The ability to adequately monitor and protect long, deep trenchless crossings installed in rock is critical to ongoing safe operation of pipelines. This paper is a case study of a long horizontally directionally drilled crossing that was subject to significant coating damage at installation.
The pipeline was protected by an impressed current system and a test method was developed to estimate the current pick-up along the pipeline from existing rectifiers. Subsequently, a current requirement test was performed to estimate the effectiveness and efficiency of a supplemental groundbed to be installed adjacent to the crossing.
A permanent cathodic protection system including monitoring was designed and installed. Recommendations for identifying this type of deficiency during the construction phase are proposed.
