The Problems and Countermeasures of Cathodic Protection Accepatnce of The Yili River Crossing by Horizontal Directional Drilling Method

Abstract

This paper aims at the problems and countermeasures of cathodic protection acceptance of the Yili River crossing project by horizontal directional drilling (HDD) method, addressing the performability of the acceptance criteria using polarization potential offset of not less than 0.7V required by the Kazakhstan Owners. Polarization potential and depolarization potential measurements as well as coating resistance measurements have been carried out based on the methods and requirements specified in NACE and ISO standard. The results show that protection coating has been damaged in the process of the HDD implement and cathodic protection system can protect the steel exposed, and that the polarization potential offset of not less than 0.7V required by the Owner cannot be met even the protection potential within the protection criteria specified in the design document. Finally, polarization potential offset of not less than 0.33V has been agreed on by all parties for the acceptance of HDD pipe section. Keywords-yili river; horizontal directional drilling crossing; cathodic protection