Study on quantification of defect size and characteristics of its probability distribution of gas transmission pipeline

By in-door detection to sampling pipeline sections on a gas transmission pipeline site in Sichan, establishes defect detection and size quantification method based on main processes of field sampling, nondestructive inspection, cutting tension failure and defect size test.Result shows by means of detection to sampling pipeline sections that there exists serious surface cracks in pipe's inner toes, with average depth of crack in 1.91mm and maximum depth in 3.85 mm.Probability distribution laws of normal distribution, lognormality and Weibull distribution are adopted and result shows cracks depth a are most approximate to normal distribution.