The Numeric Simulation Of Elastic Wave Field In Porous Medium

Due to the existence of a large number of surface water and groundwater on the earth, so saturated medium is very common. It’s a common type of medium in underground exploration and practical engineering, and also an important topic in the field of geotechnical engineering, earthquake engineering and geophysical. Saturated porous media is composed of solid phase and the flow phase. Various solid and flow phase formed the saturated porous media with different characteristics and different properties. So the research of solid phase, flow phase and the interaction between flow phase and the solid flow is an important content of the saturated medium. Through the spreading regularity and characteristics of the elastic wave in saturated medium, we can accurately analyze and judge solid phase, flow phase and the interaction between flow phase and the solid flow in saturated porous media. It’s an effective method for the research of saturated porous medium.Through the review of saturated porous media and the research achievements and current situation of the numerical simulation method, this paper based on the Biot theory of porous media, established the wave equation of elastic wave of a first order speed-stress, successfully conducted numerical simulation for elastic wave propagation in saturated porous media by using numerical simulation method for solving, and verified that there are two types of longitudinal wave and transverse wave when the elastic wave spread. At the same time, the slow p-wave attenuation is large, generally can be difficult to find.This paper adopts the staggered grid finite difference method for numerical simulation. This method is widely used, have higher precision and considering the stability of difference and dispersion, and can efficiently reflect the propagation law in the dielectric medium wave field. Use the perfectly matched layer to absorb boundary conditions in the artificial truncated boundaries. This can good weaken the wave’s reflection and scattering, then obtain the ideal effect of the absorption.Based on the Biot theory, we discussed attenuation of wave in saturated porous media, and analysed the influence of these material parameters, such as the osmotic coefficient in porosity and Darcy’s law and the fluid viscosity on elastic wave attenuation. Under this circumstance of absorbing boundary conditions, we studied and simulated the monolayer and multilayer saturated porous media simulation. We compared the wave field figure of containing gas interlayer fluid saturated with fluid saturation, and containing liquid intercalation gas saturation and gas saturation, and analyses the similarities and differences of the field figure air of the air saturated with liquid saturation. We compared the gas-solid coupling effect with water-solid coupling effects.