Displacement pile-soil and pile-soil-pile interactions problems are being ex-perimentally and numerically investigated in this thesis, using (created spe-cifically for this research) model pile installed in artificial soil deposit (dense sand). The main aim of the thesis is to develop a new approach ap-plied for the analysis of displacement pile-soil, pile-soil-pile and soil-structure interactions. In order to achieve the aim of the research the following objectives are fulfilled: design and creation of displacement model pile, preparation and investigation of prepared soil deposit, execution of single pile and different spacing pile groups vertical load tests and numerical modelling. The dissertation consists of four parts including Introduction, 3 chap-ters, conclusions, references and 2 annexes. The introduction reveals the investigated problem, importance of the thesis and the object of research and describes the purpose and tasks of the dissertation, research methodology, scientific novelty, the practical signifi-cance of results examined in the thesis and defended statements. The intro-duction ends in presenting the author’s publications on the subject of the defended dissertation, offering the material of made presentations in con-ferences and defining the structure of the dissertation. Chapter 1 is dedicated for the explanation and revision of the term pile-soil interaction, ultimate stress prediction approaches, peculiarities of single pile and pile group response under vertical loading and soil structure inter-action. At the end of the chapter, conclusions are drawn and the tasks for the dissertation are reconsidered. Chapter 2 explains in detail the experimental set up, preparation proce-dures of soil deposit and pile testing, moreover presents the main soil phys-ical either mechanical properties and vertical tests results and discussion. At the end of the chapter, conclusions are given. Chapter 3 demonstrates the procedures and the results of numerical analysis based on single pile test, moreover, the results of the analysis of soil-structure interactions are presented. The approach for the estimation of each isolated pile stiffness in pile group (when the average pile group stiff-ness is known) is given and explained in detail. At the end of the chapter, conclusions are given. 7 articles focusing on the subject of the discussed dissertation are pub-lished: one article – in the Thomson ISI register, three articles – in the jour-nals quoted in the others international data bases, one article – in confer-ence material and scientific paper in Thomson ISI data base, two articles – in material reviewed during a national and international conferences. 3 presentations on the subject have been given in conferences at national and international level.