TAI Journal (A Half Yearly Technical Journal of Indian Chapter of TAI)
Year : 2012, Volume : 1, Issue : 1
First page : ( 5) Last page : ( 10)
Print ISSN : 2277-2820.

Significance of Shotcreting and Grouting in Underground Excavation

Khali R.K., AVP-Hydro, Bahuguna Naveen, Sr. Manager-Design

GVK Projects & Technical Services Limited, Gurgaon, Haryana

Online published on 28 May, 2012.

Synopsis

Safety and stability of tunnels through weak geology is the most difficult issue in hydro power development. Hydro Projects in Himalayan terrain are prone to a lot of surprises during advancing, especially during the underground excavation for immediate relief. During flowing conditions it requires shotcreting and grouting to stablise the crown and ensure safety. A lot of modern equipments are easily available nowa-days to execute shotcrete and grouting and the project is considered safe and stable if these two activities are properly executed in a project. North Austrian Tunnelling Method (NATM) is in practice on a wider scale to stabilise very poor rock condition where we use Shotcrete, rock bolt and grouting in sequence. Further advancement includes using light weight lattice girder with shotcreting in 2–3 layers followed by extensive grouting as per the actual ground conditions. Various types of shotcrete are- plain shotcrete, dramix fibre shotcrete, reinforced shotcrete and those of grouting are-Jet grouting, contact and consolidation grouting, curtain grouting and chemical PU grouting in high seepage zone.

This paper describes the significance of shotcrete and grouting application in tunnelling. It must be useful for the practicing engineers who are involved in execution of Hydro Projects.

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