The code wrote in matlab is mainly divided into two files: 'Unsaturated_consolidation_model.m' and 'chasing_method.m'. The 'chasing_method.m' file is used to calculate the finite difference solution. The 'Unsaturated_consolidation_model.m' file mainly divided into two parts. The first part is the calculation procedure of approximate solution, and the second part is the finite difference procedure. Besides, the 'chasing_method.m' file is only used in the second part of the 'Unsaturated_consolidation_model.m' file.