Foundation pit dewatering will impact the surrounding underground environment. To mitigate the adverse effects on adjacent underground structures, groundwater recharge is commonly utilized to control groundwater drawdown outside the pit. However, under a barrier effect of underground structures, the recharge effect may be different from that without the barrier effect. Meanwhile, the results of recharging different aquifers may also be different under the barrier effect. Therefore, based on an actual foundation pit project, this paper establishes a three-dimensional finite element model to investigate the impact of recharge on the surrounding environment under the barrier effect. To be specific, the recharge simulations were conducted in aquifers at different depths, and the effects on groundwater, enclosure wall deflection, and ground settlement under each recharge condition were compared and discussed. Furthermore, the optimal recharge scheme under the barrier effect was proposed. The results show the following: (1) When recharge is conducted in an aquifer that is completely cut off by underground structures, both groundwater levels rise and enclosure deflection induced by recharge are dramatic; therefore, caution should be taken when recharging under this condition to avoid an excessive response of recharge on the surrounding environment. (2) When recharge is conducted in an aquifer that is not cut off, most of the recharged water flows far away from the foundation pit, resulting in a low recharge efficiency. (3) When recharge is conducted in an aquifer with a direct hydraulic connection between the inside and outside of the foundation pit, it can significantly raise the groundwater levels of each aquifer, and effectively control the ground settlement without obviously increasing the deflection of the enclosure; engineers could benefit from this recharge scheme to achieve a better recharge effect under the barrier effect.

This study investigates the complete process of water level elevation’s impact on structural buoyancy under varying environmental conditions (with/without surrounding barriers) using model testing. The experiments simulated the buoyancy response patterns in sandy soil layers under different hydraulic heads. Dynamic variations of structural buoyancy over time were systematically analyzed, revealing distinct differences across the working conditions. The key findings demonstrate: (1) in the presence of the barrier effect, the growth of structure buoyancy is significantly slower than that without a barrier, but the measured value of structure buoyancy in sand is basically consistent with the theoretical value of Archimedes’ law, and the reduction coefficient is between 0.78 and 0.96; (2) the influence rate of water level rise under high water head pressure on structure buoyancy is significantly higher than that under low water head pressure. Therefore, special attention should be paid to monitoring structure buoyancy when the water level rises under high water levels.