Research on Risk Identification and Assessment of the UK High-Speed Rail HS2 Project Based on the AHP-ISM Model

The High Speed 2 (HS2) project in the United Kingdom is characterised by the involvement of multiple stakeholders, stringent construction standards, high technical complexity, and a lengthy construction period. These characteristics have a significant impact on investment costs and management efficiency. The project as a whole is characterised by large-scale investment, high management complexity, and strict requirements for investment control throughout the entire project lifecycle. To effectively identify and mitigate key risks during the implementation phase, this study employs the Analytic Hierarchy Process (AHP) to develop a customised risk indicator assessment system for the HS2 project. First, through a systematic risk identification method, primary risk factors are screened and integrated to form a comprehensive risk list. Based on this list, an Explanatory Structural Model (ISM) framework is constructed to reveal the hierarchical structure and interconnections of the identified risks. The research findings indicate that three key risk categories should be prioritised during the construction phase: economic risks, general contract risks, and typical contract risks. Based on these insights, the study proposes targeted risk response strategies and management recommendations. The objective is to provide theoretical support and practical guidance for risk management in the HS2 project and similar large-scale infrastructure projects.