An Empirical Approach to Introduce the Relationship between Blast-Induced Vibration and Rock Mass Condition in Tunneling

Abstract

Blast-induced vibration is one of the engineering and public concerns in civil engineering and mining projects. Peak particle velocity (PPV) has been commonly adopted as a parameter to characterize ground vibration since 1950s. Most conventional empirical models relate PPV to a term called scaled-distance (SD) which depends the charge rate per delay and the distance between detonation and monitoring point. The PPV and SD are plotted in a logarithm-logarithm space and they are often fitted by a linear model despite the fact that the data could be quite scattered. It can be seen clearly that information such as the properties of rocks and explosives was not taken into account in the empirical equation. However, these parameters could be substantially varied in a project over a large area (for instance a long tunnel). Over- or underestimation of PPV for a given SD is very uncommon. In this investigation, attempts have been made to consider of the effect of rock mass condition on PPV by incorporating a rock mass characterization index into the empirical model. A case study of tunnel blasting in granite with different rock mass quality ranges is used as an example. An empirical relations including the rock mass quality have been proposed and validated by the vibration data collected from the project. The results show less scattered plots of the data and a better prediction of PPV.