Fracture Characteristics of Intermittent Jointed Rock Masses under Blast Loading

Abstract

Rock masses usually contain intermittent joints. The existence of joints not only significantly affects the static properties of rock masses, but also their dynamic response and stability under blast waves. The present study focuses on investigating the fundamental fracture characteristics of intermittent jointed rock masses subjected to blast loading. A series of blasting tests were conducted on organic glass samples. The results are analyzed in order to obtain the characteristics of initiation, propagation and coalescence of wing cracks in rock bridges. The study indicates that the fracture behavior of intermittent jointed rock masses may be significantly affected by the preliminary static stress fields, the density and filling states of rock joints, the incident angles of blast waves relative to the joints, and the amplitudes of incident waves. From visual observation, three initiation modes and four coalescence modes of wing cracks are suggested. Finally, a comparison has been made between the fracture characteristics of intermittent jointed rock masses under single static stress field and that of under blast loading.