A method for solving temperature field of single-row freezing pipe based on temperature rise formula of freezer
To solve the problem of the calculation insufficient accuracy in traditional analytical solution for the artificial ground freezing temperature field of the whole freezing area in the metro cross passage.At the same time,it established the analytical solution by the freezer's temperature data.Moreover,realize the accurate solution of the whole area temperature field.The calculation model for the freezing temperature field of a single row freezing pipe fitter to the temperature distribution characteristics of the meter cross passage artificial ground freezing project was established based on the relationship between the rate of temperature rise of the refrigerant after stopping freezing in the freezing pipe and the thickness of the frozen curtain generated by the same freezing pipe.Then five critical parameters in the new method were proposed.They are the refrigerant temperature rise rate V,the calculation coefficient of the frozen curtain thickness ηA and ηB,and frozen curtain thickness revision factors n1 and n2.While the methods to determine these parameters were given.Among them,the refrigerant temperature rise rate V should use the average temperature rise rate of the refrigerant at four hours after stopping freezing.Furthermore,the calculation coefficient of the frozen curtain ηA and ηB,the frozen curtain thickness revision factors n1 and n2 could be determined by numerical calculation or empirical data.Furthermore,the new temperature method applied scope and solution process was proposed.In the end,the reliability verification of the new temperature field solution method was carried out through a cross passage freezing project in Beijing.By comparing the solution results of the side wall temperature field of the cross passage with the measured temperature data,it can be seen that the temperature obtained by the new temperature field solution method and the measured temperature difference of the temperature measurement pipe was 0.43℃and 0.52℃,respectively,which are far lower than the control index of 1.0℃.At the same time,the deviation of the calculated frozen curtain thickness obtained by the new solution method and the measured frozen curtain thickness after excavation is 8～10 cm,with a deviation accuracy of about 6%,which also meets the engineering accuracy requirements in cross passage by the artificial ground freezing method.In addition,based on the calculation results and field analysis,it is pointed out that the main calculation deviation is caused by insufficient accuracy of the thermal physical parameters of the soil,drilling deviation of freezing pipe,and simplification of freezing pipe structure in the calculation.Furthermore,based on existing research results,the frozen curtain thickness calculation coefficient for typical formations in multiple cities of China is given(such as Shanghai,Changzhou,and Suzhou).This study can provide the theoretical support for implementing of the new temperature field calculation method and the whole area temperature field solution based on the freezing pipe's self-temperature data.While the use of new calculation method can effective avoid the temperature deviation calculated by traditional analytical solution's further estimate result on the area without any temperature measurement pipes.
artificial ground freezingwhole area temperature fieldprecise solutionprocess of calculationcross passage
万方数据
维普
