Propagation of high amplitude stress waves through an artificial filled joint was experimentally investigated using a modified steel Split Hopkinson Pressure Bar (SHPB) system. Quartz sand was used to simulate the joint fillings and its particle size distributions after each test are analyzed. Three deformation stages were discovered as the amplitude of the incident wave increases, i.e., initial compaction, crushing and crushing and compaction. In the initial compaction stage and the crushing and compaction stage, the fillings are mainly compacted, and thus the transmission coefficient increases with the amplitude of the incident wave. However, in the crushing stage, the transmission coefficient decreases with the increase of the amplitude of the incident wave. The observed dependence of the transmission coefficient on the wave amplitude is consistent with the particle size distribution of recovered fillings.
The filled joint commonly exists in the natural rock mass and it is often filled with granular materials such as clay, quartz sand and weathered rock as shown in Figure 1. Field investigation show that the thickness of the fillings is up to several centimeters, and fillings have a noticeable effect on the mechanical behavior of the filled joint (Barton 1974, Sinha & Singh 2000).