Tailings and Mine Waste Conference

Soil Arching as a Means to Resist Internal Erosion under High Seepage Gradients Jeldes, Isaac A.; Brink, Nicholas R.; Pauly, Matthew J.; Rondinel, Efrain A.; Seda, Jesus H.

Abstract

Internal erosion is a common cause of dam failures and is a key consideration when designing tailing storage facilities (TSFs) and water retaining structures. Initiation of internal erosion is a complex phenomenon and can be difficult to characterize. Filters are often employed to prevent particle migration and can greatly reduce the risk of internal erosion. However, defects can occur in filter layers due to differential settlement, improper construction practices, seismic shaking, or other unforeseen factors. When a filter defect is present, initiation of internal erosion of base materials becomes more likely as concentrated seepage flow paths will force particle migration through the open defect. The ability of a soil medium to arch can be advantageous as arching can resist the effect of seepage drag forces by redistributing the stresses to the zones adjacent to the defect, providing resistance to initiation of internal erosion. However, if superior tractive seepage forces exist, arching can be overcome, the soil will lose its self-supporting ability, and internal erosion will be initiated. To explore this limiting stability condition, a series of finite-element stress-deformation simulations were performed. Varying material shear strengths, defect aperture sizes, and seepage gradients and their corresponding effects on the triggering of internal erosion were evaluated. This paper summarizes the methods and results of these analyses, including applicability to tailing dam design, with the aim of providing a screening tool for practitioners to use to quickly evaluate internal erosion resistance in the presence of a filter defect.

Item Citations and Data

Rights

Attribution-NonCommercialNoDerivatives 4.0 International