Feasibility study of Thathali-Rabiopi Road Tunnel, Bhaktapur

Project Description

The Thathali-Rabiopi Road Tunnel lies in Bhaktapurr district. The Thathali Rabiopi Road Tunnel effects directly and indirectly positive influence on Bhaktapur, Nuwakot, Sindhupalchowk and Kathmandu districts. The construction of tunnel helps to develop the city at Panchkhal area and whih may be useful in reducing densely populated Kathmandu Valley population to Panchkhal area. It also helps to reduce connectivity distance of Arniko highway to reach China border, Kodari. The construction of road tunnel reduces the tentative length of the road upto 17 Km and hence reduces the travel time making the travel safe in geographically steep terrain and enhance the economic growth in these areas.

The main objective of the consulting services is to conduct the feasibility study of road tunnel to be constructed under DB or EPC Contact Model. The Feasibility study was conducted for 2 Tunnels as follows with Access Road length of 1783 m.

S. N
Description
Tunnel-1
Tunnel-2

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Tunnel shape
Modified-Horse Shoe
Modified-Horse Shoe

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Tunnel size
11.3 m* 7.44 m
11.3 m* 7.44 m

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Tunnel length
2360 m
2220 m

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Tunnel Width
Double Lane Single Tube
Double Lane Single Tube

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Excavation method
Conventional Drill and blast
Conventional Drill and blast

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Construction approach
NATM
NATM

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Carriage way width
9.5 m
9.5 m

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Escape Tunnel
Single Lane parallel to main tunnel
Single Lane parallel to main tunnel

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Escape Tunnel Size
4.22 m x 4.00 m, Inverted D-Shape with cross passage @375m interval
4.22 m x 4.00 m, Inverted D-Shape with cross passage @375m interval

•
Pavement type
Reinforced Concrete
Reinforced Concrete

Assignment Description

The Consultant undertook the management of following activities in order to meet the aforesaid objectives of the project: • Reviewed of all available background reports, maps/drawings and published information pertaining to road tunnel corridor; • Drone survey was carried out to conduct Topographic survey of proposed alignments of the tunnel and its approach roads and preparation of topographic maps in 1:1000 scale; DGPS was used for the determining the Control Points. • Carried out traffic study and transport planning. • Hydrographical studies to assess the groundwater aquifer characteristics, catchment areas and hydraulic parameters for required drainage structures; • Geological / Hydrogeological investigations to determine the nature/ properties of existing strata, rock classifications (RMR or Q), geological anomalies and any construction issues; • Geophysical/ Sub-surface investigation (MASW)-4 nos. including 2D Electrical Resistivity Survey (ERT)-4295 m. and Seismic Refraction Tomography (SRT)-600 m. • Environmental and social study to recognize the potential significant impacts and address safeguards in project cost; • Inventory survey of existing surficial and underground structures and obstacles for tunnel construction; • Identification of construction materials’ sources, quality and quantities to be taken from different source; • Assessed at least three alternative alignments based on analysis of socio-economic, traffic, topography, geology, environmental, seismic, soil and other related factors; • Established technical, social, economic and environmental feasibility of the proposed tunnel schemes; • Preparation of the preliminary design/ drawing of the 2 tunnels and its approach road (1783 m) including geometrics, portal, lining / permanent support, excavation support, operating & safety equipment, disposal area, power supply etc. • Preparation of the preliminary design/ drawing of Ventilation and Lighting systems, side drainage, subsurface drainage • Estimation the project costs, benefits and construction schedule under DB/EPC contract; • Undertook economic and financial evaluation for the preferred mode of implementation of tunnel; • Feasibility Study, Indicative Cost Estimation and Report Preparation for Tunnel alignment including approach roads