Classification and Characteristic Analysis of Damage Evolution Stages of Triaxial Compression of Sandstone Based on Dissipated Energy
MTS816 rock mechanics testing system is used to carry out conventional triaxial compression experi-ments to analyze the mechanical properties and energy evolution law of siltstone.The stress-strain curves are inte-grated to calculate the elastic energy density,dissipated energy density and input energy density of sandstone un-der triaxial compression,analyze the law of the increase of the three with peripheral pressure.Based on the dissi-pated energy theory,the evolution stage is divided and the stress characteristics are analyzed.The results show that the peak stress,the three kinds of peak energy density and the energy consumption ratio of crack extension of sandstone show a strong positive linear relationship with the peripheral pressure;under the peripheral pressure of at 10MPa and 15MPa,the rock closure stress level goes to zero,the crack initiation stress level shows a decrea-sing trend,the rock compression stage disappears,and the rock directly enters the elastic stage,which leads to a slowdown in the growth of crack initiation stress,shortening of the elastic stage,and growth of the plastic stage;the slowdown in the crack initiation stress has no effect on the growth of the peak stress and the crack extension energy consumption ratio of the sandstones with the peripheral pressure.
rock mechanicssandstoneenergy evolutioncharacteristic stress