Characteristics of stress waves recorded in small-scale field blast tests on a layered rock -soil site

A series of field blast tests was carried out in Singapore to study the properties of stress waves inside (free field) and on the surface of a granite site. The! stress wave properties inside the granite mass and on the rock surface, such as the peak value and principal frequency, as well as their spatial variations, were reported in a previous paper. Before the blast test, a soil layer of 1.5 m thickness was backfilled and compacted on the quarry test site. Accelerometers were also placed on the surface of the backfilled soil layer, inside the soil mass and on the rock-soil interface. This paper presents the recorded data associated with the backfilled soil layer. The attenuation relations of the peak particle acceleration (PPA), peak particle velocity (PPV) and especially the principal frequency (PF) of the stress wave on the soil surface, inside the soil mass and on the rock-soil surface are derived. They are compared with those recorded inside the granite mass and on the rock surface. Based on the results, the effects of different media on the stress wave propagation are discussed.