Investigation On Buckling Mechanics Of Buried Pipes

The buried pipes are playing an important role in the economic construction and daily life in the world. Many pipes which were built in the sixties and seventies of20th century have been close to their service life. There are leaking problems in some seriously damaged pipes, which result in the useless of the pipes. One of the popular and effective rehabilitations, at home and abroad, is using the trenchless technology and embedding a layer of elastic linings in the inner surface of the damaged pipes, which can save a lot of manpower and material cost. Pipe linings are often installed in host pipes that lie below the ground water level, and so the linings may be buckling when the host pipes are deeply buried. The buckling of the pipe linings can lead to instability of the pipes and cause great economic loss. So it is important to develop the research of the mechanism of buckling and unstability of the buried pipes.In this paper, the current research status for the buckling of pipe linings encased in rigid host pipes is reviewed, and the mechanism of buckling, model analysis and numerical simulation of buckling are summarized. The main study of this paper can be generalized as follows:(1) Following the theory of minimum potential energy and the theory of thin shell, an analytical solution is developed for the elastic buckling of cylindrical pipe linings with variable thickness encased in rigid host pipes. When the thickness of the pipe lining is constant, the analytical solution presented in this paper can be simplified to dock’s classic analytical solutions.(2) Two-dimensional finite element method (FEM) with ABAQUS is used to verify the analytical solutions. The FEM results are close agreement with the analytical solutions presented in this paper.(3) Local buckling of cylindrical pipe linings with variable thickness is studied with three-dimensional FEM. Parametric analysis for the critical buckling pressures is then carried out.(4) The buckling of thin walled steel jackling pipes with large diameter under axial pressure is investigated on the jacking progress. Stiffing rib is used to embed the pipes to prevent the buckling and collapses.