The intensification of global warming and humidification has exacerbated frost heave damage in seasonally frozen climate environments,which has significant impacts on the operational safety of the Qinghai Tibet Railway a-round the Qinghai Lake region.To explore the mechanism of disease occurrence,water and heat sensors of different depths were installed near the lake and railway subgrade to detect the real-time water and heat migration of the soil in the lake area.Based on monitoring data,the COMSOL Multiphysics finite element platform is applied to simulate and analyze the water pressure distribution and stability inside the railway subgrade.The research results are as follows.Shallow soil responds quickly to temperature changes,while the deeper the soil,the slower the temperature changes;The freezing time is delayed due to the increase in soil depth.The lower soil of the roadbed always maintains a negative pressure state,and the proportion of soil pore volume increases with the action of external water sources;Due to the high content of CO32-and HCO3-in Qinghai Lake water,the salt injection method,after injecting NaCl,will react with cationic Na+and CO32-to form Na2CO3 under the action of water,resulting in the intensification of soilsaltswell-ing reaction after excessive NaCl injection.The stability simulation results indicate that the instability and failure of the roadbed begin from the track surface,which cracks in the middle and slides along the slopes on both sides.Under the squeezing effect,soil particles slide downwards to fill the bottom soil layer pores.After the pores are filled,excess free state soil particles will be squeezed out from the slope corners.
关键词
青海湖地区/冻胀病害/现场试验/水热迁移
Key words
Qinghai Lake region/frost heave disease/on site testing/hydrothermal migration
维普
万方数据