Effect of Underground Blasting on Surface Slope Stability: A Numerical Approach

Stability of surface slope is a big challenge when underground excavation carried out just below the slope by the conventional drilling and blasting method. Blasting generates huge intensity of dynamic loading in the surrounding rock mass. If the intensity of dynamic loading is high, then it may be one of the reason for the triggering of instability in the surface structures. So, in the present paper, underground coal blast model has been developed using finite element method to understand the ill effects of underground blasting on the surface slope stability. Slope instability results have been represented by Peak Particle Velocity (PPV) of blast waves at varying time frames. Results have been computed on predefined specific target points which are crucial in terms of stability of surface slope. It has found that lowest bench has greater impact of blast loading and it can be dangerous from the stability point of view, whereas lower particle velocity monitored at the top most bench, compared to the other target points. It is all due to the attenuation of blast vibration energy with respect to the time and distance. From this study, it can be said that numerical modelling tool can be used to understand the phenomenon of dynamic blast vibration loading and its effects on the surface slope stability