Characteristic Response of Rock and Rock-like Materials to Explosive Loading in Controlled Experiments

摘要

This study describes the results of single-hole blasting experiments in three well-characterized materials,a granite,a limestone,and a grout-based synthetic rock.The parameters studied are the nature of the dynamic stress field around the borehole and its decay in the near-field (i.e.0.5 to 5 borehole diameters),and as a function of the dynamic properties of the target rocks.Detonating cord of varying strengths (3 g/m,5.3 g/m,and 10 g/m of PETN) with air coupling in 6.4 mm and 9.5 mm diameter define the explosive source conditions.A thin-walled copper tube was installed in the borehole to isolate the explosion gas,so that only shock stress-induced fractures and their distribution could be studied.The cylindrical test samples measured 15 cm high and 15 cm in diameter.The resulting fracture patterns were mapped by a dye penetration technique,and fragment size distribution by sieve analysis.The observed near-field pressure decay,and fracture and fragmentation characteristics will serve to calibrate numerical models for prediction of blast results.