Study on Mechanical Properties and Damage Mode of Anchor Body under Uniaxial Compression

Optimizing the parameters of the roadway anchorage support system is an important method to enhance the deformation resistance and disaster mitigation capacity of the anchored enclosing rock body in deep roadways. In order to investigate the influence of the parameter of anchor preload on the mechanical properties and damage mode of anchor solid, uniaxial compression test and mechanical property monitoring and analysis system were used to study the deformation and damage response of anchor solid under different anchor preload, and to obtain the static stress-strain curve, acoustic emission counting parameter, macroscopic cracks and the evolution of the damage mode of the anchor solid under different preloads. The results show that: Under the action of uniaxial compression load, with the increase of anchor preload, the compressive strength and elastic modulus of the anchor solid showed an increasing trend, and the preload and compressive strength showed a positive correlation function relationship at one time; The acoustic emission signal basically shows the evolution trend of “steadily rising-relatively stable-rapidly rising”, and the larger the anchor preload is, the smaller the ringing counts and cumulative counts are; High anchor preload is conducive to delaying the process of crack initiation, extension and penetration of the anchor solid, which makes the final damage mode of the anchor solid transition from tensile-shear composite damage to shear damage. The research results are of guiding significance for improving the performance of deep tunnel perimeter rock anchors against high ground stress.