Investigation of liquefaction potential of sands from the subsoil at the HPP Brežice

Phenomenon of liquefaction is characteristic for loose, saturated, fine-grained cohesionless soils. These soils tend to compact under monotonic, impulsive or repeating load (e.g. earthquake) which leads to the increase of pore water pressures and consequently to the loss of shear strength. Using “in situ” and laboratory tests the susceptibility of liquefaction of fine-grained sands under the flood embankments of the hydropower plant Brežice is investigated in the presented thesis. Suitability of this local soil for the construction of these embankments is also checked. With regard to index values representative material for investigation of dynamic properties of the soil was selected. Effect of different parameters like void ratio, water content and cyclic stress ratio on the liquefaction of the abovementioned soil was checked in controlled conditions in the laboratory. Obtained results from the samples prepared in the laboratory were then compared to the results on intact samples taken from different layers of the full scale test embankment. Results of laboratory tests were used for the evaluation of the results of in-situ investigations. Characteristics of the fine-grained sand from the hydropower plant Brežice were finally compared to Toyoura sand as a reference material