Seite - 1130 - in Book of Full Papers - Symposium Hydro Engineering

The time-dependent deformation may lead to cracking, relocation of stresses or other effects along material borders so that the behaviour under hydraulic load and seepage forces may be affected which may lead to hydrodynamic soil deformation such as suffusion and erosion [10]. The increase of pore water pressures may result from ageing of selaings, drains, filters or changes in the underground. 5. ALTERATION OF MATERIAL BEHAVIOUR For the construction of embankment dams and levees natural soils, geosynthetics, natural and articifical sealings, concrete, asphalt, etc. Are applied as summarized in [11]. All materials are subject to ageing. Corresponding to the type of material and the intensity of the loads and influences ageing is affecting the characteristics more or less strongly. The influencing factors are listed below:  Freezing and thawing  Seepage/saturation  Wind  UV-radiation  Heat  Biological impacts by animals  Anthropene long-term behaviour  Etc. These influencing factors need to be assessed for the specific types of materials which are used in embankment dams and levees such as:  Low permeable soils and natural sealings  Artifical sealings  Filter, drains and high permeable soils  Geosynthetics  Concrete The listed materials and the related aspects of ageing are discussed in detail in [12]. 6. EFFECTS ON THE DAM BEHAVIOUR AND DESIGN The process of ageing starts with the construction or with the storing of materials which shall be used for construction. In practice the end of construction (EoC) is usually used as a reference date to determine the ageing period. 1130