The construction of urban underground roads has become a solution to alleviate urban traffic congestion. However, pollutants (CO, NOx, etc.) produced by vehicle exhausts also pose risks to the drivers and passengers in tunnels, and the living environment and health of residents near the access openings. They also pose a challenge to the optimal design and smart operation and control of ventilation systems in urban underground roads. Prof. Chen Chao's team has been working with Beijing Municipal Engineering Design & Research Institute for more than 10 years on an in-depth and comprehensive research about the theoretical methods and control technologies for ventilation control of motor vehicle emissions from underground roads with complex structures, with a view to providing basic data and design method references for the optimal design and smart operation and control of ventilation systems for underground roads with complex structures in China.

By employing the field measurements of road, 1:8 scale model experiments, numerical calculations and other research methods, the team proposed a quadratic formula between traffic flow and vehicle speed, a traffic wind speed calculation model, a method to determine the emission factors of pollutants (CO, NOx, etc.) produced from motor vehicles, a diffusion model of pollutants along the direction of traffic, and a method to calculate the dynamic characteristics of mechanical ventilation systems suitable for the complex structures of China’s urban underground roads, based on the characteristics of the road structures and traffic of the complex urban underground roads in China. A set of theories, methods and technologies has also been developed to guide the optimal design and smart operation and control of ventilation systems for underground roads in complex structures.

The research results have been applied to the optimal design of ventilation systems in the complex underground roads in Qianhai, Shenzhen, and the east extension of Guangqu Road in Beijing.