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

摘要

For the design of steel liners sometimes the case 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 slenderness 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 calculation of the critical external pressure, such as, i) different types of geometric imperfections, ii) additional considering of longitudinal compression stresses due to restraint effects, iii) limited 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 p(0,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 finally also design charts are presented.