Effect of uncertain hydrothermal properties and freezing temperature on the thermal process of frozen soil around a single freezing pipe

摘要

Thermal engineering calculation of one-dimensional (1-D) freezing is an important evidence for the evaluation of heat conduction process of artificial ground freezing (AGF). In this work, an array of field experiments of the 1-D freezing processes were carried out, and the coefficient of variation (COV) and scale of fluctuation (SOF) of uncertain hydrothermal properties were obtained. A1-D stochastic hydrothermal model was proposed, and the uncertain thermal processes are computed by a self-compiled program. A model validation and comparison with the experimental and numerical temperatures were presented. According to the relationship between autocorrelation distance (ACD) and SOF for the five autocorrelation functions (ACFs), the effects of the ACF, COV and ACD of hydrothermal properties and the COV of freezing temperature on the 1-D freezing thermal process were analyzed. The results show that moisture transfer can promote the heat transfer process. The thermal process of phase change is unsteady and the corresponding standard deviation (SD) is greater. The effects of ACF of hydrothermal properties on random thermal process are insensitive. The larger the COV of freezing temperature or hydrothermal property, the larger the SD of temperature. The larger the ACD of hydrothermal property, the smaller the SD of temperature.