The objective of Research Area 4 (RA4) is to develop modelling and simulation tools that enable us to assess the impact of old infrastructure to new and vice versa and forecast the future performance in changing environment and use. We are looking at a scale of large projects, such as large infrastructure projects and whole new areas to be built next to existing infrastructure and buildings. The models and tools should be so powerful that they enable inverse analyses and data assimilation, thus allowing to use time-resolved monitoring data for feedback and model enhancement. This often requires 4D modelling, i.e. spatially 3D including the dimension of time. One often forgotten dimension that we need to account for is what is underground, so that we can integrate the effects of the underground (geological and human history of geological deposits and existing infrastructure) with what we want to design and construct now, so that the sub-soil and structures can interact in a safe and sustainable manner.