Coupled SPH-FEM analysis of piled power transmission tower system subjected to debris flow

Abstract

Debris flow is a type of highly dangerous geological hazard, which can pose significant threat to the safety of various infrastructures including power transmission tower system. However, the performance of piled power transmission tower system against debris flow has yet to be well investigated. A validated coupled SPH-FEM method was employed to investigate the behavior of a typical piled power transmission tower system subjected to various debris flows, accounting for influencing factors of slope angle, sliding distance, and density and thickness of debris flow. The findings revealed that the incorporation of power transmission tower was important to accurately estimate the impact force and horizontal displacement of the pile and the frontal piles undertook more than 70% of the total impact force; among the factors considered, the slope angle and density were found to be more influential. After examining the performance of existing prediction methods, two semi-empirical equations were proposed for respectively estimating the maximum impact force and horizontal displacement of pile based on multivariate regression analysis. Furthermore, it was found that debris flows did not likely cause steel tower to directly experience structural damages; however, its pile foundation could suffer moderate to severe damages depending on the debris flow conditions.