Chinese
civil engineers are no strangers to AI, which was used to build
Baihetan, the world’s second-largest dam, in just four years. But until
now, it has mainly played a coordinating role in projects.
Critics query green credentials of world’s second-largest hydroelectric dam after speedy build
Testing
of the technology in previous construction projects suggested smart
machines could do a better job than humans, “especially in some harsh
and dangerous environments”, said Liu and his colleagues. Liu
did not immediately respond to questions about Yangqu dam’s progress,
but according to state media reports work started at the end of last
year in Hainan Tibetan autonomous prefecture, Qinghai province.
After
“slicing” a computer model of the dam into layers, the AI at the heart
of the project would assign a team of robots to add one layer at a time,
the paper said.
Unmanned excavators will be able to identify and
load materials from a stockpile yard into a fleet of automated trucks,
some powered by electricity.
Some of the automated machinery that will be used in the 3D-print construction of Yangqu dam. Photo: Tsinghua University
Following
an optimised route calculated by the central AI, the trucks will
deliver the right materials to the right locations, at the right time,
to be located by robotic bulldozers and pavers and turned into a layer
of the dam structure.
Automated rollers press the added layer until
it is tight and firm, but they are also equipped with sensors. The
central AI uses these to monitor build quality by analysing ground
vibration and other data.
Breakthroughs in AI
technology, including deep reinforcement learning, mean the machines can
now recognise nearly all objects on site, deal with uncertainties in a
changing environment, and perform various tasks flexibly, according to
the paper.
They also do not make human errors. Liu said truck drivers
often delivered materials to the wrong location, while shocks and
strong vibration prevented roller operators from maintaining a perfectly
straight path. And most workers were unable to read the technical
design papers correctly, he added .
But
where the machines shine is their ability to work in a life-threatening
environment, without getting headaches from a lack of oxygen or
exhausted after working continuously for 24 hours, according to the
researchers.
Not all jobs in the dam’s construction will be handled
by machines. The team said the mining of fill-rocks from nearby
mountains would be done manually because of the task’s complexity.
Liu’s team said the technology could also be used in other infrastructure projects, such as airport and road construction.
“AI based on knowledge, information and data is a new tool … that will shape our future,” they said.
A
Nanjing-based civil engineering scientist, who asked not to be named
because of his role in the technical evaluation of some major
infrastructure projects, said there were limits to 3D print technology
but it would find more uses in the future.
“It cannot print a
structure consisting of different materials, such as reinforced concrete
made of steel and cement,” the scientist said.
“An army of construction robots can offset the sharp decline of manual labour caused by low birth rates,” he added.