| Nowadays,the propagation of elastic body waves and surface waves in porous media has been the key research topics of physical mathematics,soil dynamics and elastic mechanics.Based on Biot theory,most of the existing studies address the propagation characteristics of elastic waves in single-phase solid media and two-phase saturated porous media materials.However,the natural soil widely found in nature is generally unsaturated soil,which can be regarded as an unsaturated porous medium composed of soil particles and intergranular pore fluids(liquid and gas).Therefore,it is of great theoretical and practical significance to analyze the propagation characteristics and energy transport of elastic waves in unsaturated soil.This paper analyzes the decay between the wave velocity and the wave velocity and the influence between the energy distribution and the important physical parameters.First,based on the porous medium theory and continuous solid mechanics theory,combined with the mass balance equation,the momentum balance equation,the seepage continuous equation and the basic expression of the effective wave equation of the effective stress of the porous medium.The validity of Massilon sandstone physical parameters is applied to verify the known results.We analyze the change of wave velocity and wave velocity decay with saturation,porosity and frequency.Secondly,based on the characteristics of body wave propagation in unsaturated porous media,the energy distribution of Rayleigh wave propagation in unsaturated porous media is discussed.By introducing the potential function and combining with the free and permeable boundary conditions,the dispersion characteristic equation of Rayleigh-wave in the unsaturated porous medium is derived,and the calculation expression of each phase shift caused by Rayleigh-wave and the energy ratio of each component wave can be obtained.Then the influence of saturation on displacement and the energy ratio of wave and wave of Rayleigh wave are analyzed.Finally,on the basis of the propagation of the body wave and the body wave of Rayleigh wave in the unsaturated porous medium,the theoretical expression of the reflection wave and the transmission wave and the transmission coefficient of the transmission wave are discussed. |
