Experimental investigation of mechanical properties and energy features of granite after heat treatment under different loading paths

摘要

Temperature and loading history are the two main factors that influence rock microstructure and physical and mechanical properties. To explore the influence of heat treatment and loading path on mechanical properties and energy features of granite, granite samples were first heat-treated at 25 °C, 300 °C, 600 °C, and 900 °C. Then, 12 groups of triaxial compression experiments were placed under three loading paths, as follows: uniaxial compression, conventional triaxial compression, and confining pressure unloading. Mechanical properties and energy features in the deformation and failure process based on these experimental results were systematically compared and analyzed. Results demonstrate that Young’s modulus, uniaxial compressive strength, and triaxial compressive strength increased in the temperature range of 25 °C to 300 °C, but decreased in the temperature range of 300 °C to 900 °C. Under the same loading path, the gaps among total absorbed energy, dissipated energy, and elastic strain energy widened with increasing temperature from 25 °C to 900 °C. At the same temperature, the energy features’ gap under confining pressure unloading is between uniaxial and triaxial compression. The conclusions drawn in this study provide a significant reference for the design and construction of rock engineering exposed to high temperature.