Utilisation of GIS Concepts for Foundation Design on Problematic Eastern Saudi Arabian Sabkha Soil

The design of foundations on a problematic soil is considered one of the most challenging issues for the geotechnical engineers. Sabkha, or salt flat, is considered as a problematic soil that exists in coastal areas. Ar-Rayyas sabkha is covering a wide area of the Eastern Province of the Kingdom of Saudi Arabia. King Fahd Suburb in the city of Dammam, Saudi Arabia, having been identified with an extensive presence of Ar-Rayyas sabkha, is considered for this study. Many structural failures of the residential buildings in the suburb were reported. The presence of sabkha is predominating the reasons of these failures. 59 investigatory boreholes were performed at the suburb and standard penetration N-values, have been obtained for the boreholes. A regression analysis was carried out, and a prediction model of the N-values using the coordinates and the depth intervals of the boreholes as regressors was provided. Due to the low accuracy of the model, an artificial neural network model was proposed to enhance the accuracy of the prediction; however, a further enhancement was required. Using GIS concepts, the suburb was mapped, and the borehole locations were projected with their attributes on the map. Different interpolation methods were utilised to predict and interpolate the N-values between the boreholes. The inverse distance weighting method yielded the most accurate model and therefore was selected to produce the final layouts for each depth interval. Finally, a framework for the design of foundations with the aid of GIS techniques was developed.