Characteristics of surface ground motions induced by blasts in jointed rock mass

An in-situ experimental program in a jointed rock mass was designed and imp lemented to investigate the rock joint effects on stress wave propagation. Accelerometers were placed on rock surface along three lines at 0, 45 and 9 0 degrees to the predominant rock joint strike direction. Eight blasts were detonated in a charge hole drilled in the rock mass. The equivalent TNT bl ast weight ranged from 2.5 to 50.0 kg and the loading density (charge weigh t divided by the charge chamber volume) varied from 1 to 20.0 kg/m(3). A fu lly coupled detonation with a charge weight of 25.0 kg was also exploded to study the coupling effect. The recorded data are presented and analyzed in this paper. The effects of rock joints on characteristics of stress wave p ropagation such as peak value attenuation, spectrum, and spatial variations are discussed. (C) 2001 Elsevier Science Ltd. All rights reserved.