Numerical simulation of flexible rockfall barrier post foundations subjected to impact

Rapidly changing climatic conditions confront communities in alpine regions with great challenges and necessitate the continued development and optimization of geohazard mitigation solutions.One such solution is presented by flexible rockfall barriers, which constitute a frequently employed system for mitigating the risk posed by rockfall.Despite their widespread use, the design of their foundations is characterized by great uncertainty.Moreover, the construction of such foundations requires heavy machinery and constitutes a major part of the cost of the completed barrier.To optimize the design of rockfall barrier foundations, a better understanding of their mechanical behavior is needed.To this end, a three-dimensional finite element model of a rockfall barrier foundation subjected to impact is developed and implicit dynamic mechanical simulations are carried out.Results indicate that the developed finite element model is capable of predicting the forces acting on the foundation and its components during an impact event.A detailed investigation of the interaction of the individual components reveals that damage to the foundation's concrete plinth is accurately captured by the model if an over-nonlocal gradient-enhanced constitutive model for concrete is employed.Moreover, the contact between the concrete plinth and the surrounding soil is identified as a key parameter influencing the mechanical behavior of the concrete plinth during impact.This work highlights key factors influencing the mechanical behavior of rockfall barrier foundations during impact and directly complements recent full-scale impact testing of such foundations performed at the Unit of Geotechnical Engineering, University of Innsbruck.