Hydromechanics based prediction of suffusion development in spatially random soil structures

As a typical mechanism of internal erosion, suffusion has led to geological disasters in engineering structures worldwide. A slight deviation in soil structures, also known as the spatial randomness of soil parameters, determines the significant differences in this erosion process. However, owing to the lack of absolute quantitative prediction models for suffusion, this issue has not been effectively evaluated. This paper introduces initial random fields of soil properties into a hydromechanical model to quantitatively predict the possibility of suffusion, considering the random deviations in soil gradation, porosity, and permeability. Through the prediction of 50 sets of random fields, certain trends and uncertain deviations of suffusion are discovered. This certainty and uncertainty constitute the possible range of suffusion, which surrounds the prediction of the homogeneous model and will be temporally widened to larger deviations, indicating the unpredictability of the later stage of suffusion. Statistical analysis revealed that soils with more compacted porosity, more movable particles and less permeability at the seepage outlet are prone to suffusion, and this advantage gradually increases to form the upper envelope of the possible range. This phenomenon is attributed to the larger additional forces acting on the movable particles and the abundant movable particles. The hydromechanics-based model of random soil structures can theoretically estimate the possible development of suffusion and effectively assess the uncertainty of internal erosion risk in hydraulic engineering.