To explore the mechanism of uneven settlement of the cross-river subway under bidirectional cyclic load after the artificial ground freezing method, this paper analyzes the pore pressure and stiffness of saturated soft clay in Hangzhou. A dynamic triaxial apparatus was used to conduct cyclic loading tests on the reshaped silt soft soil after freezing and thawing, and the evolution patterns of pore pressure and stiffness in relation to cyclic loading cycles were quantified. The test results show that: freezing action damages the soil microstructure, and the pore pressure development level of frozen soil is higher than that of unfrozen soil; when the dynamic stress level is less than a certain value, the stiffness of silty soft soil shows a hardening trend under cyclic loading; With the soil consolidation confining pressure and radial cyclic stress ratio increases, the pore pressure stability value increases, and the increase in soil stiffness increases also. Based on the test results, a prediction model, considering the ratio of effective confining pressure to radial cyclic stress, for the development of pore water pressure in freeze-thaw soft soil under bidirectional cyclic loading is established. The study found that as the soil skeleton structure is compacted, the soil pore pressure stability value and stiffness increase. And within the range of stiffness hardening, the pore pressure stability value and stiffness increase are linearly related.