Modification of the properties of salt affected soils using electrochemical treatments
- Jayasekera, Samudra, Hall, Stephen
- Authors: Jayasekera, Samudra , Hall, Stephen
- Date: 2007
- Type: Text , Journal article
- Relation: Geotechnical and Geological Engineering Vol. 25, no. 1 (2007), p. 1-10
- Full Text:
- Reviewed:
- Description: In this project, an in situ soil treatment technique using the principles of electrokinetics was tested using laboratory experimental models in order to identify the potential of this approach in modifying and reinstating the physical properties of salt affected soils. Experiments were conducted in the laboratory using saline-sodic soils collected from two salt affected regions in central Victoria, Australia. Soil specimens were compacted in glass tanks to reproduce in situ density and in situ water content. Using mild steel electrodes inserted into the soil, a direct current was passed through the soil under a constant potential gradient of 0.5 V/cm for a period of 14 days. In separate experiments, distilled water and a saturated lime solution were introduced to the soil via the anode over this experimental period. It was observed that the soil dispersion, otherwise known as soil sodicity (measured as ESP - Exchangeable Sodium Percentage and SAR - Sodium Absorption Ratio) decreased by up to 90% in most regions of the soil between the electrodes. The compressive strength of the soil increased in excess of 100% with electrokinetic treatment alone while the lime-enhanced electrokinetic treatment led to an almost 200% strength increase. The liquid limit and plastic limit of the soil increased causing the plasticity index to decrease, indicating increases in soil compressive strength and workability. These results indicate the potential of this technique for improving the physical properties of salt affected soils both effectively and efficiently, and in particular gives hope for the remediation of salt affected land for infrastructure management and development. © Springer Science+Business Media, Inc. 2006.
- Description: C1
- Description: 2003004772
- Authors: Jayasekera, Samudra , Hall, Stephen
- Date: 2007
- Type: Text , Journal article
- Relation: Geotechnical and Geological Engineering Vol. 25, no. 1 (2007), p. 1-10
- Full Text:
- Reviewed:
- Description: In this project, an in situ soil treatment technique using the principles of electrokinetics was tested using laboratory experimental models in order to identify the potential of this approach in modifying and reinstating the physical properties of salt affected soils. Experiments were conducted in the laboratory using saline-sodic soils collected from two salt affected regions in central Victoria, Australia. Soil specimens were compacted in glass tanks to reproduce in situ density and in situ water content. Using mild steel electrodes inserted into the soil, a direct current was passed through the soil under a constant potential gradient of 0.5 V/cm for a period of 14 days. In separate experiments, distilled water and a saturated lime solution were introduced to the soil via the anode over this experimental period. It was observed that the soil dispersion, otherwise known as soil sodicity (measured as ESP - Exchangeable Sodium Percentage and SAR - Sodium Absorption Ratio) decreased by up to 90% in most regions of the soil between the electrodes. The compressive strength of the soil increased in excess of 100% with electrokinetic treatment alone while the lime-enhanced electrokinetic treatment led to an almost 200% strength increase. The liquid limit and plastic limit of the soil increased causing the plasticity index to decrease, indicating increases in soil compressive strength and workability. These results indicate the potential of this technique for improving the physical properties of salt affected soils both effectively and efficiently, and in particular gives hope for the remediation of salt affected land for infrastructure management and development. © Springer Science+Business Media, Inc. 2006.
- Description: C1
- Description: 2003004772
Lime stabilisation of an Australian silty clay and its application in construction of excavation retaining walls by cutter soil mixing
- Authors: Ranjbar Pouya, Kaveh
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: Coode Island Silt (CIS) is one of the predominant geological units in Melbourne, Australia. Having high compressibility and low shear strength, CIS is considered a problematic soft soil that challenges the construction of infrastructure in the region. To tackle such challenges, one practical approach is the application of ground improvement techniques such as in situ soil mixing. This PhD study focuses on the application of Cutter Soil Mixing (CSM) for the construction of excavation retaining walls in CIS. Although cement is widely used in most CSM projects, this study investigates the suitability of different lime types available in the Australian market as a potential alternative to cement for the stabilisation of CIS. To investigate the effect of lime stabilisation, a comprehensive geotechnical characterisation of untreated and lime treated CIS is performed. Four different lime types are used: agricultural lime, quicklime, hydrated lime and slag lime. Based on the results obtained from strength tests, slag lime was found to be the most effective among the four types that were tested. The optimum slag lime to CIS ratio is then found for the construction of retaining walls in CIS. Having the geotechnical characterisation of untreated and treated CIS from the laboratory experiments, a series of two-dimensional and three-dimensional finite element method (FEM) analyses were conducted to investigate the applicability and reliability of the selected mixing ratio for the construction of CSM excavation retaining walls in CIS. A nonlinear constitutive soil model was employed, calibrated and verified to be used in FEM analyses to investigate both the stability factor of safety and excavation-induced deformations. The results obtained for both undrained and fully coupled flow deformation analyses prove that CSM panels can be constructed by mixing slag lime and CIS to act as retaining walls to allow for deep excavation in CIS.
- Description: Doctor of Philosophy
- Authors: Ranjbar Pouya, Kaveh
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: Coode Island Silt (CIS) is one of the predominant geological units in Melbourne, Australia. Having high compressibility and low shear strength, CIS is considered a problematic soft soil that challenges the construction of infrastructure in the region. To tackle such challenges, one practical approach is the application of ground improvement techniques such as in situ soil mixing. This PhD study focuses on the application of Cutter Soil Mixing (CSM) for the construction of excavation retaining walls in CIS. Although cement is widely used in most CSM projects, this study investigates the suitability of different lime types available in the Australian market as a potential alternative to cement for the stabilisation of CIS. To investigate the effect of lime stabilisation, a comprehensive geotechnical characterisation of untreated and lime treated CIS is performed. Four different lime types are used: agricultural lime, quicklime, hydrated lime and slag lime. Based on the results obtained from strength tests, slag lime was found to be the most effective among the four types that were tested. The optimum slag lime to CIS ratio is then found for the construction of retaining walls in CIS. Having the geotechnical characterisation of untreated and treated CIS from the laboratory experiments, a series of two-dimensional and three-dimensional finite element method (FEM) analyses were conducted to investigate the applicability and reliability of the selected mixing ratio for the construction of CSM excavation retaining walls in CIS. A nonlinear constitutive soil model was employed, calibrated and verified to be used in FEM analyses to investigate both the stability factor of safety and excavation-induced deformations. The results obtained for both undrained and fully coupled flow deformation analyses prove that CSM panels can be constructed by mixing slag lime and CIS to act as retaining walls to allow for deep excavation in CIS.
- Description: Doctor of Philosophy
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