Оценка обоснованности применения метода «косого среза» к диаграмме зависимости сопротивления грунта

When determining the shear resistance of soils, conventional approach relies on Coulomb's equation, typically represented as a linear function. However, experiments, particularly in the field of small normal loads, demonstate deviations in the shear modulus values from the linear function. Cytovich proposed the "oblique slice" method, which considers the slice area in non-horizontal circular form. An attempt was made to take into account the height of the deformable sample. The experiments conducted by the authors of the study confirmed the non-linear dependence of shear resistance on normal loads and revealed contradictions in the "oblique slice" hypothesis. The purpose of the study is to assess the validity of the hypothesis to substantiate the possibility of using Coulomb's equation in practical calculations. Tests were conducted on various soil types using the consolidated-drained method. For the same samples, calculations were performed using the Cytovich "oblique cut" method, as well as calculations using a method that takes into account both an increase and a decrease in the height of the sample during the cut. A comparative analysis of the results revealed significant difference in the values of tgφ and c obtained during testing according to the GOST method and calculated using the Cytovich method. An increase in sample height occurs at low normal loads due to loosening of the soil during cutting. In this case, the cut surface is not flat but spherical, as the loosening in uneven of the soil, with the greatest loosing occurring in the central part of the sample. At high normal loads, the height of the sample decreases. The best "straightening" of the dependence between the empirical values of tangential and normal stresses occurs when taking into account an increase in the height of the sample at low normal loads, and a decrease in height at high normal loads. The use of the "oblique slice" method does not "straighten" the shear diagram. Its use in practice is not justified.