Creep mechanical properties and creep damage model of sandstone considering temperature effect based on acoustic emission

This work studies the creep mechanical properties and creep damage model of high-temperature heat treated sandstone. Acoustic emission (AE) technology is used to monitor the crack evolution of sandstone in uniaxial compression and creep experiments in real time. The influence of temperature on the mechanical properties of sandstone is analyzed through AE count, cumulative AE count, and AE absolute energy. The relationship between cumulative AE count and axial strain is discussed, and the cumulative AE count increases exponentially with increasing axial strain. Moreover, an appropriate damage evolution equation is established based on the cumulative AE count, and a nonlinear viscoelastic-plastic model capable of describing the decay creep, steady-stage creep, and accelerated creep stages of high-temperature heat treated sandstone is constructed. Through the model validation and parameter inversion, the new creep damage model can be employed to study the creep instability of geotechnical engineering under high temperature environment.