Parameters of a Ground Motion Model Induced by Mining Exploitation

Author: H. Marcak

In Poland, there are copper mines in Lower Silesia and coalmines in Upper Silesia where seismic tremors appear. They produce strong ground motion and cause building damage mostly weak, sometimes serious. The damage appears at an epicenter zone and the motion intensity diminishes rapidly with distance. It is diffi cult to assess the space distribution of seismic signals structure recorded at ground level.

The wide band of wave frequency transmitted through rock masses, the infl uence of focal mechanism and amplifi cation of seismic vibrations due to geological structures causes uncertainty in seismic signals interpretation. The tops of seismic wave amplitudes, commonly used to describe the potential of seismic wave destruction have a particularly high level of uncertainty. It can be shown that the seismic acceleration tops depends on the rupture direction. Also the time of dynamic loading should be considered when estimating the predicted infl uence of seismic vibrations on buildings. In this paper it is proposed to estimate the parameters of model describing the envelopment of particle ground motion acceleration, due to mining tremors, with the formula u = G . exp(kt). The estimation of parameters G and k from a smoothed power spectrum gives an ability to estimate the maximum value of signal envelopment and its length. Ground motion recorded in the coal mine is analyzed and building damage risk is assessed on the basis of some combination of the G and k parameters.