In order to study the deformation characteristics and constitutive model of frozen moraine soil in cold regions

the MTS-Landmark 370.10 type dynamic and static triaxial test system was applied to study the stress-strain curves and volumetric curves of frozen moraine soil at a temperatures of-3℃and-5 ℃ and confining pressures of 0.1、0.5、1、4 and 8 MPa.The results show that the stress-strain relationship of frozen moraine soil is a strain softening type

and it can be divided into 3 stages:linear

nonlinear and strain softening.The greater the confining pressure

the obvious the softening phenomenon.With the increase of axial strain

the volume of the sample contracts first

and then expands.Based on the experimental results

an improved model was proposed based on the three-parameter model of the Shen Zhujiang and the modified Duncan-Chang hyperbolic model.The calculation results of the improved model were compared with the calculation results of the three parameter model of Shen Zhujiang and the modified Duncan-Chang hyperbolic model.Results show that the improved model has good fitting effect and can be used to describe the strain softening and dilatancy characteristics of frozen moraine soil.