Simulation of the Influence of Ultra-deep Foundation on Groundwater Seepage Field Based on Unsaturated Flow

The anti-floating water level of ultra-deep foundation is affected not only by the geological conditions of water level, but also by the foundation itself. In this paper, unsaturated seepage numerical simulation is used to evaluate the influence of typical ultra-deep foundation on groundwater seepage field in Guiyang. The results show that the construction of the foundation blocks the flow of groundwater, resulting in changes in the local seepage field. The water level in the upstream of the foundation rises, while it in the downstream of the foundation decreases. The maximum rise of the water level exceeds 1 m, while the maximum decrease exceeds 0.4 m. The time of foundation influence on seepage is up to 3 years, and the first 120 days are the great influence period. The pattern of water level change is controlled by the shape of the foundation plane. Sensitivity analysis shows that permeability and hydraulic gradient have important influence on the results. Therefore, when evaluating the anti-floating water level of foundation, not only the dynamic characteristics of groundwater itself, but also the impact of foundation construction should be considered.