Local Buckling of Tubes in Elastic Continuum

A theory for the local buckling of a buried, flexible, perfect tube that utilizes linear buckling theory and an elastic continuum model for the ground is developed, with only radially inward displacement permitted. Comparisons are made with the Winkler spring support model for local buckling and multiwave solutions of both Winkler and continuum support. It is evident that the accuracy of predictions depends upon the knowledge of the localized behavior of the surrounding soil. In this solution the spring constant is taken as a function of the mode number in buckling. A graphical procedure for solving for the eigenvalues is presented. The solution represents an upper bound on local buckling of buried flexible tubes that may also be affected by imperfections in geometry and residual internal stresses.