Blasting creates a stress wave in the rock which not only causes loosening and fracturing of the rock mass, but also transference in the intermediate particles, i.e., vibration. If the vibrations created by blasting are not controlled, damage to constructions and sensitive instruments nearby can be caused, as well as possible danger to people. Therefore, excavation needs to be planned in advance and performed in a way that no hazard or inconvenience for the surrounding environment is caused. This sets tighter limitations for vibration monitoring, blasting design and implementation in urban areas. This paper concentrates on vibrations and their propagation caused by blasting in underground excavations. Some real data is studied and the results are compared to theoretical values in vibration prediction. The study reveals that one of the most important variables in hard rock excavations is the conductivity figure (rock mass quality index), which is based on measured variables such as the distance between a measuring point and a blasting site, the peak particle velocity and the maximum simultaneous charge. By planning and controlling blasts with the right tools, it is possible to optimize dependencies between allowed vibration limits and maximum simultaneous charges. This kind of monitoring of excavation vibration enables precise prediction of the conductivity figure and results in safe excavation in urban areas.
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