Reactive Transport Model of Gypsum Karstification in Physically and Chemically Heterogeneous Fractured Media

Gypsum dissolution leads to the development of karstic features within much shorter timescales than in other sedimentary rocks, potentially leading rapid deterioration groundwater quality and increasing risk catastrophes caused by subsidence. Here, we present a 2-D reactive transport model evaluate gypsum karstification physically chemically heterogeneous systems. The considers low-permeability rock matrix composed mainly discontinuity (fracture), which acts as preferential water pathway. Several scenarios are analyzed simulated investigate relevance for of: (1) dynamic update flow parameters due porosity changes; (2) spatial distribution minerals matrix; (3) time evolution inflows through boundaries model; (4) functions relating permeability, k, porosity, ϕ. average after 1000 years simulation increases from 0.045 0.29 when flow, transport, chemical boundary dynamically updated according changes. On contrary, hardly changes feedback effect is not considered, while its 0.13 if inflow occurs discontinuity. Moreover, small amounts highly soluble sulfate plays major role additional fractures. increase hydraulic conductivity largest power law with an exponent n = 5, well Kozeny-Carman modified Fair-atch k-ϕ relationships. front propagates into faster 2 3 Verma–Pruess relationships used.