Estimating extent and properties of blast-damaged zone around underground excavations

Abstract

A common technique in hard rock tunneling, and underground excavation in general, is drilling and blasting. This method of excavation assumes that damage will be done to the surrounding rock mass depending on its quality. Herein is a proposal for how to estimate blast-damaged zone extent and shape, and how to quantify rock mass properties in this zone. Comparison was made, using FEM, between models with and without blast-damaged zone consideration through analyzing its impact on the support load. Results showed greater support loads in the case of blast-damaged zone modeling. Also, comparison was made between the proposed method for blastdamaged zone quantification and quantification using blast damage factor D. Results showed that in both cases, the support loads are in same magnitude order. In other words, compared to the blast damage factor D method, the proposed is more objective and makes it possible to describe the blasting process before it is actually done.

Application of the tensile strength to rock blasting

“…Among later works, Zou and al [3] clarifies the appearance of radial cracks around a blasthole as a result of tangential tensile stresses first seeming a couple hole radii out from the blasthole divider. The spread of these cracks in bench blasting is, moreover, proven to be influenced by tensile waves, which are reflected from the front of the bench [4]. Results from examinations of the rest rock damage at blasting addi tionally reinforce researchers on the strength of rock materials.…”

Fragmenting of cylindrical rock specimens under explosive load: Comparison between model and laboratory results

“…Practical application of this theory was demonstrated for the estimation of blasted rock fragmentation [13] and for the blast damage zone extent estimation [14].…”

Experimental determination of best performing cut in Lece underground mine

“…Importance of the proper cut design are widely reported and explained in literature (AyalaCarcedo, 2017;Zhang, 2016;Xu, Li, Liu, & Zhang, 2019). Damage of surrounding rock mass due to improper blasting is one of the problems that needs to be taken care of since it may provide instabilities (Torbica & Lapčević, 2016;Torbica & Lapčević, 2015;Torbica & Lapčević, 2018) and higher quantity of materials to be handled. Previous works on blasting optimization in Lece mine were considering ring blasts and is available in (Duranović, et al, 2018).…”