Overview on failures of urban underground infrastructures in complex geological conditions due to heavy rainfall in China during 1994–2018

• A database consisting of 378 failure cases was established for analyses. • Trends and distributions of heavy rainfalls in China were characterized. • Spatio-temporal distribution patterns of the failures were identified. • Urbanization, climate and geological conditions were key factors. Currently, global warming is increasing rainfall intensities worldwide, particularly in China. This climate change has caused numerous underground infrastructure failures, which threatens the sustainable development of urban environments. Most failures brought about secondary hazards in densely populated areas, which often caused massive damages and casualties and/or injuries. Thus, a summary of such failures and their contributing factors on a national scale is essential for understanding the adverse influences of climate change on infrastructures, which can help urban planners, designers and engineers to improve city resilience. In this paper, an overview of 378 underground infrastructure failures in China associated with heavy rainfall was conducted. First, the latest rainfall characteristics in China were analyzed. Then, a review was conducted in four aspects, i.e., infrastructure types, involved strata, and temporal and geographic distributions. Finally, contributing factors of the failures were discussed. Several major findings were obtained: (1) the failure numbers had increased significantly since 2010, mainly attributed to the intensification of rainfall in rapidly urbanizing regions; (2) the resilience of underground infrastructures against heavy rainfall is governed by the performance of existing drainage facilities nearby; and (3) more failures clustered in the urban environments featuring highly concentrated rainfalls and thick-layered unsaturated coarse-grained soils.