Investigation of a modified gap stiffness model for water-saturated granular porous media

The author has proposed a modified gap stiffness model incorporated into the Biot model, known as the BIMGS model. The model demonstrated that the experimental results could be reasonably explained. It describes acoustical relaxation caused by local flow in the gap between grains. In this study, the micro-geometric structure of a gap was investigated experimentally, and the results showed the grain diameter dependence of the contact radius and separation distance. Moreover, the compressional wave speeds and attenuation in water-saturated silica sands as a function of frequency were calculated and examined. The results demonstrated the existence of two attenuation peaks.