Abstract

This paper presents two new extensions to the DDA method. The extensions consist of sequential loading or unloading and rock reinforcement by rockbolts, shotcrete or concrete lining. Examples of application of the DDA method with the new extensions are presented. Simulations of the underground excavation of the Unju Tunnel of Kyungbu High Speed Railway Project in Korea were carried out to evaluate the influence of excavation sequence and reinforcement on the tunnel stability. The results of the present study indicate that improper selection of excavation sequence could have a destabilizing effect on the tunnel stability. On the other hand, reinforcement by rockbolts and shotcrete can stabilize the tunnel. It is found that, in general, the DDA program with the three new extensions can now be used as d practical tool in the design of underground structures. In particular, phases of construction (excavation, reinforcement) can now be simulated more realistically.

Keywords

• Discontinuous deformation analysis;
• Excavation sequence;
• Rock reinforcement;
• Rockbolts;
• Shotcrete;
• Construction phases

• 불연속 변형해석법;
• 굴착순서;
• 암반보강;
• 록볼트;
• 숏크리트;
• 시공단계;

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References

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2. Ph.D. thesis Extensions to the Discontinuous Deformation Analysis for jointed rock masses and other block systems Lin, C.T.
3. Journal of the Korean Geotechnical Society v.15 no.3 Modeling the Effect of Water, Excavation Sequence and Reinforcement on the Response of Tunnels Kim, Y.I.
4. Ph.D. thesis Modeling the Effect of Water, Excavation Sequence and Reinforcement on the Response of Blocky Rock Masses Kim, Y.I.
5. Total Report on Instrumentation of UNJU Tunnel Kyungbu High Speed Railway Project 4-3 Section Daewoo Institute of Construction Technology
6. The Art of Tunnelling Szechy, K.