Modeling explosive/rock interaction during presplitting using ALE computational methods

摘要

Arbitrary Lagrangian Eulerian (ALE) computational techniques allow treatment of gases, liquids and solids in the same simulation. ALE methods include the ability to treat shock waves in gases, liquids and solids and the interaction of shock waves with each other and with media from one of the other categories. ALE codes can also treat explosive detonation and the expansion of the explosive gases and their interaction with air and solids. ALEGRA is a 3-D ALE code that has been developed at Sandia National laboratories over the past few years. ALEGRA has been applied to a 2-D simulation of presplitting using decoupled explosives in rock blasting with very interesting results. The detonation of the explosive at the bottom of the hole sends a shock wave up the borehole driven by the explosive gas expanding into air. The explosive gas compresses the air against the stemming column where it rebounds and recompresses at the bottom of the borehole. This type of ringing takes several cycles to damp out. The explosively induced expansion of the borehole is also treated by ALEGRA as well as the shock wave imparted to the rock. The presentation of this paper will include several computer animations to aid in understanding this complex phenomenon.