Methods of Calculating Soil Freezing Depth of High-Speed Railway (HSR) Subgrade in Cold Climate Conditions in People’s Republic of China

Abstract

Purpose: Methods for calculating soil freezing depth of high-speed railway subgrade are de-veloped given its multilayer structure. Methods: Existing methods for soil freezing depth calculation have been reviewed, advanced Berggren method for calculating soil freezing depth of HSR subgrade and numerically modeling method for subgrade temperature regime on the basis of mathematical model given moisture migration are proposed. The calculation reliability is confirmed by comparison with numerical simulation results and the results of the calculation by method based on Chinese and Russian railway construction standards. Re-sults: The results of soil freezing depth calculations by different methods are similar. It is reasonable to use advanced Berggren method to calculate soil freezing depth for multilayer system. Numerical modeling method makes it possible to predict soil freezing depth includ-ing depth change of freezing and thawing caused by climate warming. Practical signifi-cance: To calculate soil freezing depth of HSR subgrade, it is advisable to use advanced Berggren method. The developed model can be used both to study the logic of subgrade thermal regime distribution at freezing and thawing and to project the thickness of protec-tive layers against a frost for HSR subgrade construction.