Studies on soil-foundation interaction in the sabkha environment of Eastern Province of Saudi Arabia
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Saudi Digital Library
Abstract
The large, extremely flat, saline, evaporative areas situated either along the coasts or farther inland of many arid, semi-tropical countries are known by the word 'sabkha'. The main distinguishing features of sabkha are its heterogeneous matrix and its highly concentrated ground-water. These characteristics of sabkhas contribute to many unresolved geotechnical problems which could hamper the performance of foundations. In an attempt to assess the safety and serviceability of foundations in eastern Saudi sabkha environments, a full-scale research was conducted to: (i) study the sabkha, its load-bearing and compressibility characteristics as well as other relevant geotechnical properties to assess the safety of foundations; and (ii) investigate the interaction between foundation materials and chloride and/or sulfate salts in the sabkha to evaluate the performance of plain and blended cements in resisting reinforcement corrosion and sulfate attack to assess the durability of foundations. Results of this research indicate that the surficial sabkha soil is very loose and possess low strength. Some standard techniques, such as sieve and hydrometer, permeability and consolidation, are shown to be inappropriate. The collapse potential of sabkha, as determined by a modified oedometer, rather than its compressibility, is classified as 'very severe trouble'. Silica fume and BFS blended cements exhibited deterioration to a higher degree than other cements in both pure sulfate and high sulfatechloride environments. The chloride beneficiation for these two cements is only marginal because of the excessive magnesium decomposition of C-S-H due to the lower CH content, which is shown to be unhampered by the presence of chloride ions. However, reinforcement corrosion, as determined by time to initiation of corrosion and corrosion current density, is much lesser in silica fume and BFS cements due to their denser structure. The concomitant presence of sulfate ions aggravat