As urbanization accelerates across China, cities are looking beneath the surface to address pressing challenges. The innovative development and utilization of underground space have become pivotal in optimizing urban structures and alleviating issues such as congestion, insufficient logistics, and environmental concerns.
In 2021, the Xi’an Happiness Forest Belt Project, the world’s largest comprehensive underground space utilization initiative, commenced operations. With a total investment exceeding 24 billion yuan ($3.3 billion) and an underground development area of 920,000 square meters, this project exemplifies China’s commitment to subterranean solutions.
By the end of 2022, Chinese cities had cumulatively developed 2.962 billion square meters of underground space. Additionally, the total operating mileage of urban rail transit lines surpassed 10,000 kilometers, highlighting the extensive use of subterranean areas in transportation, municipal services, and commerce.
Tackling Urban Challenges Underground
Underground spaces are being harnessed to address various urban challenges. For instance, to mitigate parking difficulties in densely populated areas and older residential communities, cities are constructing intelligent automated multi-level underground garages. The Miduqiao underground garage in Hangzhou, with a depth of 34.2 meters spanning 19 floors, occupies just 150 square meters at the surface while providing 112 parking slots. This innovative approach saves over 80 percent of land resources compared to traditional parking structures.
To combat insufficient logistics space in urban cores, underground warehousing and logistics systems are being developed. In the Rongdong District of Xiong’an New Area, a comprehensive underground transportation system features a two-level structure about 10 meters tall. The upper level accommodates autonomous vehicles for logistics distribution, while the lower level houses pipelines for essential municipal services such as water, electricity, gas, heating, and networks.
Natural disasters like urban flooding due to extreme rainfall are also being addressed through underground solutions. The Dadonghu Deep Tunnel Project in Wuhan, Hubei Province, is China’s largest deep tunnel for wastewater transmission, with an average depth exceeding 30 meters and a total length of 17.5 kilometers. This deep tunnel drainage system effectively enhances the city’s drainage capacity, mitigating the risks of flooding.
Overcoming Challenges in Underground Development
Despite significant progress, the rapid development of underground spaces presents challenges. Issues such as unclear ownership rights, the need for technological advancements in engineering and equipment, and ensuring safety during operation and maintenance require attention.
Clarifying Ownership Rights
Unclear delineation of operating rights and ownership of underground spaces has led to inconsistent management standards. To address this, cities like Beijing, Shanghai, Hangzhou, and Chengdu have enacted regulations governing the development and utilization of urban underground spaces. These measures aim to establish a sound legal framework, encouraging investment and standardizing management practices.
Advancements in Engineering Technology
The construction of super-deep, large-scale, and long-distance underground projects demands breakthroughs in engineering technology and equipment. Companies such as China State Construction and China Railway Construction Corporation Limited (CRCC) are making strides in this area. They have developed advanced machinery like the Shaft Excavation Cutting Machine (SECM) and the “Dream” shaft roadheader, capable of constructing super-deep vertical shafts exceeding 100 meters.
Ensuring Safety and Maintenance
Safety in underground spaces is paramount due to their enclosed nature and limited access points, which can pose challenges during emergencies. To enhance safety, first- and second-tier cities are conducting comprehensive geological surveys up to 50 meters below the urban surface. These “transparent city” initiatives aim to provide detailed geological information, laying the groundwork for scientific development and safe operation of underground spaces.
A Strategic Resource for Sustainable Urban Growth
Underground space is emerging as a crucial strategic resource in China, playing a vital role in alleviating urban issues, supporting green and low-carbon development, and enhancing urban renewal. Rational development and utilization of these subterranean areas are essential tasks for the high-quality growth of cities. As China continues to pioneer innovative underground solutions, it charts a new course for urban development and sets an example for sustainable city planning worldwide.
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Exploring diverse and composite utilization of underground space
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