Mass-gravity-scaling technique to enhance computational efficiency of explicit numerical methods for quasi-static problems

Abstract

Large deformation numerical analysis adopting explicit integration scheme is commonly employed in geotechnical analysis to simulate quasi-static problems involving large soil deformations. The computational time for the conduct of such analysis is often very time consuming particularly for complex 3-dimensional soil-structure interaction problems. As an extension to the mass-scaling technique, a mass-gravity-scaling (MGS) technique is proposed in this study to improve the computational efficiency substantially. By scaling the material density and model gravity correspondingly, the soil initial stress state that is essential for realistic soil response can be maintained. This enables the increase in the critical time step resulting in a significant reduction in computational time. Three quasi-static large soil deformation geotechnical problems involving T-bar penetration, spudcan-pile interaction, and pile-reinforced slope are presented to illustrate the application of the MGS technique simulated in finite element (Coupled Eulerian-Lagrangian and Updated Lagrangian) and finite difference methods. It is established that an appropriate scaling factor should be chosen by considering a trade-off between computational time and accuracy of analysis. For selected problems, a hybrid-MGS technique can be employed by selectively applying different scaling factors over specific domains to improve the accuracy and efficiency of the solution technique.