Geophysics for the Seac Pai Van Water Treatment Plant | China

Project summary

Service provided:  Control of Jet Grouting columns using Cyljet™ technique
Location:  Coloane, Macau
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Client:  Macao Water Supply, Suez NWS
Period of the service:  2018 - 2018
Duration of service:  1 month
Sixense solutions used: 

Images of the project

The need to secure the water supply

With a population of 650,000, Macau is an increasingly populated area and receives over 30 million tourists each year, putting additional pressure on the limited natural resources. Water scarcity will increase in the coming years with the completion of the Hong Kong-Zhuhai-Macao bridge and the development of large-scale recreational facilities that will strengthen the region’s tourist and economic appeal.

Suez NWS will invest approximately 106 Million euros in the new Seac Pai Van water treatment plant. With a water supply capacity of 130,000 cubic metres per day, the facility will increase Macao’s overall capacity to 520,000 cubic metres per day and help to meet the region’s water demand in the next decade.


A Cyljet premiere in Macao

As part of the future underground works, a curtain wall of jet grouting columns will be constructed. The Cyljet technique has been proposed and carried out to obtain the precise diameter of the columns level by level.

Six columns were tested during a trial plot, prior to the production phase.

The target diameter was achieved in the upper sandy layer, and in the lower highly decomposed granite. At the middle part of the columns, where geology is composed of gravelly clay and difficult to cut when jetting, Jet Grouting was not performing well and target diameters were not achieved. This has been confirmed by additional corings of some of the columns.

Jetting parameters were adjusted during the production stage in order to reach the targeted diameter.

Project Key figures

6 measured columns
-1 to -10 m BGL depth
80 cm as target diametre

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