Installation of Fine-Grained Organic Dredged Materials in Combination With Geosynthetics in the German Dredgdikes Research Dike Facility

Abstract

In the project DredgDikes with partners from Poland and Germany different dredged materials from the South Baltic Sea region are investigated with respect to their application in dike construction. Two large-scale experimental dikes have been built, one in Germany and one in Poland. Additionally, an extensive laboratory testing programme has been realised and a considerable monitoring test programme will be followed. Based on a short general description of the project this paper covers the issue of installation technology for the dredged materials used and a discussion of geotechnical parameters to be determined for material evaluation and quality control. Due to the high and variable natural water contents of the organic soils together with their inhomogenous composition the compactability is difficult to predict and proctor values may not be reliably determined. During the installation three different compaction technologies were compared and no extreme differences could be found, which is why the compaction with a caterpillar was chosen for efficiency on site. The critical analysis of the data, however, shows slightly better compaction results for the roller compactors. In general the degree of compaction was comparably low. Therefore, different possibilities to improve compaction are discussed in this paper, such as the homogenisation of the dredged material by simple in situ mixing technologies, which will be issues for further research.

Inverse Infiltration Modeling of Dike Covers Made of Dredged Material Using PEST and AMALGAM

“…3, the cross-section primarily saturates through the dike toe. This may even be a realistic scenario-the cover material M2 was installed in layers on top of the profiled sand core [22]. In the toe region, a possible machine-induced deformation of the core cross-section together with the exact profile of the dike surface may have caused local areas with reduced cover layer thickness.…”

“…This study focuses on one of the material combinations, namely cross-section D, consisting of a stable body made of a poorly graded sea sand "S" and a cover layer of approximately 1 m thickness, made of dredged material, "M2" (Figure 1). The cover layer was installed and compacted in layers of 0.30 m, using the caterpillar tracks for compaction perpendicular to the longitudinal axis [22]. A drainage pipe has been installed inside the sand core at the land-side toe to collect infiltrating water.…”

“…There is also an option to adjust the anisotropy parameter A [1] of the flow parameters (quotient of the vertical and horizontal hydraulic conductivity coefficients). The dredged material was installed in layers, as explained above [22], and even though significant effects are not expected, the presence of an anisotropic behavior of the K s value in the plane of the cover layer and perpendicular to the surface is possible. However, the implementation of such factors might cause interdependencies in combination with the K s -values and other model parameters.…”