基于已建立的非饱和土中的波动方程，导出4种体波的波速以及衰减的解析表达式。数值分析了4种体波的波速、衰减与孔隙率以及Lame常数 、 之间的关系。结果表明，随孔隙率的增大，P1波和S波的波速有所提高，P2波和P3波的波速随孔隙率的增大而有所减小；3种P波的衰减有所增大，其中以P3波变化最为显著。P1波、P3波和S波的波速基本上不随Lame常数 变化，P2波的波速随Lame常数 的增大而稍有增大。P2及S波的衰减基本不随Lame常数 变化，P1、P3波的衰减随Lame常数 的增大而有所减小。3种P波的波速基本上不随Lame常数 变化，S波的波速随Lame常数 的增大而有所增大。P2及S波的衰减基本不随Lame常数 变化，P1、P3波的衰减随Lame常数 的增大而有所减小，其中P3波的变化最为显著。

Based on the wave propagation equation in unsaturated soils, four kinds of body waves i.e. one is S wave, and other three are P waves, P1 wave, P2 wave and P3 wave, according to the wave velocity are found in unsaturated soils through theoretic deduction. Analytic expressions for wave velocity and attenuation are proposed. Numerical analysis about the relation between the wave velocity, attenuation and the void ratio and Lame constants are carried out. The results show that with the increasing of void ratio, the velocity of P1 wave and S wave become enhance; and the attenuation of three kinds of P waves becomes great, especially for P3 wave. Almost the velocity of P1, P3 and S don’t change with the changes of Lame constant , and the velocity of P2 wave become a little faster with the increasing of Lame constant Almost the attenuation of P2 wave and S wave don’t change with the Lame constant . The attenuation of P1 wave and P3 wave become smaller with the increasing of Lame constant Almost the velocity of three kinds of P waves don’t change with the variation of Lame constant , but the velocity of S wave becomes faster with the increasing of Lame constant . Almost the attenuation of P2 wave and S wave don’t change with the variation of the Lame constant . The attenuation of P1 wave and P3 wave decreases with the increasing of Lame constant , especially for P3 wave.