ZHENGZHOU -- Construction has started in Zhengzhou, capital of Central China's Henan province, to use a shield tunneling method to create an underground parking lot.

It is the first time the protective drilling method has been used in China's busy downtowns to solve parking difficulties.

The project undertaken by China Railway Engineering Equipment Group Co Ltd uses a supportive structure to protect the ground work while drilling an underground tunnel, which is located 6 meters under a 3,000-square-meter public square.

With the new construction method, workers only need to open a small area on the ground's surface to send the shield tunneling machine underground to carry out tunneling.

Gao Yi, director of the company's underground design institute, said the project will be completed in five months and provide 100 public parking spaces.

Tan Shunhui, chair of China Railway Engineering Equipment Group Co Ltd, said that the company set up the institute to explore the use of underground space in China's busy urban areas for parking, multi-purpose corridors and subway stations.

Shield tunneling can reduce the risks of underground engineering and ground demolition work in urban development, said Tan.