Trelleborg steps up to Russian metro tunnel test

ERJ staff report (TP)

St. Petersburg, Russia – Trelleborg’s engineered products operation has supplied a profile from its range of tunnel segment gaskets for the ‘extension line 5’ project of the Metro system in St. Petersburg, Russia.

The “challenge” was to create a gasket that could operate at lower depths and higher pressures than a standard bored tunnel but still meet a guaranteed life of 100 years.

Working closely with engineers for the Metrostroy St. Petersburg, Trelleborg provided its largest elastomeric tunnel segment gasket, the CS024C, and its high performance sprayable adhesive to securely bond the gaskets to each segment. Deeper than the standard bored tunnel at 55 metres below ground, Trelleborg calculated the hydrostatic pressure at an increased 10 bar, as opposed to the usual 5 bar, to guarantee safety and performance for 100 years.

Nikolay Laptev, Deputy Chief Engineer – Head of technological department at Metrostroy St. Petersburg, said: “Infrastructure within St. Petersburg is being invested in heavily and this extension project is just the start of it. Due to the size of the development it was imperative that a manufacturer was specified that could cater for the size and depth of the tunnel, as well as meet stringent pressure and testing requirements. Trelleborg approached the challenge head-on and proved to be a very experienced and trustworthy partner.

“We have a long-standing and successful history with Trelleborg on projects such as the St. Petersburg storm surge barrier and would be keen to work closely with Trelleborg again in the future.”

Located in the pre-cast grooves surrounding the mating faces of each segment, Trelleborg’s elastomeric gaskets give a “secure” rubber-to-rubber waterproof seal as soon as the segments are bolted together. Even when faced with natural ground movement and harsh wet and dry conditions, the seals remain “functional and watertight”.