Numerical modelling of vibrational effects on buildings from blasting

Övrigt konferensbidrag, 2023

It is well known that blasting in rock may cause structural damages to nearby buildings. There are various national standards that regulate acceptable blast induced vibration levels. These standards are sometimes criticized for being outdated with a need of revision. Such a revision should be based on deeper knowledge on the various aspects that causes damages to buildings from vibrations; either based on distance, frequency or some other measures. It is thus of importance to develop more reliable numerical predictions on ground and structural vibrations from blasting in rock, as this enables a more efficient rock excavation process that may lead to both economic and environmental savings.
The present work is a continuation of [1] where numerical simulations are carried out based on the finite element method with both two-dimensional and three dimensions models. The numerical simulations have been used to carry out parameter studies on simplified buildings exposed to vibration loads. Parameters that are varied in these studies have been geometry, material and load characteristics in the form of load frequency and wave propagation speed in the ground. Comparisons are made with experiments carried out in Norway by NGI.
The work concludes several features that have notable influence on the structural vibration:
• The parameters and modelling related to the ground-building interaction are important:
o Both vertical and horizontal coupling effects should be captured.
o The damping properties of the ground-building interaction need to be taken into account.
• Simplified two-dimensional models generally capture the lowest fundamental vibrational modes of the building.
• Global effects (eigenfrequencies and vibrational modes) and local effects (stress concentrations near corners etc.) are coupled in an intricate manner.