Objectives Facing the needs of digital twins for the whole life cycle of railway, the problems exist in independent expression, decentralized management and difficult in-depth integration of the continuously changing railway geographic and geologic data for a long time.

Methods This paper takes railway geographic and geologic elements as an inseparable whole, and proposes an integrated expression model of the three-domain association for railway geographic and geologic data, which includes ontology domain, change domain and state domain. First, it takes spatial-temporal change as the center and defines the change participants (elements), drivers (events) and presentation modes (processes). Then, it defines a multi-level spatial-temporal change association relationship between state level, entity level and process level. Finally, it constructs a knowledge graph of railway geologic data with multi-domain association, and finely portrays the semantic association relationship between three aspects of geological elements, events and processes.

Results and Conclusions The importance and potential of the model in typical tunnel construction applications are analyzed.