Optimization study on artificial ground freezing in elliptical tunnel construction: A comprehensive analysis of groundwater flow and thermodynamic parameters of soil

• Numerical analysis is conducted to assess effects of groundwater flow in AGF process. • A novel design approach is proposed for freeze pipe layouts in elliptical tunnel face. • The design concepts are implemented using a Gravitational Search Algorithm (GSA). • GSA algorithm employed for optimal design significantly reduced the freezing time. • Sensitivity of thermodynamic parameters regarding the efficiency of AGF is analyzed. Recently, there has been a growing interest in the use of Artificial Ground Freezing (AGF) to temporarily stabilize unstable ground at tunnel construction sites. Recognizing that the effectiveness of this method is significantly influenced by groundwater flow, it is crucial to conduct a sophisticated thermal-hydraulic coupling analysis to assess the potential adverse effects of groundwater flow in the artificial ground freezing process. This study establishes a numerical analysis model to evaluate the efficiency of AGF and proposes a novel design approach for freeze pipe layouts in elliptical tunnel face under conditions of excessive groundwater flow. These design concepts are implemented using a Gravitational Search Algorithm (GSA) and the COMSOL Multiphysics platform integrated with MATLAB. Furthermore, the study employs a constructed simulation model to analyze and assess the sensitivity of thermodynamic parameters concerning the efficiency of AGF under groundwater flow conditions. The findings contribute valuable insights to the field of tunnel construction and ground stabilization.