Innovative rock support under flowing water conditions in underground caverns

DOI

10.2991/rare-16.2016.5How to use a DOI?

Keywords

groundwater ingress; storage cavern; rock support; grouting; mechanical packer;

Abstract

Underground construction of tunnels and caverns is an ever challenging project by virtue of the likelihood of encountering uncertain ground conditions. This is true despite all advancement in the field of prediction tools, equipment and instrumentation. One major factor leading to such uncertainties is ground water ingress during underground excavation. The excavation and installation of primary rock supports under flowing water condition is a significant challenge. This is even more difficult for storage cavern where apart from instability due to ground water, water loss through excavated segments, hinders the groundwater table conservation and threatens the basic premise of a saturated rockmass surrounding the storage cavern.Located in the Peninsular gneissic complex on west coast of India, the underground rock cavern under consideration has a geological setting comprising 2 to 3 sets of sub vertical and one set sub-horizontal joint set. Some of these cited joint sets were observed to be permeable and acted as water conduit during excavation. Owing to a saturated rockmass above, the uncontrolled water flow through these joints hindered the rock support installation process, particularly as significant leakage from the drilled holes for the rock bolts.In order to counter the problem, an innovative method of support to rockmass as well as grouting the surrounding rock mass was used by using mechanical packers with rebars. This indigenous method, with existing logistics, helped to successfully handle rock support under the flowing water seepage conditions, without any additional cost implication to project in this regard. The present paper outlines the detail methodology of installation of improvised rock bolts to deal with rock support in zones of water ingress.

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  - Pal Saikat
AU  - G. Kannan
AU  - Rath Ranjit
AU  - Nanda Atul
PY  - 2016/11
DA  - 2016/11
TI  - Innovative rock support under flowing water conditions in underground caverns
BT  - Proceedings of the conference on Recent Advances in Rock Engineering (RARE 2016)
PB  - Atlantis Press
SP  - 35
EP  - 39
SN  - 2352-5401
UR  - https://doi.org/10.2991/rare-16.2016.5
DO  - 10.2991/rare-16.2016.5
ID  - Saikat2016/11
ER  -