Tunnel Design & Specialities

Binocular Road Tunnel Dimensions: 33,6m wide x 11,9m high Length: 40m x 3 lanes NATM excavation with Barrel Vault Method, through Bedrock with extensive tree / root system.

Subway running tunnels 2 x 1,400 ft (427m) long, 20' wide x 21' high with a section of 342 sqft (32m²). Tunnels included a section with chemical grouted arch pre-support in P2 sands installed using directional drilling methods. "Closed Bag" PVC waterproofing using sectioning system. Unreinforced concrete final lining.

Preliminary design studies for the construction of a 4-way escalator shaft using NATM. Escalator shaft 11.5 m span, approx. 60 m long by 32 m deep, initial lining 300 mm thick reinforced sprayed concrete.

Design of temporary shotcrete lining (150 mm thick) to support excavation for a perimiter r.c. beam at the base of the escape shaft piled walls. Shotcrete required to support the ground due to the foundations of a live railway viaduct located 2 m from the shaft walls.

Road tunnel with 2 lanes and a lenght of 400 ft. Study into the construction of either a single tunnel or a binocular tunnel with central pier using the shotcrete support method with ground freezing pre-support to protect overlying historic building.

10.3 m ID shaft, 33.5 m deep with a sprayed concrete (fcu 25 N/mm²), shell 250 mm thick. Two breakout eyes at base level, with 3.73 m diameter 400 mm thick collars.

Complex layout of urban highway ramps with numerous off and on slips, intersections and over ramps. Mined tunnel option developed using primary shotcrete lining, with lattice girders, waterproofing and reinforced concrete secondary lining. Design of Alternative construction sequencing.

Ramp S-N, two lane highway, total length 600 ft, span 41 to 48 ft. Doorframe Slab Method adopted in areas where the cover was < 10 ft. Utility room breakout and pump station shaft. Reinforced shotcrete primary lining; waterproofing system with a reinforced conrete secondary lining.

3 x twin track railway tunnels. Approximately 12m span. Oblique to 35m wide chalk spine. 1 x 7m span access tunnel, 35m long.

Approximately 14 m span twin track railway tunnel. Approximately 200m long. Using doorframe slab method.