Research On Loess Ground Freezing Wall Thickness Prediction Method And Engineering Application

Artificial Ground Freezing has been widely used in mining engineering, tunnel construction, and deep foundation pit bracing engineering. The Research and Application of Artificial Ground Freezing in China’s urban construction is more in the Yangtze River Delta region like Shanghai, Jiangsu, Zhejiang and so on, but less in the Midwest loess region, there are still many problems in the troubled engineering loess ground freezing wall design and engineering applications. This paper intends to the study on loess ground freezing wall forming process and its engineering application, propose prediction method of frozen wall thickness considering the influence of soil moisture, freezing pipe installation spacing and other factors, and provide theoretical support and technical guidance on the loess plateau construction applicationsBy numerical calculation analyzed loess ground freezing wall temperature field change process in the ring piping conditions, Summarized the variation of the temperature field. As time goes by, frozen wall temperature experienced rapid decline, slow decline, stabilized in three stages. In the ring piping conditions, frozen wall thickness of the medial extended freeze faster than the outside, and a relatively large thickness of the outer. After thawing frozen pipes applied, Freezing fronts extend outward from the frozen pipe, thickness increases, and gradually, growth rate decreased, eventually forming stable thickness of frozen wall. Further revealed the influence of soil moisture, brine temperature and freezing pipe installation spacing and other factors on the formation of frozen wall. brine at a fixed temperature, to the same soil density, larger water content of the soil, frozen wall is formed faster, on the same soil water content, frozen wall forming speed with decreasing temperature of the brine increases, with the freezing tube spacing decreases. Loess stable frozen wall thickness with increasing soil water content increases with decreasing temperature of the brine increases, with the freezing tube spacing increases. Based on the numerical results, obtained by fitting considering soil moisture and freeze tube spacing ring piping under conditions determined formula frozen loess wall thickness. Further based on the calculation results under straight piping conditions, fitting considering soil moisture and freeze freezing tube spacing determined loess wall thickness calculation formula.Based on the temperature monitoring data of a frozen loess wall project, revealed the loess freezing wall temperature field variation in actual project, and compared with numerical simulation results. The reaction temperature field variation both are basically the same. Comparison with the measured thickness of frozen wall thickness is calculated by freezing fitting formula confirms the rationality of the fitting formula.