Finite element analysis on mechanical behavior of semi-exposed pipeline subjected to debris flows

Abstract

Before the debris flow occurs, the continuous rainfall may cause the pipeline to be partially exposed (semi-exposed pipeline). The semi-exposed pipeline will be under great threat when the debris flow comes. To study the mechanical behavior of semi-exposed pipeline subjected to the debris flow, a finite element model of interaction between soil and semi-exposed pipeline under the impact of debris flow was established for the practical working conditions of semi-exposed pipeline. Effects of relevant parameters were analyzed, including the velocity of debris flow, impact angle of debris flow, massive stone, and parameters of corrosion pit (i.e. the depth, length, and width of corrosion pit). The results show that the velocity and the impact angle of debris flow and massive stone in the debris flow have a significant influence on the stress and deformation of the pipeline, but the exposed length of pipeline has little impact. Non-pressure pipeline can withstand the greater velocity of debris flow. In addition, parameters of corrosion pit (depth, length, and width) all have some impact on pipeline stress. Based on the result of multiple regression analysis, the effects of relevant parameters of corrosion pit on the maximum Von Mises stress of pipeline are ranked as follows: corrosion depth (A) > corrosion width(B) > corrosion length (L). People can propose an effective protection strategy for the pipeline subjected to debris flow based on the research results.