Abstract
Results of analyses on localized jointing system are presented to study the link of groundwater inflow and joint orientations along the 2000 m excavation of Tunnel Boring Machine (TBM-1) site, Karak in conjunction with the construction of Pahang–Selangor Raw Water Transfer Tunnel project. Geology along the tunnel route is predominantly the Main Range Granite Batholith with a lesser extent of metasedimentary rocks of the Karak Formation. Structurally, TBM-1 is dominated by joints oriented at N–S, NW–SE, and NE–SW directions. Strike slip faults that cross-cut the intrusive Main Range Granite rocks trending faults formed the most prominent structures in the vicinity of the Karak. This section of tunnel alignment consists of 2000 meters in length of Ch.8,821.77 m to Ch.10,821.77 m; 456 joints were mapped to create anisotropic conditions of rock section. Eleven significant locations experienced stoppages, thereby affecting the TBM daily progress, and such stoppages were mainly caused by sudden high-pressure groundwater inrushes or wet joint condition. Potential leakage places are identified by three main types of joints orientations. The most permeable tunnel section is in parallel with the main lineament orientation, followed by perpendicular to the tunnel drive direction, and crossing some voids that create pocket water zones.
PUBLIC INTEREST STATEMENT
The invention of Tunnel Boring Machine (TBM) has revolutionized the demand for more high-profile tunnel constructions; making it bigger, deeper and longer than the previously built. This trend is predicted to continue with the tunneling activity around the world to remain booming with the general growth of construction and the world economy. But, in tunneling project, the bigger the scale of project, the greater the engineering challenges to deals with. This paper presents one of the biggest challenges in any tunnelling project when digging through the unforeseen underground condition, which is the potential of groundwater flooding. High groundwater flows into the tunnel area is one of the most unpredictable events in tunneling due to various factors such as the complex geology and environmental conditions. Nonetheless, this research only deals with the crack or fractures properties found in the bedrock. These cracks behave as a piping system for water to easily move and finally flow into the tunnel area that at present acts as a sink.
Acknowledgements
This research project is financially supported by the Ministry of Higher Education, Malaysia under the Exploratory Research Grant Scheme (No. 673044). Permission to assess tunnel sites and data are acknowledged with the support from the Ministry of Energy, Green Technology and Water, Malaysia.
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Hareyani Zabidi
I am part of Mineral Resources Engineering, Universiti Sains Malaysia (USM). My research is mainly focuses on rock mechanics and engineering geological aspect of mining industries. This scope explores the role of geology in mining and geotechnical to further enhance the engineering quality of everyday practice and thus minimizing the potential of geohazard. My scope of work presents a vital link between the two more conventional fields of geology and engineering, looking particularly at the interaction between discontinuities and deformation consequences to the overall performance of engineering structures and ground projects. Most of the times, my works engage with the government offices, local authorities and related industries, for example studies on the safety practice of rock slope cut in quarries and mines, potential of karst hazard in the Kinta Valley and Klang Valley and the geoengineering aspect of Interstate Raw Water Transfer (ISRWT) project and TNB Hydroelectric project.