In the town of Katwijk in the Netherlands, directly east of the residential nucleus of Rijnsburg, a new residential neighbourhood, ‘De Horn’, is being set out. The area to be developed is situated between the Collegiantstraat, the Oegstgeesterweg and the Oegstgeesterkanaal. The plan is to construct 410 houses and a park. An impression of the area to be developed can be seen here.
There are two extremely interesting aspects of our advice on the development of this area:
- On the location of the park, there is an old Merovingian burial field which must be preserved;
- The geology in this area is very variable because of the presence of barrier bars which result in a sharp variation in the soil profile.
With regard to the Merovingian burial field, GEO2 Engineering B.V. has prepared a review of the anticipated increase in stress and settlement prediction of the burial field, where it is planned to heighten the terrain.Due to the fact that the terrain is of great archeological importance, soil drilling in this area was not permitted although this did take place on the surrounding terrain. Nevertheless, in this area (as part of the archeological research) a large amount of hand-drilling took place, to a maximum depth of 3.0 metres below surface level. By combining all the geotechnical information, the presence of the littoral dunes could be modelled accurately. On the basis of this assembled information, GEO2 has by way of colour-mapping been able to define the areas with a similar settlement expectation.
The advantage of such a map is that the areas which are susceptible to settlement are immediately apparent as well as where there is a question of soil/ground imbalance.