Non-megalithic burial structures (Passy-type monuments) are important for the emergence of the monumentality to the early Middle Neolithic (Cerny Culture, 4700-4300 BC) in the Paris Basin (France). However the appearance of their architecture remains poorly understood: it is long ditched monuments, sometimes dug over 300 m. As, they underwent such erosion, no superstructure is kept in elevation. A 2D simulation and 3D restoration projects (STP3D projects) was used to test a large number of architectural hypotheses: the presence of a mound, fences, structuration and subdivision of the monumental space.

These virtual restorations are based on stratigraphic observations made on the field and a posteriori (establishment of an erosion model), but also on ethnographic and experimental observations.

We use Structural analysis techniques which are commonly used to evaluate the design performance of buildings. Nevertheless, few of these methods are used in archeology to analyze earthworks. This may be because the indices stratigraphic field surveys seem to be enough to establish architectural interpretations. But, with the higher efficient computing capacity currently available on desktop PC’s, more intensive computational methods can now be applied by the researcher to explore questions of structural possibility and stability. Numerical methods including Finite Element Methods (FEM) and its variants can be used to understand potential modes of structural failure.

Passy-type monuments had to be visible and imposing buildings with an obvious social and symbolic role. These structures had apparently a fairly long life, punctuated by reconstruction and maintenance of ditches, of mound and fences. Until a state of ruin, they are perhaps still visible in the  landscape. We tested the stability of earthworks, ditch, embankment and mounds to the effects of duration of time, etc.. Moreover, it seemed important to assess the strength of wooden structures: the resistance of timber buildings (timber gravers and wooden fences) under the weight of large mound.

The use of specialized geotechnical methods allows verifying a number of issues. It permits proposing high mounds of more than 5 m. They could have a relatively short life without repairs and cleaning ditches. This experiment / simulation accelerated by the FEM shows that the earthworks erode at high speed, perhaps across a few months. This result minimizes the imposing appearance provided by the frozen image of the virtual restoration. Moreover, according to field data, the sepulchral architecture could resist in short time under the influence of mass filling.

 With this project, we could approach a lot of issues to understanding this kind of structures:
- Time: short time (lifetime of a monumental structure, lifetime of a necropolis) ; long time (lifetime of the monumental landscape)
- Space / Landscape
- Erosion