The effect of the pre-consolidation pressure on soil slip strength parameters of the clay soils

Soft clay soils are problematic soils that are frequently encountered with low shear strength and settlement problems. They can show large deformations when exposed to vertical axial pressure. Therefore, it is very important to determine the slip resistance parameters and consolidation settlement of soils correctly. Consolidation is the subsidence of the pore water pressure, which increases with the increase in the effective vertical stress as a result of the application of vertical axial pressure to the soil layer, and the settlements formed by the displacement of the soil grains. Settlements are events that take a long time. For these reasons, scientists have worked on obtaining statistically significant equations to save time and accurately predict fit. In this study, the relationship between shear strength parameters and pre-consolidation pressures of low and high plasticity clay soils at different consolidation pressures was investigated. Low and high plasticity clay soils prepared in liquid consistency were pre-consolidated at 25 kPa, 50 kPa, 100 kPa, 200 kPa and 400 kPa pressures. Unconfined pressure, shear box and vein tests and shear strength parameters cohesion (c) and internal friction angles (ϕ) of the consolidated samples were found. No significant correlations could be established between the cohesion and internal friction angles and the pre-consolidation pressure. As a result, equations with the lowest error amount and the highest correlation coefficient were created that can predict shear strength parameters depending on the pre-consolidation pressure and can be used for practical purposes, with the data obtained from the free pressure, shear box and Veyn experiments for low plasticity and high plasticity clay soils.