Deep-water pipelines' pipes stability at laying and presence on the bottom

Formulation of a question and decision of a problem of the pipelines stability during the laying on large depths and at presence on the bottom (before an internal pressure submission) are given. A form of pipeline with puprose to definite efforts in it is investigated. Two problems were mutually investigated: Deformation and second form of instability (i.e. bucling) for limiting load - extremal pressure tension and bending for empty (unpressurized) pipeline, The pipeline's behaviour at laying and the presence on the bottom with taking into account the results of the problem. The influence of initial, imperfections and wall thickness varying in circumferential and constant by the length and work of material behind elasticity limit were taken into account in common. The decision algorithm considering the geometrical and phisical nonlinearity of the problem was made and corresponding programs are developed and mass accounts of examples was executed.