Trelleborg to seal Hong Kong subsea rail tunnel

Trelleborg, Sweden – Trelleborg’s engineered products operation has won a contract with Penta Ocean and China State JV, to seal an immersed tube tunnel in Hong Kong, the rubber parts company announced on 19 Feb.

The Shatin to Central Link project is a tube tunnel spanning 1.3 kilometers of the Victoria Harbour and will carry twin rail tracks to connect Kowloon to Hong Kong Island.

The project will consist of 11 concrete elements of approximately 160 metres each, which will be towed to the construction site by sea.

The elements will be connected using Trelleborg’s Gina gaskets, which are supplied as closed rectangular frames to seal each sectional element, along with Omega seals to connect each segment together.

According to Trelleborg, both seals have the ability to withstand seismic activity and absorb movement.

“Our tunnel seals enable installers to deploy a lighter force jack to seal the deeper joints, as the Gina gasket is softer and able to close more easily upon initial compression,” said Andre de Graaf, sales manager infrastructure for Trelleborg’s engineered products operation.

Therefore, he added, they help reduce costs and the time it takes to close the seals.

Trelleborg’s Gina gasket serves as a primary seal to prevent water ingress due to external water pressure. It has an outer dimension of 370mm x 370mm and consists of different rubber hardnesses for better sealing performance.

The Omega seal serves as a secondary, safety seal that can withstand extreme movements. It is designed with two cross-weaved reinforcement layers made of polyamide for durability and strength. The seals can perform at 3.8 bars pressure at a depth of 28 meters, but have the ability to withstand up to 5.0 bars.

“The combination of the two seals enables the transfer of hydrostatic loads and movements between the tunnel ends, caused by soil settlement, creep of concrete, temperature effects and earthquakes,” Trelleborg stated.

Site works have been initiated on the Victoria Harbour and Trelleborg has started production of gaskets for the project.