Physics of liquefaction phenomena around marine structures

Understanding of the physical backgrounds is essential for good engineering practice-with respect to liquefaction of sandy soils around and beneath marine structures. Several types of liquefaction can be distinguished. The corresponding physical phenomena are briefly described. Among them are: compressibility of soil skeleton, dilation, contraction, elastic versus plastic deformation, interaction between pore water and soil skeleton, compressibility of pore water, monotonic versus cyclic response, instantaneous versus residual liquefaction, drainage and pre-shearing. In each particular case just a limited number of these phenomena is relevant and needs to be modeled. A survey of typical cases is presented and the relevant phenomena are discussed. Most will be elaborated on in other papers appearing in this issue. This paper may help to discover the relationship between the different papers.