Lateral deformation of expressway embankment on the Qinghai-Tibet Plateau: field observation and theoretical model

This study discusses a two-year-long field observation of the lateral deformation and ground temperature of an experimental expressway embankment on the Qinghai-Tibet Plateau. The distribution features and evolution process of lateral deformation were obtained and analysed. The results showed that the maximum lateral deformation over 2 years was higher than 14 mm and continues to increase. Large lateral deformations occur only at two depths and can be disregarded at other depths. In layers with large lateral deformation, the cumulative lateral deformation grows periodically during the thawing period and decreases during the freezing period. The distribution and evolution features of the monitored lateral deformation indicated that it was caused by thermal stress, and the lateral deformation may be identified as creep-springback deformation under variable thermal stress conditions. Finally, a creep model under a periodic thermal load was established to verify the effectiveness of the proposed lateral deformation mechanism in explaining the lateral deformation behaviour of embankments. The calculations showed that the proposed mechanism can explain the crucial features and accumulation of lateral deformation. The results and analyses reported in this study can provide new references for research on road deformation and disease development.