Study on the subsidence influence law of isolated grouting for overlying rock and filling mining in adjacent working faces

Isolated grouting for overlying rock and filling mining is an important way to achieve coal mining under building, railway and water. In order to clarify the influence law of isolated grouting mining factors on surface subsidence,taking the isolated grouting operations at the No. 2307 and No. 2309 working faces of Zhaozhuang No. 2 coal mine as engineering background,the subsidence deformation under different mining influence factors was analyzed by theoretical analysis,theoretical calculation and numerical simulation. The results show that the mining width of the working face is positively correlated with surface subsidence,tilt,horizontal movement and horizontal deformation. When the mining width exceeds 175 m, the surface deformation cannot be effectively controlled. The width of the isolated coal pillar is negatively correlated with surface subsidence, tilt,horizontal movement and horizontal deformation. When the width of the coal pillar exceeds 35 m,the effect of continuing to increase the width of the coal pillar on the control of surface subsidence is not obvious. Increasing the injection-production ratio can significantly reduce the subsidence deformation of the surface. The monitoring results of surface deformation of the working face show that the deformation indexes under the superimposed influence of mining in adjacent working faces can all be controlled within a reasonable range,which can meet the anti-deformation requirements of surface buildings.