Determination of the hydrodynamic condition in artificial ground freezing based on multi-field coupling theory

Abstract

Artificial Ground Freezing (AGF) represents a widely adopted auxiliary technology utilized to mitigate groundwater infiltration and ensure the stability of excavation faces in underground construction endeavors. Notably, the hydrodynamic condition stands as the primary contributor to the non-uniformity observed in the freezing curtain. However, directly assessing the hydrodynamic condition during the construction of AGF poses a formidable challenge. In this study an moisture-heat model was initially formulated, incorporating two boundary treatment methodologies, to quantify temperature variations throughout the AGF under different hydrodynamic conditions. Given the inherent uncertainties associated with hydrodynamic conditions, a novel approach grounded in optimization theory (MHO) was proposed and integrated with the moisture-heat model. This methodology aims to ascertain the hydrodynamic condition within AGF by minimizing the summation of squared differences between calculated and monitored temperatures at selected, typical measurement points throughout the entire freezing. The proposed method was numerically resolved and subsequently validated through rigorous laboratory tests conducted by fellow researchers. The results indicate that the methodology presented in this paper offers more accurate predictions of hydrodynamic conditions; the comparison between calculated and monitored temperatures under optimized hydrodynamic conditions exhibits a significantly closer alignment than that obtained when solely considering horizontal hydrodynamic conditions.