Water Release and Consolidation Model of Aquitard Considering Moving Non-Darcy Flow Interface

T he slow seepage velocity in the aquitard is not conducive to m onitoring its w ater release process, so the consolidation model is often used to comprehensively evaluate the evolution process of land subsidence. However, the traditional consolidation model assumes that the seepage law in the aquitard meets Darcy's law, which may be inconsistent with the actual situation. Therefore, a consolidation model considering the interface of moving non-Darcy flow region is established in this study, and the numerical solution of the model is established by using the finite difference method, in which the permeability coefficient and void ratio are assumed to be functions of stress. Compared with the existing models and indoor experimental data, the reliability of this research model is verified. The results show that the new model can more accurately simulate the consolidation process of aquitard induced by the instantaneous drawdown of water level. The consolidation model considering the moving non-Darcy flow interface delays the dissipation process of excess pore water pressure, but does not affect the total dissipation and total settlement of pore water pressure. For the consolidation model considering the attenuation of permeability coefficient, the time for the dissipation of pore water pressure and the settlement to reach the stability is obviously prolonged, and the variable permeability coefficient delays the time for the moving interface to reach the stability, causing the stable position of the moving interface to move upward. © 2023 China University of Geosciences. All rights reserved.