Analysis of overburden activity law of filling mining with ultra-high water material and application

Abstract

In order to ensure the stability of surface structures in the mining process of filling test face in Taoyi Mining Area of Handan Mining Group, an active mechanical model of open filling and fully mechanized overlying rock with ultra-high water material was established based on the field geological conditions, deflection equations of backfill support zone and empty roof zone are derived. Through uniaxial and triaxial compression tests, the elastic coefficient of backfill with high water material in 1-7 days is obtained, and then the subsidency deformation of the key stratum is almost zero after the backfill is in the consolidated state. The subsidence of key layers in the filling transition zone, the initial setting zone and the suspended roof area is large, and the subsidence increases with the increase of the suspended roof distance and the advancing length of the working face. Therefore, it is calculated that the suspended roof distance should be kept within 16 m when the safety factor is set as 1.2. By testing the surface subsidence during the mining of the test working face, the surface subsidence coefficient is only 0.05 and the maximum surface subsidence value is 119 mm, which verifies the accuracy of the analysis results of the mechanical model and effectively restrains the movement of overburden and surface subsidence.

Keywords

• super high-water material
• open backfilling mining
• overburden strata movement
• roof hanging distance
• subsidence