Abstract:

In order to study the influence of separation layer grouting filling on water retention effects of the stratum, a spatial evolution model for seepage and fracture fields of formation rock mass was constructed. In addition, the evolution characteristics of water conductivity of formation rock mass after the spatial filling of separation layers were explored. The results show that the high-value areas of fracture length, porosity, and hydraulic conductivity of rock mass are concentrated from the two ends of the separation layer to the central area due to the influence of overburden. When the separation layer is not filled, the two ends of the critical layer above the separation layer are affected by tensile and shear damage. The fractures at both ends of the critical layer develop obviously, and the porosity and hydraulic conductivity increase. With the increase in filling height, the critical layer is not completely destroyed due to the support of the filling body after the span falls. The porosity and hydraulic conductivity are relatively reduced. The simulation results of rock fracture, porosity, hydraulic conductivity, and water head show that filling separation layers can effectively reduce the seepage flow of aquifers. In addition, higher filling heights of separation layers indicate better water retention effects.

Key words: separation layer, grouting filling, water retention effect, critical layer, numerical simulation