Electrokinetic stabilisation of soft clay

• Main Author: Ahmad Tajudin, Saiful Azhar
• Published: University of Birmingham 2012
• Subjects: 530.4; QC Physics
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.558912

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 V/m across a soil sample approximately 400 mm. The first stage involved testing of a ‘pure’ system with distilled water as the main pore electrolyte fluid supplied under zero hydraulic gradient conditions for periods of 3, 7 and 14 days. The second stage repeated test using calcium chloride and distilled water (CaCl-DW), DW and sodium silicate (DW-NaSiO) and CaCl-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,.