List of Titles

Effect of rock mass permeability and rock fracture leak-off coefficient on the pore water pressure distribution in a fractured slope

- Shaghaghi, Tahereh, Ghadrdan, Mohsen, Tolooiyan, Ali

Authors: Shaghaghi, Tahereh , Ghadrdan, Mohsen , Tolooiyan, Ali
Date: 2020
Type: Text , Journal article
Relation: Simulation Modelling Practice and Theory Vol. 105, no. (2020), p. 1-13
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Description: The reliable assessment of the stability of saturated slopes becomes a challenging task when slopes are consisting of discontinuous materials and containing pre-existing joints. The discontinuous nature of the slopes' material could increase the overall permeability of the slope, while existing joints facilitate groundwater leakage through the joint surfaces into the slope which subsequently exerts a major impact on deformation and the effective stress distribution. This paper aims to study the Pore Water Pressure (PWP) distribution changes in a saturated fractured slope by conducting advanced coupled pore fluid diffusion and stress-strain analyses, while investigating the sensitivity of results to the variation of permeability and leakage properties of fracture surfaces. Modelling of jointed slopes is carried out using the e-Xtended Finite Element Method (XFEM) in conjunction with the Finite Element Method (FEM). In this study, the fluid flow inside the joint is the major focus at which the constitutive response of the fluid inside the joint considers both tangential and normal flows. To demonstrate the state-of-the-art simulation technique presented in this paper, simulation of a fractured slope at the second largest open-pit mine in Australia is performed as a case study. This study shows the effect of a variable leak-off coefficient of the joint surfaces and the permeability magnitude on the pore water pressure distribution.
Description: This research has been supported financially by the Earth Resources Regulation of the Victorian State Government Department of Economic Development, Jobs, Transport and Resources. The first and second authors are funded by the GHERG LV Batter Stability Project Scholarship and Faculty Tuition Scholarship of Federation University Australia.

Investigation of an Australian soft rock permeability variation

- Tolooiyan, Ali, Dyson, Ashley, Karami, Mojtaba, Shaghaghi, Tahereh, Ghadrdan, Mohsen

Authors: Tolooiyan, Ali , Dyson, Ashley , Karami, Mojtaba , Shaghaghi, Tahereh , Ghadrdan, Mohsen
Date: 2020
Type: Text , Journal article
Relation: Bulletin of Engineering Geology and the Environment Vol. 79, no. 6 (2020), p. 3087-3104
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Description: In this study, permeabilities of Victorian Brown Coal (VBC) as an Australian soft rock are determined for a range of depths of a continuous coal seam located at the batter crest of the Yallourn brown coal open-cut mine in Victoria, Australia, by implementing a Lugeon packer testing procedure. Permeability values are determined both analytically and by numerical simulation and are compared with laboratory test results. Field testing resulted in permeabilities several orders of magnitude higher than laboratory testing, suggesting the existence of fractures common to lignite structures on a greater scale than can be observed in the laboratory. The variation of depth-based field and laboratory permeabilities is discussed, as well as the necessary conditions required for the numerical modelling of packer testing within VBC. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
Description: Department of Economic Development, Jobs, Transport and Resources, DSDBI The second and third authors are funded by the Australian Government Research Training Program (RTP) and the GHERG scholarship programme.

FEM and XFEM approaches to Investigate the Hydromechanical Interactions within a jointed soft-rock slope

- Shaghaghi, Tahereh

Authors: Shaghaghi, Tahereh
Date: 2020
Type: Text , Thesis , PhD
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Description: One of the most significant challenges of open-cut mining is to provide stability for the excavated slopes. Unrealistic predictions of the slopes’ behaviour during and after mining operations can lead to the failure of slopes, and this may pose a threat to human lives, the economy, and the environment. By excavating soft rock masses in open-cut mines, pre-existing joints can open and new joints can form behind excavated slopes. This phenomenon is due to the geotechnical character of the materials and stress relief movements of the excavated slopes. The stability of slopes in the rock masses is significantly influenced by the existence of discontinuities such as joints. The water flows in the opened joints can change the pore water pressure distribution in the slopes. The interaction between the joints and the water may impose different loading scenarios on the open-cut mines and put the safety of mining operations at risk. The analysis of slope stability can become more complicated because of the presence of water, discontinuities, and their interaction within the slopes in open-cut mines. This study investigates the hydromechanical interactions in the saturated jointed slopes due to pore water pressure changes. The second-largest open-cut mine in Australia, the Yallourn brown coal open-cut mine located in Victoria, was chosen as the case study for this research. In this study, several coupled pore fluid diffusion and stress-strain analyses are conducted using the extended finite element method (XFEM) in conjunction with the finite element method (FEM). This study firstly examines a joint aperture and pore water pressure changes of the excavated jointed slope due to installing a drainage system and backfilling in front of the slope. Secondly, a series of sensitivity analyses are carried out on the pore water pressure distribution changes to the variation of the permeability magnitude of the material and leakage properties of the joint surfaces. Finally, to control the pore water pressure of the saturated jointed slope, a series of drainage systems is designed. The arrangement and length of the drains are optimised by conducting a series of sensitivity analyses on the leakage properties of the joint and the permeability of the soft rock.
Description: Doctor of Philosophy

A solution to the inverse pulsed eddy current problem enabling 3D profiling

- Ulapane, Nalika, Nguyen, Linh, Miro, Jaime Valls, Dissanayake, Gamini

Authors: Ulapane, Nalika , Nguyen, Linh , Miro, Jaime Valls , Dissanayake, Gamini
Date: 2017
Type: Text , Conference proceedings
Relation: 2018 13th IEEE Conference on Industrial Electronics and Applications (ICIEA); Wuhan, China; 31 May 2018 - 02 June 2018 p. 1267-1272
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Description: When a Pulsed Eddy Current (PEC) sensor assesses a metallic surface (i.e., a wall of finite thickness), the inverse problem involves quantification of the geometry and material properties of the wall. Once a PEC sensor is calibrated for a particular material, and the material under test happens to be considerably homogeneous, the inverse problem reduces to quantification of geometry alone. The state-of-the-art in the industry produces a quantification of this geometry only in the form of average wall thickness remaining underneath the sensor footprint, and produces a 2.5D map containing wall thickness information. Therefore, this paper contributes by proposing a solution that can jointly estimate the remaining wall thickness as well as lift-off (i.e., offset from the sensor to the surface of healthy material), in order to advance PEC sensing outputs by enabling estimation of wall condition in 3D. Since PEC maps are used as inputs for stress calculation and remaining life prediction of certain infrastructure like critical pipes, 3D profiles may become a richer form of input for such applications than 2.5D maps. Since PEC sensing is commonly used to assess ferromagnetic materials, this paper focuses on similar materials as well. The solution is demonstrated in simulation alone and future work should focus on experimental implementations.

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