Tunnel Design & Specialities

Silver Line Phase III is an underground extension of the Silver Line from the current terminal at South Station into Downtown Boston. The tunnels through Boston's Chinatown lie up to 25m below surface and include ca. 1400m long-running tunnels, two stations and complex underground junctions. The NATM design alternatives for LRT / Busway tunnels are located beneath existing subway stations and running tunnels. 3D modelling tools were utilised to create multiple alignments.

MUNI planned a 2.7 km underground extension to the Third Street Light Rail Project. The underground section would start near Bryant Street, run along Third Street, cross under four BART Tunnels at Market Street and continue under Geary and Stockton Streets to Clay Street. Dr.Sauer and Partners was the designer for the SEM Tunnel Structures at Chinatown Station and prepared detailed excavation and support sequences as well as procedures for the construction of the large caverns and final design documents for SEM construction.

Exchange Place is a key station on the PATH commuter rail service between New York and New Jersey. After the World Trade Center collapse, the station and river crossing running tunnels were closed. Precautions were taken to prevent flooding of the subway system from broken water mains and sewer lines. Turning existing elements into a terminus and extending the platform tunnels by 45m involved excavating new crossovers, modifying the 5 existing tunnels, raising the invert and crown up to 3m and back filling unneeded tunnel spaces to create the ground in which new spaces could be excavated.

The Pajares Rail Tunnel is part of the new Leon-Asturias High Speed Rail Line, and with a length of 25.7km one of the longest tunnels in the world. The project encompasses twin 10m dia. TBM hard rock tunnels, bifurcation chambers, cross passages, and emergency stops. The tunnel is lined with a pre-cast segmental lining made from high-strength with a thickness from 50 to 60cm. The connection between the access tunnel and the main tunnel requires the construction of a large-span Bifurcation Chamber and a short mined tunnel.

High Speed 2 (HS2) is a high-speed railway between London Euston, the English Midlands, North West England, Yorkshire, and there are plans to extend the line to North East England and the Central Belt of Scotland. The project is currently split to two phases, namely a first phase between London and Birmingham, then a second branched phase to Manchester Piccadilly via Crewe and Manchester Airport, furthe to Leeds via the East Midlands Hu and Sheffield. 

Beacon Hill Station is part of the 22.5 km initial segment of Sound Transit's Central Link Light Rail. It is located 49 m below the ground surface in complex glacial soils with multiple groundwater horizons. The project comprises deep mined station tunnels and two 1.5 km long running tunnels excavated using a tunnel boring machine. The mined station was excavated through compressible glacial soils with multiple groundwater horizons using conventional mining techniques. The access shafts and station headhouses were constructed using slurry walls and cut-and-cover techniques.