Numerical simulation study on mining−induced damage law of mining roadway under double−lane layout

To address the deformation and failure issues of retained roadways in the dual−winding layout induced by mining activities, this study took the return airway of the 502 working face in a certain mine as the research background. FLAC3D was employed to simulate the rock deformation and stress distribution of the surrounding rock during the excavation and mining stages, thereby revealing the dynamic response laws under the influence of mining disturbances. The results show that stress concentration occurs within 30 meters in front of and 100 meters behind the mining face. The peak stress on the coal pillar side reaches −15.5 MPa, which is significantly higher than that on the non−coal pillar side, and the 100−meter area behind the working face is the core zone with intense stress variation. The stress disturbance of mining on the retained roadway presents a dynamic evolution, and the variation trends of vertical and horizontal stresses are consistent. The stress fluctuates periodically and stabilizes after the working face advances 300 meters (within the first 300 meters of advancement, the peak stress increases by 1.2 MPa every 100 meters, and remains stable thereafter).As the influence of dynamic pressure on the surrounding rock gradually deepens, the deformation of the surrounding rock gradually enters the plastic stage. When the maximum principal stress exceeds the limit, the failure range expands; the deviation of principal stress triggers inconsistent deformation of the roof, floor, and sidewalls. The failure of the roof and floor shows an asymmetric distribution (at 500 meters, the maximum deformation of the roof is 1.33 times that of the floor, and the deformation of the right sidewall is 0.44 times that of the left sidewall), and the deformation near the working face and the drift is the most significant (the maximum displacement of the roof and floor reaches 120 mm, and that of the two sidewalls reaches 90 mm). Based on the above laws, the adaptability, application limitations, promotion calibration requirements, and specific prevention measures of mining roadways in the dual−winding layout under different geological conditions and roadway geometric shapes were discussed, which further clarifies the engineering practicality and promotion value of the research method. This study systematically clarifies the coupling influence mechanism of retained roadways in the dual−winding layout under the dynamic mining activities of multiple working faces, providing a quantitative basis for the stability control of roadways under similar conditions.