n the thesis, the effect of water content on compaction and the effect of compaction on strength, compressibility and water permeability of the soil were investigated. Laboratory tests were carried out on a sample of karst clay, classified as fat clay (CH). To determine the optimum water content and maximum dry density of the karst clay, the standard Proctor test (SPP) was performed. Then the uniaxial compressive and shear strength, compressibility and water permeability, using two standard procedures, were measured on differently moisturized compacted specimens. The results show that water content and compaction have no significant effect on the drained shear strength of karst clay, while the other investigated state parameters depend on both. Higher water content of compacted samples results in lower uniaxial compressive strength. Samples with higher water content are also more compressible. Karst clay compacted at sub-optimal water content is sensitive to the effects of water. This translates into significantly lower uniaxial compressive strength of saturated specimens compared with uniaxial compressive strength of unsaturated specimens compacted at equivalent initial water content. In the compressibility test, swelling of samples that were compacted at sub-optimal water content, as a result of overflooding, was detected. Water permeability measurements in a permeameter with variable hydraulic gradient generally show a decline of water permeability coefficient with increasing water content and load step. We did not detect a similar pattern with water permeability coefficient measurements in the triaxial cell. Based on the deviations in measured water permeability coefficients, we also note that the measured value of water permeability coefficients depends on the measurement method used.
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