Waterproofing for Hong Kong West Island Line
Location: Hong Kong
Market sector: Underground construction
Product used: MasterSeal 345
The background
Master Builders Solutions Hong Kong was awarded a contract to supply waterproofing products for the 3km underground tunnel linking the newly added MTR stations from Sheung Wan to Sai Ying Pun, the University of Hong Kong and Kennedy Town. The construction work is part of the West Island Line extension project initiated by MTR Corporation Limited.
The challenge
Gammon-Nishimatsu WIL Joint Venture, the project contractor, decided to “freeze” the soil following the spray concrete process, to overcome the soft soil conditions in the area, which could hamper their construction work. However, the soft soil engineering they undertook resulted in a temperature drop in the shotcrete, to -3 degrees Celsius. As a result, the shotcrete surface temperature is cold and moisture comes from condensation. The temperature of the affected area had to be maintained at 20 degrees Celsius to ensure the shotcrete surface was dry enough for the successful application of MasterSeal 345, a waterproofing membrane for concrete.
Our solution
The underground construction team was called in to tackle the technical issue. It was resolved with the placement of PVC canvas sheets, to isolate the area earmarked for treatment. To ensure the required temperature level for the sprayed concrete, jet heater guns and ventilation fans were also used. Eventually, the shotcrete surface dried up and was ready for waterproofing application. Considerable savings in time and manpower were achieved due to the remedial work, much to the client’s satisfaction.
View complete project reference
Map indicating the alignment of the West Island Line.
Image courtesy of MTR Corporation Limited.