A testing procedure and methodology has been developed to provide more realistic pipe-soil response curves which account for differing soil types, pipe and trench geometries and backfill conditions. Such curves increase the reliability of the pipe-soil interaction analyses, and help to reduce overall conservatism in definition of springs for pipe-soil interaction.
Pipe-soil spring response is now generally determined by geotechnical engineering estimation of the soil properties which are used as inputs to simple pipe-soil interaction guidelines. A new dual axis field test procedure, including equipment and interpretative methodology has been developed to directly measure soil response curves for bearing and shear interactions. A numerical modelling protocol interprets these measurements to directly assess pipe-soil spring responses, rather than relying on simplified guidelines.
This paper includes the field and laboratory testing and associated numerical modelling used in the development of the pipe-soil spring response process, as well as the initial results of trials with the new dual axis testing system. The next step for this initiative will be the development of a database of field test data, from which significant advancements can be made to further improve pipe spring recommendations.