Location

Silkyara to Barkot, Uttarkashi district, Uttarakhand

Length

4.531 km (Not 531 km; Typo corrected)

Highway Section

Part of NH-134 (formerly NH-94) under Chardham Mahamarg Project

Connectivity

Connects Dharasu–Yamunotri section enabling access to Yamunotri, Badrinath, Kedarnath

Tunnel Type

Two-lane, bi-directional road tunnel with separate escape passage

Construction Mode

EPC (Engineering, Procurement & Construction)

Rock Type Encountered

90% Phyllite a very weak, metamorphic rock

Tunnel Design Method

New Austrian Tunnelling Method (NATM) Adaptive technique with real-time monitoring

Funding Source

National Highway (Original) [NH(O)] Scheme, MoRTH

Estimated Cost

₹853 crore

Strategic Importance

Enhances all-weather connectivity to Char Dham Pilgrimage Circuit

Travel Time Benefit

Reduces travel time by approximately 1 hour

Significance

Played a role in 2023 rescue of 41 trapped workers after tunnel collapse

Nearby Pilgrimage Sites

Yamunotri (~50 km), Gangotri, Kedarnath & Badrinath

Additional Notes

Baba Baukhnag temple consecrated at tunnel’s mouth; renaming proposal in process

Atal Tunnel (Rohtang)

Himachal Pradesh

9.02 km

Leh–Manali Highway

Longest highway tunnel above 10,000 ft; All-weather access to Lahaul

Zojila Tunnel

Jammu & Kashmir–Ladakh

14.15 km (ongoing)

Srinagar–Leh Highway (NH-1)

Asia’s longest bi-directional tunnel; Strategic Ladakh access

Nashri–Chenani Tunnel

Jammu & Kashmir

9.28 km

NH-44 (Jammu–Srinagar)

India’s longest road tunnel (till Atal); all-weather Jammu-Kashmir link

Silkyara–Barkot Tunnel

Uttarakhand

4.531 km

NH-134 (Chardham Mahamarg)

Critical to Char Dham Yatra; NATM construction

Banihal-Qazigund Tunnel

Jammu & Kashmir

8.5 km

Jammu–Srinagar National Highway

Replaces old tunnel; reduces distance & travel time

Pir Panjal Tunnel (Rail)

Jammu & Kashmir

11.2 km

Jammu–Baramulla Rail Line

India’s longest railway tunnel; strategic for freight & mobility

Kuthiran Tunnel

Kerala

1.6 km (x2 tubes)

NH-544 (Thrissur–Palakkad)

First tunnel in Kerala; reduces travel time through Western Ghats

Parwanoo–Solan Tunnel

Himachal Pradesh

8.8 km (total)

NH-22 (now NH-5)

Enhances all-weather movement on Kalka–Shimla route

Himalayas

Atal, Zojila, Silkyara, Banihal

Military logistics, border access, tourism, disaster-resilient transport

Western Ghats

Kuthiran, Parwanoo-Solan

Connectivity across rugged terrain; economic corridor boost

North-East India

Upcoming tunnel projects

Border area development, trade, all-season transport routes

Name of Project

Chardham Mahamarg Vikas Pariyojna (Char Dham Highway Development Project)

Launched by

Government of India Ministry of Road Transport & Highways (MoRTH)

Inauguration Year

2016

Estimated Cost

Approx. ₹12,000 crore

Executing Agency

National Highways & Infrastructure Development Corporation Ltd (NHIDCL) & Border Roads Organisation (BRO)

States Covered

Uttarakhand

Total Length

Approx. 889 km of all-weather roads

Core Objective

Enhance all-weather connectivity to four holy shrines—Yamunotri, Gangotri, Kedarnath & Badrinath

Design Features

2-lane paved shoulders, tunnels, viaducts, retaining walls, slope stabilization & avalanche protection measures

Environmental Clearances

Under purview of Environmental Impact Assessments (EIA) & Forest Conservation Act (FCA)

Tunnelling Involved

Key tunnels Silkyara Bend–Barkot Tunnel, Chamba Tunnel, Rudraprayag Bypass Tunnel, etc.

Connectivity Boost

Shortens travel time & ensures uninterrupted access in landslide-prone, high-altitude Himalayan terrain

Religious Importance

Supports Chardham Yatra a major pilgrimage drawing lakhs of devotees annually

Strategic Relevance

Enhances border area connectivity near Indo-China frontier (especially Gangotri & Badrinath sectors)

Weather Resilience

Designed for round- -year operation even during monsoons, snowfall or landslides

Controversies

Environmental concerns, SC rulings on road width, deforestation & slope instability due to road widening

Supreme Court Verdict (2021)

Upheld 10m-wide road width for defence needs in strategic border stretches, deviating from 5.5m eco-friendly norm

Cultural Integration

Monuments & way-side amenities themed around mythology & culture of Char Dham

Yamunotri

Western Garhwal Himalayas

Uttarkashi

3,293 m

Source of River Yamuna; seat of Goddess Yamuna

Gangotri

Bhagirathi River Valley

Uttarkashi

3,100 m

Source of River Ganga (Bhagirathi); sacred to Goddess Ganga

Kedarnath

Mandakini River Valley

Rudraprayag

3,583 m

Jyotirlinga of Lord Shiva; part of Panch Kedar

Badrinath

Alaknanda River Valley

Chamoli

3,133 m

Vishnu Temple; part of Sapta Badri & a major Vaishnavite pilgrimage site

Tunnels

Silkyara–Barkot (4.531 km), Chamba Tunnel, Rudraprayag Bypass Tunnel

Bridges & Viaducts

Numerous bridges over rivers like Bhagirathi, Alaknanda, Mandakini

Slope Stabilization

Use of rock bolts, retaining walls & bioengineering techniques

Avalanche Protection

Steel sheds & controlled blasting zones in high snow risk areas

Disaster Resilience

Built-in evacuation paths, warning signage, escape tunnels & drainage systems

Monitoring Tech

GPS-based systems, satellite monitoring & real-time geological stress tracking

Deforestation

Large-scale cutting of trees, especially in ecologically fragile Himalayan regions

Landslides & Instability

Increased after aggressive hill cutting & blasting in sensitive zones

Cultural Impact

Risk to heritage sites & ancient temples near widened roads

SC & Expert Panels

Debate on road width (5.5m eco-friendly vs. 10m strategic), landslide impact, resettlement

Definition

A machine that uses a rotating circular shield to bore through soil & rock.

A method that involves monitoring & adjusting tunnel support based on rock conditions.

Application

Typically used for larger, more consistent rock formations or soft ground.

Suitable for more complex geological conditions especially variable or weak rock.

Cost

High upfront costs due to machine purchase, maintenance & operation.

Lower initial costs as it involves more manual labor & less mechanized equipment.

Excavation Speed

Faster excavation with large projects due to continuous operation of TBM.

Slower excavation compared to TBM as process is more manual & dependent on rock behavior.

Tunneling Environment

Better suited for stable & uniform rock formations.

More adaptable to unpredictable or fractured rock conditions.

Tunneling Accuracy

High precision & uniform tunnel shape.

Precision depends on monitoring & adjustment leading to slight variations in tunnel shape.

Rock Type

Best for strong, competent rock types or soft ground.

Can work well in a variety of rock types including weaker or highly fractured rocks.

Operational Efficiency

High, once TBM is operational, it allows for continuous excavation.

Dependent on real-time monitoring & support adjustments, potentially causing delays.

Environmental Impact

Less environmental disturbance due to minimal blasting or drilling.

More environmental impact due to blasting & excavation in unstable conditions.

Risk Factors

Minimal risk of tunnel collapse but high risk of machine failure in tough geological conditions.

Risk of collapse or deformation in weak ground or variable conditions; requires constant monitoring.

Maintenance

Expensive maintenance especially in challenging terrains.

More flexible but requires significant manual labor & expertise for support adjustments.

Purpose

Primarily designed for trains & high speed transit.

Designed for vehicular traffic including cars & trucks.

Design Criteria

Requires smooth & strong infrastructure to support high-speed trains.

Needs sufficient height & width for various vehicle types including heavy trucks.

Tunnel Size

Typically narrower than road tunnels due to limited clearance for trains.

Larger in cross-section to accommodate vehicles with more airspace for ventilation.

Safety Considerations

Safety features include train control systems, fire suppression & evacuation platforms.

Focuses on vehicle safety, including ventilation, escape routes & fire prevention systems.

Ventilation

Generally requires high-performance ventilation systems to manage smoke & fumes from trains.

Requires larger ventilation systems due to vehicle exhaust emissions especially for tunnels with high traffic.

Construction Methods

Often uses Tunnel Boring Machines (TBM) for construction due to precise requirements.

Uses both TBM & conventional methods like drilling & blasting.

Cost

Typically higher cost due to complex design & safety measures for trains.

Can vary depending on traffic capacity but generally lower than rail tunnels due to fewer safety demands.

Speed Requirements

Tunnel design must support high-speed travel requiring specific geometric designs.

Tunnel design focuses on steady flow of traffic but not optimized for high speeds like rail tunnels.

Environmental Impact

Minimal pollution from trains if electrified  though construction can cause significant disruption.

Significant air pollution from vehicles inside tunnel particularly in dense traffic areas.

Maintenance

Requires regular inspection & maintenance of rail tracks signaling systems & tunnel structure.

Maintenance includes road surface repair, lighting, ventilation & traffic management systems.

PRACTICE QUESTION

Q. Discuss key engineering & environmental challenges involved in construction of Chardham Mahamarg Vikas Pariyojna (Char Dham Highway Project) & its strategic importance for both pilgrimage & national security.