Experimental Study of the Water-Sediment Two-Phase Seepage Characteristics in Rock Fractures and the Influencing Factors

Abstract

The water-sediment two-phase seepage in coarse fractures is one of the major factors to trigger mine water inrush disasters. Based on seepage mechanics theory, a mechanical model of the water-sediment two-phase seepage in coarse fractures was established. An experimental system was also developed to study the seepage characteristics under various conditions. The relationships between the absolute value of the pressure gradient and the seepage velocity were analyzed during the test process. The nonlinear characteristics of the seepage test were revealed. In addition, variation laws of the absolute value of the pressure gradient with the sand volume fraction and the sand particle size were illustrated, which were related to the loss of pressure during the particle movement. The impacts of the sand volume fraction and the sand particle size on the equivalent fluidity and β -factor of non-Darcy flow were discussed and analyzed. It was determined that the local turbulence was the main reason for the change of nonlinear variation characteristics of seepage parameters.

Visualizing water seepage dynamics in grotto relics via atom-based representative model

“…Fluid flow through macro-scale channels, i.e., faults, joints, fracture and so on, is crucial for evaluating the stability of geotechnical engineering and the mechanical behaviors in rock mass because they are recognized as the main channel for water migration. The finite element (FE) method and finite difference (FD) method were commonly used methods in solving complex problems in seepage mechanics and engineering, evolving from the seepage path, seepage process to hydraulic fracturing and coupling implementation [12][13][14][15][16]. The FE and FD method proved successful in evaluating water seepage from macro-scale, but there is little relevant research associated with the water seepage of fractured rock in grotto relics.…”