Microbial Induced Calcite Precipitation (MICP) is an innovative technique for soil grouting in which injected bacteria supplemented with chemicals lead to calcite precipitation in soils. A comprehensive research work is carried out to better understand and describe the phenomenon of miscible and reactive biogrout injection in saturated, deformable soil. A mathematical model accounting for the biohydro- mechanical couplings existing between fluid flow, bacterial concentration evolution, exchanges between phases, transport and miscibility is developed.Finite element modelling of column injection tests is carried out to validate the formulation and to demonstrate the potentiality of the developed model.