Nonlinear Rankine pressure of unsaturated soil under transient infiltration

To investigate the spatiotemporal effect of transient rainfall infiltration on the earth pressures, a novel solution scheme is proposed by integrating transient seepage and the envelope shell model of unsaturated shear strength. The acquisition method of equivalent parameters (i.e., cohesion and friction angle) is put forward, presenting the nonlinearity of shear strength in both two dimensions: net normal stress and matric suction. Moreover, Iverson model is modified to depict the general initial distribution of pressure head and the post-rainfall dissipation by introducing the Gaussian function and the recession coefficient. Finally, the nonlinear Rankine earth pressure characteristics are captured by linking the matric suction, mass density, and the shear strength parameters in a self-consistent fashion. Case validation and parametric analysis show good adaptability of the proposed model in calculating the unsaturated earth pressure with depicting the subtle and overlooked effect of soil unit weight during water infiltration. Thus, it contributes to evaluating the influence of transient infiltration on the performance of retaining structures under rainfall conditions.