The architecture, engineering and construction (AEC) industry appears hesitant to embrace new digital innovations. One of the few recent successful examples is the introduction of the building information modeling (BIM) paradigm. However, the focus here lies mainly on the building itself and does not support the construction environment. This paper presents a methodology for the development and application of Digital Twins representing and supporting the working environment of a construction site. By combining available geodata with real-time sensor data from mobile construction machines, it is possible to create always-up-to-date Digital Twins of the relevant objects and processes in the field in order to facilitate supervision, additional planning steps, management, control and security activities. The proposed concept is currently being tested on a local test site to generate, update and adapt the Digital Twins as well as to incorporate additional semantic information about e.g. the soil and various working processes.