Abstract：Based on a series of basal hypothesis on soft soil，a basic anti-consolidation equation of saturated soft ground is deduced under the condition of unloading，and the corresponding analytical solution under the condition of single-level constant-speed unloading is obtained. Then the mechanism of rebound deformation is analyzed，and the calculation formula of rebound deformation is provided. Based on the case history，the generation and dissipation process of the negative excess pore water pressure in the anti-consolidation zone of the ground improved by surcharge preloading are studied，and the development law of rebound is obtained，which explains the phenomena of the small rebound magnitude and fast stabilization after unloading.
