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)
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.
2020, Vol. 39 
