Inspection & Maintenance

The Puerto Suello Tunnel is a 400 m long single-track rail tunnel in San Rafael, California and was constructed in 1879. The 4.9 m wide and 6.8 m high tunnel was partially destroyed by a fire in 1961, was rebuilt for freight service in 1967 and closed in the mid-1980s. The tunnel was acquired by SMART in 2003, who retrofitted and then reopened it for commuter rail service in 2017.

The ground overburden above the tunnel reaches a maximum of 45 m and the tunnel was constructed using cut-and-cover and mined construction methodologies.

Bank Station is a London Underground station located in the City of London financial district. It is a key interchange served by five existing lines. The Bank Station Capacity Upgrade (BSCU) comprises the construction of new tunnels adjacent to and connecting with the existing tunnels. Defects surveys of the LU existing facilities predicted to be impacted by the BSCU works had to be carried out before construction started. All existing facilities expected to be within the 1 mm settlement contour were inspected for defects.

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.

NATM test tunnel, heavy support Aligning pole (d= 5 cm) should make deformations possible.

The Washington Metropolitan Transit Authority (WMATA) faces serious problems related to water intrusion in sections of the Red Line. Especially in the Northwestern Section water leakage by far exceeds the acceptable limits. The consequences include electrical malfunctions, icing and clogging of the drainage system as well as deterioration of the tracks and the utilities in the tunnels. They are detrimental to an efficient operation and represent considerable safety hazards. The report describes a permanent, none adhesive waterproofing layer system for the rehabilitation of the WMATA Red Line tunnels and underground structures. It shows the feasibility and constructibility of the selected approach for a single tunnel and shaft, similar solutions will be developed for adits, crossovers, etc.

The Russia Wharf segment is the last, but most challenging section of the Silverline Phase II construction for the Massachusetts Bay Transportation Authority (MBTA). The line is designed to provide a dualmode bus rapid transit connection between the central business district in South Boston to the new Convention Center. The tunnel passes diagonally under the 100 year old Russia Wharf complex, which comprises three seven-story buildings with steel frames and brick facades listed in the National Register of Historic Places. The chosen construction method was NATM in conjunction with ground freezing, for the first time in the US. Steel fibre reinforced concrete was used for temporary and permanent lining.