Abstract:

An analytical solution for the steadystate temperature field of threepipe freezing and water sealing at the corner of a foundation pit is derived to investigate the temperature field distribution of local freezing and water sealing for leakage in the retaining structure of foundation pit engineering. The derivation is based on thermal potential superposition theory and the mirror image method, considering the influence of the adiabatic boundary of the diaphragm wall. The analytical and numerical results of different characteristic sections are compared to validate the accuracy and applicability of the analytical solution. The findings are as follows: (1) The temperature error of each characteristic section under steadystate conditions is within 0.3 ℃, indicating that the analytical solution is accurate. (2) The freezing model gradually becomes stable with increasing freezing time, and the temperature error decreases from 17.1 ℃ on the 10th day to 0.3 ℃ on the 100th day of freezing. The analytical solution shows applicability and accuracy with freezing time. (3) The diaphragm wall with thermal insulation material limits the dissipation of cold energy, which is conducive to the cooling of soil between the positive corner of the foundation pit and the axial plane of the freezing pipes. The frozen soil temperature at the symmetrical position of the axial plane of the freezing pipes is significantly higher (the maximum temperature difference is 17 ℃), indicating a bad freezing effect. (4) The adiabatic boundary should be considered to improve the positional relationship with freezing pipes.

Key words: foundation pit engineering, water leakage, local freezing, temperature field, analytical solution, adiabatic boundary