A Study of Burn Cuts for One-step Raise Excavation based on Numerical Simulation and Field Blast Tests
发表刊物：International Journal of Rock Mechanics and Mining Sciences
关键字：One-step raise excavation; Cut blasting; Parameters optimization of prime cut hole; Numerical simulation; Field tes
摘要：Over the past several decades, raise excavation has been widely employed in underground mining, civil engineering and military engineering. One-step raise excavation with burn cuts, where all the boreholes are predrilled and detonated at one time and no workers need to be underneath the freshly blasted and dangerous
ground, is an important and promising method in raise excavation. Cut parameters, especially the parameters of
prime cut which used empty hole as a free surface and swelling space, have significant influence on the effect of
raise formed. In this study, two small-scale experimental methods, spiral hole spacing method and observation
hole method, are designed to determine the prime cut parameters such as hole spacing (L), stemming length (Ls1,
Ls2) and air deck length (La) which are normally determined by empirical formula. In order to study the feasibility of the two methods, numerical analysis and experimental tests are conducted in V zone of Sandaozhuang
molybdenum mine (SMM), in which there are large numbers of underground goafs need to be controlled by filled
raise. The Riedel–Hiermaier–Thoma (RHT) material model, which considers compression damage and tension
damage effect under blasting loading, is employed in the LS-DYNA software to study the rock damage zone.
Meanwhile, the field tests are carried out according to the two small-scale experimental methods. The comparison results show that the damage zone of numerical simulation has a good agreement with the experimental
data. Further, the optimal prime cut parameters obtained from experimental tests are applied in one-step filledraise excavation, and a 23 m raise that meets the design requirements is formed through the proposed technology. The results indicate that these cut parameters determined by the small-scale experiments are suited for
one-step raise excavation. This study can provide two simple field experiments to determine the important prime
cut parameters of one-step raise excavation.