Electrokinetic stabilisation of soft clay

Ahmad Tajudin, Saiful Azhar (2012) Electrokinetic stabilisation of soft clay. PhD thesis, University of Birmingham.

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Abstract

The application of chemical ground improvement using the electrokinetic stabilisation (EKS) method has the potential to overcome problems soft highly compressibility soil. This technique has the potential to enhance the strength and reduce compressibility of a wide range of soils. The aim of this study was to evaluate the use of EKS as an effective method to strengthen soft clay soils. A detailed laboratory programme of work was conducted using the initial base model developed by Liaki (2006). This study was conducted in two stages using laboratory scale models, using an inactive kaolinite clay. The test model using reusable Electrokinetic Geosythentics (EKG) developed at the Newcastle University to apply a constant voltage gradient of 50 Vlm across a soil sample approximately 400 rnrn. The first stage involved testing of a 'pure' system with distilled water as the main pore electrolyte fluid supplied under zer,o hydraulic gradient conditions $ for periods of 3, 7 and 14 days. The second stage repeated test using calcium chloride and distilled water (CaC1-DW), DW and sodium silicate (DW-NaSiO) and CaC1-NaSiO, at the anode and cathode, respectively. Throughout both physical and chemical characteristics were measured. This enabled assessment of the design and configuration that could be used in the field together with a number of key limitations. The data presented herein enables a fuller understanding of the mechanisms contributing to the improvements achieved and how effective monitoring through the use of relatively simple test, e.g. pH and Atterberg Limits, can be achieved. Specifically cation exchange was considered to be the main mechanism causing a significant increase in shear strength observed for the CaCl-DW system with the increase seen to be more uniform across the soil sample for a period up to 14 days. This was supported by results of Atterberg limits, pH, electrical conductivity and chemical concentrations. Precipitation and cation exchange are the main contributors to the increase of shear strength for the CaC1-NaSiO system after 7 and 14 days treatment. However, precipitation of CSH gels has greater influence on the shear strength at the near proximity of cathode followed by cation exchange at the near proximity of anode and at the remainder of the soil sample.

Item Type:Thesis (PhD)
Subjects:T Technology > TA Engineering (General). Civil engineering (General) > TA703-711 Engineering geology. Rock mechanics. Soil mechanics.
ID Code:4676
Deposited By:Normajihan Abd. Rahman
Deposited On:27 Dec 2013 11:26
Last Modified:27 Dec 2013 11:26

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