提出了一种新的带有弹性覆盖层的刚性半空间模型 ,并对弹性层中的平面应变波进行了模态分析 分析表明 ,在混合边界条件下 ,弹性层中的平面应变波具有两个模态———对称模态和反对称模态 在这两种模态下 ,P波和SV波都是不耦联的 在基本模态下 ,P波和SV波都是非弥散的 而其它的模态均具有弥散性质 A new rigid half-space model with elastic cover is presented. The modal analysis of the plane strain wave in the elastic layer shows that under the mixed boundary conditions, the plane strain wave in the elastic layer has two Modality—symmetry mode and anti-symmetric mode In both modes, P-wave and SV-wave are not coupled. In the basic mode, both P-wave and SV-wave are non-dispersive while others are Modality is diffuse