Long-term deformation rules of railway embankments in permafrost regions: Classification and prediction

Abstract

The long-term deformation rule of the embankment can reflect the impact of environmental factors on the embankment during different periods, and the deformation rule of the embankment is also the ultimate expression of embankment structure change under the interaction of various environmental factors. This study presents two classification methods for such deformation rules, which are based on long-term deformation monitoring data spanning 2006–2020, and obtained from 39 embankment sections along the Qinghai–Tibet Railway (QTR). The deformation rules of railway embankments in permafrost regions can be classified into five categories based on the accumulated deformation: slight heave, slight settlement, slow settlement, rapid settlement, and damage type. In addition, the curve trend of the embankment deformation can be used to categorize the deformation rules into five types: linear, step, fluctuating, U-shaped, and heave. The formation mechanism and characteristics of each type are summarized and analyzed. The results indicate that the linear type is the most unstable type, and the embankment experiences continuous and significant settlement deformation. Finally, two prediction models are established for the long-term deformation rules of embankments in permafrost regions. These models are used to establish the relationship between the early deformation rates and long-term deformation rules of the embankment, and can be used to predict whether the deformation rule of an embankment after 10 years of completion is linear. This study aims to provide early decision support for embankment stability evaluation, deformation prediction, reinforcement, and other studies in permafrost regions.