Numerical Simulation Analysis Of Temperature Field And Insulation Measures Of Subgrade For Ha-Qi Passenger Dedicated Line

In our country, the distribution of the frozen soil is more extensive, which accounts for about 75% of the total land area in our country, and the seasonal frozen soil area accounts for 53%. Seasonal frozen soil as a result of the winter easily cause the frost heave of high-speed railway subgrade, and the subgrade will melt in spring. The high-speed railway subgrade in freezing and thawing cycles occurs irregularity of the track,mud pumping and other damage, which puts forward a huge challenge to the railway construction. Therefore, in order to make damage of the high-speed railway subgrade in Seasonal frozen regions, the analysis of the formation mechanism of the frost heave in seasonal frozen regions and the temperature field distribution law of subgrade is very important for the insulation measures of subgrade in frozen regions. In this Thesis, Based on the background of Ha Qi high-speed railway of DK221+150 cross section, temperature field distribution law of subgrade under different thermal insulation measures is obtained by numerical simulation, and research of high-speed railway subgrade in frozen regions reasonable insulation measures.The main research contents of this Thesis include:(1)This thesis analyzed several main factors that influence high-speed railway subgrade frost heave in frozen regions from the soil, moisture and temperature.(2)Combined with the ground temperature monitoring data of the DK221+150 section of Ha Qi high-speed railway, the variation law of the ground temperature amplitude with depth was studied. The distribution law of the ground temperature and the freezing depth variation law of high-speed railway subgrade in seasonal frozen soil area were analyzed.(3)According to the engineering example of Ha Qi high-speed railway, the numerical model of the temperature field of subgrade was established by ABAQUS finite element software, and the rationality and reliability of model was verified by comparing with the temperature measured data.(4)In order to study the thermal insulation effect of foamed concrete insulation board on high-speed railway subgrade in seasonal frozen soil area and optimize length of foamed concrete insulation board laying on subgrade, the temperature field numerical simulation of foamed concrete insulation board subgrade were carried out under different conditions. The simulation results show that: foamed concrete insulation board has an obvious thermal insulation effect on subgrade. In addition, suggest that the laying method of insulation board was laid on the whole subgrade surface and the length of insulation board laying on the subgrade slope extends to 2.6 m from shoulder.