Bemessung von beulgefährdeten Druckschachtpanzerungen unter Außendruck - Teil 1: Unversteifte Rohre

For the design of steel liners sometimes the ca-se of external pressure is relevant, due to water pressure in the rock mass. In the cases of inspection with empty pipe the steel liner is susceptible to shell buckling, due to high slender-ness of the steel pipe. The design rules in practice, based on analytical and empirical models, were developed in the 1960– ies. This contribution sums up the results of a research project, with the aim of including more realistic effects for the calcula-tion of the critical external pressure, such as, i) different types of geometric imperfections, ii) additional considering of longi-tudinal compression stresses due to restraint effects, iii) limi-ted radial stiffness of the rock mass. Part 1 contains the cases of unstiffened steel liners. First the design models in practise for calculation of the critical external pressure p0,cr are presented and their results are compared. Based on the presented numerical results of a comprehensive FE – study the most accurate design models are shown and fi-nally also design charts are presented.