ABSTRACT
The paper describes the development of a reliable method of estimating in-situ stress ratio based on the investigation of geological structures in the Latrobe Valley, specifically the Loy Yang Mine, its relationship to the stress regime, and back analysis of the ground displacement observed in the mine. 2D finite difference program FLAC modelling techniques were used to simulate the expected ground movement, horizontal strain and to establish a relationship between in situ stress and displacement. Sensitivity analysis was carried out with a range of stress ratios. An elastic constitutive models was analysed, the elastic model displayed close calibration with the observed field deformation data. Based on geological structures of the area, a NNW-SSE regional compressive stress across the Latrobe Valley exists. From the model study, it was found that in situ stress ratio (horizontal stress to vertical stress) in the Loy Yang mine lies in the range of 0.5–0.7
