NUMERICAL ANALYSIS OF STORM-INDUCED RESPONSE OF INFILTRATION BERMS CONSTRUCTED WITH BALTIMORE DREDGED-MATERIAL

Abstract

The Port of Baltimore requires sustained, large-scale dredging to maintain navigable channel depths, producing sediment volumes projected to exceed the long-term capacity of existing containment facilities. This challenge necessitates the development of innovative reuse and beneficial use strategies. Vegetated Earthen Berms (VEBs), recognized as a Best Management Practice for stormwater management under Maryland regulations, offer a structurally viable and environmentally compatible application for dredged material. While prior research has established amendment requirements for baseline berm performance, a generalized performance-based design framework for VEBs under transient, storm-induced hydraulic loading remains largely undeveloped. To enable the development of such a framework, this study characterizes the geotechnical and hydraulic properties of dredged material and its blends with wheat straw, recycled glass aggregate, and sand, with the aim of maximizing dredged material use while meeting VEB performance requirements. Consolidated drained triaxial tests were performed to determine shear strength parameters, while saturated and unsaturated hydraulic conductivity were characterized using constant head permeameters and HYPROP, respectively. Soil-water characteristic curves were correlated with vegetation establishment through percent green cover measurements. Laboratory-derived properties were incorporated into transient finite element analyses in SLOPE/W and SEEP/W, evaluating rapid drawdown, lateral spreading, seepage, piping, and overtopping erosion across a range of berm heights, water retention ratios, drainage area ratios, and subgrade conditions. Piping resistance and infiltration under climatic stresses emerged as critical performance criteria, with their governing parameters- water retention ratio, berm height, subgrade hydraulic conductivity, and drainage area ratio - forming the basis of the performance-based design framework developed in this study. Wheat straw amended dredged material is recommended as the preferred blend for VEB construction.