The electrokinetic stabilization approach towards sabkha soil physical and chemical properties improvement at rabigh, Saudia Arabia / Zaheer Uddin Babar

Faculty of Civil Engineering Technology

Thesis (Master of Science) -- Universiti Malaysia Pahang – 2024

Includes bibliographical references

Sabkha soil, a prevalent formation in the Arabian Gulf within the Kingdom of Saudi Arabia, especially along its coastal regions, has been the subject of extensive research over the past quarter-century. These investigations have aimed to gain insights into the nature of sabkha soil and to comprehensively characterize it, with a specific focus on augmenting its mechanical properties and resilience. In geotechnical terms, successful construction in sabkha soil areas depends on significantly improving the soil's strength and durability while also optimizing treatment costs. Expansive Sabkha Soil, in particular, presents critical geotechnical challenges, including low shear strength, high compressibility, high salinity, and the presence of chemical elements such as SO4 and Cl. Moreover, these clayey-rich sedimentary materials have the potential to cause severe settlement and ground heave, necessitating effective solutions before commencing construction projects in expansive sabkha soil regions. This study aims to address these challenges through an environmentally sustainable electrokinetic stabilization technique. Three sabkha soil samples (Rabigh-I, Rabigh-II, and Rabigh-III) were collected from distinct locations within Rabigh City, Saudi Arabia. The electrokinetic stabilization technique involved two phases: Phase-I applied a voltage gradient of 40 V for 1, 3, and 7 days, while Phase-II applied a direct electric current of 80 V for the same durations. Laboratory testing at the Geotechnical & Material Testing Laboratory revealed significant improvements in both geotechnical characteristics and chemical extraction of sabkha soil. Results indicated a substantial enhancement in shear strength, with values rising from 116 to 435 kPa for Rabigh I, 122 to 411 kPa for Rabigh-II, and reaching 585 kPa for Rabigh-III. Additionally, there was a notable decrease in swell pressure, with values decreasing from 265 to 38 kPa for Rabigh I, 287 to 45 kPa for Rabigh-II, and reaching 29 kPa for Rabigh-III. Simultaneously, there was a significant reduction in moisture content, with Rabigh-I decreasing from 34.5% to 7%, Rabigh II from 32.5% to 11.2%, and Rabigh-III from 37.1% to 9.5%. Furthermore, using 80V for 7 days led to a remarkable reduction in SO4 by 76%, Cl by 90%, and salinity by 99%. Augmenting the voltage gradient and extending the operational duration yielded significant improvements, making this technique highly recommended for fortifying weak soils and enhancing their geotechnical attributes. This study contributes to the ongoing efforts to understand and mitigate the challenges associated with sabkha soil, providing valuable insights for sustainable construction practices in the region.