Analyzing Effects of Soil Parameters on Buried Pipe Behavior and Deciding Governing Parameter Using Statistical Approach

Abstract

One of the most common and practical difficulties a pipeline engineer faces at the initial stage of the project is the lack of Soil survey data. Hence, various soil parameters like soil type, density, friction angle, cohesive pressure, depth of cover, pipe coating etc. are needed to be assumed. The critical designs like anchor block requirement, pipe route changes, support loads which involve a huge cost are required to be ‘Issued for Construction’ based on assumed data. This paper briefly illustrates and compares the results obtained from the two most common buried pipe stress analysis methods viz. ‘American Lifeline Alliance - Appendix B’ (1) and ‘Stress Analysis Methods for Underground Pipelines’ (2) and shows their effects graphically on the various Stress Analysis results like pipe movement, end force, active length (virtual anchor length) and bending stress generated in the buried pipeline. Further, this paper comes up with an unique application of ANOVA, a Statistical method, to find out the most significant soil parameter affecting the said results. The paper explains this method with a solved example. These results are useful for a pipeline engineer to determine the governing soil parameter in the design and thus provide a useful tool to make optimum assumptions in absence of soil data so as to minimize the changes in future design and helps saving the cost of the project due to rework.Copyright © 2015 by ASME