浅海声反射损失的实验研究

本文介绍在水深40—90米的浅海海域中三种类型沉积层海底上,用爆炸声源进行的海底反射损失的实验研究结果。实验结果与按均匀半空间底模型计算所得海底反射损失的理论曲线作了比较。结果表明:反射损失值明显地与底的类型有关,细砂底的反射损失较小,粉砂质泥次之,而粉砂质粘土的反射损失较大;对于同类型的海底,孔隙度大者反射损失也较大。此外,还讨论了沉积物中场速的两种经验公式的适用性。

AN EXPERIMENTAL STUDY OF THE ACOUSTICAL REFLECTION LOSS IN SHALLOW SEAS

Presented in this paper is an experimental study of measurements of the bottom reflection loss by means of explosive sound sources in shallow sea regions with depths ranging from 40 to 90 metres and sediments of different types. The results obtained are compared with theoretical calculations based on measured sediment parameters and the homogeneous half-space bottom model. It is found that the value of the bottom loss varies remarkably with the type of sediment: it is small for fine sand bottom. larger for silty mud, while the largest bottom loss occurs in silty clay. For sea bottoms where sediments are of the same type. those sediments with larger porosities have larger reflection loss. Also discussed is the applicability of the two empirical formulae for estimating the sound velocity in sediments from porocity and grain size respectively.