Creep properties and damage constitutive relation of mudstone under uniaxial compression at high temperature

The step load creep experiments on mudstone specimens are carried out at normal temperature and high (700℃) temperature using MTS 810 rock mechanics servo-controlled testing system and MTS 652.02 high temperature furnace. The corresponding creep curves and creep empirical equation for mudstone are obtained. A creep constitutive model for mudstone is established considering temperature effect. The creep test data of mudstone at different temperatures are used to carry out the identification of the creep damage model, and the creep parameters are obtained. It is found that the model can well describe the creep properties in the whole process by comparing the results obtained from the creep damage model and the creep test data. The rationality and correctness of the creep damage model are validated. To some extent, the research results enrich the basic theory of rock mechanics and provide valuable reference for the design of rock engineering at high temperature.