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A Simple Numerical Procedure for Assessing the Effect of Ground Improvement Around a Circular Tunnel Excavated in Mohr-Coulomb Rock Mass  

Lee, Youn-Kyou (군산대학교 해양시스템공학)
Publication Information
Tunnel and Underground Space / v.18, no.2, 2008 , pp. 98-106 More about this Journal
Abstract
When a tunnel is excavated in a rock mass of poor condition, the adjacent zone of excavation surface may be reinforced by adopting the appropriate methods such as grouting and rock bolting. The reinforced effect can be evaluated by use of various numerical approaches, where the reinforcing elements may be expressed as distinct discretizations or smeared into the equivalent material properties. In this study, a simple numerical method, which can be classified as the latter approach, was developed for the elasto-plastic analysis of a circular tunnel. If a circular tunnel in a Mohr-Coulomb rock mass is reinforced to a finite thickness, the reinforced annulus may have different material properties from the in-situ rock mass. In the proposed elasto-plastic method for assessing the reinforcing effect, Lee & Pietruszczak (2007)'s method is applied to both the reinforced annulus and the outer insitu rock mass of the fictitious tunnel, and then two results are combined by enforcing the compatibility condition. The method were verified through comparing the results with the proposed method and the commercial finite difference code FLAC. When taking the variation of deformation modulus and strength parameters in the reinforced zone into account, the distributions of stress and radial displacement were much different from those obtained with the assumption of homogeneous rock mass.
Keywords
Circular tunnel; Elasto-plastic analysis; Mohr-Coloumb rock mass; Reinforcement;
Citations & Related Records
Times Cited By KSCI : 1  (Citation Analysis)
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