Abstract:In order to study the effect of layered ground on dynamical deformation of unfree field,which is a very complex and hard to deal with,firstly the concept of unfree field is explained and a sand layered subsoil is suggested as an example of unfree field. According the different causes to induce the deformation of subsoil and structures,the total settlement or the deformation is divided into the volume compresion of soil under recycled shear force,added settlement by dynamical action from the up-structures,and the settlement from soil deformation by modulus degeneration of dynamical nonlinearity. A cone model is introduced to analyze the scattered source and research the interaction of structures and multi-layers-subsoil. The solving process is given to analyze and evaluate the settlements,and satisfied actory results are obtained.