Use of Continuum Buckling Theory for Evaluation of Buried Plastic Pipe Stability

A buckling theory for design of buried plastic pipes is described, which combines linear shell stability theory for the structure with elastic continuum analysis for the assessment of ground support. The theory provides stability estimates which are superior to those generated using ‘spring’ models for the soil, predictions of phenomena such as long-wavelength crown buckling without the need to pre-guess the deflected shape, and rational assessment of the influence of shallow cover and the quality and quantity of backfill material. As well as describing the continuum buckling theory, the literature is briefly reviewed, buckling as a performance limit for buried plastic pipe is discussed, and the selection of appropriate soil and polymer moduli for use in the theory is also considered.