Afcons uses Robbins EPB TBM to Complete Third Bore for Chennai Metro Project

Contractor Afcons Infrastructure Ltd used a 6.65 m (21.8 ft) diameter Robbins EPB TBM to bore through in Chennai Metro, making it the contractor's third tunnel to be bored by the machine for the project. The three separate bores for the EPB are part of an increasing trend as many Robbins EPBs have been used on multiple tunnel drives with good performance.

Robbins EPBs are built one third heavier than any other EPB in the market and are designed for 10,000 hours of usable life, making them ideal for use over many kilometers. “Robbins is known for designing resilient machines,” says Mr. Gopal Dey, Afcons Senior Manager. “For this project, we needed a machine that was specifically tailored to project conditions from soft clay to mixed ground with rock. Robbins EPB TBMs have unique design features that optimize the machine for the geology.”

Robbins EPB TBM

Robbins EPBThe Robbins EPB was originally supplied in 2012 for twin bores in weathered and highly fractured granitic rock, also part of the Chennai Metro project.
After completing its original twin tunnels, the EPB was refurbished in preparation to bore its latest 1.8 km (1.1 mi) section. During refurbishment, the inner seal greasing system was changed from auto to manual mode, and the foam nozzle system was modified. These changes optimized the machine for excavation in the highly variable mixed face conditions encountered in the first two tunnels.

The EPB was launched on February 3, earlier this year. According to contractor Afcons, the machine faced a major challenge right out of the gate. “When the TBM came out of the launching shaft, a few rings were erected, and then the machine had to cross a live railway track, which meant there would be a possibility of ground settlement,” says Afcons Director, Mr. Manivannan. “At this stage, we had to closely monitor TBM’s face pressure and advance the machine at a uniform rate to ensure proper primary grouting.” The bore’s geology mainly consisted clayey sand and about 60 meters (197 ft) of mixed ground.

Adds Mr. Dey, “We chose this machine for this project due to the underground geology in Chennai, which continuously changes from soil to mixed ground. We also liked that Robbins EPB machines are designed with active articulation to allow the machine to turn or steer with ease.”

During active articulation, thrust cylinders react evenly against the entire circumference of the tunnel lining, even in a curve - a design that eliminates the problem of tunnel lining deformation. This feature enabled the machine to negotiate through well-controlled conditions.

Robbins EPB TBMAfter completing twin bores, the Robbins EPB was refurbished for clay, sand, and rock conditions, which included a new inner seal greasing system and foam nozzle system.

With all three tunnels, Robbins field service team was on location to assist and support as required. During the course of each bore, the team advised Afcons on how best to maneuver through challenging ground and provide instruction for machine operation. The ability of the contractor and manufacturer to work well together, as Robbins and Afcons have throughout their contracts, was critical to the good advance rates. The result was a robust machine that advanced at rates of 80 mm (3 in) per minute in challenging conditions.

This latest tunnel connects multiple stations along the metro line, starting from Washermenpet through to Sir Theagaraya and to Kurukpet. The Chennai Metro Project will provide the much-needed transportation to a rapidly developing city.

NBM&CW December 2017

GHH adds Shotcreting Machine to its - Tunneling Equipment Solutions

GHH is offering state-of-the-art and proven IS26 Concrete Spraying (Shotcrete) machine in India. The machine is suitable for shotcreting application in medium and large sized tunnels with cross sections ranging Read More ...

Kishanganga Hydro Power project – A New Power House

Inaugurated by the Prime Minister of India, the Kishanganga Hydro Electric Power project is the first mega hydro power plant to be awarded as EPC to HCC by NHPC. Located at Bandipore in north Kashmir, the Read More ...

Tunneling to Prosperity: Solutions, Equipment and Technologies

India is one of the fastest growing markets for tunnel construction due to various infrastructure development projects underway across the country. Tunnels are required for hydroelectric power projects, for improving road Read More ...

CREG: Tunneling Specialist

China-based China Railway Engineering Equipment Group Co., Ltd (CREG) is a subsidiary of the public- listed China Railway Engineering Corporation (CREC), a Fortune 500 company and a key state-owned company under Read More ...

Intermodality & Last Mile Connectivity - Creating Smart Walkable Spaces

Urban congestion needs to be addressed by encouraging high quality and innovative energy-efficient public transport integrating it with other forms of paratransit, ensuring last mile connectivity; working on Read More ...

Ashram Metro Station - An Engineering Masterpiece

One of the main challenges of constructing a station in the Delhi Metro Network, especially in a busy and densely populated area, is designing it according to the ambience and the limited space allocated. Constructing Read More ...

Transit Oriented Development - Challenges and Proposed Regulatory Framework

Transit Oriented Development (TOD) complements the concept of new urbanism. Compact, mixed-use communities are the answer to suburban problems. Due to the dynamic nature and multiplicity of underlying Read More ...

Simulating oversize and heavy vehicle manoeuvres using AutoTURN® from Transoft Solutions.

Use AutoTURN® to design infrastructure adjustments to safely operate trucks transporting wind turbine components. By Er. Alessio Gori - collaborator at POLITECNICA INGEGNERIA ED ARCHITETTURA SOC. COOP. Read More ...

Urgent Course Correction Imperative for Indian Railways

Railways’ freight and passenger businesses over the 5-year period, i.e., 2014-15 to 2018-19 (budgeted) indicate a flat growth. The number of total passenger journeys would record a CAGR of 0.22%, passenger kilometres Read More ...

Meeting Emerging Urban Transport Challenges

The Ministry of Housing and Urban Affairs has envisaged growth of urban transport along with a low carbon footprint through seamless implementation of a New Metro Rail Policy, announced last year Read More ...

Tunnelling Through the Ages

History has seen the evolution of tunnelling starting with cave formation, for water management, underground transportation, mineral extraction and for warfare purposes. The oldest reference of a tunnel was Read More ...

Robbins Slurry TBM ramps up for Mumbai Metro Line 3

The first of two Slurry TBMs, a rebuilt 6.65 m (21.8 ft) diameter machine, passed its factory acceptance on September 4, 2017 in Singapore. The machine, fitted with a Robbins cutterhead and outer Read More ...

Tunnelling Technologies & product support keep pace with construction complexities

Advanced technologies, mechani- sation of equipment with heightened safety features, and timely service and technical support to end-users can help the construction industry deal with construction complexities Read More ...

Delhi Metro’s Underground Revolution

The Delhi Metro’s underground construction in its third phase of expansion cannot be considered anything short of a revolution. Close to 80 kilometres of underground tunnels have been laid beneath Read More ...

Chenani-Nashri Tunnel — An Engineering Marvel

The Chenani-Nashri tunnel is a single-tube bi-directional tunnel, with a 9.35-metre carriageway, vertical clearance of 5 metres, and a parallel escape tunnel with cross passages connecting to the main Read More ...

Gotthard Tunnel:World’s longest railway tunnel opens in Switzerland

Gotthard Tunnel
After nearly 2 decades of construction, the Gotthard Base Tunnel was officially opened on June 1, 2016 and exceeded all previous dimensions in terms of tunnel length, engineering and logistics Read More ...
NBM&CW

New Building Material & Construction World

New Building Material & Construction World
MGS Architecture

Modern Green Structures & Architecture

Modern Green Structures & Architecture
L&ST

Lifting & Specialized Transport

Lifting & Specialized Transport
II&TW

Indian Infrastructure & Tenders Week

Indian Infrastructure & Tenders Week