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
- Full Text: false
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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.
Liberating soil data for profitable agriculture and catchment health in the Corangamite region, Australia
- Authors: Dahlhaus, Peter , Nicholson, Cameron , Ryan, Bret , MacLeod, Andrew , Milne, Robert
- Date: 2018
- Type: Text , Journal article
- Relation: New Zealand Journal of Agricultural Research Vol. 61, no. 3 (2018), p. 333-339
- Full Text: false
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- Description: Detailed soil data has been collected in the Corangamite region of south-east Australia for over 80 years, as a testament to the productive value of the region’s agricultural soils. Soil science over that period has resulted in soil maps, soil investigation sites and archival materials that provide valuable baseline data for the analysis of trends over time. This legacy data has been brought together with contemporary data in the award-winning Soil Health Knowledge Base, an Internet portal based on spatial data infrastructure that interoperably federates data (open data, research data, industry data, sensor data, legacy data, crowdsourced data … any available data). The portal provides the best available data sources for research and consulting, as well as functions for both the private reward and the public good. The ultimate intent is to provide timely decision support for agricultural enterprises and catchment managers to protect, enhance and restore soil health.
Stable isotopes as indicators of water and salinity sources in a southeast Australian coastal wetland: Identifying relict marine water, and implications for future change
- Authors: Currell, Matthew , Dahlhaus, Peter , Ii, Hiroyuki
- Date: 2015
- Type: Text , Journal article
- Relation: Hydrogeology Journal Vol. 23, no. 2 (2015), p. 235-248
- Full Text: false
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- Description: The Lake Connewarre Complex is an internationally protected wetland in southeast Australia, undergoing increasing environmental change due to urbanisation. Stable isotopes of water (
Groundwater-level response to land-use change and the implications for salinity management in the West Moorabool River catchment, Victoria, Australia
- Authors: Dahlhaus, Peter , Evans, Timothy , Nathan, Erica , Cox, Jim , Simmons, Craig
- Date: 2010
- Type: Text , Journal article
- Relation: Hydrogeology Journal Vol. 18, no. 7 (2010), p. 1611-1623
- Full Text: false
- Reviewed:
- Description: The connection between the removal of native vegetation, rising water tables and increasing stream salinity has been established for many catchments across Australia. However, the West Moorabool River in south west Victoria is an example of a catchment where there has been little discernable effect on groundwater levels following land clearing. Over the past 150 years, a significant portion of the catchment has been cleared of dense forest for agricultural development. Historic standing water-level records from 1870-1871 and 1881 are compared with contemporary measurements (1970s to 2007) recorded in the government bore databases. The data show that the earliest recorded groundwater levels are well within the seasonal range of values observed today. By integrating geology and hydrogeology with historical observations of groundwater levels, climate data and land use, the contemporary field observations of stream salinity are linked to the changed water use and shift in rainfall. In contrast to the normally accepted axiom, reafforestation as a management strategy to mitigate the rising salinity in the West Moorabool River catchment would seem inappropriate. © 2010 Springer-Verlag.
- Description: The connection between the removal of native vegetation, rising water tables and increasing stream salinity has been established for many catchments across Australia. However, the West Moorabool River in south west Victoria is an example of a catchment where there has been little discernable effect on groundwater levels following land clearing. Over the past 150 years, a significant portion of the catchment has been cleared of dense forest for agricultural development. Historic standing water-level records from 1870-1871 and 1881 are compared with contemporary measurements (1970s to 2007) recorded in the government bore databases. The data show that the earliest recorded groundwater levels are well within the seasonal range of values observed today. By integrating geology and hydrogeology with historical observations of groundwater levels, climate data and land use, the contemporary field observations of stream salinity are linked to the changed water use and shift in rainfall. In contrast to the normally accepted axiom, reafforestation as a management strategy to mitigate the rising salinity in the West Moorabool River catchment would seem inappropriate. © 2010 Springer-Verlag.
Beyond hydrogeologic evidence : Challenging the current assumptions about salinity processes in the Corangamite region, Australia
- Authors: Dahlhaus, Peter , Cox, Jim , Simmons, Craig , Smitt, C. M.
- Date: 2008
- Type: Text , Journal article
- Relation: Hydrogeology Journal Vol. 16, no. 7 (2008), p. 1283-1298
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- Description: In keeping with the standard scientific methods, investigations of salinity processes focus on the collection and interpretation of contemporary scientific data. However, using multiple lines of evidence from non-hydrogeologic sources such as geomorphic, archaeological and historical records can substantially add value to the scientific investigations. By using such evidence, the validity of the assumptions about salinity processes in Australian landscapes is challenged, especially the assumption that the clearing of native vegetation has resulted in rising saline groundwater in all landscapes. In the Corangamite region of south-west Victoria, salinity has been an episodic feature of the landscapes throughout the Quaternary and was present at the time of the Aboriginal inhabitants and the first pastoral settlement by Europeans. Although surface-water salinity has increased in some waterways and the area of salinised land has expanded in some landscapes, there is no recorded evidence found which supports significant rises in groundwater following widespread land-use change. In many areas, salinity is an inherent component of the region's landscapes, and sustains world-class environmental assets that require appropriate salinity levels for their ecological health. Managing salinity requires understanding the specific salinity processes in each landscape. © Springer-Verlag 2008.