Researchers have developed a technology they say could ease the disruption caused by digging up busy streets to lay underground pipes.
Researchers at Polytechnic University yesterday unveiled TunnelingGSV, which enables companies to lay utility pipes without having to dig trenches.
Engineers in the past 30 years have increasingly used trenchless methods, with pipes installed into holes bored underground.
'Trenchless methods minimise the traffic and environmental impact, dust and noise. But these methods are much more costly and time-consuming, compared to open-trench methods,' said a spokesman for the Water Supplies Department.
The tunnel-boring machines used to lay pipes without a trench are expensive - a mid-range local model costs about HK$12 million, while a high-end German version can cost double that amount.
Unforeseen problems can also add to the cost. The ground can be hard or soft, while unseen obstacles sometimes push a drill off-course or trap it underground.
'Ninety per cent of all trenchless projects will encounter some difficulty in tunnelling,' said Dr Lu Ming, an associate professor at the university's civil and structural engineering department.