Surface Deformation Control And Practice With Solid Backfill Mining Under Embankment

Embankment is along the rivers, channels, lakes, coastal or flood-diversion area, reclamation area edge, built to block water. In China, there are a lot of coal trapped under embankment. Generally large size waterproof coal pillar or restricted mining thickness of exploitation are applied to mine the trapped coal resource, which not only waste a lot of coal but not ensure the safety of the embankment. Also it could endanger the operation of local major hydraulic engineering. In recent years, solid backfill mining technology is regarded as one of the green mining technology and makes a graet breakthrough in mining “Three Under” trapped coal. Both the theory and engineering practice have proved that solid backfill mining can exploit the coal recource at hight recovery rate, in the meantime, it can control surface subsidence and protect surface buildings. Therefore, this paper comes up the method to exploit coal with solid backfill mining under the embankment. By using theoretical analysis, laboratory test, numerical simulation and industrial test, the key protection factor for embankment deformation is analyzed, and the dedoramtion mechanism of embankment affected by solid backfill mining movements. The prediction model for embankment deformation is established. Besides, controllable factors and influence laws for embankment deformation is created and tested in instu. The main innovative achievements are as follows:(1) Based on the deformation form of embankment under mining process, the key parameter for controlling embankment deformation is to decrease the subsidence and movement of embankment. By analyzing surface deformation mechanism with solid backfill mining, the controllable factors for backfill mining under embankment are backfill quality and mining area.(2) According to the structural characteristics of the mound type embankment, tensile force on the embankment is selected as the failure criterion. The embankment deformation mechanical model during mining process is established to calculate the relationship between embankment deformation parameters and tensile force.(3) With backfill ratio chosen as characterization parameters, embankment deformation prediction model is created based on backfill ratio. Combined with the embankment stability criterion, backfill ratio design method and design process are proposed under multi backfill mining working faces.(4) By numerical simulation analysis, the stability of embankment variation is obtained when different influence factors in solid backfill mining working face are changed. According to the results of theoretical analysis, laboratory test and numerical calculation, the backfill ratio is desiged in the test area. The solid backfill mining process is optimized, and the industrial experiment succeedes, which achieved good engineering application effects.