Study on Shear Creep Characteristics of Carbonaceous Mud Shale at Different Moisture Contents Under Temperature Cycling

Mine slope landslides can lead to significant geological disasters. To investigate the impact of temperature cycling on the internal mechanisms that trigger these disasters in weak interlayers with varying moisture contents, a THMC-B multi-field coupled simulation device was employed to conduct shear creep tests on carbonaceous mud shale with varying moisture contents across 16 temperature cycles (ranging from −5 °C to 65 °C). Based on the observed creep characteristics and related patterns, a rheological constitutive model for carbonaceous mud shale was established to characterize the damage effects at different moisture contents during temperature cycling. The experimental results indicate the following: under temperature cycling conditions, an increase in moisture content rapidly reduces the mechanical properties of carbonaceous mud shale, rendering it more susceptible to shearing at the same failure stress level and consequently shortening the overall creep time; higher moisture content prolongs the duration of the deceleration creep stage in carbonaceous mud shale; and the improved constitutive model accurately represents the entire shear creep process of carbonaceous mud shale, with fitting coefficients exceeding 0.95. These research findings can provide certain references and insights for the study of shear creep characteristics of weak interlayers in mine slopes.