Abstract: The idealized drainage boundary conditions (completely permeable or completely impermeable) in traditional consolidation theory are difficult to accurately depict the complex boundaries in actual engineering projects, often leading to discrepancies between theoretical predictions and measured results. To address this issue, the authors proposed the concept of a continuous drainage boundary, which more realistically captures the time-dependent characteristics of drainage boundaries. When considering the temporal effects of boundary drainage capacity, the one-dimensional consolidation rate of soil is no longer a univariate function of the time factor, but rather demonstrates a strong correlation with the interface parameter that quantifies boundary drainage efficiency. This represents a fundamental departure from the single time factor relationship inherent in traditional TERZAGHI theory. Through experimental design and theoretical analysis, a methodology for determining the interface parameter was established. This paper reviews the evolution of consolidation theories incorporating time-dependent boundary effects and explores practical applications of continuous drainage boundary theory in geotechnical engineering projects, including dynamic migration patterns of undrained symmetric planes and the optimal design of horizontal sand drainage layers. Finally, the applicability of continuous drainage boundary consolidation theory in multi-field coupling analyses and in complex loading conditions is prospected.