7/31/2019 SIN Subm Gas.

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Client:

Singapore Power Gas

Angsana Drive, Jurong Island238164 Singapore

Value of Contract:

EUR 13.8 million

Share:

100%

Construction Period:

01/2011 12/2012

PROJECT DESCRIPTION:

Zblin Singapore Branch was awarded the 13.8 million Submarine GasTransmission Pipeline Project by Power Gas Ltd., Singapore in January2011 with a contract duration of 24 months. The scope comprised sinking oftwo deep shafts and an ID2000mm reinforced concrete tunnel. The tunnel has

a record length of 1.55 km, crossing beneath the busy shipping lanes of theWest Jurong Channel. Following the construction of the tunnel a DN700 mmhigh pressure gas transmission pipeline will be installed inside. Temporaryjacking and receiving shafts were constructed with circular 1m thick diaphragmwalls of ID14 m and ID7.5 m respectively with depths over 30 meters.Due to the highly variable geological conditions, a Dual Mode TBM wasdeployed to operate in both earth pressure balance and slurry modes, therebyproviding greater flexibility, safety and efficiency during tunneling.Zblin designed and produced all jacking pipes used on the project at its ownquality accredited pipe factory in Thailand. The tunnel design provided for 9intermediate jacking stations to assist with the pipe jacking process over the1.55 km drive. An effective lubrication system was in place to overcome thehigh skin friction, and this further eliminated the need to use all 9 Inter-Jackstations during the drive.

A major challenge for this project was the tunnel alignment control survey.Accuracy in terrestrial survey was achieved through an innovative vertical bobplumb-down system. Precision in the TBM guidance was guaranteed through aUniversal Navigation System (UNS). The north-seeking gyro-compass systemcontrolled and monitored the horizontal alignment, and a hydrostatic waterlevel system monitored the tunnel elevation.Constant checks and monitoringsaw the tunnel vertical alignment at 28 mm and the horizontal alignment at 113mm at breakthrough, well within the acceptable tolerances for a long singledrive tunnel.The tunneling operations were completed in 123 days with an average rate of12.6m/day, some 32 days ahead of schedule with no lost time injuries andmajor safety incidents.As a result of implementing a well-planned project and skills of highly trainedprofessionals a record-breaking tunneling milestone was achieved safely,ahead of time and within budget.

SUBMARINE GAS TRANSMISSION

PIPELINE PROJECTSINGAPORE

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