海底土体失稳过程分类及其声学特征

海底斜坡土体失稳是海底比较常见的重力侵蚀过程。由于人们无法直接接触海底，对其研究绝大多数是事后借助于声学和地质学调查手段进行。文章根据一般饱水土体运动机理及变形程度和运动状态对海底斜坡土体不稳定性进行分类：蠕动、滑动和流动，并探讨它们形成过程的力学基础以及声学识别特征。蠕动是指海底土颗粒之间发生相对位移，但整体上未发生明显的位移。其相应的声学识别特征是：连续不规则波状反射结构。滑动是指失稳土体在海底斜坡上做块体运动。其声学探测记录表现为：张性裂隙、内部结构完整的滑体以及伴有负载形成的地形等。流动是指失稳土体完全崩解形成流体在海底斜坡上运动。沉积物流在流动中出现线形纹理和平行层理非常清楚的中断为标志，而且被没有内部结构或层理的声学透明物质充填等声学识别特征。

Classification of failure proceses of submarine soil and main acoustic characteristics

Submarine soil instability is gravitational erosion process, which frequently happens on the sea floor. Due to unaccessible, the sea floor is studied by acoustical and geological methods. This paper presents the classification of submarine soil instability based on the mechanics of its failure process, deformation and movement, and the acoustical characteristics of its mobile types, which including creep, slide and flow. Creep means relative movement between soil grain and not obvious displacement with irregular, wavy surface echo and several continuous internal reflectors. Slide indicates mass movement of destroyed soil along the submarine slope with irregular blocky, lumpy or hyperbolic masses bounded upslope by scarps or scar. Flow is the last stage of the deformation of submarine soil destroyed, whose acoustic characteristics is transparent mass, partly disrupted reflection, and so on.