By J Gaunt, J J Trott and J B Stevens, TRRL
This paper was first published in GE’s April 1976 issue
With the objective of providing data for use in the development of improved methods of structural design and construction of buried flexible pipelines, a programme of full scale tests is being carried out at the Transport and Road Research Laboratory. Dynamic and static loadings are applied to shallow-buried pipes when installed in different beddings and with different degrees of compaction. Pipe deflections wall strains and soil pressures are measured and used to assess the structural performance of the pipes.
The results demonstrate the critical importance of the standard of workmanship achieved during the installation of buried flexible pipes. Large variations in the amount of deflection of the pipes under load have been found in a number of experiments identical in all except the standard of workmanship in placing the fill around the pipes. Further, low quality materials placed to a high standard of workmanship have produced the same performance as high quality materials placed to a low standard. It is concluded. that more effort must be made at the design stage to make a realistic assessment of the standard of workmanship likely to be achieved during construction.