Compressed gas energy storage in abandoned mines is considered one of the most promising large-scale energy storage technologies, but the uncertainty of stress distribution and plastic damage in narrow gas storage roadways under complex conditions seriously threatens the safety and stability of underground gas storage facilities. The bi-directional computational mechanics model for non-isobaric narrow gas storage spaces is established first, the analytical solution for stress calculation and the implicit equation of plastic zone boundaries for surrounding rocks in the non-isobaric narrow energy storage spaces are derived, Then, the distribution of stress field in surrounding rocks in non-isobaric narrow spaces under air pressure disturbance and the influence of air pressure on the evolution of stress field are studied, and the distribution law of plastic zone in energy storage roadways is revealed based on the implicit equation of the plastic zone boundary. At the same time, the types of plastic failure are analyzed in combination of numerical simulation methods, and finally the failure degree of the non-isobaric gas storage space is studied. The results show that: (1) The maximum principal stress of the surrounding rock exhibits an axisymmetric distribution, gradually decreasing with the increase of the distance from the central axis, and the amplitude gradually weakens, eventually tending towards the stress of the original rock; (2) As the stress R0, of the overlying rock increases, the pressure equilibrium point linearly increases, the lateral pressure coefficient increases, the pressure equilibrium point linearly decreases first and then increases, the roadway radius increases, the pressure equilibrium point gradually decreases, and the decreasing trend gradually decays. (3) When λ is less than 1, the “elliptical” plastic zone appears only at the roof position of the roadway, mainly manifested as tensile and shear failure; when λ is 1, the “circular” plastic zone appears around the roadway, mainly manifested as shear failure; when λ is greater than 1, the elliptical plastic zone appears only at the both sides of the roadway, mainly manifested as shear failure; (4) As the inflation load increases, the radius of the plastic zone and the proportion of failure gradually increase, and the trend decreases; As the radius of the roadway increases, the radius of the plastic zone and the depth of failure of the non-isobaric roadway gradually increase, and the trend increases; As the radius of the roadway increases, the radius of the plastic zone and the depth of failure of the non-isobaric roadway gradually increase, and the trend increases; the better the lithology is, the smaller the depth of plastic failure will be, and the more significant the impact of lithology on failure will be.
 

M-C Criterion; Inflation Load; Non-Isobaric Roadway; Mechanical Disturbance Law; Characteristics of Plastic Zone