Engineering geology for weak rocks of Abu Hamour surface and ground water drainage tunnel Phase-1, Doha, Qatar

DOI

10.2991/rare-16.2016.7How to use a DOI?

Keywords

weak/soft rocks; EPB TBM; deep shafts; Q; RM;, geological mapping

Abstract

This paper discusses results of analysis from geotechnical database collected during field mapping of shafts in weak/soft rocks of Abu Hamour tunnel project area of South Doha, Qatar. Shafts are connected to the main tunnel by short tunnels – adits, excavated using sequential excavation method. Shaft and adit excavation was carried out by excavators while tunnels were TBM mined. A comprehensive geotechnical data collection system in weak/soft rocks has been created and successfully implemented. It involved geological mapping of 25 shafts and relogging of 18 boreholes drilled at shaft locations. The authors correlated common classification systems: Q and RMR from 3 phases of design/construction: original assessment using boring logs from contract documents, relogging of the core available from the same borings and shaft mapping. Original assessment when compared with shaft mapping results has been generally conservative. Mapping results when compared with re-logging of the available shaft borings were generally optimistic. When mapping results were compared with re-logging effort in 72% - RMR, 61%-Q, results were similar. In 18%-RMR, 22%-Q mapping turned up more optimistic than re-logging and only about 10%-RMR, 18%-Q largely for near the surface results, mapping showed worst rock that otherwise would have been predicted. The project involved construction dewatering, by deep wells or/and multiple soil treatment using injection (grouting) techniques as methods of water control during construction in the shafts and adits. Some locations required more effort to control the water inflow than others. The correlations with observed rock mass conditions to increased dewatering and injection efforts are presented. It is the first TBM tunnel project in Qatar. Civil works has been largely completed while the project is scheduled for delivery by January 2017

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/).

Download article (PDF)

TY  - CONF
AU  - J.B. Stypulkowski
AU  - A.K. Pathak
AU  - F.G. Bernardeau
PY  - 2016/11
DA  - 2016/11
TI  - Engineering geology for weak rocks of Abu Hamour surface and ground water drainage tunnel Phase-1, Doha, Qatar
BT  - Proceedings of the conference on Recent Advances in Rock Engineering (RARE 2016)
PB  - Atlantis Press
SP  - 44
EP  - 49
SN  - 2352-5401
UR  - https://doi.org/10.2991/rare-16.2016.7
DO  - 10.2991/rare-16.2016.7
ID  - Stypulkowski2016/11
ER  -