为了研究双相介质瑞雷面波的形成机制及传播规律,促进瑞雷面波资料处理方法的发展。文章根据弹性波动方程,采用交错网格有限差分算法,对二维各向同性弹性介质做解析解与数值解的对比,在此基础上,将PML吸收边界条件,改进的镜像法应用于双相介质波动方程中,并作了稳定性分析,对双相介质水平层状、起伏分界面等典型模型瑞雷面波及体波在内的全波场进行研究。结果表明:基于弹性介质解析解与数值解的对比,在误差接受范围内,研究双相介质是可行的;把稍作改进的镜像法应用于双相介质中,能够有效地处理瑞雷面波自由边界问题;通过详细分析双相介质瑞雷面波及体波在内的全波场的信息,对以双相介质为基础的地震波勘探有一定的指导作用。
In order to study the mechanism and propagation of Rayleigh surface wave in biphasic media and promote the development of data-processing method of Rayleigh surface wave, the authors applied finite difference method with staggered grids to simulate the 2D isotropic elastic media based on the elastic wave equation, and made a comparison between the analytical and numerical solutions. On such a basis, the PML absorbing boundary condition and improved image method can be applied to the two-phase medium wave equation to simulate the typical media model including horizontal layer and undulating interface, analyze the full wave information including the Rayleigh surface wave and body wave, and make a stability analysis. The results show that, on the basis of the comparison between the numerical solution and the analytical solution of the elastic media within the acceptable range of the error, the study of biphasic me- dium is feasible. The slight improvement of the image method can be applied to biphasic media to deal with free boundary condition problem of the Rayleigh surface wave effectively. The detailed analysis of the full wave field information of biphasic media including the Rayleigh surface wave and body wave shows that it has played a guiding role in the seismic exploration on the basis of biphasic media.