To study the surface deformation law of insufficient mining goaf with thick loose layers after grouting, and evaluate the effectiveness of grouting and filling method in treating strip goaf areas, taking a thick loose layer strip goaf of Daizhuang Coal Mine in Jining as an example, theoretical analysis, numerical calculation, surface deformation observation, and deep rock optical fiber monitoring methods were used to compare and analyze the surface deformation laws of the goaf before and after grouting treatment. The results show these as follows. Under the influence of superposition of strip type insufficient mining in the goaf of thick loose layer, the subsidence of goaf decreases during the active period of surface movement, while the residual deformation increases in the later period, the maximum total subsidence of goaf is 611.8 mm and the residual subsidence is 157.8~288.1 mm by using probability integral method and numerical calculation, the surface residual deformation of goaf has great influence on the proposed high-rise buildings. The cumulative subsidence of the surface in the goaf treated by grouting filling method during observation period after grouting is -5.6~-1.5 mm. The comprehensive analysis of deep distributed optical fiber monitoring and surface leveling observation shows that the subsidence of the overlying rock in the goaf after grouting is less than 1 mm/a, and the analysis shows that the surface deformation after grouting is mainly caused by the settlement of the upper thick loose layer. The adoption of grouting filling method can significantly shorten the movement time of overlying strata in the goaf and effectively reduce the deformation of deep strata in the goaf, calculate and analyze the surface deformation value after grouting tends to be stable, the goaf site is in a stable state, and the grouting treatment effect is good, meeting the needs of high-strength engineering construction. The research results can provide guidance for surface deformation prediction, site stability evaluation and treatment effect detection after grouting in goaf under similar conditions.

thick loose layer  /  strip goaf  /  grouting treatment  /  surface deformation  /  optical fiber monitoring