Laboratory modeling and analysis of slopes of different geometry under the effect of precipitation

Abstract

Back stability analysis, in-lab testing, and field tests may all be used to assess the behavior of stability of slopes. Each of these approaches has benefits and drawbacks compared to one another. Amongst these approaches, laboratory modeling stands out with its ability to prepare identical samples, keep external conditions under control, and measure deformations precisely. In this study, laboratory-based slope models at 1(Horizontal)/1(Vertical), 2/3, and 1/3 angles including the effects of precipitation and external loading were created. The results of these models were compared with those of the Plaxis 2D software. First, models were built using highly permeable cohesionless coarse-grained soils, and mixtures containing high plasticity clay (bentonite) at different rates were then prepared to investigate the effect of fine-grained soils on stability. Laboratory tests such as sieve analysis, specific gravity, consistency limits, Standard Proctor, and direct shear were used to assess the geotechnical index and mechanical properties of soils. Incremental surcharge loads were placed on the slope models and surface deformations, and local and general collapses under the effect of precipitation were observed. Laboratory model results highlighted that the fines content had a non-negligible effect on stability. When the slope behaviors were examined, it was observed that the models with a 1/3 slope had more severe local fractures and collapses. The stability of the slope is negatively affected when bentonite content in soil mixtures rises. The results of Plaxis 2D analysis are compatible with those of laboratory model tests and the factor of safety values obtained from Plaxis 2D range from 0.98 to 11.4.

Keywords

• Laboratory model
• Plaxis 2D
• Precipitation
• Slope angle
• Slope stability

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