Abstract:The Duncan-Chang nonlinear elastic model is widely used to calculate the stress-strain relationship of coarse-grained soils in water conservancy projects such as cofferdam construction and earth-rock dams. However, the Duncan-Chang model has relatively many parameters, and the calculation results often cannot fully reflect the dilatancy characteristics of the soil. In order to solve the above shortcomings, based on the Duncan-Chang model, this paper proposes a more simplified parameter form of stress-strain expression, and based on the Shen Zhujiang model, a quadratic parabolic form is used to describe the strain, and the model parameter form Improved and established a volume ratio expression reflecting the relationship between soil body strain and axial strain. Finally, the improved model is verified by the test results of coarse-grained soil and cohesive soil. The results show that the theoretical calculation results are in good agreement with the experimental results, and the improved model can better reflect the characteristics of soil body strain and the stress-strain relationship, which provides a reference for the calculation of the soil stress-strain relationship in actual engineering.