Investigating the response of small-diameter buried steel pipes to axial ground movements

Priyom, Sudipto Nath (2025) Investigating the response of small-diameter buried steel pipes to axial ground movements. Masters thesis, Memorial University of Newfoundland.

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Abstract

Small-diameter steel pipes are widely used for energy transportation to domestic supplies across Canada. These distribution pipelines often encounter ground movement, leading to pipe distress and failures. This research focuses on the responses of distribution pipes to axial ground movement using full-scale tests and numerical modeling. In the full-scale laboratory tests, a soil box was moved axially at a constant speed while a steel pipe buried in the soil box was restrained at one end, simulating the axial ground movement. Three different pipe diameters (26.7 mm, 60.3 mm, and 114.3 mm) were studied. Two compaction techniques, namely, hand tamper compaction and vibratory plate compaction, were used to examine the effects of different backfill compaction methods. The soil box was moved at three constant speeds (0.5 mm/min, 1.0 mm/min, and 2.0 mm/min) to observe the impact of varying ground displacement rates. Strain at the pipe’s restrained end and pipe elongation were also measured. The test results for the 114.3 mm pipe at a pulling rate of 0.5 mm/min were simulated using finite element (FE) analysis to examine the soil-pipe interaction numerically, which could not be measured during experiments. The effect of interface dilation was found to be negligible in the numerical simulation, indicating that the increase in axial soil resistance on the pipe under dense sand conditions was most likely due to compaction-induced ground stresses and the surface roughness of the pipe. Three different approaches were employed to simulate the compaction-induced ground stresses and the resulting peak axial soil forces for the 114.3 mm diameter pipe. The effect of pipeline misalignment on the results was also studied using FE analysis.

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