Preparation of Waelplas site for construction work, ‘s Gravenzande

One of the present activities within GEO2 Engineering B.V. is the provision of advice on site preparation for construction work. An example of this is the new construction project Waelplas in ‘s Gravenzande.


For this project an analysis of settlement has been carried out, including the raising of the surface level of the complete project area, as well as the relevant public highways and preparatory channels for sewage pipe systems.

The first step in carrying out a settlement analysis was to determine the final settlement resulting from the desired raising of surface level. The following step was to determine how much settlement compensation was necessary and what actual measures for accelerating the settlement (such as temporary additional raising of surface level or vertical drainage) would satisfy the desired requirements for the final settlement.

In addition to the regular analysis of settlement, this project has also examined the effect of the planned heightening works on an existing gas pipe which runs through the project terrain.


During the development of a new housing area, there is almost always the need to partly construct, or to lay out a completely new, sewage pipework system. This also applies to this project.

To be able to install the sewage system in dry conditions, a temporary dewatering system has been designed, taking into account the throughput, the type of dewatering, the influence of the surroundings and the need to meet building license requirements.

Other aspects

In addition to settlement analysis and advice about dewatering, we can provide a complete geotechnical plan, in which the following aspects are detailed:

  • Retaining constructions such as sheet pile walls and facings;
  • Assessment of drainage quay walls with various possible failure mechanisms;
  • Analysis of possible bursting;
  • Use of light-weight surface-heightening materials such as BIMS (pumice) or EPS (expanded polystyrene);
  • Effects on buildings and cables or pipework.