Finite element study on temperature field of subway connection aisle construction via artificial ground freezing method

Based on the engineering background of the connection aisle reinforcement construction in Nanning Subway Line 3 using artificial ground freezing technology, this study investigates the development and spatial distribution of temperature field during artificial freezing using three-dimensional finite element method. Validation between finite element results and measured results is firstly conducted in order to verify the feasibility of numerical method. The temperature field contours as well as the time-dependent -1 degrees C and - 10 degrees C isotherms in different sections of frozen soil are then explicitly examined. The critical zones are identified and the formation of frozen soil curtain with time in the surrounding of connection aisle is discussed. With the aid of the numerical model, further investigations into a series of influencing factors such as the thermal physical parameters and soil condition factors are made in a systematic and rational manner. It is found that the thermal conductivity has a significant effect on the time-dependent freezing temperature while the phase change latent heat has little effect. The effects of initial ground temperature, brine cooling plan and soil type are also analysed, and the cementtreatment of sandy and soft soils enables a better freezing effect. This study may benefit the understanding of temperature field behaviour of frozen soil surrounded subway connection aisle during artificial freezing and therefore provide certain reference for both academic and industrial researchers in similar fields.

Automated summary

This study investigates the development and spatial distribution of temperature field during artificial freezing in the connection aisle reinforcement construction of Nanning Subway Line 3 using a three-dimensional finite element method. Critical zones and the formation of frozen soil curtain are identified while the effects of thermal physical parameters and soil conditions are analyzed systematically. The study provides insights into temperature field behavior of frozen soil during artificial freezing, benefiting both academic and industrial researchers in similar fields.