The underground pipes group at the laboratory is carrying out work to determine the loads on buried pipelines, and their effects on the pipes concerned.as part of the programme a steel pipeline was instrumented where it passes under a minor road, and observations were made during the backfilling and subsequent loading tests in the period between October 1970 and June 1971. The pipes are 1.83m in diameter,with a wall thickness of 12.7 mm.over the test length sand was used for bedding the pipe and for backfilling the trench,the crown of the pipe being 1.60 m below road level. This report gives the results of soil pressure measurements around and above the pipe,changes in the internal diameter, and strain in the pipe wall around the circumference. The measured deflections were small (no more than 4.0 millimetres at any stage),as were the strains in the pipe wall. Comparisons are made with calculated deflections by the Spangler formula,and by a finite element analysis. (Author/publisher)
Samenvatting