Pipe-jacking stoppages modelled using direct shear interface tests
McCabe, Bryan A. O’Dwyer, Kevin G. Sheil, Brian B Burke, Padraig F.
McCabe, Bryan A.
O’Dwyer, Kevin G.
Sheil, Brian B
Burke, Padraig F.
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Publication Date
2022-09-19
Type
conference paper
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McCabe, Bryan A., O’Dwyer, Kevin G., Sheil, Brian B., & Burke, Padraig F. (2022). Pipe-jacking stoppages modelled using direct shear interface tests. Paper presented at the ICPMG2022 10th International Conference on Physical Modelling in Geotechnics, KAIST Daejon, Korea, 19-23 September.
Abstract
In long pipe-jacking drives used for installing utility pipelines, maximum jacking load requirements are usually governed by skin friction at the pipe-soil interface. In addition, field experience has shown that transient peaks in skin friction arise upon recommencement of jacking after stoppages; these stoppage durations can be short (due to the addition of a pipe to the string) or long (due to weekend stoppages or breakdowns) and constitute a risk for pipe-jacking contractors. In this paper, the problem is replicated in the laboratory using direct shear interface tests using a concrete specimen in one half of the apparatus and sand/bentonite mixtures in the other. Once critical state conditions were reached in these tests, stoppages of various durations (from 30 mins up to 2 weeks) were incorporated and the increase in shear stress upon recommencement of shearing was noted. From the experiments, there appears to be a threshold stoppage duration beyond which the skin friction increase appears to plateau, suggestive of a time-limited process within the bentonite. These skin friction data are shown to provide an upper bound to corresponding stoppage data from pipe-jacking drives in sandy ground conditions.
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University of Galway
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Attribution-NonCommercial-NoDerivatives 4.0 International