EFFECT OF SPATIAL VARIABILITY OF SOIL PROPERTIES ON SLOPE STABILITY

Abstract

Problem Statement and Purpose. On the slope surface numerous deformations are currently observed. These are contraction cracks, cracks with a lowered shoulder, houses movement, landslide stall walls, etc. There is also a retreat of lip of the coastal ledge and of the edge, debris and landslides in the nearlip part of the plateau. In this regard, the study of spatial variability of soil properties and slope stability assessment is an important task.The purpose of the paper is to study the clay soil physical and mechanical properties spatial variability patterns of the slope in Ovidiopolsky district of Odessa region and its impact on the slope stability taking into account the seismic and hydrodynamic forces.Data & Methods. Landslides monitoring on the key area has been carried out by engineering geological survey SMC LLC "Odesgorstroy”. using the results of field (geodetic survey) and laboratory studies. The shear strength parameters were deter­mined by direct shear test for natural and water-saturated soils. The data was pro­cessed analytically and graphically using statistical characteristics. The slope stability assessment was performed using "blocks method" (G. M. Shakhunyants method). Results. It is revealed that the areas where slope soils have high moisture content are weakened areas. Clay soil strength characteristics depend on the degree of their destruction and saturation. The values of these characteristics significantly decreased with the increase in moisture. This leads to the appearance of weakened areas in the landslide massif. When landslide occur, the structural bonds in clay soils are de­stroyed in the slip surface area, which leads to an increase in surface energy, to the hydration of clay minerals and an increase in soil moisture. That is. a synergistic ef­fect is observed in the slip area, which is reflected in the mutual reinforcement of soil weakening processes.The calculation shows that in most cases the decrease of the slope stability coeffi­cients is due to a decrease in the strength properties related to negative changes in hydrogeological conditions.