Calcium clay layers are widely distributed in the Huainan-Huaibei mining area

with the characteristics of low freezing point

strong frost heave

easy disintegration upon contact with water

and low strength

posing a severe challenge to construction using freezing methods. To investigate the mechanical response of frozen calcareous clay under complex stress paths

true triaxial compression tests were performed on the ZSZ-2000 frozen soil true triaxial test platform

varying confining pressures

temperatures

moisture contents

and intermediate principal stress ratios. The strength and deformation characteristics of frozen calcareous clay under these varying conditions were analyzed. The test results indicate that the strength of frozen calcareous clay has a good quadratic relationship with the intermediate principal stress coefficient b and confining pressure

is negatively correlated with temperature

and positively correlated with moisture content. Furthermore

the rate of increase in the failure strength of frozen calcareous clay decreases as the moisture content rises. The failure strength is significantly influenced by the intermediate principal stress and confining pressure

showing both strengthening and weakening effects. A critical intermediate principal stress coefficient of =0.75 and a critical confining pressure of =3 MPa were identified. As the confining pressure rises

the volumetric strain gradually shifts from initial shear contraction followed by shear dilation to pure shear contraction. Moreover

as the b value increases

the peak volumetric strain of the samples also increases. Based on the experimental results

an improved Duncan-Chang model was developed

taking into account the effects of temperature

moisture content

and intermediate principal stress coefficient

and its reliability was verified. The research findings provide a theoretical foundation for optimizing frozen wall design and deep shaft excavation using freezing methods.