Shallow-hole blasting mechanism and its application for gob-side entry retaining with thick and hard roof

Abstract

In order to avoid large area roof weighting and other dynamic disasters for gob-side entry retaining with thick and hard roof, combined with geological conditions and engineering practice of gob-side entry retaining with hard roof in Xinchao Colliery, this paper uses theoretical analysis to expound the zone characteristics of shallow-hole blasting and gives out calculation formula of zones respectively. Also the numerical calculation software of LS-DYNA3D is used to establish a model for shallow-hole blasting, analyze the evolution law of the effective stress and confirm relevant parameters of shallow-hole blasting with theoretical calculation results. Based on these research results, control countermeasures have been proposed, which include shallow-hole blasting technology for immediate roof caving, roadside backfill body construction technology with high water material for main roof caving, and road-in support technology of combination bolt support with hydraulic prop support. The field practice and observations show that the application of shallow-hole blasting technology has achieved an expected effects for ground rock control