聚氨酯在浅部地层冻结管保温中的节能研究

Research on Polyurethane Applied to Energy Saving in Freezing Tube Insulation of Shallow Ground

针对冻结施工中浅部地层冷量散失,产生的冻胀危害永久井架安全的情况,将单管稳态导热温度分布曲线用于冻结管保温层及周围土体的温度分布,得出土体显热散冷量公式,然后结合相变换热公式分析冻结管在保温前后周围土体的相变换热量,最后给出工程实例测温数据及数值拟合曲线,验证单管稳态温度分布曲线的适用性。数据分析表明:159 mm冻结管经50 mm聚氨酯保温后,壁外降温幅度约为保温前的50%,冻结管外3 m范围内温度降幅明显;未保温冻结管管外1m处温度降至0℃需60 d,而保温后则需210 d以上,同样冻结期内产生相变土体体积远小于未保温情况,从而节省大量潜热耗冷量。

According to the evaporation of the freezing value during the ground freezing construction in the shallow strata and the condition of the frost heaving danger to the safety of the mine permanent headframe,a single tube stable thermal conducted temperature distribution curve was applied to the temperature distribution of the freezing tube insulation layer and the surrounding soil and a sensible heat evaporation formula of soil was obtained.In combination with the phase converted heat formula,the paper analyzed the phase converted heat values of the soil before and after the insulation of the freezing tube and provided the project site measured temperature data and the numerical fitted curves.The adaptability of the single tube stable temperature distribution curve was confirmed.The data analysis showed that after the 159 mm freezing tube insolated with 50 mm polyurethane,the outer wall temperature reduction of the freezing tube would be 50% before the insulation and the temperature within 3 m around the outer of the freezing tube insulated could be obviously reduced.As for the freezing tube with no insulation,the temperature within 1 m around the outer of the freezing tube would be reduced to 0 ℃ within 60 days and the temperature of 0 ℃ reached within 1 m around the outer of the freezing tube with the insulation would require over 210 days.With the insulation,within the same freezing period,the phase converted soil volume occurred would be less than the no insulation condition and thus great latent heat freezing value could be saved.