Abstract
To explore the influence of crack angle on the mechanical properties, energy evolution, and damage evolution of sandstone, uniaxial loading tests were conducted on sandstones with different crack angles. Through the stress–strain curve, the influence of the crack angle on the mechanical properties was analyzed. Based on energy theories and principles, the influence of crack angle on the energy conversion mechanism was analyzed. Based on crack angle and dissipated energy, a damage model considering the initial damage to the fractured sandstones was established. The following conclusions were drawn: (1) The strength and elastic modulus of sandstone decrease with an increase in crack angle, and Poisson’s ratio increases with an increase in crack angle; prefabricated cracks affect the crack initiation position, and accelerate the formation of fracture surfaces. (2) The stress–strain curve was divided into compaction stage, elastic stage, yield stage, and failure stage. The larger the crack angle, the longer the yield stage and the shorter the failure stage. (3) At the peak point, the elastic energy, dissipated energy, and input energy of fractured sandstone always decrease with an increase in crack angle; the energy consumption ratio increases with an increase in crack angle; and the energy storage ratio decreases with an increase in crack angle. (4) The damage variable shows a trend of slow accumulation–steady accumulation–rapid accumulation; the crack angle affects the initial damage of the specimen, and the dissipated energy affects the variation trend of the damage variable.
Highlights
In underground engineering, there are various levels of defects within the rock mass, such as faults, cracks, holes, voids, gaps, pores, etc
Jiang et al [16] carried out triaxial loading test on mudstone and found that under the same confining pressure, the energy storage ratio of mudstone increased with the increase in water content, and the energy storage limit decreased linearly with the increase in water content
There is no unified standard for the division of each stage in the process of rock deformation; most of studies have focused on intact samples, whereas few have examined the effect of the crack angle on the energy evolution and damage characteristics of fractured rock
Summary
There are various levels of defects within the rock mass, such as faults, cracks, holes, voids, gaps, pores, etc. The above scholars have undertaken extensive research on the mechanical properties, crack development laws, energy evolution and damage evolution of rock masses and have achieved fruitful results. There is no unified standard for the division of each stage in the process of rock deformation; most of studies have focused on intact samples, whereas few have examined the effect of the crack angle on the energy evolution and damage characteristics of fractured rock. According to the energy consumption ratio and peak point, the stages of rock deformation and failure are divided; combined with the energy dissipation theory and previous theoretical achievements, a damage model considering the initial damage in a fractured rock mass is established.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
