Investigation of dredged materials in combination with geosynthetics used in dike construction

Abstract

In the project DredgDikes with partners from Poland and Germany different dredged materials from the South Baltic Sea region are investigated for their application in dike construction. Two large-scale experimental dikes have been built, one in Germany and one in Poland. Additionally, a large variety of laboratory tests and experiments have been performed and a considerable monitoring test programme will be followed. This paper contains a general description of the project as well as first results from a laboratory flume test, field investigations on seepage and the information about a planned climatic chamber experiment, all performed at the University of Rostock, where the focus is laid on fine-grained dredged materials in combination with geosynthetics solutions. The flume experiments showed a very high strength of the dredged materials samples with grass cover. The first seepage test at the large-scale test dike in Rostock showed good performance of the geosynthetic drainage solution applied as well as the stability of the dredged material with respect to rapid drawdown of the water level. The comparison of measurements inside the dike and a seepage model showed considerably higher hydraulic conductivity in the field compared to that determined in the laboratory, however still in the range suited for coastal dike cover materials. To investigate the cracking behaviour of the ripened fine-grained dredged material a climatic chamber experiment has been set up which is also discussed briefly.