Parameter optimization and monitoring analysis of isolated pillar

Aiming at the problem of resource waste caused by excessive design thickness of horizontal isolated pillar in the −320 m middle mining area of Liguanji Iron Mine, the parameters of isolated pillar are optimized by theoretical calculation and numerical simulation, and the thickness is recommended to be no less than 23 m. In order to monitor the stability of isolated pillar in mining, a set of ground pressure monitoring system is established in the −320 m middle section of mine. The results of stress and displacement monitoring show that the rock mass above the isolated pillar has no large-scale stress concentration and obvious deformation during the monitoring period, and is in a stable state as a whole. The spray layer cracking occurs in a small range due to geological structure in a local area, but it has not reached the failure scale that affects the stability, and the isolation pillar parameters can be adjusted timely according to the monitoring data.