On Shallow Foundation Design along the Coast of Qatar

The near surface, highly weathered limestones of the state of Qatar have complex lithologies attributable to post depositional changes that have altered hard rocks into soils and carbonate soils into a rock matrix. The matrix often clayey, sometimes cemented (with gypsum, anhydrite, and /or calcite) is not a rock nor could be considered as a soil per se. These deposits are: difficult to sample; extremely variable in composition and properties; and are susceptible to degradation, particularly when wet. The paper presents typical geotechnical information from selected sites where these deposits have been encountered. Plate load test data, carried out to predict settlements, are shown. Arrival at appropriate foundation geometries and allowable bearing capacities, consistent with field conditions, are noted. For the present, design of shallow foundations along the coast of Qatar has remained empirical and dependent upon site-specific information aided by judgment, local experience, and plate load test results. Moving forward, and thus reducing uncertainty in design of shallow foundations, requires long-term commitment to: i) proper analysis and scrutiny of appropriate field data, ii) modeling of soil/rock behavior, and iii) arrival at "well thought out" guidelines to help practitioners overcome the difficulties when designing shallow foundations.