ABSTRACT
This chapter provides a discussion on the properties of the various types of subsoil that prevail in the river area, the required soil mechanics investigation, and the way in which representative strength parameters for the dike design can be derived from this investigation. For a reliable estimation of the stability and deformation of the dike, it is essential to determine the composition, the type of soils of the various layers and the properties of the ground at, under, and near the dike by means of a soils investigation. A large number of characteristic features of the subsoil in the geological, soil mechanical and hydrological sense can be assessed by special methods of investigation on the site. The most commonly used methods are: geoelectrical and electromagnetic soil investigation; cone penetration tests; borings; the vane test; pumping and well tests; and infiltration tests. Extensive investigations into the geohydrological parameters of an area are often carried out by drinking-water supplyers.
