Fully hydro-mechanical coupled Plug-in (SUB+) in FEFLOW for analysis of land subsidence due to groundwater extraction

Abstract

Extensive groundwater extraction leads to the drawdown of the groundwater table, which can increase the stress of soils and lead to land subsidence. Analyses of land subsidence generally require numerical models based on the poroelasticity theory. FEFLOW is a well-known commercial finite element software that is one of the most widely used for groundwater, heat transfer, and transport modelling. However, it is not capable of modelling land subsidence. Here, we introduce a plug-in called SUB+ and a pre-processing software PSUB that can be used for fully coupled land subsidence analyses using the poroelasticity theory. The plug-in and the software are developed using C++ with Qt-Framework. The Eigen and Intel MKL libraries are used for matrix operations and the sparse matrix solver. Although FEFLOW is closed-source, SUB+ and PSUB are open-source and available on GitHub. Keywords: Groundwater modelling, Land subsidence, FEFLOW Biot’s theory, Fully coupled hydro-mechanics