Adaptive method coupling in geotechnics

Three methods are basically used in the simulation of geotechnical problems: boundary element (BEM), finite element (FEM) and distinct element (DEM) methods. The choice of method depends on the expected physical behaviour (predominantly continuous elastic, visco-plastic or discontinuous). Since this may change for different parts of the domain to be analysed, the best approach is to use a combination of at least two of the above mentioned methods. Starting from an elastic boundary element analysis, the aim of the project is to develop a simulation methodology that will identify zones where non-linear, or discontinuous behaviour, is expected to occur, so as to automatically discretise these zones into either finite or discrete elements. This will ensure that the different methods are used where they are best suited, without any additional effort required by the user, which will lead to more accurate and efficient predictions. It is planned to demonstrate the program on two practical examples in geotechnics: the analysis of a tunnel excavation where zones near the excavation boundary exhibit discontinuous behaviour and the analysis of the stability of a well bore junction in the petroleum industry. The development of the simulation program will be significantly speeded up by the availability of an existing BEM program being developed at the Institute. The work can be seen as a continuation of the FWF project P15523-No7 "Numerical Simulation of tunnel advance with the BEM".