Unified assessment of mass loss behaviors in soluble, biodegradable, and internally erodible geomaterials

Abstract

Dissolution of soluble soil, biodegradation of municipal solid waste (MSW), and internal erosion of gap-graded soil are typical mass loss processes of geomaterials, which result in various engineering problems. These three processes are conceptually analogous and examined by a unified assessment of their behaviors considering the initial properties of geomaterials and testing conditions. This study collected additional data from twelve soil dissolution tests and five long-term MSW biodegradation tests. We then established a comprehensive mass loss behavior dataset based on the available studies and the supplementary data obtained from this study. In addition to the flow-reactive fraction, two initial volumetric properties are also critical, which are void ratio before mass loss (esolid,0) and inert-to-reactive size ratio. A characteristic parameter (Λ), describing the ratio between the change in voids volume and the change in flow-reactive solids volume, is correlated with the strain and change in esolid. The volumetric and structural changes of all the flow-reactive geomaterials are categorized into Λ = -1 for pseudo-stable, -1 ≤ Λ < 0 for collapsible, 0 ≤ Λ <esolid,0 for hyper-collapsible, and Λ ≥ esolid,0 for readily densified. A three-dimensional plot constructed by the three critical initial properties is divided into eight zones based on the different Λ values, which correspond to distinct mass loss behaviors. The a priori Λ estimation and corresponding zonation for a wide variety of flow-reactive geomaterials is shown to be beneficial for research and practice.