International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 10 Issue: 05 | May 2023
p-ISSN: 2395-0072
www.irjet.net
Analyzing the role of Segmental lining in the tunnels with Tunnel Boring Machine (TBM) at Vishnugad Pipalkoti Hydroelectric project (4*111 MW). A case study Prashant Sharma1, Monu Rajpoot, Saurabh Soni3 ¹ M. Tech Transportation Engineering, IIMT University Meerut (U.P.) 2Associate professor, Civil department, IIMT University Meerut (U.P.) 3 Professor,
Civil department, IIMT University Meerut (U.P.)
-------------------------------------------------------------------------***-----------------------------------------------------------------------Abstract -Segmental Lining in tunnels have the potential to play a significant role in managing & providing sufficient strength to the tunnels rather than time consuming concrete lining. The segmental lining or lining with precast segments is very fast process as various segments which are pre-constructed or pre-casted with required grade of concrete & reinforcement, categorized as per rocks classification and geological conditions of the tunnels gets installed with automatic Tunnel Boring Machine (TBM). The process of installation is a continuous process i.e., just needed pre-casted segments to install. Since direct cost of project is associated with time and hence studies and research are made to minimize the cost of construction and reducing project duration. Concrete lining has proved to be a time-consuming process since involvement of various necessary preparations viz. placing of reinforcement followed by shuttering that after concrete of necessary grade according to the design mix needs to be feed and ultimately curing. Construction of the project gets delayed therefore to avoid such issues concrete lining is now days replaced by the Segmental lining as this practice having various advantages when compared with Concrete lining. (Segmental method also have a better aesthetic view than lining since it can’t be uniform). Key Words: Concrete segments, Segmental Lining, Tunnel Boring Machine (TBM), Concrete Lining, rocks classification, rock formation, headrace tunnel, shear zone.
1. INTRODUCTION The project area of Vishnugad Pipalkoti Hydroelectric project is located at northern India in the province Uttarakhand at Alaknanda River. The hydro power plant is containing a reservoir beside the river with intake and desilter`, the headrace tunnel, surge shaft, underground powerhouse as well as the tailrace tunnel. The electric power of the plant is given with 4 x 111 MW. The report at hand is focusing at the segmental lining of the headrace tunnel, describing the geometrical design of the segmental lining and its erecting structural analysis. Salient features of VPHEP Dam/ water level at dams:
Type Concrete Gravity Dam, Length 89.55 m., Height 65 m., Top El-1270 m., Foundation El1205, FRL-1267 m.
Headrace tunnel:
Length 13.4 Km, Dia. 8.8 m. (finish), Design flow: 228.86 m³/s and circular shaped
Surge Shaft
Restricted Orifice Type, Dia. 15 m./22 m., Height 140 m.
Pressure shaft
Nos 02/04, Type Circular, Dia. 5.2m/3.65 Length 310m/35m
Powerhouse
Type U/G, Size 146x20.3x50, Unit 04 nos. (each 111 MW), Turbine types: Francis
Surge tank
Type U/G, Size 150x16x35, Max. Surge Level 1040m, Min. 1026.5m
Tailrace tunnel
Size 8.8 m. dia. (Horse shoe shaped), Length 3070 m.
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