The parameter variations in the aquitard have an important influence on the migration laws of contaminants in the aquitard. In order to study the influence of dynamic changes in parameters during pumping on the migration laws of Light Non-aqueous Phase Liquid (LNAPL) in the aquitard, the one-dimensional consolidation and groundwater flow equations for the aquitard were employed to derive the governing equations for the migration of LNAPL in the aquitard. A self-designed experimental platform was developed to investigate the effects of the pore water pressure, consolidation deformation, and pumping rate on LNAPL migration during pumping. The laboratory experimental results indicated that during pumping, the migration behavior of LNAPL in the aquitard typically exhibited a trend toward the pumping well and the overlying aquifer. The closer to the pumping well, the greater the change in the pore water pressure, the greater the amount of consolidation deformation, the earlier the state of densification, and the slower the migration rate of LNAPL in the aquitard. The nearer to the bottom of the aquitard, the larger the amount of consolidation deformation in the aquitard and the slower the migration rate of LNAPL in the aquitard. Also, the pumping rate had an important influence on groundwater flow movement and contaminant migration. The characteristics of parameter variations in the aquitard and laws of LNAPL migration during pumping were systematically studied and analyzed; these research results can provide a reference for the prediction and remediation of LNAPL in contaminated sites.

To investigate the seepage behavior in a single fracture, a nonlinear seepage model based on boundary layer theory was developed. An analytical formula for calculating nonlinear flow in a single fracture was derived, providing a new method for assessing non-Darcy flow in single fractures. The flow in this formula consists of two parts: the viscous layer and the inertial layer. When the undetermined coefficient λ is equal to 0.5, the formula is simplified to the traditional cubic law. Under high hydraulic gradient conditions, the formula can be simplified for practical use. COMSOL software was used to explore the relationships between fracture length, fracture width, hydraulic gradient, and flow rate under high hydraulic gradient conditions. Additionally, a semi-empirical formula for calculating non-Darcy flow in single fracture was derived. The flow rates calculated using the proposed method were compared with those obtained from the Forchheimer equation, the Schrauf model and the cubic law. The results confirmed the accuracy and effectiveness of the proposed analytical formula.