Tunneling through adverse geological conditions in granitic terrain

DOI

10.2991/rare-16.2016.41How to use a DOI?

Keywords

granitic terrain; twin tunnels;sripadayellampalli reservoir; medaram tank; rock tunneling quality index

Abstract

Generally it is pre mind setup that granitic terrain is always suitable for tunneling media and requirement of detail feasibility studies are minimize accordingly. To facilitated irrigation and other utility en-route of seven draught prone Districts of Telangana State, Dr B R Ambedkar lift irrigation project is under construction. Twin tunnels 9.55 km length with 10 m finished dia are being constructed to lift water from SripadaYellampalli Reservoir to Medaram tank. Granitic rock with dominant intrusive zones of amphibolites/basic enclaves were observed in the studied tunnel length. Problematic zones categorized into fair, poor and very poor rock classes with occasional bands of good rock class based on rock tunneling quality index 'Q' between chainage 8.298 and 9.865 km. This zone observed dripping to flowing in nature, created difficulties for tunneling. Heavy steel ribs were erected for rock mass supports in poor and very poor tunnel reaches as per design drawing. These problematic zones are responsible for delaying the construction progress and created vulnerable situation for the tunneling work. Modifications /changes in excavations plan was done, which was very much essential as per the site condition to achieve the targeted quantity of excavation within the time frame. Intelligently changes in excavations were planned based on the anticipated poor rock masses at ahead of tunnels reaches. Modification was based on the subsurface exploration data. In this paper emphasis are made on the requirement of detailed feasibility study along the tunnel alignment even the tunneling media is made up of granite

Copyright

© 2016, the Authors. Published by Atlantis Press.

Open Access

This is an open access article distributed under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).

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TY  - CONF
AU  - D.S. Rawat
AU  - A.K. Naithani
AU  - L.G. Singh
AU  - Jain Prasanna
AU  - Rajesh Patel
AU  - Rao G. Srinivasa
AU  - Singh Khilap
AU  - Nath K. Ravindra
AU  - R.N.S. Babu
PY  - 2016/11
DA  - 2016/11
TI  - Tunneling through adverse geological conditions in granitic terrain
BT  - Proceedings of the conference on Recent Advances in Rock Engineering (RARE 2016)
PB  - Atlantis Press
SP  - 261
EP  - 265
SN  - 2352-5401
UR  - https://doi.org/10.2991/rare-16.2016.41
DO  - 10.2991/rare-16.2016.41
ID  - Rawat2016/11
ER  -