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| Inversion and prediction of long-term uplift deformation of high-speed railway subgrade in central Sichuan red-bed |
| DAI Zhangjun1，GUO Jianhua1，2，ZHOU Zhe1，2，CHEN Shanxiong1，YU Fei1，LI Jian1 |
| (1. State Key Laboratory of Geomechanics and Geotechnical Engineering，Institute of Rock and Soil Mechanics，
Chinese Academy of Sciences，Wuhan，Hubei 430071，China；
2. University of Chinese Academy of Sciences，Beijing 100049，China) |
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Abstract Many high-speed railways in the Southwest of China are facing the problem of expansive rock. The long-term uplift deformation of the subgrade caused by expansive rock will seriously affect the safe of the rail. The central Sichuan red-bed refers to the Jurassic red mudstone widely distributed in the Sichuan Basin，which is a typical expansive rock. At a high-speed rail station in central Sichuan，after the deep excavation and unloading of the red-bed subgrade，a new water seepage channel was formed in the bedrock due to the engineering reconstruction，so that the red-bed mudstone that originally in a closed water-proof state established hydraulic connection with the environment. As a result，the slow water absorption and expansion of the red-bed mudstone was the main reason for the long-term continuous uplift deformation of the subgrade. In order to reveal the long-term uplift deformation mechanism and evolution law of the subgrade caused by the expansion of the red-bed，the analysis method was explored，and the deformation measured data was used to invert the red-bed mudstone expansion caused by the infiltration of water through the fissures. On this basis，the prediction of the long-term uplift deformation of the subgrade was carried out. The results showed that，the deformation of the uplift of the subgrade developed rapidly in the first 5 years and it continued to develop during 5 to 15 years，but the deformation rate gradually slowed down. After 15 to 30 years，the deformation rate of the uplift further slowed down，but still showed a slow linear growth trend and failed to reach a stable state.
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2020, Vol. 39 
