) data, review of rainfall data and the development of a landslide volume frequency model. The development of this model allowed hazards to be readily communicated and risks to be assessed. The actual design and construction of the Shallow Landslide Barriers and the Debris Flow Barriers that followed on from these assessments will be discussed in a subsequent companion paper.
{"title":"Bulli Pass Landslide Risk Management Part 1 - Hazard Assessment","authors":"Andrew Hunter, P. Flentje, Alan Moon","doi":"10.56295/agj5735","DOIUrl":"https://doi.org/10.56295/agj5735","url":null,"abstract":"The Princes Highway along Bulli Pass is a narrow, heavily trafficked two lane section of the Princes Highway that traverses steep slopes on a grade of 9H:1V on the Illawarra Escarpment, about 11 km north of Wollongong, and 75 km south of Sydney in New South Wales (NSW), Australia. It is an important arterial road for the northern suburbs of Wollongong, connecting Mt Ousley Road (M1 Princes Motorway) at the crest of the escarpment to the suburb of Thirroul on the coastal plain at the base of the escarpment. Bulli Pass has a long history of landslide and rockfall events, some of which were reported as early as 1890. One of the most significant of these events occurred on 17 August 1998 during a 1 in 100 year rainfall event. The 1998 landslide event comprised approximately 38 debris flows and slides and numerous rockfalls which partially inundated a number of cars and trapped about 15 cars on the pass. More recently, in early 2015, a small rockfall penetrated the windscreen of a car travelling up the pass. Transport for New South Wales (TfNSW) commissioned an investigation into slope instability hazards affecting the road in late 2011. This was followed in 2015 by a Risk Mitigation Options study and the detailed design of risk mitigation works in 2016. This paper provides an overview of the methods used to investigate hazards and assess risk at the site over a five year period. This has included research into the landslide history, geomorphological mapping, acquisition and review of airborne laser scanning (ALS) data, review of rainfall data and the development of a landslide volume frequency model. The development of this model allowed hazards to be readily communicated and risks to be assessed. The actual design and construction of the Shallow Landslide Barriers and the Debris Flow Barriers that followed on from these assessments will be discussed in a subsequent companion paper.","PeriodicalId":43619,"journal":{"name":"Australian Geomechanics Journal","volume":null,"pages":null},"PeriodicalIF":0.2,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46205709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Thornthwaite Moisture Index (TMI) is an established climate parameter for geotechnical engineers to categorise a site and enable estimation of seasonal ground movements associated with soil moisture changes. TMI assessment and mapping for the Northern Territory are presented, using the TMI calculation method commonly used for similar recent studies elsewhere in Australia. The assessment included the analysis of 17 sites within the Northern Territory and one site in Queensland which has enabled development of Climate Zone classifications. Climate data was obtained from the Australian Bureau of Meteorology to calculate the TMI on a ‘year by year’ basis over a target period of 29 years (1990 to 2019). Related work in Queensland (Fox 2002) and Western Australia (Hu et al, 2016) has guided the development of the Northern Territory Climate Zone Map. Further work is required to characterise the soil moisture behaviour in arid zones. A general lack of guidance in AS2870 (2011) for arid areas, including much of the Northern Territory, could be addressed with further research and development.
Thornthwaite湿度指数（TMI）是岩土工程师对场地进行分类并能够估计与土壤湿度变化相关的季节性地面运动的既定气候参数。采用澳大利亚其他地方最近进行的类似研究中常用的TMI计算方法，对北领地的TMI进行了评估和绘制。评估包括对北领地的17个地点和昆士兰的一个地点的分析，这使得气候区分类得以发展。气候数据是从澳大利亚气象局获得的，用于在29年（1990年至2019年）的目标期内“逐年”计算TMI。昆士兰（Fox 2002）和西澳大利亚（Hu et al，2016）的相关工作指导了北领地气候带图的绘制。需要进一步的工作来表征干旱地区的土壤水分行为。AS2870（2011）中普遍缺乏对干旱地区（包括北领地大部分地区）的指导，可以通过进一步的研究和开发来解决。
{"title":"Thornthwaite Moisture Index and Climate Zones in the Northern Territory","authors":"Stephen Jackson","doi":"10.56295/agj5733","DOIUrl":"https://doi.org/10.56295/agj5733","url":null,"abstract":"The Thornthwaite Moisture Index (TMI) is an established climate parameter for geotechnical engineers to categorise a site and enable estimation of seasonal ground movements associated with soil moisture changes. TMI assessment and mapping for the Northern Territory are presented, using the TMI calculation method commonly used for similar recent studies elsewhere in Australia. The assessment included the analysis of 17 sites within the Northern Territory and one site in Queensland which has enabled development of Climate Zone classifications. Climate data was obtained from the Australian Bureau of Meteorology to calculate the TMI on a ‘year by year’ basis over a target period of 29 years (1990 to 2019). Related work in Queensland (Fox 2002) and Western Australia (Hu et al, 2016) has guided the development of the Northern Territory Climate Zone Map. Further work is required to characterise the soil moisture behaviour in arid zones. A general lack of guidance in AS2870 (2011) for arid areas, including much of the Northern Territory, could be addressed with further research and development.","PeriodicalId":43619,"journal":{"name":"Australian Geomechanics Journal","volume":null,"pages":null},"PeriodicalIF":0.2,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41869873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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