Hard rock

Luck Stone Corporation (LSC) is the nation's largest family owned and operated producer of crushed stone, sand and gravel. At their plant in Leesburg, Virginia, Luck Stone Corporation acquired a new quarry, which is located to the West of Goose Creek river. An inter-quarry tunnel was constructed to link the existing South-Eastern pit with the new West pit. The tunnel's cross section is approximately 45 feet in diameter, and the tunnel's length is approximately 1275 feet. The tunnel crosses the Goose Creek river approximately 50 feet beneath. The excavation method was drill and blast in hard rock (diabase).

Luck Stone Corporation (LSC) planned to open a new quarry on the Western side of Goose Creek river, a component of the Virginia Scenic Rivers System. A tunnel was envisioned to connect the new Western quarry with the existing South-Eastern one below the river. The rock cover between the tunnel and the river was approximately 50 feet. The tunnel is 1275 feet long with a diameter of 45 feet. It is designed to accommodate large scale mining trucks as well as a conveyor belt for material transport which is scheduled to be installed in the future.

Inspected tunnel connects two quarries at the Luck Stone Corporation Fairfax plant. The tunnel crosses beneath the Lee Highway (US Route 29), in a North-South direction. Built ca. 1975, the tunnel is partially unlined and in rock; approx. 190 feet long and approx. 22 feet wide and 22 feet high. As the Northern quarry side is already exhausted, the tunnel is rarely used with just one or two transits per day.
Dr. Sauer & Partners performed an in-depth inspection of a connector tunnel; assessed the tunnel condition and provided remedial measures.

The Brenner Base Tunnel (BBT) is a 64km long railway tunnel connecting Austria and Italy. Once completed, it will be the world's longest rail link underground. In addition to the two main tubes, the project comprises a complex set up of exploration adits, crosscuts, emergency stops and additional access tunnels, excavated by TBM and SCL methods. Dr. Sauer & Partners provided tender support services for the 18km lot H51 Pfons-Brenner and was responsible for creating the bid documents as well as conducting QA/QC services. The documents covered issues such as TBM choice, annular gap filling, reuse of excavated rock, rail delivery of construction materials, construction logistics and pre-excavation grouting.

Los Bronces copper mine, an open-pit operation at an altitude of 3500m ASL in the Chilean Andes, planned to utilise a tunnel for further deposit exploration and development. The project consisted of an 8.2km tunnel link between Los Bronces and Confluencia, connecting two processing plants. By applying drill and blast methods, a chamber was prepared to launch a 4.5m diameter tunnel boring machine which took over further excavation. A difficult geological and hydrological setting, extreme weather conditions as well as the high altitude and the rough terrain, provided a challenging environment.

A major collapse during construction of the Thierre Tunnel in 2009 led government officials to call on NATM experts to come up with an innovative fix for the 5.6km, two-lane twin tunnel, which is part of the new Reshen Kalimash Motorway. Recommended stabilisation measures by the Dr. Sauer/iC JV such as backfilling, ribs and fibre shotcrete were implemented and halted creep movements. An alternative design was developed and replaced the original horseshoe profile by an ovoid shape. Pre-treatment, excavation works and support installation were accompanied by extensive monitoring.

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.