True Triaxial Experimental Study of the Strength and Energy Characteristics of Fractured Sandstone

The strength of fractured rock significantly affects the safety and stability of underground engineering construction projects. To gain a deeper understanding of the strength and energy evolution characteristics of fractured rock, this paper carries out an experimental study on the strength of sandstones with different inclination angles under true triaxial stress conditions. The experimental results show that: With the change of the fissure inclination angle (α), the initiation stress has a small change under the condition of α of 15°~45°, and shows a rapid increase under the condition of α greater than 45° (60°,75°,90°). The damage stress and peak stress in general show a trend of first decrease and then increase. According to the calculation results of the energy theory: With the increase of α, the total strain energy, elastic strain energy and dissipative strain energy of the specimen at the time of damage show a trend of decreasing and then increasing, which has a good correspondence with the peak strength of the specimen. The research results can provide theoretical reference for the stability assessment of fissured rock engineering.