In order to know about the joint effect on the unloading triaxial rheological rules of pelitic siltstone

step unloading triaxial rheological experiments with the same initial confining pressure were carried out under different deviatoric stresses. The precast method of joint specimen and the test process are introduced; then the variance law of axial and lateral rheological strains of joint specimen under different deviatoric stresses is investigated. The results show that the axial and lateral rheological strains of jointed specimen increase with the decrease of confining pressure; and the increasing tendency of jointed specimen with the dip angle ? of 0°is the steepest; and followed by jointed specimen with the dip angle ? of 60°; and is rather gentle with the dip angle ? of 40°. Meanwhile

the effect of joint on the variance tendency of axial and lateral rheological rates is analyzed; and the unloading rheological failure mechanism of specimen with different joint inclinations is also discussed in detail. Based on the experimental results

the unloading triaxial rheological law of joint pelitic siltstone is mastered

so as to bring important reference for the establishment of rheological constitutive model of joint rock mass and the identification of parameters.