Unified formula for average temperature of frozen soil wall by row-piped freezing

Taking into account the poor accuracy of “Chengbing” formula and the complexity of theoretical solutions, a unified empirical formula was proposed to calculate the average temperature of single-row-pipe,double-row-pipe and three-row-pipe frozen soil wall. This formula is concluded from the form of the equivalent section method. Within the possible range of the freezing pipe layout parameters for the practical engineering conditions,a comprehensive error analysis was carried out,comparing the average temperature calculated by empirical formula with the numerical inte- gration of analytical solutions. The results demonstrate that the error of the solution calculated by empirical formula can be controlled within ±1 ℃ ,which bears more favorable accuracy for engineering compared with “Chengbing” formula. Meanwhile,the concise form of the empirical formula makes it possible for its wider application in practical projects.