Evolution Mechanism and Monitoring Technology of Overburden Deformation in Underground Mining with Grout Injection

Taking working face 8006 of a coal mine in North China as the engineering background, the contact stress of each rock stratum interface is calculated based on the principle of composite beam to predict the development position of the separation layer. The distributed fiber optic sensing technology monitors the horizons where the abscission develops. The test results can accurately reflect the deformation characteristics of the overlying strata in the field, which provides an important theoretical basis and guiding role for the design of the overlying strata grouting scheme in this coal mine. The results show that when the working face is fully mined, the separation layer is mainly developed between the coarse-grained sandstone and the lower sandy mudstone at a distance of 265 m from the coal seam roof. The grouting scheme is effective, which can provide a useful reference for similar grout injection in overburden separation projects.