In the bustling world of urban infrastructure development, the construction of metro link passages often encounters challenging soil conditions, particularly in coastal areas with soft soil strata. A recent study published in *Chengshi guidao jiaotong yanjiu* (Urban Rail Transit Research) sheds light on the intricacies of freezing methods used in such projects, offering valuable insights for the energy sector and construction industry alike. The research, led by CHEN Junhao from the College of Civil Engineering at Fujian University of Technology, focuses on the development of temperature fields during freezing construction for metro link passages within the same interval in soft soil strata.
The study takes a deep dive into two link passages of Shanghai Rail Transit Line 15, utilizing a three-dimensional finite element numerical model established with ANSYS software. This sophisticated approach allows for a detailed analysis of how cooling capacity loss affects the development of freezing temperature fields. “The implementation effects of the freezing method vary across different stratigraphical and surrounding environmental conditions,” explains CHEN Junhao. “Our research aims to understand these variations better, particularly within coastal soft soil strata.”
One of the key findings of the study is that while two adjacent link passages in the same interval exhibit similar temperature field development laws, the cooling capacity loss in the brine circulation system can significantly impact freezing efficiency. The soil temperature decrease rate in the first link passage was found to be lower than that in the second passage, highlighting the importance of maintaining optimal cooling capacity. “The freezing efficiency of the first link passage is inferior to that of the second passage,” notes CHEN Junhao. “However, the difference in temperature field development gradually diminishes with prolonged freezing duration.”
The research also reveals that the freezing effect in the silty sand layer surpasses that in the gray silt layer, with freezing development speeds of 31.05 mm/day and 28.53 mm/day, respectively. After 45 days of freezing, the freezing curtain thickness around the weak sections of the first link passage reaches 2.2 meters, with an average temperature of -10.23℃. These findings have significant implications for the energy sector, particularly in optimizing the use of freezing methods in metro link passage construction.
The study’s insights could shape future developments in the field by providing a better understanding of the factors influencing freezing efficiency. This knowledge can lead to more effective and energy-efficient construction practices, ultimately reducing costs and environmental impact. As urbanization continues to expand, particularly in coastal regions, the demand for robust and efficient construction methods will only grow. The research published in *Chengshi guidao jiaotong yanjiu* offers a crucial step forward in meeting these demands, ensuring that the construction industry can adapt and thrive in the face of challenging soil conditions.
In the words of CHEN Junhao, “Our findings provide a foundation for further research and practical applications, ensuring that the freezing method remains a viable and efficient option for metro link passage construction in soft soil strata.” As the industry continues to evolve, such research will be instrumental in driving innovation and sustainability in urban infrastructure development.