Formulae and methods for the analysis and design of joint packers between pipes in pipe-jacked tunnels are investigated. The aim is to determine their appropriate application in different situations which arise during tunnelling. Proposals of the preliminary European Standard give a formulation which confirms the work of Norris extended by Haslem. However, further analysis of pipeline behaviour is needed to apply it. Four such analyses are considered: the Australian Concrete Pipe Association method for cracked pipes explained by Ripley and a new proposal reducing its assumptions and approximations; and methods for both rigid and flexible pipes capable of sustaining tensile stress as Haslem reported. Reinforced concrete pipes typically used in Great Britain sustain tensile stress. Because all pipes in Norris's study were reinforced, allowing for flexure of the pipes is shown to be more appropriate than analysis for cracked pipes. The Australian method underestimates the maximum stress at the end of the pipe compared with the adjusted analysis suggested. Further practical investigation is necessary to determine when either method is suitable. In comparison with performance in real tunnelling works observed by Norris, calculated contact stress seems to discriminate conditions predicting pipe damage more finely than the preliminary European proposals.
Stress formulation for joints in pipe-jacked tunnels
Tunnelling and Underground Space Technology ; 12 , Suppl 1-2 ; 39-48
1998
10 Seiten, 10 Quellen
Aufsatz (Zeitschrift)
Englisch
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