Evaluation on the SPT Based Design Approach for Shallow Foundations

Abstract

This research evaluated four SPT-based design equations used to estimate the carrying capacity of shallow footing. Using different methods, two plate load tests performed on silty clay and clay soil in Nasiriyah have been used to obtain the ultimate load-carrying capacity. Further, this study aims to utilize the finite element method based on Plaxis 3D foundation software to simulate the behavior of load settlement of the foundation with actual dimensions. It was concluded that the numerical analysis methods showed a good convergence to the actual test results, where the numerical results were 67 and 65 ton/m2 for two projects, respectively. The field values were 70 ton/m2 for projects with a number of possibilities in determining the failure areas of the soil to give a sufficient picture of the load expectations. The boundary of the influence zone obtained by the finite element method has functioned as an influence zone proposed for a new proposed equation which gave a good convergence with the measured bearing capacity values.

Keywords

• shallow foundation
• plate load test
• finite element method
• ultimate bearing capacity