LAUSR

Abstract The suitability of lime-stabilized weathered red mudstone (LSWRM) as a subgrade filler material has not been comprehensively investigated. This study aims to determine the dynamic response and cumulative settlement characteristics of a newly designed LSWRM subgrade and evaluate the adaptability of LSWRM for use in high-speed railways (HSRs). Full-scale model testing of the LSWRM subgrade was performed using a cyclic loading apparatus. Under dynamic wheel loads and rainfall conditions, the distribution characteristics of the dynamic stress, dynamic displacement, and acceleration of the subgrade were monitored. The cumulative settlement law of the subgrade bed was analysed to determine the adaptability of LSWRM. Through a comparison with the standard Group A&B subgrade, the dynamic wheel load was identified as a main factor influencing the distributions of the dynamic parameters, whereas the influence of daily rainfall was limited. The dynamic parameters showed a saddle-shaped transverse distribution. Additionally, the appropriate thickness of the subgrade bed was evaluated based on the dynamic stress attenuation characteristics, and the cumulative settlement of the bottom layer accounted for 0.3% of the subgrade bed height. These dynamic parameters can meet the requirements of existing HSR specifications, and thus, filling the bottom layer with LSWRM is an appropriate option.