Asymmetric Deformation Mechanism of Roadway with Continuous Mining and Continuous Backfilling

Continuous mining and continuous backfilling (CMCB) is an effective method to control surface subsidence and implement resource utilization of solid waste. To address the issue of asymmetric deformation of the surrounding rock, threatening the overall stability of roadways with CMCB, the deformation characteristics of the roadways at the 2112 CMCB working face of the Liangjia Coal Mine were analysed, and the deformation laws were studied. The mechanism of asymmetric deformation of roadways with CMCB was revealed, and control measures were proposed. The results showed that the roadway with backfilling body on one side and coal on the other side (BBSCS) has roof-to-floor convergence of 16–310 mm, left-to-right convergence of 12–330 mm, and asymmetric deformation. With the increase of load, the coal side appears sign of damage first, and its deformation increases faster than that of the backfilling body side, and the asymmetric deformation of the roadway is more significant. When the ultimate load is reached, the displacement of the coal side is 3.3 times that of the backfilling body side. The asymmetric deformation control measures of the roadway are adopted to reinforce the support of the roof and coal of the roadways with BBSCS. The field test showed that the asymmetric deformation control measures reduce the roof-to-floor convergence by 71.0% and the left-to-right convergence by 74.2%. This strategy effectively controls the asymmetric deformation of the roadways, reduces the deformations of the surrounding rock, and ensures the overall stability of the roadways.