Seyyed Mohammad Hashemi - Master of Geotechnical Engineering, Faculty of Engineering, Islamic Azad University Central Tehran Branch, Tehran, Iran
Iraj Rahmani - Assistant Professor, Department of Geotechnical Engineering, Road, Housing and Urban Development Research Center (BHRC), Tehran, Iran

Today, the back analysis methods are known as reliable and effective approaches for estimating the soil strength parameters in the site of project. The back analysis can be performed by genetic algorithm and particle swarm optimization in the form of an optimization process. In this paper, the back analysis is carried out using genetic algorithm and particle swarm optimization in order to determine the soil strength parameters in an excavation project in Tehran city. The process is automatically accomplished by linking between MATLAB and Abaqus software using Python programming language. To assess the results of numerical method, this method is initially compared with the results of numerical studies by Babu and Singh. After the verification of numerical results, the values of the three parameters of elastic modulus, cohesion and friction angle (parameters of the Mohr–Coulomb model) of the soil are determined and optimized for three soil layers of the project site using genetic algorithm and particle swarm optimization. The results optimized by genetic algorithm and particle swarm optimization show a decrease of ۷۲.۱% and ۶۲.۴% in displacement differences in the results of project monitoring and numerical analysis, respectively. This research shows the better performance of genetic algorithm than particle swarm optimization in minimization of error and faster success in achieving termination conditions.

Back Analysis; Soil Strength Parameters; Genetic Algorithm; Particle Swarm Optimization; Python; Excavation