Effect of in-situ stresses on the stability of coal mine development workings

Among the different types of ground control problems associated with underground coal mining, those related to in-situ stresses are the most common ones affecting the safety of a mining operation. As a result, this has been the focus of many ground control research works done in the recent years. More work has been done in this thesis to add additional information on the in-situ stress related ground control issues of the underground coal mine development workings.;Three-dimensional finite element modeling has been done to examine the Influence of the in-situ maximum horizontal stress angle on the stability of both the entry and the intersection. Distribution patterns of safety factors were used to explain the location of roof failure in the entry or the intersection. Also, the effect of in-situ stress ratios on the stability of development openings was studied. To make the work more general, both low and high in-situ stress fields have been considered.;In general, the modeling results indicated that the entries oriented in the direction of the in-situ maximum horizontal stress were in the best condition while those oriented at 90° were in the worst condition. (Abstract shortened by UMI.)