Experimental study on the stress wave attenuation effect of filled cracks in rocks under confining pressure

To study the effectiveness of filled cracks as a means of anti-blasting and wave-elimination for underground protective structures, 36 one-dimensional impact tests were carried out on the intact rock specimens and rock specimens with filled cracks using the SHPB apparatus. The transmittance, stress wave velocity and peak stress value of the specimen under different working conditions were obtained. The impacts of confining pressure level, filling thickness and filling material types on stress wave attenuation were analyzed. The results show that, with the increase of the thickness of the filled cracks, the transmittance of the specimen, stress wave velocity, and stress wave peak stress attenuate clearly. The greater the thickness of the filled crack, the smaller the transmission energy of the stress wave during the propagation process. With the increase of confming pressure, the wave-eliminating effect of filled cracks is reduced due to the closure of pores, but still demonstrate stress wave attenuation effect to some extent. Therefore, using particles with higher compressive strength as crack-filling material and increasing filling thickness can effectively improve the wave-eliminating effect in engineering protection.