Utilizing GIS for Estimation Bearing Capacity of Shallow Foundation in Baquba City, Iraq

Abstract

This paper aims to estimate the allowable bearing capacity of shallow foundations in Baqubah City, Diyala Governorate, Iraq, using Geographic Information System (ArcGIS Pro) together with Terzaghi’s bearing-capacity equation. Three common foundation types were considered in the analysis, such as square foundations (1.5 × 1.5 m), strip foundations (1 × 1 m), and rectangular foundations (2 × 4 m), and the calculations were conducted at different foundation depths across the study area. The analysis was based on geotechnical information obtained from 76 boreholes distributed in different locations within Baqubah City. Soil parameters available in the investigation reports were used to calculate the allowable bearing capacity values. In some boreholes where the undrained shear strength (Cu) was not directly available in the reports, the values were estimated from Standard Penetration Test (SPT) results using empirical correlations commonly reported in geotechnical literature. The calculated results were then integrated with GIS techniques to produce spatial maps showing the differences in allowable bearing capacity in the study area. The Inverse Distance Weighting (IDW) interpolation method was used to produce these maps based on the available borehole data. This method was chosen because it is simple and works well when the number of available data points is limited. The maps prepared in this paper show that the soil bearing capacity is not the same across Baqubah city and that the allowable bearing capacity changes from one place to another depending on soil conditions and foundation depth. The results showed that the allowable bearing capacity ranges from (3.1 to 22.9) t/m² with higher values showed in northern parts due to stronger soil conditions. These results provide useful preliminary information for engineers when selecting suitable foundation types during the early stage of foundation design. Still, detailed geotechnical investigations are required for final design before construction.