The investigation of horizontal soil displaoement!3 in front and behind the near fields of laterally loaded piles are described. The low-frequency (quasi-static) loads is amounted tor. Two series of laboratory tests on steel pipe model were carried out, and then analyzed by computer program. It is shown that the predictions in generally good agreement.
Experimental study of pile-soil interaction kinematic schemes at different deformation phases give a base for solution or mixed elastoplastic problems. The investigation of soil deformation around offshore piles is difficult on some reasons (cost, no special technique for deep water). Usually only integral characteristics such as curves "p-y" and pile material stresses were measured in field and laboratory conditions. Some authors considered the particles displacements on soil surface with a help of marks of 9-ifferent kinds and photogrammetry method (Robinsky and Morrison, 1964). There areknown the visualization techniques of "particle trajeotoriel3 such as holographic and X-rays methods, using of color sand bands, photo and video recording. This methods were very useful for study of soil kinematics during vertical stamp indentation in laboratory. Malyshev (1980) proposed to fix a photocamera to moving stamp under vertical load that gave a possibility to registrate a form of compacted core before stamp and particle trajeotories in relative coordinate system. It should be noted that under stable particle motion their trajectories coincides with now lines on which the velocity vectors are tangential. "As mentioned earlier, a study of kinematic picture is important because in surface zone, where pile have the large deflections, the soil have the plastic behavior with flow around pile and where the elastic continuum theory is not valid. Changeability of soil density and other properties can greatly influence on stress state in this zone.
