Analytical study on steady seepage of a foundation pit adjacent to a structure

For a foundation pit adjacent to a structure with a common retaining wall, current mathematical models do not consider the interactions between seepage resulting from dewatering and the adjacent structures with the common retaining wall. In this study, the steady-state continuity equation of the seepage field considering an adjacent structure and retaining wall thickness is formulated by region dividing. The hydraulic head and water pressure are solved respectively using Fourier series expression and Bernoulli's principle. A numerical model is established in FLAC3D to validate the accuracy of the analytical solution. The maximum deviation of analytical results is merely 2.76%, and the computation time is only two thousandths of that required by the numerical simulation. Further analysis is conducted on the effects of various engineering parameters on water pressure distribution, resultant water pressure and exit gradient, revealing that retaining wall thickness, adjacent structure width and upper/lower soil permeability ratio have non-negligible inhibitory effects on seepage, while pervious layer thickness exhibits a promotive effect and adjacent structure depth shows no influence on seepage. In conclusion, the proposed analytical solution can produce efficiently produce accurate results, making it valuable for practical applications in foundation engineering.