Elastic-Plastic-Brittle Unified Solution of Surrounding Rocks in Deep Openings

The surrounding rocks in deep openings are deformed too large and fractured frequently during excavation process. Taking the circular tunnel as the research object, surrounding rocks are divided into the cracked region, the plastic region and the elastic region. Based on the plane strain condition and twin shear strength theory, the analytical solutions for the stress and displacement are derived and the individual region radii are obtained. The strengthening effect of the intermediate principal stress on rock stress and the effect of elastic modulus deterioration on rock mass deformation are discussed with examples. Finally, some new conclusion has obtained, which provide meaningful theoretical foundations for reinforcement of tunnel project. (C) 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of China Academy of Safety Science and Technology, China University of Mining and Technology(Beijing), McGill University and University of Wollongong.