Pipeline Laying and Embedment in Soft Clayey Soils: Statistical Description and Field Observations

The as-laid embedment of subsea pipelines is a key parameter in pipeline design impacting directly in the pipe-soil interaction. In general, the measured as-laid embedments are frequently greater than predicted by traditional static penetration models considering only the pipe submerged weight in the vertical load. The source of this discrepancy is commonly associated with additional vertical pipe-soil contact force from pipeline catenary touchdown zone and dynamic lay effects resultant from dynamic vessel and pipeline movements. This study presents a statistical description of superficial strength parameters associated with the statistical data from as-laid embedment of pipelines with similar pipe bearing pressure and installed by reel-lay and J-lay methods in deepwaters on soft clay soils. The statistical approach presents an improved methodology to estimate the likely range of aslaid pipeline embedment giving an important contribution regarding the reliability of theoretical static penetration models and a guidance for statistical calibrated upper, mean and lower bounds values of the dynamic touchdown lay factor f_dyn for pipeline normal installation, pipeline assembly connections or abandonment and recovery conditions in Brazilian deepwater scenario.