A Comparative Analysis of Bearing Capacity of Pile Foundations Using SPT Measurements for Nasiriyah Soil

Abstract

Pile foundation is essential in structures including buildings, storage tanks, and bridges especially in geotechnical applications. The bearing capacity of pile foundations must be evaluated, and evaluating this usually involves the use of the static load pile testing method which is however expensive. Another approach is based on data derived from field tests including the Standard Penetration Test (SPT), which is normally conducted during investigation of the site. Nevertheless, there is no common technique to analytically determine the bearing capability of pile foundations because of the complexities in pile-soil-pile interaction. Different empirical methods that are developed from SPT results are widely used for estimation of the bearing capacity but the result using this approach could be different from that of the other methods of design approach. This paper analyses seven empirical equations derived from SPT for the estimation of pile foundation-bearing capacity. The data considered in this work is a part of the site investigation for water intake in Nasiriyah for the water intake project, which is provided by SPT test results of six boreholes. The nature of the subsoil was estimated from SPT data and was categorized according to disturbed and samples. The number of blows from the SPT was adjusted before performing the computational analysis with them. The results confirmed that it expressed the greatest of all bearing capacities consistently when applying it to six of the SPT results. However, other methods resulted in the lowest bearing capacity values for the piles. Some methods produced mid-range values, while others yielded higher values compared to the conservative estimates provided by certain methods. Based on this, it can be concluded that the method with the lowest values serves as a more conservative approach for estimating pile-bearing capacity.