中文摘要：

以便更精确地预言底部 backscattering 力量， seafloor 的成层的结构被考虑。seafloor 被看作液体沉积层被有限厚度盖住的一个有弹性的一半空间地下室。根据水，沉积层，和地下室里的精明的声学的地，四种散布机制被考虑，包括从水沉积接口散布的粗糙，从沉积层散布的体积，从沉积地下室接口散布的粗糙，并且卷从地下室散布。然后，为适用于低频率(0.1-10 kHz ) 的成层的 seafloor 的一个 backscattering 模型被建立。模拟结果证明从从地下室散布的沉积地下室接口和体积散布的粗糙在相对低频率是更突出的(在 1.0 kHz 下面) 。当时随频率的增加，对全部的底部散布的他们的贡献逐渐地变得弱。并且结果最终来临到预言高周波(10-100 kHz ) 底部散布模型。当在地下室的 shear 波浪的健全速度和变细逐渐地减少时，模型的预言趋于到完整的液体模型的，它在另一个方面为成层的 seafloor 验证 backscattering 模型。

英文摘要：

In order to predict the bottom backscattering strength more accurately, the stratified structure of the seafloor is considered. The seafloor is viewed as an elastic half-space basement covered by a fluid sediment layer with finite thickness. On the basis of calculating acoustic field in the water, the sediment layer, and the basement, four kinds of scattering mechanisms are taken into account, including roughness scattering from the water-sediment interface, volume scattering from the sediment layer, roughness scattering from the sediment-basement interface,and volume scattering from the basement. Then a backscattering model for a stratified seafloor applying to low frequency（0.1-10 kHz） is established. The simulation results show that the roughness scattering from the sediment-basement interface and the volume scattering from the basement are more prominent at relative low frequency（below 1.0 kHz）. While with the increase of the frequency, the contribution of them to total bottom scattering gradually becomes weak. And the results ultimately approach to the predictions of the high-frequency（10-100 kHz） bottom scattering model. When the sound speed and attenuation of the shear wave in the basement gradually decrease, the prediction of the model tends to that of the full fluid model, which validates the backscattering model for the stratified seafloor in another aspect.