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40905 Civil Engineering
2Finite element analysis
10913 Mechanical Engineering
1Arbitrary Lagrangian Eulerian
1Bearing resistance
1Cavity expansion
1Cone Penetration Test
1Cone penetration test
1Extended finite element method
1Failure surface
1Finite-element analysis
1Footing
1Geothermal energy
1Ground source energy
1Heat conduction
1Intermediate geotechnical material
1Over-consolidated sand
1Probabilistic methods

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Unconfined Expansion Test (UET) for measuring the tensile strength of organic soft rock

- Tang, Zhan, Tolooiyan, Ali, Mackay, Rae

**Authors:**Tang, Zhan , Tolooiyan, Ali , Mackay, Rae**Date:**2017**Type:**Text , Journal article**Relation:**Computers and Geotechnics Vol. 82, no. (2017), p. 54-66**Full Text:**false**Reviewed:****Description:**An Unconfined Expansion Test (UET) is presented for measuring the tensile strength of Intermediate Geotechnical Materials (IGM). The test is performed by generating radial cavity expansion inside a cylindrical specimen. Pressure redistributes evenly around the cavity wall during the test. Tensile failure initiates on the weakest plane around the cavity and radially propagates across the specimen. By also capturing the stress-strain relationship and deriving the shear modulus, a UET is also capable of measuring the tensile elastic modulus of the material. An eXtended Finite Element Method (XFEM) analysis using Abaqus/Standard has been carried out to verify the UET test results. © 2016 Elsevier Ltd

- Tolooiyan, Ali, Gavin, Kenneth

**Authors:**Tolooiyan, Ali , Gavin, Kenneth**Date:**2011**Type:**Text , Journal article**Relation:**Computers and Geotechnics Vol. 38, no. 4 (2011), p. 482-490**Full Text:**false**Reviewed:****Description:**The paper considers two techniques to model the Cone Penetration Test (CPT) end resistance, qc in a dense sand deposit using commercial finite element programmes. In the first approach, Plaxis was used to perform spherical cavity expansion analyses at multiple depths. Two soil models, namely; the Mohr-Coulomb (MC) and Hardening Soil (HS) models were utilized. When calibrated using simple laboratory element tests, the HS model was found to provide good estimates of qc. However, at shallow depths, where the over-consolidation ratio of the sand was highest, the relatively large horizontal stresses developed prevented the full development of the failure zone resulting in under-estimation of the qc value. The second approach involved direct simulation of cone penetration using a large-strain analysis implemented in Abaqus/Explicit. The Arbitrary Lagrangian Eulerian (ALE) technique was used to prevent excessive mesh deformation. Although the Druker-Prager soil model used was not as sophisticated as the HS model, excellent agreement was achieved between the predicted and measured qc profiles.

Numerical and finite element analysis of heat transfer in a closed loop geothermal system

- Hemmingway, Phil, Tolooiyan, Ali

**Authors:**Hemmingway, Phil , Tolooiyan, Ali**Date:**2014**Type:**Text , Journal article**Relation:**International Journal of Green Energy Vol. 11, no. 2 (2014), p. 206-223**Full Text:**false**Reviewed:****Description:**Analysis of the thermal regime created by a geothermal borehole heat exchanger is performed using a closed form radial heat flow equation, a geothermal borehole heat exchanger design tool, and a finite-element model. Climatic, heat exchanger construction, and building load data are entered into the heat exchanger design tool to create a theoretical model along with thermal parameters from a number of geological formations. Output data from the design tool model are used in conjunction with the closed form radial heat flow equation to calculate the predicted temperature with respect to time and distance from the heat exchanger for the modeled ground formations. The output data from the design tool are also used to create a number of finite-element method models against which the predictions calculated using the closed form radial heat flow equation can be compared. A good correlation between the temperatures predicted by the finite-element models and the closed form equation calculations is observed. However, when used within its recommended limiting conditions, the closed form equation is shown to slightly underestimate the temperature of the ground when compared with the finite-element model predictions. The limiting conditions associated with the closed form equation are discussed in the context of the output from the finite-element method models.

An investigation of correlation factors linking footing resistance on sand with cone penetration test results

- Gavin, Kenneth, Tolooiyan, Ali

**Authors:**Gavin, Kenneth , Tolooiyan, Ali**Date:**2012**Type:**Text , Journal article**Relation:**Computers and Geotechnics Vol. 46, no. (2012), p. 84-92**Full Text:****Reviewed:****Description:**Significant research effort has led to improvements in our ability to estimate the ultimate bearing resistance of footings in sand. These techniques often estimate the footing resistance at relatively large displacements, typically 10% of the footing width, q b0.1. Cone Penetration Test (CPT) design methods typically link q b0.1 and q c through a constant reduction factor, α. A range of α factors for shallow footings have been proposed, some methods suggest that α is constant and while others that it varies with footing width and depth (or stress level). There is a dearth of field data with which to compare these correlation factors, in particular where foundation width and depth have been varied in the same ground conditions. For this reason finite element analyses have proven to be a useful tool for performing the parametric studies required to asses factors controlling α. This paper describes the results of numerical analyses performed to investigate α factors for soil profiles which were calibrated using the results of the CPT tests performed at a dense sand test-bed site. The numerical model was first used to perform parametric analyses to consider the effect of footing width, B and footing depth, D on the α factor mobilised in dense Blessington sand. In order to assess the effects of relative density, footing tests in a range of natural sands with variable in situ densities were modeled. The results of the finite element analyses suggest that a direct correlation between q b0.1 and q c can be established at a given test site which is independent of footing width and depth and is relatively weakly dependent on the sands relative density if the zone of influence of the foundation considered is large enough. © 2012 Elsevier Ltd.

**Authors:**Gavin, Kenneth , Tolooiyan, Ali**Date:**2012**Type:**Text , Journal article**Relation:**Computers and Geotechnics Vol. 46, no. (2012), p. 84-92**Full Text:****Reviewed:****Description:**Significant research effort has led to improvements in our ability to estimate the ultimate bearing resistance of footings in sand. These techniques often estimate the footing resistance at relatively large displacements, typically 10% of the footing width, q b0.1. Cone Penetration Test (CPT) design methods typically link q b0.1 and q c through a constant reduction factor, α. A range of α factors for shallow footings have been proposed, some methods suggest that α is constant and while others that it varies with footing width and depth (or stress level). There is a dearth of field data with which to compare these correlation factors, in particular where foundation width and depth have been varied in the same ground conditions. For this reason finite element analyses have proven to be a useful tool for performing the parametric studies required to asses factors controlling α. This paper describes the results of numerical analyses performed to investigate α factors for soil profiles which were calibrated using the results of the CPT tests performed at a dense sand test-bed site. The numerical model was first used to perform parametric analyses to consider the effect of footing width, B and footing depth, D on the α factor mobilised in dense Blessington sand. In order to assess the effects of relative density, footing tests in a range of natural sands with variable in situ densities were modeled. The results of the finite element analyses suggest that a direct correlation between q b0.1 and q c can be established at a given test site which is independent of footing width and depth and is relatively weakly dependent on the sands relative density if the zone of influence of the foundation considered is large enough. © 2012 Elsevier Ltd.

Probabilistic investigation of RFEM topologies for slope stability analysis

- Dyson, Ashley, Tolooiyan, Ali

**Authors:**Dyson, Ashley , Tolooiyan, Ali**Date:**2019**Type:**Text , Journal article**Relation:**Computers and Geotechnics Vol. 114, no. (2019), p. 1-15**Full Text:**false**Reviewed:****Description:**The Random Finite Element Method (RFEM) is an increasingly popular tool in geotechnical engineering, especially for analysis of spatial variation and uncertainty in slope stability. Although the method has gained prominence in recent years, topological effects of strong and weak zones and the impact of their locations remain largely unknown. Although numerous potential slip surface realisations can be generated with RFEM, probabilistic failure statistics are often governed by several representative slip surfaces (RSS). In this research, random field similarity methods and clustering techniques are coupled with RFEM slope stability simulation to determine the impact of shear strength spatial patterns on slope failure mechanisms and safety factors. Regions of significance are highlighted within a case study of a Victorian open-cutbrown coal mine, with particular attention given to the effects on the slope failure surface as well the factor of safety. Results are presented of Factor of Safety distributions when particular slip surfaces and clustering constraints are imposed, providing further understanding of the impacts of shear strength characteristics on probabilistic simulation results.

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