Characterizing the generation and environmental impacts of subway-related excavated soil and rock in China

With rapid urban expansion in China, subway construction activities have been widely promoted. Accordingly, a large amount of subway-related excavated soil and rock (ESR) are generated and disposed mainly through dumping sites every year, which threatens the natural environment and poses high landslide risks. This study is therefore designed to characterize the generation, composition, flows and potential impacts of ESR in China. The results show that with the promotion of subway and increasing public awareness of recycle ESR, the generation of ESR has increased from 0.2 million m3 in 1965 to 79 million m3 in 2018 with a cumulative CO2 mitigation of 417.2 million tonnes by 2018 and will keep increase in coming decades (e.g., approximately exceed 200 million m3 by 2030). South and East China account for 60% of the total ESR which aligns well with their growing population and economic activities. Besides backfilling and landscaping, ESR were mainly sent to dumping site or unregulated landfill sites, which accounts for 87% of total generation. It was estimated and predicted that the dumping disposal of ESR has cumulatively occupied a land area of 212 ± 25 km2 from 2004 to 2030. Moreover, this study compared the management of ESR between China and developed countries, and recommendations for environmentally sound management of ESR were proposed.

Publication year:2020