FINITE ELEMENT STUDIES OF PROPAGATION OF RADIAL CRACKS IN SMOOTH BLASTING. FRACTURE OF CONCRETE AND ROCK: RECENT DEVELOPMENTS. PAPERS PRESENTED AT THE INTERNATIONAL CONFERENCE, UNIVERSITY OF WALES, COLLEGE OF CARDIFF, SCHOOL OF ENGINEERING, SEPTEMBER 20-22, 1989

In this paper, the function of explosive stress waves and quasi-static gases pressure in blasting were discussed. It was considered that in smooth blasting after stress waves outdistanced the propagating radial cracks, quasi-static pressure played a decisive role. The finite element technique was used to calculate the stress intensity factors of radial cracks under quasi-static pressure. The influences of gases penetration into radial cracks on radial cracks propagation, the influence of crack number, crack length, empty hole on radial cracks propagation, and the influences of long radial cracks on short radial cracks were studied and analysed. For two boreholes, the characters of radial cracks propagation were also studied and analysed.(A) For the covering abstract of the conference see IRRD 829348.