Abstract: The regional excavation project of Fuhe river channel is an early key project of the construction of the Yangtze River new city. In this project, the rebound deformation of the lower stratum caused by the widening and deepening of the river will affect the safe operation of the high-speed railway bridge. In this paper, the laboratory compression rebound tests of the silty clay and the muddy silty clay were performed for the main excavated strata, and the effects of unloading ratio and unloading stress level on the rebound modulus and rate of rebound of soil are discussed. The test results show that the lateral compression modulus and rebound modulus of the soil vary nonlinearly with the overburden pressure, and both of them increase with the increase of overburden pressure; the rebound modulus and rebound of soil decrease with the increase of unloading ratio; with the increase of unloading stress level, the rebound modulus increases and the rebound decreases.

Key words: Compression Rebound Test, Unloading Ratio, Critical Unloading Ratio, Rebound Modulus