Abstract Summary
Earthquakes are the most intensive sources of free-field vibration. The buildings are also threatened by vibrations caused by other reasons, such as the travel of trucks, passenger cars, trams, and trains, including metro trains, but also mining rockbursts, resulting from underground and open-cast exploitation in mining areas. However, mine-induced rockbursts, as a result of underground and open-cast exploitations are also a hazard to buildings. This problem occurs in many countries all over the world. Additionally, as in the case of earthquake-induced vibrations, the soil-structure interaction (SSI) phenomenon is observed in the case of mining tremors. In this paper, an investigation of one of the SSI consequences – differences between the simultaneously recorded free-field and building foundation vibration, is performed. The research was carried out on the example of an actual, typical, masonry, low-rise office building situated in a coal basin in Poland – the Upper Silesian Coalfield (USC). Two methods of evaluation were used in the analysis: experimental with the use of full-scale tests and numerical with the use of finite element method (FEM) modelling. A rich set of experimental data (including several hundred strong mining tremors) was collected from the free-field and foundation acceleration stations equipped with vibration monitoring. Using the measurement data, very important parameters that affect the SSI phenomenon were considered, e.g. magnitude of mining tremor energy, epicentre distance of mining rockburst, and peak ground value of vibration. Besides the full free-field and building foundation vibration simultaneously registered in the time domain, corresponding response spectra (dimensional and dimensionless) and the ratio of those response spectra were used in the analysis. Numerical analysis of the transmission of the free-field wave to the building foundation is based on three-dimensional (3D) FEM models. The models considered both fixed and flexible supports of buildings with parameters resulting from the properties of the subsoil. Various conceptions of modelling the ground vibration transfer to the foundation were discussed. Additionally, the influence of changes in site conditions on the SSI phenomenon was investigated in the case of low-rise office building vibration induced by mining rockbursts. The collected experimental data allowed for the verification of the proposed models.
