Effect of Joints on the Strength of Tunnels. Research on Rock Bolt Reinforcement
Technical rept. no. 5, 1 Jul 1967-30 Jun 1968
GOODMAN (RICHARD E) BERKELEY CA
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Rock and joint properties were reviewed as a basis for developing the analyses. The review discussed failure criteria for the rock and joint properties. Improved methods of sampling and testing joints were explored in detail. Pile Driver test sections were used as a basis for analysis. Two approaches of analysis of the rock to predict performance of rock bolted and unlined test sections were used. The first method called finite element was used on one section only. This methods complexity prevented its application to other sections. Discontinuities, heterogeneities, and local failures can be taken into account by finite elements, but the representation is only two dimensional. Joint influence analysis, the second method, was applied to many sections. In comparison to the finite element method, joint influence analysis is relatively simple to use. Joints and rock bolts are assumed not to modify the stress distribution in the joint influence analysis however, the method represents a three dimensional approach. Comparisons were made to post-shot cross sections of the Pile Driver openings to evaluate the methods of analysis. The finite element method is more powerful the joint influence analysis is easier to use.
- Civil Engineering