L51672 Weight Coating Design for Submarine PL On-Bottom Stability

There were two main objectives of this research. The first objective was to verify SINTEFs' pipe/soil interaction model test results, on which the A.G.A. Level 2 and 3 soil models are based. The second objective was to quantify the amount of conservatives built into the model equations for stiffer clay soils (above 30 psf shear strength). The original testing (at SINTEF) was done in soft clay soils (30 psf), and extrapolations to stiffer soils were done very conservatively, because data was not available. To accomplish these two objectives, pipe-soil interaction model tests were conducted at Texas A&M University in clay soils of approximately 30, 75, and 150 psf shear strength. Twenty-seven monotonic loading tests, and fifty-seven cyclic tests concluding with pipe break-out were performed. This is roughly four times the amount of testing originally done on clay by SINTEF. The test parameters and results are summarized in Table 1-1 for the monotonic loading tests, and Table 1-2 for the
cyclic (displacement controlled) loading tests.