The Effects of Corrosion Pattern and Trench Fill on the Ovalization of Buried Steel Pipe

Because there is no closed-form solution to predict ovalization of buried pipe with an uneven pattern of wall loss that is subjected to soil and surface loads, a conservative screening approach has been to assume a uniform wall loss around the pipe circumference, with a wall thickness equal to the thinnest, most corroded spot. To improve on this grossly conservative approach, this paper numerically studies the effects of uneven corrosion patterns around the circumference on the ovality of the pipe, using finite element simulation of the corroded pipe and surrounding soil. A second topic addressed in this paper is the effect of trench fill material on the ovality of the pipe, in the case where the trench fill has different soil moduli, caused by variations in compaction or materials, including controlled low-strength material (CLSM).