In this paper, we propose a semantic trajectory model handling complex trajectories. We consider that a trajectory is composed of multiple aspects which are all different viewpoints from which it can be observed. This model also allows for the representation of explanatory factors that influenced the episodes that compose a trajectory. We here deal with a particular type of trajectory: the life trajectories of individuals or citizens. The residential aspect in life trajectories is particularly relevant for decision makers and urban planning experts who try to understand the residential choices of inhabitants in order to adjust their decisions. Those choices depend on factors related to the home (type, size...), and to the surroundings (accessibility, amenities ...) but they can only be fully apprehended by taking into account the life circumstances of the individuals, along their family, or professional or even spare-time activities viewpoints.