A biochemical-thermo-hydro-mechanical coupling of degradable soils

Abstract

A general framework of coupled biochemical-thermo-hydro-mechanical (THMBC) processes has been developed to analyze the complex phenomena in degradable soils, such as municipal solid and natural gas hydrate, whose solid skeleton can be decomposed by biological or chemical reactions. The frame contains the linear momentum equilibrium equation, the mass conservation equations for the liquid and gas phases, the energy conservation equation. The evaporation and condensation of water, and the dissolution of gas in water are considered in the mass conservation equation of the fluid. The biochemical reaction rate can be used to link the source and sink terms of the fluid with solid mass loss, meanwhile to give a quantitative description of changes in porosity and strain. The impact of the solid mass loss and the porosity change on the hydro-mechanical properties are involved. As a case study, a model describing the coupling process of landfilled MSW was proposed. In this model, the constitutive model considering the influence of degradation was used, and the degradation chemical formula of the degradable component was given. The results of a large-scale experiment were compared with numerical simulations.