MODELLING OF THE STRESS-STRAIN STATE OF THE LANDSLIDE SLOPE OF MOUNT PYVYKHA DURING BANK PROTECTION MEASURES AT THE KREMENCHUK RESERVOIR

Abstract

The authors study the stability of the landslide slope of the coast of the Kremenchuk reservoir, within which the state geological monument of Ukraine – Mount Pyvykha – is located. The destruction of the mount began after the Kremenchuk reservoir was created in the late 1960s. The engineering and geological conditions of the coastline have been repeatedly studied to develop protective measures to preserve the mount. However, due to the destructive activity of waves, the coastline is constantly being destroyed, and landslides are occurring. Engineering and geological studies were carried out to study the possibility of preserving Mount Pyvykha in its current state, including the collection and systematisation of previously conducted surveys and additional fieldwork and laboratory testing of soil samples collected along the entire length of the coast. For a more detailed study of the coastal stability problem, the stress-strain state of the slope was modelled using the Plaxis software package designed to calculate the stability and determine the deformations of geotechnical structures using the finite element method. Soil modelling is based on an elastic-plastic problem so that characteristics determined by standard methods can describe the properties of the soil environment considered in the calculation. The finite element method allows for creating a design scheme that considers any soil layering. In addition, Plaxis is distinguished by the completeness and illustrative nature of the calculation results. Based on the modelling results, the most dangerous zones of landslide processes and slope stability parameters along the most hazardous profiles were determined. Based on the study of the location of the zones with maximum shear stresses in the cross-sections, the most probable positions of the sliding planes of the soils that make up the slope were obtained. The values of the slope stability coefficients in the critical state are significantly less than one, which indicates the emergency condition of this slope. Safe zones for equipment location during bank protection works were also determined, considering the distance of possible movement of the soil mass from the foot of the slope.