Thermomechanical impact of Underground Coal Gasification exploitation
Abstract
Underground mining by coal combustion (Underground Coal Gasification - UCG), raise the questions of the mechanical behavior of the site and of the stability of the overburden rock layers. By studying the underground reactor, its inlet and outlet, we confirmed the key role played by mechanical damage and thermo-mechanical phenomena. Deformation or collapse above the cavity may cause a collapse in the overlying layers or a subsidence at surface level. These phenomena highly depend on the thermoporomechanical behavior of the rock surrounding the cavity (the host rocks). The numerical results presented in this paper are derived from models based on different assumptions describing a raw geological background. Several 3D and 2D nonlinear finite element modeling are performed based on two methods. On the basis of the analysis of the numerical results, we can highlight the main factors influencing the behavior and the mechanical stability of overburden and consequently the UCG process evolution.References
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