Risk assessment and remediation strategies for highway construction in abandoned coal mine region: lessons learned from Xuzhou, China

The influence of abandoned mine subsidence on transportation facilities is a growing concern due to rapid urbanization and industrialization in China. Transportation infrastructures are being or will be developed in many areas with potential subsidence problems. Consequently, it is necessary to assess and mitigate the long-term and progressive residual subsidence effects on transportation facilities in such regions. This paper presents an integrated framework to identify and mitigate the risks of abandoned mine subsidence on highway infrastructures. The framework comprises four steps: comprehensive investigations of abandoned mine features; identification of subsidence mechanisms, conceptual model construction and risk assessment; optimization of remedial solutions and development of a management strategy. A case study that demonstrates a successful application of the framework is also presented in this paper. In this example, a technique that integrates remote-sensing analysis throughout surface features with conventional investigation methodologies is proved to be a potential tool to detect and understand areas that might be at risk of surface subsidence. Based on the analysis of the representative failure mechanisms observed in situ and the influencing factors, a methodology has been developed to assess the geohazards associated with mine subsidence. Moreover, the proposed criteria for stability classification allowed us to define three geohazard levels on a regional scale. Subsequently, based on a brief review of remedial works made in China, the paper gives some recommendations to identify the most appropriate solutions to mitigate residual subsidence risk on transportation infrastructures. Such integrated decision-making framework will assist practitioners and regulators in identifying the potential risks of residual subsidence on transportation routes, optimising the most appropriate alignments, and assessing risk management practices.