TUNNEL SUPPORT SYSTEM DESIGN BY USING EMPIRICAL, OBSERVATIONAL, AND NUMERICAL METHODS
Tunnel excavation causes deformation and insitu stress redistribution in rock mass around a tunnel. The occurring stress due to tunnel excavation is able to increase beyond rock mass strength around the tunnel and cause the formation of plastic zone. This condition can cause tunnel collapse due to t...
Saved in:
| Main Author: | |
|---|---|
| Format: | Theses |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/40295 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | Tunnel excavation causes deformation and insitu stress redistribution in rock mass around a tunnel. The occurring stress due to tunnel excavation is able to increase beyond rock mass strength around the tunnel and cause the formation of plastic zone. This condition can cause tunnel collapse due to the burden of plastic zone that is formed as the effect of excavation. Rock mass classifications such as rock mass rating and Q, can give tunnel support based on rock mass classes. The recommended support system is based on rock mass quality around the tunnel while every rock mass class needs different support strength. Because of that, to complete the existing support, observational (CCM) and numerical methods are used so that the amount of support strength needed can be calculated by each rock mass quality and safety factor of the support. Therefore, this research uses specific RMR variation data from Asef, Reddish, & Lloyd study (2000) to improve initial understanding and as verification to combine these methods. Designed support system by combining empirical, observational and numerical methods had generated a support system for RMR and Q rock mass classifications.
The application of support system from the research result in Notog and Nanjung tunnels based on the results of tunnel analysis using support from the research result is relatively more effective than the other one using RMR support. Because of the induced stress, ratio between induced stress and in situ stress, and resulting displacement is relatively smaller around the tunnel while the resulting strength factor is relatively larger with the support safety factor exceeding 1.5. The support safety factor > 1.5 indicates no fracture occurring on utilized shotcrete support because the given support strength can receive the burden that is transferred by surrounding rock mass. Therefore, steel sets do not receive larger load transfer. |
|---|